Electrical Contacts - User contributions [en]

Electromechanical Components

2014-06-02T14:47:30Z

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Test
Plastic molded or encapsulated components are of increasing importance due to rising requirements for smaller, lighter, and more compact designs with cost efficient pricing. Wherever mechanics and electronic meet, electromechanical components can be used in a multitude of applications, such as in automotive, communications, appliance, and consumer electronics engineering.
In automotive applications such components are used in ever increasing volumes. In hybrid housings electronic components are integrated into components for increasingly more complex engine management functions. Strip-molded contact parts are for example used for seat adjustment, and airbag sensors; assembled contact parts are important functional components among others for memory mirror positioning units.

Electromechanical components usually consist of stamped circuit patterns (lead frames) which are coated in the contacting areas with functional surface layers. They serve as the electrical connections of the component to the outside wiring. The lead frames are over-molded with plastics or mounted into plastic molded parts. In addition electronic components can be added to increase the level of product integration. Utilizing the metal–plastic compound the mechanical stability of the plastic is combined with the conduction of electrical energy and electronic signals through the lead frame. In this way protective enclosures for electronic controls of machinery are created which at the same time serve as connecting points to the outside wiring. This can be achieved through hybrid frames and housings. Over-molding of contact components or assembly of different single parts in plastic enclosures can also be used to manufacture electromechanical components.

For achieving the highest possible functionality of the end product a close cooperation between the manufacturer and the end user in the early phases of development and design of new custom tailored electromechanical components is recommended. Innovative and cost-efficient designs can be realized through the combination of the know-how of the manufacturer in for example contact, coating, stamping, plastics processing, and assembly technologies and the mostly rather complex requirement profile given by the end user.

Besides the contact components the plastic materials are the critical building blocks for electromechanical components. Plastics used are mostly technical thermoplastics and heavy-duty plastics which fulfill the requirements for high mechanical strength, temperature stability, and fatigue strength <xr id="tab:Frequently Used Plastic Materials and their Properties"/>. For the final selection of a plastic material economical considerations and the avoidance of environmentally hazardous ingredients such as for example flame retardants must be considered. The application of the most suitable contact material coating and the selection of carrier materials are covered in chapters [[Contact Carrier Materials|Contact Carrier Materials]], [[Surface Coating Technologies| Surface Coating Technologies]] and [[Applications for Bonding Technologies|Applications for Bonding Technologies]].

<figtable id="tab:Frequently Used Plastic Materials and their Properties">
<caption>'''Frequently Used Plastic Materials and their Properties'''</caption>

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!rowspan="2" style="text-align:center;"| Type of Plastics: Poly-condensate Sub-Type: Thermo- plastics Abbrev.
!colspan="6" style="text-align:center; padding:2px"| Properties
|-

!Density [g/cm3]
!Reinforcement Materials
!mechanical
!electrical
!thermal
!resistant against
|-
|'''PPS'''
|1.34 - 1.64
|glass fibers, graphite fibers
|very high mechanical strength and stiffness even at high temperatures, low toughness, very low creep, better properties with addition of 40% glass fibers
|excellent isolation properties, very low dielectric losses
|usable up to 240°C, short term up to 270°C, low combustibility, self-extinguishing, non-dripping
|up to 220°C no known solvents, conc. sodium hydroxide, conc. hydrochloric and sulfuric acid, good hydrolysis resistance
|-
|'''PA6 PA66 PA610 PA11 PA12 A amorph'''
|1.12 - 1.14 1.13 - 1.14 1.06 - 1.08 1.04 1.01 - 1.02 1.06 - 1.12
|glass fibers, graphite fibers, mineral powders, glass beads, chalk, lubricants such as graphite, MoS2
|depending on the PA type, crystalline structure and water content; high mechanical strength, stiffness, and toughness; higher mech. strength through stretching; very tough after water absorption; high fatigue strength, good impact toughness, abrasion resistant, good sliding properties through addition of graphite and MoS2; increased mechanical strength with glass and graphite fiber addition
|depending on water content, good surface resistance reduces static surface charge, high dielectric losses, good resistance against creep currents
|upper use temperature 80 – 120°C depending on type, short term up to 140 – 200°C, mostly boil resistant, can be sterilized, narrow softening range
|aliphatic and aromatic hydrocarbons, gasoline, oils, greases, some alcohols, esters, ketenes, ether, many chlorinated hydrocarbons, weak alkaline solutions
|-
|'''PBT'''
|1.29
|glass fibers, glass beads, minerals, talcum
|very high toughness at low temperatures, good stiffness and mechanical strength, good long term stability, low abrasion at good sliding properties
|good isolation properties, good dielectric strength, little effect of humidity
|good thermal stability, use temperature 60 – 110°C, short term higher, with glass reinforcement up to 200°C, low 
tendency to turn yellow, very low thermal expansion, burns with sooty flame and drips
|aliphatic and aromatic hydrocarbons, fuels, oils, greases
|-
|'''LCP'''
|1.40 - 1.92
|glass fibers, minerals
|very high precision and dimensional stability, high stiffness at low wall thickness, low thermal expansion coefficient; reinforced, better sliding ability, electrically conductive and suitable for electroplating types
|dielectric losses depend on surface coating, good electrical conductivity; depending on type suitable for anti-static 
applications
|use temperature 200 – 250°C, good high temperature stability, very low thermal expansion, resistant to soldering temperatures < 250°C, difficult to combust and self-extinguishing
|good resistance against widely used organic solvents, i.e. acetone, methanol, chlorine gas, acetic acid
|-
|'''PPA'''
|1.26 - 1.85
|glass fibers, minerals
|high impact strength with good mechanical strength and stiffness, very high dimensional stability at high temperatures, very low humidity absorption
|very low electrical losses
|use temperature up to 185°C, standard types with UL94-HB classification, special flame protective types
|very good resistance against typically used organic solvents, i.e. acetone, methanol, etc., water based solutions (DI water, 10% ammonium hydride, typical liquids used in the automobile such as brake fluid, motor oil, etc
|}
</figtable>

== Hybrid Frames and Housings==

Hybrid frames and housings serve as the connecting points between mechanics and electronics <xr id="fig:Component with hybrid housing for use in automobiles"/>. They allow the transmission of signals or electrical energy. The connection to the current paths inside the housing is mostly done by bonding with aluminum wires. The over-molded lead frames are typically manufactured from aluminum clad strip materials which are well suited for bonding. The connectors integrated into the housing for transferring the current paths to the outside are coated with tin, silver, or gold, depending on specific requirements.
<figure id="fig:Component with hybrid housing for use in automobiles">
[[File:Component with hybrid housing for use in automobiles.jpg|right|thumb|Component with hybrid housing for use in automobiles]]
</figure>

== Continuous Strip Over-Molding==

In strip form over-molded contact parts reduce the complexity of assembly of the finished product. This complexity constantly increases with adding additional subcomponents <xr id="fig:Examples of strip over molded contact components"/>.

The strip over-molded contact parts can be tested for various quality parameters during manufacturing to continuously ensure the ever increasing reliability requirements of the end components.

Combining stamping and molding techniques in an automated production line allows the stamped contact parts to be molded into plastics as a complete functional unit. This also allows to reduce manufacturing tolerances to levels below those achievable with conventional assembly methods.
<figure id="fig:Examples of strip over molded contact components">
[[File:Examples of strip over molded contact components.jpg|right|thumb|Examples of strip over molded contact components]]
</figure>

<figure id="fig:Examples of assembled contact components">
[[File:Examples of assembled contact components.jpg|right|thumb|Examples of assembled contact components]]
</figure>

==Assembled Contact Components==
For applications and materials which do not allow strip over-molding, semi or fully automated assembly processes can be utilized. Different single parts like printed circuit boards, stamped parts, or contact components are assembled together with plastic molded parts on specialized equipment to complete functional components with low tolerances and high levels of functionality <xr id="fig:Examples of assembled contact components"/>. This also allows to integrate components which otherwise are difficult to mount onto circuit boards or carriers, such as capacitors, coils, or sensor elements into the functional component assembly. Contact parts used in these components are already tested on the assembly machine for quality parameters and functionality.

Manufacturing of Single Contact Parts

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The group of single contacts includes contact rivets, contact tips, and formed parts such as weld buttons. Contact spheres (or balls) are today rarely used because of economical considerations.

===Contact Rivets===

====Solid Contact Rivets====

Solid contact rivets are the oldest utilized contact parts. Their manufacturing requires a ductile contact material and is done without scrap on fully automated special cold heading machines. A wire slug is cut off and the rivet head is formed by pressing and hammering. This way contact rivets with various head configurations such as flat, domed, spherical, or pointed can be manufactured depending on the final application and switch or relay design.
<figure id="fig:Typical Contact Shapes of Solid Contact Rivets">
[[File:Ty_pical_Contact_Shapes_of_Solid_Contact_Rivets.jpg|right|thumb|Typical Contact Shapes of Solid Contact Rivets]]
</figure>
*Typical Contact Shapes of Solid Contact Rivets (<xr id="fig:Typical Contact Shapes of Solid Contact Rivets"/>)

*Contact Materials Au-, AgPd-, PdCu-Alloys, Ag, AgNi 0,15 (ARGODUR-Spezial), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CdO), Ag/SnO2 SISTADOX), Ag/ZnO (DODURIT ZnO),Ag/C 97/3*, Cu * dimensionally very limited

*Dimensional Ranges (<xr id="fig:Dimensional Ranges"/>) The respective parameters cannot be chosen independently of each other. They mainly depend on the ductility of the required contact material. Before a final decision on the dimensions we recommend to consult with the contact manufacturer. 
<figure id="fig:Dimensional Ranges">
[[File:Dimensional Ranges.jpg|right|thumb|Dimensional Ranges]]
</figure>
*Qualitätsmerkmale und Toleranzen (<xr id="fig:Qualitaetsmerkmale und Toleranzen"/>)
<figure id="fig:Qualitaetsmerkmale und Toleranzen">
[[File:Qualitaetsmerkmale und Toleranzen.jpg|left|Qualitaetsmerkmale und Toleranzen]]
</figure>

<table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse"><tr><th>Characteristics</th><th>Form A Form B Form CRounded headf Trapeziodal Trapeziodal head, radiused head,flat</th><th>Suggested test equipment</th></tr><tr><td>a) Head diameter d1 [mm]</td><td>d1< 4 + 0,06 During optical measurementd1> 4 - 0,06 disregard cornerradius R3</td><td>Comparator,Measuring microscope</td></tr><tr><td>b) Head thicknessk [mm]</td><td>d1< 4 + 0,03d1> 4 + 0,08</td><td>Micrometer, Dial indicator</td></tr><tr><td>c) Shank diameter d2 [mm]</td><td>d2< 2 - 0,06d2> 2 - 0,08</td><td>Micrometer</td></tr><tr><td>d) Shank length [mm]</td><td>+ 0,15</td><td>Micrometer, Dialindicator, Comparator</td></tr><tr><td>e) Radius at centerof contact surfaceR1 [mm]</td><td>Form A und B: Within the head thicknesstoleranceForm C: Allowable deviation from flatness: convex: within head thickness toleranceconcave: 0.005 d1</td><td>Comparator,Comparator template, Radius gage</td></tr><tr><td>f) Radius at edge of contact surface R2 [mm]</td><td>Form A: Smooth transition to R1Form B: 1.5 R2 allowedForm C: <0,1d1</td><td>Profile template,Comparator, Radius gage</td></tr><tr><td>g) RadiiR3 and R5 [mm]</td><td>Sligth rounding allowed</td><td>Comparator</td></tr><tr><td>h) Transition radius head underside to shank R4 [mm]</td><td>d2 < 2 R4 < 0,08 if covered by DIN 46240 pg.1 d2 > 2 R4 < 0,1d2 > 3 R4 < 0,2</td><td>Comparator if in doubt: microsection</td></tr><tr><td>i) Allowed deviationfrom cylindrical shape</td><td>max. 7° 30’: or d2 < l, l > 0,7 mm and k < 0,6 d1.max. 15°: for all other rivets</td><td>Comparator</td></tr><tr><td>k) Concentricity between head and shank center line [mm]</td><td>d1 < 4 0,15d1 > 4 0,2in general: approx. 70% of allowable deviationper DIN 46240</td><td>Comparator, Specialturn fixture</td></tr></table>

==== Composite Contact Rivets====
Clad rivets for which only a part of the head (composite or bimetal rivets) or also the shank end (tri-metal rivets) are composed of contact material – with the balance of the body mostly being copper – have replaced for many applications solid rivet versions because of economical considerations. The cost savings depend on the contact material and its required volume for a specific application. These composite rivets are also produced scrap-less from wire material on special machinery with two process variations utilized.

During ''cold bonding'' and heading the bond between the contact material and the copper is achieved without external heat energy by high plastic deformation at the face surfaces of the two wire segments <xr id="fig:Cold_bonding_of_bimetall_rivets"/> (Fig. 3.1). <figure id="fig:Cold_bonding_of_bimetall_rivets">
[[File:Cold_bonding_of_bimetall_rivets.jpg|right|thumb|Cold bonding of bimetall rivets (schematic)]]
</figure> The bonding pressure must be high enough to move the lattice components of the two metals within a few atom radii so that the adhesion forces between atoms become effective.
Therefore the head to shank diameter ratio of 2:1 must be closely met for a strong bond between the two metals.

During ''hot bonding'' the required heat energy is applied by a short term electrical current pulse <xr id="fig:Hot_bonding_of_bimetal_rivets"/> (Fig. 3.2). <figure id="fig:Hot_bonding_of_bimetal_rivets">
[[File:Hot_bonding_of_bimetal_rivets.jpg|right|thumb|Hot bonding of bimetall rivets (schematic)]]
</figure> In the case of Ag and Cu a molten eutectic alloy of silver and copper is formed in the constriction area between the two wire ends. When using metal oxide containing contact materials the non-soluble oxide particles tend to coagulate and the bonding strength between the component materials is greatly reduced. Therefore the cold bonding technology is preferred for these contact materials. The during cold bonding required high surface deformation ratio can be reduced for the hot bonding process which allows the head to shank diameter ratio to be reduced below 2:1.

For composite rivets with AgPd alloys as well as alloys on the basis of Au, Pd, and Pt the above methods cannot be used because of the very different work hardening of these materials compared to the base material copper. The starting material for such composite rivets is clad strip material from which the contact rivets are formed in multiple steps of press-forming and stamping. Similar processes are used for larger contact rivets with head diameters > 8 mm and Ag-based contact materials.

*Typical contact shapes for composite rivets (<xr id="fig:Typical_contact_shapes_for_composite_rivets"/>)
<figure id="fig:Typical_contact_shapes_for_composite_rivets">
[[File:Typical_contact_shapes_for_composite_rivets.jpg|right|thumb|Typical contact shapes for composite rivets]]
</figure>
*Contact materials Ag, AgNi 0,15 (ARGODUR), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CDO), Ag/SnO2 (SISTADOX), Ag/ZnO (DODURIT ZNO) 

*Base materials Cu 

*Dimensional ranges (<xr id="fig:Dimensional_ranges"/>) These parameters cannot be chosen independently of each other. They depend mainly on the mechanical properties of the contact material. Before specifying the final dimensions we recommend to consult with the contact manufacturer. 
<figure id="fig:Dimensional_ranges">
[[File:Dimensional_ranges.jpg|right|thumb|Dimensional ranges]]
</figure>
*Quality criteria and tolerances (<xr id="fig:Quality_criteria_and_tolerances"/>)

<figure id="fig:Quality_criteria_and_tolerances">
[[File:Quality_criteria_and_tolerances.jpg|left|Quality criteria and tolerances]]
</figure>

<table class="twocolortable">
<tr><th>Criteria</th><th>Form B Form CTrapezoidal head, Trapezoidal head radiused flat</th><th>Suggested testequipment</th></tr><tr><td>a) Head diameterd1 [mm]</td><td>During optical measurement disregard corner radius R3 + 0.1</td><td>Comparator, measu-ring microscpope</td></tr><tr><td>b) Head thicknessk [mm]</td><td>+ 0.1</td><td>Micrometer,Dial indicator</td></tr><tr><td>c) Shank diameterd2 [mm]</td><td>Deviation from roundness and conical shape ofshank only within allowed diameter tolerance d2 < 1.5 - 0.08d2 > 1.5 - 0.1</td><td>Micrometer</td></tr><tr><td>d) Shank length l[mm]</td><td>+ 0.15</td><td>Micrometer, Dial indicator, Comparator</td></tr><tr><td>e) Radius at centerof contact surfaceR1 [mm]</td><td>Form B: + 10%, but not below+ 0.5 mmForm C: Allowable deviation from flatness: convex: within head thickness tolerance concave: 0.005 d1</td><td>Comparator, Comparator template, Radius gage, Profile template</td></tr><tr><td>f) Radius at edgeof contact surfaceR2 [mm]</td><td>per DIN 46240: Form B and C max. 0.5 without DIN:max. 1</td><td>Profile template,Comparator, Radius gage</td></tr><tr><td>g) RadiiR3 and R5 [mm]</td><td>Sligth rounding allowed</td><td>Comparator</td></tr><tr><td>h) Transition radiushead underside to shank R4 [mm]</td><td>d2 < 2 R4 < 0.08 d2 > 2 R4 < 0.1 d2 > 3 R4 < 0.2</td><td>Comparator, if in doubt: micro-section</td></tr><tr><td>i) Allowed deviation from cylindrical shape</td><td>d1 < 4 up to 7°30’ + 2°30’d1 > 4 up to 10° + 5°</td><td>Comparator, Measu- ring microscope, if in doubt: microsection</td></tr><tr><td>k) Concentricity bet-ween head and shank center line [mm]</td><td>5% of d1</td><td>Comparator,Measuring microscope, Special turn fixture</td></tr><tr><td>l) Contact layerthickness [mm]</td><td>In center area of 0.5 d1 s> nominal thicknessRemaining head area must be covered</td><td>Measuring micros- cope, Microsection</td></tr></table>

*Typical contact shapes of tri-metal rivets (<xr id="fig:Typical_contact_shapes_of_tri-metal_rivets"/>)
<figure id="fig:Typical_contact_shapes_of_tri-metal_rivets">
[[File:Typical_contact_shapes_of_tri-metal_rivets.jpg|right|thumb|Typical contact shapes of tri-metal rivets]]
</figure>
*Contact materials Ag, AgNi 0,15 (ARGODUR), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CDO), Ag/SnO (SISTADOX), Ag/ZnO (DODURIT ZNO) 

*Base materials Cu 

*Dimensional ranges (<xr id="fig:Dimensional_ranges2"/>)
<figure id="fig:Dimensional_ranges2">
[[File:Dimensional_ranges2.jpg|right|thumb|Dimensional ranges]]
</figure>
*Standard values for rivet dimension

<table class="twocolortable" style="width:75%">
<tr><th>d1</th><th>k</th><th>1</th><th>d2</th><th>α</th><th>r1</th><th>s1</th><th>s2</th></tr><tr><td>3.0</td><td>0.8</td><td>2.0</td><td>1.5</td><td>7.5°</td><td>4.0</td><td>0.4</td><td>1.0</td></tr><tr><td>4.0</td><td>1.0</td><td>2.5</td><td>2.0</td><td>7.5°</td><td>8.0</td><td>0.5</td><td>1.2</td></tr><tr><td>5.0</td><td>1.2</td><td>3.0</td><td>2.5</td><td>10°</td><td>12.0</td><td>0.6</td><td>1.4</td></tr></table>

==== Braze Alloy Clad Contact Rivets====
For special cases, especially high surrounding temperatures with high thermal and mechanical stresses during switching operations, a full metallurgical bond between the contact rivet and the contact carrier may be required to prevent a loosening of the connection and early failures of the device. To accomplish this superior bond a thin layer of brazing alloy is added to the underside of the head and the rivet shank. During assembly a thermal treatment is added after the mechanical staking.

====Contact Rivets with Brazed Contact Material Layers====
For certain applications contact rivets with non-ductile or brittle materials such as tungsten, silver–tungsten, or silver–graphite are required. Rivets with these contact materials can only be fabricated by brazing. Small round tips are brazed to pre-fabricated copper or steel bases using special brazing alloys in a reducing atmosphere.

=== Contact Tips===
Flat or formed contact tips, welded or brazed to contact carriers, are frequently used in switching devices for higher power technology. Depending on the contact material and specified shapes these tips are produced by various manufacturing processes. The most frequently used ones are:

*Stamping from strips and profiles
*Cutting from extruded rods
*Pressing, Sintering, and Infiltrating
*Pressing, Sintering, and Re-Pressing
*Pressing and Sintering

For stamping sufficiently ductile semi-finished materials are needed. These are mainly silver, silver–alloys, silver–nickel, silver–metal oxide, and silver–graphite (with graphite particle orientation parallel to the switching surface). Silver–metal oxides and silver–graphite need an additional well brazable or weldable silver layer on the underside which can be bonded to the bulk of the contact material by various processes. To further facilitate the final attachment process strips and profiles are often coated on the brazing underside with an additional thin layer of brazing alloy such as L-Ag 15P (CP 102 or BCuP-5).
For Ag/C with the graphite orientation perpendicular to the switching surface the brazable underside is produced by cutting tips from extruded rods and burning out graphite in a defined thickness.

The press-sinter-infiltrate process (PSI) is used mainly for Ag/W and Cu/W material tips with tungsten contents of > 50 wt%. A silver or copper surplus on the underside of the tip later facilitates the brazing or welding during final assembly.

The press–sinter–re-press method (PSR) allows the economic manufacturing of shaped contact parts with silver or copper contents > 70 wt%. This process also alloys parts pressed in two layers, with the upper being the contact material and the bottom side consisting of pure Ag or Cu to support easy attachment.

Press–sinter processes are limited to smaller Ag/W contact tips with a Ag content of approximately 65 wt%.

*Contact materials Ag, AgNi 0,15 (ARGODUR Spezial), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CdO), Ag/SnO2 (SISTADOX), Ag/ZnO (DODURIT ZnO), Ag/C (GRAPHOR), Ag/W (SIWODUR), Ag/WC (SIWODUR C), Ag/WC/C (SIWODUR C/C), Ag/Mo (SILMODUR), Cu/W (CUWODUR) 

*Typical contact shapes of tips and formed contact parts (<xr id="fig:Typical_contact_shapes_of_tips_and_formed_contact_parts"/>)
<figure id="fig:Typical_contact_shapes_of_tips_and_formed_contact_parts">
[[File:Typical_contact_shapes_of_tips_and_formed_contact_parts.jpg|right|thumb|Typical contact shapes of tips and formed contact parts]]
</figure>
*Dimensional ranges Attachment Method: Welding Bonding Area: approx. 5 – 25 mm2 Attachment Method: Brazing Bonding Area: > 25 mm2 

Because of the wide variety of shapes of contact tips and formed contact parts the user and manufacturer usually develop special parts specific agreements on quality and tolerances.

===Weld Buttons===

For contacts used at higher temperatures, such as for example in controls for stove tops, the use of contact rivets or the direct welding of silver based contact materials on steel or thermo-bimetal carriers is usually not feasible. For such applications weld buttons are suitable contact components.

Weld buttons are round or rectangular tips manufactured from clad contact bimetal or in some cases tri-metal semi-finished materials. The surface layer is produced from the specified contact material, the bottom weldable layer from a material with higher electrical resistivity such as steel, nickel, or for example a copper-nickel alloy. For precious metal savings a third high conductive layer of copper may be inserted between the contact material and weld backing. To improve the welding process the underside often has an embossed pattern with one or more weld projections.

The manufacturing of weld buttons from bi– or tri–metal strip requires a ductile contact material. Weld buttons with tungsten contact layers are therefore produced by brazing of tungsten discs to a weldable pre-formed base.

*Typical contact forms of weld buttons (<xr id="fig:Typical_contact_forms_of_weld_buttons"/>)
<figure id="fig:Typical_contact_forms_of_weld_buttons">
[[File:Typical_contact_forms_of_weld_buttons.jpg|right|thumb|Typical contact forms of weld buttons]]
</figure>
*Contact materials Ag, AgNi 0,15 (ARGODUR-Spezial), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CdO), Ag/SnO2 (SISTADOX), Ag/ZnO (DODURIT ZnO) 

*Carrier materials Ni, Fe, CuNi, CuNiZn et.al. 

*Dimensional Ranges (<xr id="fig:13neuDimensional -Ranges"/>)
<figure id="fig:13neuDimensional -Ranges">
[[File:13neuDimensional -Ranges.jpg|right|thumb|Dimensional Ranges]]
</figure>
*Quality criteria of standard weld buttons (<xr id="fig:16Quality_criteria_-of_standard_weld_-buttonsneu"/>)
<figure id="fig:16Quality_criteria_-of_standard_weld_-buttonsneu">
[[File:16Quality_criteria_-of_standard_weld_-buttonsneu.jpg|right|thumb|Quality criteria of standard weld buttons]]
</figure>

==References==
[[:Manufacturing Technologies for Contact Parts#References|Manufacturing Technologies for Contact Parts]]

Template:MainArticles

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Platinum Metal Based Materials

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The platinum group metals include the elements Pt, Pd, Rh, Ru, Ir, and Os <xr id="tab:Properties, Production Processes, and Application Forms for Platinum Metals"/> (Tab. 2.6). For electrical contacts platinum and palladium have practical significance as base alloy materials and ruthenium and iridium are used as alloying components. Pt and Pd have similar corrosion resistance as gold but because of their catalytical properties they tend to polymerize adsorbed organic vapors on contact surfaces. During frictional movement between contact surfaces the polymerized compounds known as “brown powder” are formed which can lead to significantly increase in contact resistance. Therefore Pt and Pd are typically used as alloys and not in their pure form for electrical contact applications.

<figtable id="tab:Properties, Production Processes, and Application Forms for Platinum Metals">
'''Table 2.6: Properties, Production Processes, and Application Forms for Platinum Metals'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Element
!Properties
!Processing
!Forms of Application
|-
|Ru Ruthenium
|Dull grey to silvery white, very hard and brittle, in the presence of oxygen resistant to acids, oxidizes during heating in air
|Vapor deposition, sputtering, powder metallurgy, warm-forming only possible at 1200 – 1500°C
|Powder; in sheet form, as coatings, and as wire mostly as alloying component
|-
|Rh Rhodium
|Almost silvery white, very hard and brittle, not soluble in acids, oxidizes in air during red anneal
|Electroplating, vapor deposition, sputtering, after warm-forming at 800 – 1000°C cold working is possible
|Coatings (electroplated), alloying component, in limited form as sheet and wire
|-
|Pd Palladium
|Dull white, resistant to most acids, oxidizes at red anneal
|Electroplating, vapor deposition, sputtering, cold working
|Sheet, strip, tubing, wire, rivets, and coatings
|-
|Os Osmium
|Bluish white, hardest platinum metal, very brittle, resistant against non-oxidizing acids, oxidizes easily on air
|Powder metallurgy
|Powder, alloying component
|-
|Ir Iridium
|Almost silvery white, very hard and brittle, acid resistant, oxidizes at red anneal
|Vapor deposition, sputtering, powder metallurgy, warm-forming possible at 1200 – 1500°C
|Powder, alloying component, in limited amounts as sheet
|-
|Pt Platinum
|Grey white, ductile, acid resistant except for aqua regia, HBr, and HJ, oxidation resistant at red anneal
|Electroplating, vapor deposition, sputtering, cold working
|Sheet, strip, tubing, wire, rivets, coatings
|}
</figtable>

Rhodium is not used as a solid contact material but is applied for example as a electroplated layer in sliding contact systems. Ruthenium is mostly used as an alloying component in the material PdRu15. The metals osmium and iridium have no practical applications in electrical contacts.

Since Pd was for the longest time rather stable in price it was looked at as a substitute for the more expensive gold. This was followed by a steep increase in the Pd price which caused a significant reduction in its use in electrical contacts. Today (2011) the Pd price again is lower than that of gold.

Alloys of Pt with Ru, Ir, Ni, and W were widely used in electromechanical components in the telecommunication industry and in heavy duty automotive breaker points <xr id="tab:Physical Properties of platinum metals"/> (Tab. 2.7).

<figtable id="tab:Physical Properties of platinum metals">
[[File:Physical Properties of platinum metals.jpg|right|thumb|Physical Properties of the Platinum Metals and their Alloys]]
</figtable>

Today these components have been replaced in many applications by solid state technology and the usage of these materials is greatly reduced. Pd alloys however have a more significant importance. PdCu15 is widely used for example in automotive flasher relays. Because of their resistance to sulfide formation PdAg alloys are applied in various relay designs. The ability to thermally precipitation harden some multi component alloys based on PdAgAuPt they find special usage in wear resistant sliding contact applications. Pd44Ag38Cu15PtAuZn is a standard alloy in this group <xr id="tab:Mechanical_Properties_of_the_Platinum_Metals_and_their_Alloys"/> (Tab 2.8) und <xr id="fig:Contact_and_Switching_Properties_of_the_Platinum_Metals_and_their_Alloys"/> (Tab. 2.9)

Platinum and palladium alloys are mainly used similar to the gold based materials in the form of welded wire and profile segments but rarely as contact rivets. Because of the high precious metal prices joining technologies are used that allow the most economic application of the contact alloy in the area where functionally needed. Because of their resistance to material transfer they are used for DC applications and due to their higher arc erosion resistance they are applied for medium electrical loads up to about 30W in relays and switches <xr id="fig:Application_Examples_and_Form_of_Supply_for_Platinum_Metals_and_their_Alloys"/> (Table 2.10). Multi-component alloys based on Pd with higher hardness and wear resistance are mainly used as spring arms in sliding contact systems and DC miniature motors.

'''Table 2.8: Mechanical Properties of the Platinum Metals and their Alloys'''

<figtable id="tab:Mechanical_Properties_of_the_Platinum_Metals_and_their_Alloys">
<table class="twocolortable">
<tr>
<th rowspan="2">Material</th><th colspan="2">Tensile Strength [MPa]</th><th colspan="2">Elongation A [%]</th><th colspan="2">Vickers Hardness HV 1</th></tr>
<tr><th>soft</th><th>70% cold worket</th><th>soft</th><th>70% cold worket</th><th>soft</th><th>70% cold worket</th></tr>
<tr><td>Pt (99,95)</td><td>150</td><td>360</td><td>40</td><td>3</td><td>40</td><td>120</td></tr>
<tr><td>PtIr5</td><td>260</td><td>550</td><td>25</td><td>2</td><td>85</td><td>160</td></tr>
<tr><td>PtIr10</td><td>340</td><td>570</td><td>24</td><td>2</td><td>105</td><td>210</td></tr>
<tr><td>PtRu10</td><td>650</td><td>1000</td><td>24</td><td>2</td><td>195</td><td>320</td></tr>
<tr><td>PtNi8</td><td>640</td><td>950</td><td>22</td><td>2</td><td>200</td><td>320</td></tr>
<tr><td>PtW5</td><td>530</td><td>860</td><td>21</td><td>2</td><td>150</td><td>270</td></tr>
<tr><td>Pd (99,95)</td><td>200</td><td>420</td><td>42</td><td>2</td><td>40</td><td>90</td></tr>
<tr><td>PdCu15</td><td>400</td><td>780</td><td>38</td><td>2</td><td>90</td><td>220</td></tr>
<tr><td>PdCu40</td><td>550</td><td>950</td><td>35</td><td>2</td><td>120</td><td>260</td></tr>
<tr><td>PdNi5</td><td>340</td><td>700</td><td>25</td><td>2</td><td>95</td><td>200</td></tr>
<tr><td>Pd35AuAgPt</td><td></td><td></td><td></td><td></td><td></td><td>420*</td></tr>
<tr><td>Pd44Ag38Cu15 PtAuZn</td><td/><td/><td/><td/><td/><td>405*</td></tr>
<tr><td>Pd40Co40W20</td><td/><td/><td/><td/><td/><td>680*</td></tr>
</table>
</figtable>

*maximum hardness

<figtable id="fig:Contact_and_Switching_Properties_of_the_Platinum_Metals_and_their_Alloys">
<table class="twocolortable">
<caption> '''Table 2.9: Contact and Switching Properties of the Platinum Metals and their Alloys'''</caption>
<tr><th>Material</th><th>Properties<th colspan="2"></th></tr><tr><td>Pt</td><td>Very high corrosion resistance</td><td/></tr><tr><td>PtIr5 - 10</td><td>Very high corrosion resistance, low contact resistance</td><td>High arc erosion resistance, high hardness</td></tr><tr><td>PtRu10</td><td>Very high corrosion resistance, low welding tendency</td><td>Low contact resistance, veryhigh hardness</td></tr><tr><td>PtNi8</td><td>Low material transfer tendency</td><td>Very high hardness</td></tr><tr><td>PtW5</td><td>Low material transfer tendency</td><td>High hardness</td></tr><tr><td>Pd</td><td>Strong tendency to “Brown Powder” formation</td><td>Less arc erosion resistant than Pt</td></tr><tr><td>PdCu15PdCu40</td><td>Tendency to “Brown Powder” formation</td><td>Mostly resistant to materialtransfer, high hardness</td></tr><tr><td>PdNi5</td><td>Strong tendency to “Brown Powder” formation</td><td>Low welding tendency</td></tr><tr><td>Pd44Ag38Cu15PtAuZn</td><td>High mechanical wear resistance</td><td>Standard material for slidingcontact brushes</td></tr></table>
</figtable>

<figtable id="fig:Application_Examples_and_Form_of_Supply_for_Platinum_Metals_and_their_Alloys">
<table class="twocolortable">
<caption>'''Table 2.10: Application Examples and Form of Supply for Platinum Metals and their Alloys'''</caption>
<tr><th>Material</th><th>Application Examples</th><th>Forms of Supply</th></tr><tr><td>Pt (99,95)</td><td>Relays</td><td>Contact rivets, welded contact parts</td></tr><tr><td>PtIr5PtIr10PtRu10PtNi8PtW5</td><td>Relays, sliding contact systems,automotive ignition breaker points</td><td>Semi-finished Contact Materials:Wire, seam-welded contact profilesContact Parts:Tips, wire-formed parts, solid and composite contact rivets, welded contact parts</td></tr><tr><td>Pd (99,95)PdNi5</td><td>Relays</td><td>Micro-profiles (weld tapes), contact rivets, welded contact parts</td></tr><tr><td>PdCu15PdCu40</td><td>Automotive flasher relays</td><td>Micro-profiles, composite contact rivets</td></tr><tr><td>Pd35AuAgPtPd44Ag38Cu15PtAuZnPd40Co40W20</td><td>Potentiometers, slip rings, miniatureDC motors</td><td>Wire-formed parts, welded wire segments, multi-arm sliding contact brushes</td></tr></table>
</figtable>

<xr id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum_(Degussa)"/>Influence of 1-20 atom% of different additive metals on the electrical resistivity p of platinum (Degussa)

<xr id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum"/>
Influence of 1-22 atom% of different additive metals on the electrical resistivity p of palladium

<xr id="fig:Phase_diagram_of_platinum-iridium"/>Fig. 2.27: Phase diagram of platinum-iridium

<xr id="fig:Phase_diagram_of_platinum-nickel"/>
Fig. 2.28: Phase diagram of platinum-nickel

<xr id="fig:Phase_diagram_of_platinum-tungsten"/>
Fig. 2.29: Phase diagram of platinum-tungsten

<xr id="fig:Phase_diagram_of_platinum-copper"/>
Fig. 2.30: Phase diagram of palladium-copper

<xr id="fig:Strain_hardening_of_Pt_by_cold_working"/>
Fig. 2.31: Strain hardening of Pt by cold working

<xr id="fig:Softening_of_Pt_after_annealing_for_0.5_hrs_after_80%_cold_working"/>
Fig. 2.32: Softening of Pt after annealing for 0.5 hrs after 80% cold working

<xr id="fig:Strain_hardening_of_PtIr5_by_cold_working"/>
Fig. 2.33: Strain hardening of PtIr5 by cold working

<xr id="fig:Softening_of_PtIr5_after_annealing_for_1_hr_after_different degrees_of_cold_working"/>
Fig. 2.34: Softening of PtIr5 after annealing for 1 hr after different degrees of cold working

<xr id="fig:Strain_hardening_of_PtNi8_by_cold_working"/>Fig. 2.35: Strain hardening of PtNi8 by cold working

<xr id="fig:Softening_of_PtNi8_after_annealing_for_1_hr_after_80%_cold_working"/>
Fig. 2.36: Softening of PtNi8 after annealing for 1 hr after 80% cold working

<xr id="fig:Strain_hardening_of_PtW5_by_cold_working"/>Fig. 2.37: Strain hardening of PtW5 by cold working

<xr id="fig:Softening_of_PtW5_after_annealing_for_1_hr_after_80%_cold_working"/>Fig. 2.38: Softening of PtW5 after annealing for 1hr after 80% cold working

<xr id="fig:Strain_hardening_of_Pd_99.99_by_cold_working"/>Fig. 2.39: Strain hardening of Pd 99.99 by cold working

<xr id="fig:Strain_hardening_of_PdCu15_by_cold_working"/>Fig. 2.40: Strain hardening of PdCu15 by cold working

<xr id="fig:Softening_of_PdCu15_after_annealing_for_0.5_hrs"/>Fig. 2.41: Softening of PdCu15 after annealing for 0.5 hrs

<xr id="fig:Strain_hardening_of_PdCu40_by_cold_working"/>Fig. 2.42: Strain hardening of PdCu40 by cold working

<xr id="fig:Softening_of_PdCu40_after_annealing_for_0.5_hrs_after_80%_cold_working"/>Fig. 2.43: Softening of PdCu40 after annealing for 0.5 hrs after 80% cold working

<xr id="fig:Electrical_resistivity_p_of_PdCu_alloys"/>Fig. 2.44: Electrical resistivity p of PdCu alloys with and without an annealing step for forming an ordered phase

<div class="multiple-images">

<figure id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum_(Degussa)">
[[File:Influence of platinum degussa.jpg|left|thumb|<caption>Influence of 1- 20 atom% of different additive metals on the electrical resistivity p of platinum (Degussa)</caption>]]
</figure>

<figure id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum">
[[File:Influence of palladium.jpg|left|thumb|<caption>Influence of 1-22 atom% of different additive metals on the electrical resistivity p of palladium</caption>]]
</figure>

<figure id="fig:Phase_diagram_of_platinum-iridium">
[[File:Phase diagram of platinum iridium.jpg|left|thumb|<caption>Fig. 2.27:Phase diagram of platinum-iridium</caption>]]
</figure>

<figure id="fig:Phase_diagram_of_platinum-nickel">
[[File:Phase diagram of platinum nickel.jpg|left|thumb|<caption>Fig. 2.28:Phase diagram of platinum-nickel</caption>]]
</figure>

<figure id="fig:Phase_diagram_of_platinum-tungsten">
[[File:Phase diagram of palladium copper.jpg|left|thumb|<caption>Fig. 2.29:Phase diagram of platinum-tungsten</caption>]]
</figure>

<figure id="fig:Phase_diagram_of_platinum-copper">
[[File:Phase diagram of palladium copper2.jpg|left|thumb|<caption>Fig. 2.30: Phase diagram of palladium-copper</caption>]]
</figure>

<figure id="fig:Strain_hardening_of_Pt_by_cold_working">
[[File:Strain hardening of Pt by cold working.jpg|left|thumb|<caption>Fig. 2.31: Strain hardening of Pt by cold working</caption>]]
</figure>

<figure id="fig:Softening_of_Pt_after_annealing_for_0.5_hrs_after_80%_cold_working">
[[File:Softening of Pt after annealing.jpg|left|thumb|<caption>Fig. 2.32: Softening of Pt after annealing for 0.5 hrs after 80% cold working</caption>]]
</figure>

<figure id="fig:Strain_hardening_of_PtIr5_by_cold_working">
[[File:Strain hardening of PtIr5 by cold working.jpg|left|thumb|<caption>Fig. 2.33: Strain hardening of PtIr5 by cold working</caption>]]
</figure>

<figure id="fig:Softening_of_PtIr5_after_annealing_for_1_hr_after_different degrees_of_cold_working">
[[File:Softening of PtIr5 after annealing.jpg|left|thumb|<caption>Fig. 2.34: Softening of PtIr5 after annealing for 1 hr after different degrees of cold working</caption>]]
</figure>

<figure id="fig:Strain_hardening_of_PtNi8_by_cold_working">
[[File:Strain hardening of PtNi8 by cold working.jpg|left|thumb|<caption>Fig. 2.35: Strain hardening of PtNi8 by cold working</caption>]]
</figure>

<figure id="fig:Softening_of_PtNi8_after_annealing_for_1_hr_after_80%_cold_working">
[[File:Softening of PtNi8 after annealing.jpg|left|thumb|<caption>Fig. 2.36: Softening of PtNi8 after annealing for 1 hr after 80% cold working</caption>]]
</figure>

<figure id="fig:Strain_hardening_of_PtW5_by_cold_working">
[[File:Strain hardening of PtW5 by cold working.jpg|left|thumb|<caption>Fig. 2.37: Strain hardening of PtW5 by cold working</caption>]]
</figure>

<figure id="fig:Softening_of_PtW5_after_annealing_for_1_hr_after_80%_cold_working">
[[File:Softening of PtW5 after annealing.jpg|left|thumb|<caption>Fig. 2.38: Softening of PtW5 after annealing for 1 hr after 80% cold working</caption>]]
</figure>

<figure id="fig:Strain_hardening_of_Pd_99.99_by_cold_working">
[[File:Strain hardening of Pd-99 99by cold working.jpg|left|thumb|<caption>Fig. 2.39: Strain hardening of Pd 99.99 by cold working</caption>]]
</figure>

<figure id="fig:Strain_hardening_of_PdCu15_by_cold_working">
[[File:Strain hardening of PdCu15 by cold working.jpg|left|thumb|<caption>Fig. 2.40: Strain hardening of PdCu15 by cold working</caption>]]
</figure>

<figure id="fig:Softening_of_PdCu15_after_annealing_for_0.5_hrs">
[[File:Softening of PdCu15 after annealing.jpg|left|thumb|<caption>Softening of PdCu15 after annealing for 0.5 hrs</caption>]]
</figure>

<figure id="fig:Strain_hardening_of_PdCu40_by_cold_working">
[[File:Strain hardening of PdCu40 by cold working.jpg|left|thumb|<caption>Strain hardening of PdCu40 by cold working</caption>]]
</figure>

<figure id="fig:Softening_of_PdCu40_after_annealing_for_0.5_hrs_after_80%_cold_working">
[[File:Softening of PdCu40 after annealing.jpg|left|thumb|<caption>Softening of PdCu40 after annealing for 0.5 hrs after 80% cold working</caption>]]
</figure>

<figure id="fig:Electrical_resistivity_p_of_PdCu_alloys">
[[File:Electrical resistivity p of PdCu alloys.jpg|left|thumb|<caption>Electrical resistivity p of PdCu alloys with and without an annealing step for forming an ordered phase</caption>]]
</figure>

</div>
<div class="clear"></div>

==References==
[[Contact Materials for Electrical Engineering#References|References]]

Testing Procedures for Power Engineering

2014-04-23T13:22:13Z

80.152.203.11:

==13.4 Testing Procedures for Power Engineering==

The testing of electrical contacts for power engineering applications serves on the one hand the continuous quality assurance, on the other one the new and improvement development efforts for contact materials. To optimize the contact and switching performance contact materials and device designs have to complement each other. The success of such optimizing is proven through switching tests.

The assessment of contact materials is performed using metallurgical test methods as well as switching tests in model test set-ups and in commercial switching devices. While physical properties such as melting and boiling point, electrical conductivity, etc. are fundamental for the selection of the base metals and the additional components of the materials, they cannot provide a clear indication of the contact and switching behavior. Metallurgical evaluations and tests are used primarily for determining material and working defects. The actual contact and switching behavior can however only be determined through switching tests in a model switch or preferably in the final electromechanical device.

Model testing devices offer the possibility of quick ratings of the make and break behavior and give a preliminary classification of potential contact materials. Since such tests are performed under ideal conditions they cannot replace switching tests in actual devices.

The electrical testing of commercially produced switching devices should follow DIN EN or IEC standards and rules. Special test standards exist for each type of switching device which are differentiated by:

* Make capacity
* Break capacity
* Electrical life
* Temperature rise

The following chapters are limited to metallurgical analysis and the testing of the most important properties of switching devices such as electrical life, temperature rise, and switching capacity.

===13.4.1 Metallurgical Analysis===

The main characteristic for the appraisal of contact materials for power engineering is the optical evaluation of their microstructure in a metallographic mount. This provides a picture of the internal structure of the materials. It allows detecting structural in-homogeneity, grain boundary enrichments, cracks, material separations, or defects in the brazing interface. The metallographic view is however limited to the one two-dimensional plain in which the mounting cut was made.

<xr id="fig:Microstructure of a powder metallurgical Ag CdO material"/> (Fig. 13.11) shows the microstructure of a Ag/CdO contact material after being affected by electrical arcing. In the lower part the starting material structure is visible. In the upper part the de-mixing of the composite material through the effects of the switching arc is clearly demonstrated. This “switching structure” shows in certain areas depletion of metal oxide which increases the probability of contact welding during subsequenbt make operations. Additional analysis by X-ray probing in a scanning electron microscope (SEM) allows the micro analysis of the elements present in the contact surface region.
<figure id="fig:Microstructure of a powder metallurgical Ag CdO material">
[[File:Microstructure of a powder metallurgical Ag CdO material.jpg|right|thumb|Microstructure of a powder metallurgical Ag/CdO material after being affected by intense electrical arcing]]
</figure>

===13.4.2 Testing According to IEC/EN===

====13.4.2.1 Electrical Life====

The electrical life of contactors, motor switches, and auxiliary current switches used in power engineering is classified into use categories which are shown in <xr id="tab:Important Use Categories and Their Typical Applications for Contactors and Power Switches"/> (Tab. 13.1).

The making and breaking currents for tests IEC/EN 60947-4-1 are shown in <xr id="tab:Verification of Electrical Life Conditions for Make and Break Tests of Contactors and Motor Starters by Utilization Category"/> (Tab. 13.2) for the different use categories.

The electrical life of a motor switch is influenced primarily by arc erosion which is generated during make and break arcs on the contact surface. During AC-3 testing, for which the make current is six time the nominal rated current, the arc erosion is mainly caused by the make arcs, especially if frequent contact bounces > 2 ms occur. Therefore the bounce characteristic of switching devices primarily used for “normal” use in switching on and off electrical motors is of critical importance. If make and break currents are the same, as in the ultilisation categories AC-1 and AC-4, the break erosion dominates the arc erosion so much that make erosion can be neglected.

<figtable id="tab:Important Use Categories and Their Typical Applications for Contactors
and Power Switches">
'''Table 13.1: Important Use Categories and Their Typical Applications for Contactors and Power Switches'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!colspan="6" style="text-align:left"| Contactors, Motor Starters according to IEC/N60947-4-1
|-
!Type of current
!Utilisation category
!Typical application
|-
|Alternating current (AC)
|AC-1
|Non-inductive or slightly inductive loads, resistance furnaces
|-
|
|AC-2
|Slip ring motors: starting, switch-off
|-
|
|AC-3
|Squirrel-cage motors: starting, switch-off, switch-off during running4)
|-
|
|AC-4
|Sqirrel-cage motors: starting, plugging, reversing, inching
|-
|Direct current (DC)
|DC-1
|Non-inductive or slightly inductive loads, resistance furnaces
|-
|
|DC-3
|Shunt motors: starting, plugging, reversing, inching, dynamic braking
|-
|
|DC-5
|Series motors: starting, plugging, reversing, inching, dynamic braking
|-
!colspan="6" style="text-align:left"| Auxiliary Current Switches according to IEC/EN 160947-5-1
|-
!Type of current
!Utilisation category
!Typical application
|-
|Alternating current (AC)
|AC-12
|Controlling resistive semiconductor loads in feed circuits of optoelectronics
|-
|
|AC-14
|Controlling small electromagnetic loads (72 VA max)
|-
|
|AC-15
|Controlling electromagnetic loads (> 72 VA)
|-
|Direct Current (DC)
|DC-12
|Controlling resistive semiconductor loads in feed circuits of optoelectronics
|-
|
|DC-13
|Controlling of electro magnets under direct current
|-
|
|DC-14
|Controlling of electromagnetic loads under direct current with power saving resistors in circuits
|}
</figtable>

The electrical life for the utilization categories AC-3, DC-3, and DC-5 must be at a minimum 5% of the mechanical lifetime of a switching device.
The conditions for make and break tests of auxiliary current switches and control circuit devices are described in IEC/EN 60947-5-1. Usually the
electrical life of auxiliary switches is of lesser importance since these devices see only smaller loads. Under certain conditions however requirements for make and beak capacity can be as high as 10 times the nominal current. This results in very severe requirements on the dielectric strength and recovery voltage of the arc affected region immediately after arcing.

<figtable id="tab:Verification of Electrical Life Conditions for Make and Break Tests of Contactors and Motor Starters by Utilization Category">
'''Table 13.2: Verification of Electrical Life Conditions for Make and Break Tests of Contactors and Motor Starters by Utilization Category'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Ultilisation Category
!Current
!colspan="3" style="text-align:center"| Make operation
!colspan="3" style="text-align:center"| Break Operation
|-
!
!Ie/A
!I/Ie
!U/Ue
!cos φ
!Ic/Ie
!Ur/Ue
!cos φ
|-
|AC-1
|Alle Werte
|1
|1
|0.95
|1
|1
|0.95
|-
|AC-2
|Alle Werte
|2.5
|1
|0.65
|2.5
|1
|0.65
|-
|AC-3
|Ie ≤ 17 Ie > 17
|6 6
|1 1
|0.65 0.35
|1 1
|0.17 0.17
|0.65 0.35
|-
|AC-4
|Ie ≤ 17 Ie > 17
|6 6
|1 1
|0.65 0.35
|6 6
|1 1
|0.65 0.35
|-
!
!Ie/A
!I/Ie
!U/Ue
!L/R [ms]
!Ic/Ie
!Ur/Ue
!L/R [ms]
|-
|DC-1
|All values
|1
|1
|1
|1
|1
|1
|-
|DC-3
|All values
|2.5
|1
|2
|2.5
|1
|2
|-
|DC-5
|All values
|2.5
|1
|7.5
|2.5
|1
|7.5
|}
</figtable>

Ie = Rated operational current 
I = Make (ON) current 
Ic = Break (OFF) current 

Ue = Rated operational voltage 
U = Voltage 
Ur = Recovery voltage

[[File:AC3 contact arc erosion of two differently produced Ag SnO2 contact materials.jpg|right|thumb|AC-3 contact arc erosion of two differently produced Ag/SnO2 contact materials in a 37 kW contactor 1 Ag/SnO2 88/12, produced by conventional powder metallurgy with MoO3 additive, extruded 2 Ag/SnO2 88/12, powder manufacturing by the reaction-spray process with CuO and Bi2 O3 additives, extruded]]

====13.4.2.2 Temperature Rise====

Testing for temperature rise is required only for switching devices in the new stage. During use however over the entire life of the device no damages due to temperature rise are allowed in the device or at ist terminal points.
<figure id="fig:Maximum movable bridge temperature rise for different contact materials">
[[File:Maximum movable bridge temperature rise for different contact materials.jpg|right|thumb|Maximum movable bridge temperature rise for different contact materials in a 132 kW contactor after high load (AC-4) switching
1 Ag/CdO 88/12 sintered
and extruded
2 Ag/SnO27.5In2O32.5
internally oxidized
3 Ag/SnO2 88/12
sintered and extruded
4 Ag/SnO2 11.5 WO3 0.5 sintered and extruded
5 Ag/SnO2 11.6 MO4 0.4
sintered and extruded]]
</figure>
For the assessment of contact materials a temperature rise test is frequently performed after a specified number of switching operations accompanied by arcing <xr id="fig:Maximum movable bridge temperature rise for different contact materials"/> (Fig. 13.13). The most important characteristic is the measured temeperature rise of the movable bridge contacts. If a certain upper limit of temperature is reached, adjacent plastic components may be irreversibly damaged.

====13.4.2.3 Analysis of the Switching Sequence====

In switching devices, which are actuated by AC actuator magnets, the contact parts can close and open synchronously at a specific phase angle relative to the voltage-zero of the supply voltage. Of similar importance is the sequence of closing and opening of the contacts with regards to the three phases. The closing and opening delays define at which time delay after the first phase (or pole) the other phases close and open.

Relevant experiments have shown that combined effects of synchronism, phase sequence and switching delay can, under severe adverse conditions,
lead to extreme damage, especially on at least one of the phases or poles. They are the cause of early failure of this phase and therefore the complete switching device and can happen as early as after only 30% of the normally expected lifetime. Because of variations in the mechanical characteristics of switching devices from manufacturing processes life testing cannot be performed on one device alone. Only statistical analysis of tests from multiple device samples can be used as reliable results. Such a procedure is however time consuming and costly. If however every single switching operation during a test is monitored for bounce behavior, on- and off-switching synchronization and related phase sequencing and phase delays, the arc moving behavior, and especially arc energy which is transferred during make and break arcing to the contact pieces, and then these data are properly analyzed, is it possible to assess a specific contact material from a test in only one device alone. Only statistical analysis of tests from multiple device samples can be used as reliable results. Such a procedure is however time consuming and costly. If however every single switching operation during a test is monitored for bounce behavior, on- and offswitching synchronization and related phase sequencing and phase delays, the arc moving behavior, and especially arc energy which is transferred during make and break arcing to the contact pieces, and then these data are properly analyzed, is it possible to assess a specific contact material from a test in only one device.

====13.4.2.4 Switching Capacity====

The main requirement for low voltage power switches is the withstanding of high short circuit currents. The short circuit switching capacity of power switches is determined in tests according to IEC/EN 60947-2 (Tab. 13.3). These test differentiate between the maximum short circuit current switching capacity (ultimate current limit) ICU and the operational (or service) short circuit current capacity ICS .

When specifying ICU it must be guaranteed that short circuit current up to the maximum limit value can be interrupted safely. After its occurrence it must be possible to switch on one additional time onto the not yet eliminated short circuit and again interrupt this short circuit current again safely. The switch does not have to be functional any more after this second interruption. A switch specified for ICS must still be capable to protect the circuit and be further usable within certain limitations.

To safely withstand short circuit currents high requirements are imposed on the weld resistance of the materials used for the mating contacts. During short circuit switching the contact force between the contacts pairing is reduced by electromagnetic forces. Above a certain device specific current value the contacts will separate. This generates an electrical arc with contact material melting at its root points. During the next closing of the contacts this can cause contact welding, prohibiting the opening of the contacts during a subsequent short circuit and therefore eliminating the safety function of the switching device.

<figtable id="tab:Testing for the Short Circuit Breaking Capacity of Low Voltage Power Switches According to IEC/EN 60947-2 (Shortened Summary)">
'''Table 13.3: Testing for the Short Circuit Breaking Capacity of Low Voltage Power Switches According to IEC/EN 60947-2 (Shortened Summary)'''

</figtable>

===13.4.3 Testing According to UL and CSA===

The test standards for North America according to UL (USA) and CSA (Canada) differ in part substantially from those of the IEC and harmonized European EN standards. In the US and Canada the standards differentiate between switchgear for power distribution, for example low voltage circuit breakers and power switches covered by UL 489 (UL = Underwriters Laboratories) and CSAC22.2 No. 5-02 (CSA = Canadian Standard Association) and those for industrial switching devices, for example contactors covered by UL 508 and CSA-C22.2 No. 14 respectively. For industrial controls contactors and other switching devices are often classified in the USA according to NEMA (National Electrical Manufacturers Association) current rating. North American standards emphasize the prevention of fires and therefore have high limit requirements on temperature rise. They also require larger air and creep gaps than those of IEC, which leads to significant differences in the design of the switches and their contact systems.

==References==
[[Testing Procedures#References|References]]

Template:MainArticles

2014-04-22T09:47:36Z

80.152.203.11:

<article count="2" length="450"/>

{{Special:RecentChanges/5}}

Electroplating (or Galvanic Deposition)

2014-04-10T11:18:25Z

80.152.203.11: /* Selective Electroplating */

==== Electroplating Solutions – Electrolytes====
The actual metal deposition occurs in the electrolytic solution which contains the plating material as metal ions. Besides this basic ingredient, the electrolytes contain additional components depending on the processes used, such as for example conduction salts, brighteners, and organic additives which are codeposited into the coatings, influencing the final properties of the electroplating deposit.

===== Precious Metal Electrolytes=====
All precious metals can be electroplated with silver and gold by far the most widely used ones <xr id="tab:Precious Metal Electrolytes for Technical Applications"/> (Tab. 7.2) and <xr id="tab:Precious Metal Electrolytes for Decorative Applications"/> (Tab. 7.3).
The following precious metal electrolytes are the most important ones:

*Gold electrolytes For functional and decorative purposes pure gold, hard gold, low-karat gold, or colored gold coatings are deposited. Depending on the requirements, acidic, neutral, or cyanide electrolytes based on potassium gold cyanide or cyanide free and neutral electrolytes based on gold sulfite complexes are used. 

*Palladium and Platinum electrolytes Palladium is mostly deposited as a pure metal, for applications in electrical contacts however also as palladium nickel. For higher value jewelry allergy protective palladium intermediate layers are used as a diffusion barrier over copper alloy substrate materials. Platinum is mostly used as a surface layer on jewelry items. 

*Ruthenium electrolytes Ruthenium coatings are mostly used for decorative purposes creating a fashionable “grey” ruthenium color on the surface. An additional color variation is created by using “ruthenium-black” deposits which are mainly used in bi-color decorative articles. 

*Rhodium electrolytes Rhodium deposits are extremely hard (HV 700 – 1000) and wear resistant. They also excel in light reflection. Both properties are of value for technical as well as decorative applications. While technical applications mainly require hard, stress and crack free coatings, the jewelry industry takes advantage of the light whitish deposits with high corrosion resistance. 

*Silver electrolytes Silver electrolytes without additives generate dull soft deposits (HV ~ 80) which are mainly used as contact layers on connectors with limited insertion and withdrawal cycles. Properties required for decorative purposes such as shiny bright surfaces and higher wear resistance are achieved through various additives to the basic Ag electrolyte. 

<figtable id="tab:Precious Metal Electrolytes for Technical Applications">
'''Table 7.2: Precious Metal Electrolytes for Technical Applications'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Range
!colspan="2" style="text-align:center"|Deposit Properties Hardness
!Areas of Application
|-
!
!
!HV
!Purity [kt]
!
|-
|colspan="5" |'''Gold electrolytes'''
|-
|AUROMET TN
|3.2 - 4.2
|ca. 70
|99.99% Au
|Base-deposits
|-
|AUROMET XPH
|0.3 - 0.6
|160 - 180
|99.8% Au
|Base-deposits for stainless steel etc.
|-
|DODUREX COC
|4.6 - 4.9
|160 - 180
|99.6% Au
|Printed circuit boards, connectors, contact parts, etc.; hard gold coatings for rack and barrel plating
|-
|DODUREX HS 100
|4.3 - 4.6
|160 - 180
|99.6% Au
|High speed process for connectors and PCB plating
|-
|PURAMET 202 PURAMET 402
|5.5 - 6.5 7.0 - 7.5
|60 - 80 60 - 80
|99.99% Au 99.99% Au
|High purity gold coatings for electrical and electronic parts incl. semi conductors and PCBs; for demanding requirement on bonding properties
|-
|colspan="5" |'''Platinum metal electrolytes'''
|-
|RHODOPLAT T
|strongly acidic
|900
|99.0% Rh
|Ductile rhodium deposits for thicker layers, reed contacts, sliding contacts
|-
|RUTHENIUMBAD
|stronglyacidic
|900
|99.0% Ru
|Crack free thick ruthenium deposits
|-
|PLATINBAD 5
|stronglyacidic
|240 - 260
|99.9% Pt
|High temperature switching devices, etc
|-
|DODUPAL 3
|7.0 - 8.0
|220 - 250
|99.9% Pd
|Thin palladium layers as diffusion barrier
|-
|DODUPAL 5
|7.0 - 8.0
|220 - 250
|99.9% Pd
|Connectors and contact parts
|-
|DODUPAL 10
|8.0 - 8.5
|350 - 400
|80.0% Pd
|Pd/Ni for connectors and contact parts
|-
|colspan="5" |'''Silver electrolytes'''
|-
|ARGOL 30
|cyanidebased
|a pprox. 90
|99.9% Ag
|rowspan="4" |Contact parts, connectors
|-
|ARGOL HS 100
|approx. 9.0
|90 - 120
|99.9% Ag
|-
|ARGOL 2000
|approx. 12.0
|
|
|-
|ARGOL 400
|
|160 - 180
|
|}
</figtable>

=====7.1.1.1.2 Non-Precious Metal Electrolytes=====

The most important non-precious metals that are deposited by electroplating are: Copper, nickel, tin, and zinc and their alloys. The deposition is performed in the form of pure metals with different electrolytes used <xr id="tab:Typical Electrolytes for the Deposition of Non-Precious Metals"/>(Table 7.4).

*Copper electrolytes Copper electrolytes are used for either depositing an intermediate layer on strips or parts, for building up a printed circuit board structure, or for the final strengthening during the production of printed circuit boards. 

*Tin electrolytes Pure tin and tin alloy deposits are used as dull or also bright surface layers on surfaces required for soldering. In the printed circuit board manufacturing they are also utilized as an etch resist for the conductive pattern design after initial copper electroplating. 

<figtable id="tab:Precious Metal Electrolytes for Decorative Applications">
'''Table 7.3: Precious Metal Electrolytes for Decorative Applications'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Bereich
!colspan="2" style="text-align:center"|Deposit Properties
!Areas of Application
|-
!
!
!Hardness HV
!Purity [kt]
!
|-
|colspan="5" |'''Gold electrolytes'''
|-
|DURAMET 1N14 DURAMET 2N18 DURAMET 3N DURAMET 265S DURAMET 333S DURAMET 386S
|3.4 - 3.8 3.4 - 3.8 3.4 - 3.8 3.4 - 3.8 3.2 - 3.6 3.4 - 3.8
|1N 2N 3N Hamilton 1N Hamilton
|23 23 23 23 23 23
|Jewelry, watches, writing instruments, frames for glasses, fixtures
|-
|HELODOR 630
|8.5 - 9.5
|rose colored
|22
|Frames for glasses, jewelry, watches, writing instruments
|-
|DODUPLAT Y18 DODUPLAT Y18HS
|9.5 - 10.5 9.5 - 11
|2N 2N
|18 16
|Jewelry, watches, writing instruments
|-
|AUROMET TN AUROMET 2 AUROMET 4
|3.2 - 4.2 3.2 - 4.0 3.2 - 4.2
|Pure Gold 2 - 3N 2 - 3N
|23 23 23
|Colored gold for jewelry, watches, writing instruments, fixtures, frames for glasses, etc.
|-
|colspan="5" |'''Platinum metal electrolytes'''
|-
|RHODIOR 2 RHODIOR 20 RHODIOR 25 RHODIOR 40
|< 1 < 1 < 1 < 1
|white white white white
|99.99%Rh 99.99%Rh 99.99%Rh 99.99%Rh
|Bright white rhodium coatings with high hardness for jewelry, watches, writing instruments, etc.
|-
|RUTHENIUMBAD
|strongly acidic
|grey/black
|99.0%Ru
|Very hard and luster retaining Ruthenium coating
|-
|PLATINBAD
|strongly acidic
|white
|99.9%Pt
|Jewelry, watches, etc.
|-
|DODUPAL 3
|7.0 - 7.6
|Pd - color
|95%Pd
|Thin Pd/Zn coating as Ni-free diffusion barrier
|-
|DODUPAL 10
|8.0 - 8.5
|white
|80%Pd
|Pd/Zn alloy for jewelry
|-
|DODUPAL 12
|7.0 - 8.0
|white
|95%Pd
|Pd/Zn alloy for decorations
|-
|colspan="5" |'''Silver electrolytes'''
|-
|ARGOL 2000
|11.5 - 12.5
|bright white
|99.9%Ag
|Jewelry, watches, decoration
|}
</figtable>

*Nickel electrolytes Nickel layers are mostly used as diffusion barriers during the gold plating of copper and copper alloys or as an intermediate layer for tinning 

*Bronze electrolytes Bronze coatings – in white or yellow color tones – are used either as an allergy free nickel replacement or as a surface layer for decorative purposes. For technical applications the bronze layers are utilized for their good corrosion resistance and good brazing and soldering properties. 

<figtable id="tab:Typical Electrolytes for the Deposition of Non-Precious Metals">
'''Table 7.4: Typical Electrolytes for the Deposition of Non-Precious Metals'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Range
!Electrolyte temperature [°C]
!Current density [A/dm²]
!Yield [%]
|-
|colspan="5" |'''Copper electrolytes'''
|-
|Cyanide copper
|10 - 13
|40 - 65
|0 .5 - 4
|70-95
|-
|Acidic copper
|<1
|20 - 35
|2 - 8
|<100
|-
|colspan="5" |'''Nickel electrolytes'''
|-
|Watts nickel (Sulfate)
|3 - 5
|40 - 70
|3 - 10
|95-97
|-
|Sulfamate nickel
|3 - 4
|30 - 60
|5 - 20
|95-97
|-
|colspan="5" |'''Tin electrolytes'''
|-
|Acidic tin (Sulfate)
|<1
|18 - 25
|1 - 3
|<100
|-
|Alkaline tin
|>10
|75 - 80
|2 - 17
|max.95
|-
|colspan="5" |'''Bronze electrolytes'''
|-
|DODUBRONCE W
|Strongly alkaline
|55 - 60
|0.5 - 1.5
|
|-
|DODUBRONCE G
|Strongly alkaline
|45 - 50
|2 - 3.5
|
|-
|DODUBRONCE AF
|Strongly alkaline
|58 - 62
|0.5 - 1.5
|
|}
</figtable>

==== Electroplating of Parts====
The complete or all-around electroplating of small mass produced parts like contact springs, rivets, or pins is usually done as mass plating in electroplating barrels of different shape. During the electroplating process the parts are continuously moved and mixed to reach a uniform coating.

Larger parts are frequently electroplated on racks either totally or by different masking techniques also partially. Penetrating the coating into the interior of drilled holes or tubes can be achieved with the use of special fixtures.

'''Electroplated Parts'''

[[File:Electroplated Parts.jpg|left|Electroplated Parts]]

<div class="clear"></div>
*'''Materials'''
{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
!colspan="2" style="text-align:center"|Coatings
|-
|Precious metals
|Pure gold, hard gold (HV 150 – 250), palladium, palladium-nickel, rhodium, pure silver, hard silver (HV 130 – 160)
|-
|Non-precious metals
|Copper, nickel, tin, tin alloys
|-
|Carrier materials
|Copper, copper alloys, nickel, nickel alloys, iron, steel, aluminum, aluminum alloys, composite materials such as aluminum – silicon carbide
|}

*'''Coating thickness'''

{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
|Precious metals:
|0.2 – 5 μm (typical layer thicknesses; for Ag also up to 25 μm)
|-
|Non-precious metals:
|Up to approx. 20 μm
|-
|Tungsten
|0.5 N
|-
|Tolerances:
|Strongly varying depending on the geometrical shape of parts(up to 50% at a defined measuring spot). It is recommended to specify a minimum value for the coating thickness at a defined measuring spot
|}

*'''Quality criteria'''
Besides others the following layer parameters are typically monitored in-process and documented:

*Coating thickness
*Adhesion strength
*Porosity
*Solderability
*Bonding property
*Contact resistance
These quality tests are performed according to industry standards, internal standards, and customer specifications resp.

==== Electroplating of Semi-finished Materials====
The process for overall electroplating of strips, profiles, and wires is mostly performed on continuously operating reel-to-reel equipment. The processing steps for the individual operations such as pre-cleaning, electroplating, rinsing are following the same principles as those employed in parts electroplating.

The overall coating is usually applied for silver plating and tin coating of strips and wires. Compared to hard gold or palladium these deposits are rather ductile, ensuring that during following stamping and forming operations no cracks are generated in the electroplated layers.

==== Selective Electroplating====
Since precious metals are rather expensive it is necessary to perform the electroplating most economically and coat only those areas that need the layers
for functional purposes. This leads from overall plating to selective electroplating of strip material in continuous reel-to-reel processes. Depending
on the final parts design and the end application the processes can be applied to solid strip material as well as pre-stamped and formed continuous strips or utilizing wire-formed or machined pins which have been arranged as bandoliers attached to conductive metal strips.

The core part of selective precious metal electroplating is the actual electroplating cell. In it the anode is arranged closely to the cathodic polarized
material strip. Cathode screens or masks may be applied between the two to focus the electrical field onto closely defined spots on the cathode strip.

Special high performance electrolytes are used in selective electroplating to reach short plating times and allow a high flow rate of the electrolyte for a fast electrolyte exchange in the actual coating area.

For a closely targeted electroplating of limited precious metal coating of contact springs so-called brush-electroplating cells are employed <xr id="fig:Brush Tampon plating cell"/> (Fig. 7.1). The “brush” or “tampon” consists of a roof shaped titanium metal part covered with a special felt-like material. The metal body has holes in defined spots through which the electrolyte reaches the felt. In the same spots is also the anode consisting of a fine platinum net. The pre-stamped and in the contact area pre-formed contact spring part is guided under a defined pressure over the electrolyte soaked felt material and gets wetted with the electrolyte. This allows the metal electroplating in highly selective spots.

<figure id="fig:Brush Tampon plating cell">
[[File:Brush Tampon plating cell.jpg|right|thumb|Brush (or “Tampon”) plating cell; 1 Strip; 2 Anode; 3 Electrolyte feed; 4 Felt covered cell]]
</figure>
For special applications, such as for example electronic component substrates, a dot shaped precious metal coating is required. This is achieved with two belt masks running synchronous to the carrier material. One of these two masks has windows which are open to the spot areas targeted for precious metal plating coverage.

'''Summary of the processes for selective electroplating'''

*'''Immersion electroplating'''
Overall or selective electroplating of both sides of solid strips or pre-stamped parts in strip form

*'''Stripe electroplating'''
Stripe electroplating on solid strips through wheel cells or using masking techniques

*'''Selective electroplating'''
One-sided selective coating of solid, pre-stamped, or metallically belt-linked strips by brush plating

*'''Spot electroplating'''
Electroplating in spots of solid strips with guide holes or pre-stamped parts in strip form

'''Typical examples of electroplated semi-finished materials'''
(overall or selectively)
[[File:Typical examples of electroplated semi finished materials.jpg|left|Typical examples of electroplated semi-finished materials (overall or selectively)]]

<div class="clear"></div>
*'''Materials'''
{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
!Type of Coatings
!Coating Thickness
!Remarks
|-
|colspan="3" |'''Gold electrolytes'''
|-
|Pure gold Hard gold (AuCo 0.3)
|0.1 - 3 μm
|In special cases up to 10 μm
|-
|Palladium-nickel (PdNi20)
|0.1 - 5 μm
|Frequently with additional 0.2 μm AuCo 0.3
|-
|Silver
|0.5 - 10 μm
|In special cases up to 40 μm
|-
|colspan="3" |'''Non-precious Metals'''
|-
|Nickel
|0.5 - 4 μm
|Diffusion barrier especially for gold layers
|-
|Copper
|1 - 5 μm
|Intermediate layer used in tinning of CuZn
|-
|Tin, tin alloys
|0.8 - 25 μm
|materials
|}

*'''Carrier Materials'''
Copper, copper alloys, nickel, nickel alloys, stainless steel

*'''Dimensions and Tolerances'''

[[File:Dimensions and Tolerances.jpg|left|Dimensions and Tolerances]]

*'''Tolerances'''

{| class="twocolortable" style="text-align: left; font-size: 12px;width:30%"
|-
|Coating thickness approx.
|± 10 %
|-
|Coating thickness and position
|± 0,5 mm
|}

*'''Quality Criteria'''
Mechanical properties and dimensional tolerances of the carrier materials follow the typical standards, i.e. DIN EN 1652 and 1654 for copper and copper alloys. Depending on the application the following parameters are tested and recorded (see also: Electroplating of parts):

*Coating thickness
*Solderability
*Adhesion strength
*Bonding property
*Porosity
*Contact resistance

These quality tests are performed according to industry standards, internal standards, and customer specifications resp.

==References==
[[Surface Coating Technologies#References|References]]

Electroplating (or Galvanic Deposition)

2014-04-10T11:17:28Z

80.152.203.11: /* Selective Electroplating */

==== Electroplating Solutions – Electrolytes====
The actual metal deposition occurs in the electrolytic solution which contains the plating material as metal ions. Besides this basic ingredient, the electrolytes contain additional components depending on the processes used, such as for example conduction salts, brighteners, and organic additives which are codeposited into the coatings, influencing the final properties of the electroplating deposit.

===== Precious Metal Electrolytes=====
All precious metals can be electroplated with silver and gold by far the most widely used ones <xr id="tab:Precious Metal Electrolytes for Technical Applications"/> (Tab. 7.2) and <xr id="tab:Precious Metal Electrolytes for Decorative Applications"/> (Tab. 7.3).
The following precious metal electrolytes are the most important ones:

*Gold electrolytes For functional and decorative purposes pure gold, hard gold, low-karat gold, or colored gold coatings are deposited. Depending on the requirements, acidic, neutral, or cyanide electrolytes based on potassium gold cyanide or cyanide free and neutral electrolytes based on gold sulfite complexes are used. 

*Palladium and Platinum electrolytes Palladium is mostly deposited as a pure metal, for applications in electrical contacts however also as palladium nickel. For higher value jewelry allergy protective palladium intermediate layers are used as a diffusion barrier over copper alloy substrate materials. Platinum is mostly used as a surface layer on jewelry items. 

*Ruthenium electrolytes Ruthenium coatings are mostly used for decorative purposes creating a fashionable “grey” ruthenium color on the surface. An additional color variation is created by using “ruthenium-black” deposits which are mainly used in bi-color decorative articles. 

*Rhodium electrolytes Rhodium deposits are extremely hard (HV 700 – 1000) and wear resistant. They also excel in light reflection. Both properties are of value for technical as well as decorative applications. While technical applications mainly require hard, stress and crack free coatings, the jewelry industry takes advantage of the light whitish deposits with high corrosion resistance. 

*Silver electrolytes Silver electrolytes without additives generate dull soft deposits (HV ~ 80) which are mainly used as contact layers on connectors with limited insertion and withdrawal cycles. Properties required for decorative purposes such as shiny bright surfaces and higher wear resistance are achieved through various additives to the basic Ag electrolyte. 

<figtable id="tab:Precious Metal Electrolytes for Technical Applications">
'''Table 7.2: Precious Metal Electrolytes for Technical Applications'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Range
!colspan="2" style="text-align:center"|Deposit Properties Hardness
!Areas of Application
|-
!
!
!HV
!Purity [kt]
!
|-
|colspan="5" |'''Gold electrolytes'''
|-
|AUROMET TN
|3.2 - 4.2
|ca. 70
|99.99% Au
|Base-deposits
|-
|AUROMET XPH
|0.3 - 0.6
|160 - 180
|99.8% Au
|Base-deposits for stainless steel etc.
|-
|DODUREX COC
|4.6 - 4.9
|160 - 180
|99.6% Au
|Printed circuit boards, connectors, contact parts, etc.; hard gold coatings for rack and barrel plating
|-
|DODUREX HS 100
|4.3 - 4.6
|160 - 180
|99.6% Au
|High speed process for connectors and PCB plating
|-
|PURAMET 202 PURAMET 402
|5.5 - 6.5 7.0 - 7.5
|60 - 80 60 - 80
|99.99% Au 99.99% Au
|High purity gold coatings for electrical and electronic parts incl. semi conductors and PCBs; for demanding requirement on bonding properties
|-
|colspan="5" |'''Platinum metal electrolytes'''
|-
|RHODOPLAT T
|strongly acidic
|900
|99.0% Rh
|Ductile rhodium deposits for thicker layers, reed contacts, sliding contacts
|-
|RUTHENIUMBAD
|stronglyacidic
|900
|99.0% Ru
|Crack free thick ruthenium deposits
|-
|PLATINBAD 5
|stronglyacidic
|240 - 260
|99.9% Pt
|High temperature switching devices, etc
|-
|DODUPAL 3
|7.0 - 8.0
|220 - 250
|99.9% Pd
|Thin palladium layers as diffusion barrier
|-
|DODUPAL 5
|7.0 - 8.0
|220 - 250
|99.9% Pd
|Connectors and contact parts
|-
|DODUPAL 10
|8.0 - 8.5
|350 - 400
|80.0% Pd
|Pd/Ni for connectors and contact parts
|-
|colspan="5" |'''Silver electrolytes'''
|-
|ARGOL 30
|cyanidebased
|a pprox. 90
|99.9% Ag
|rowspan="4" |Contact parts, connectors
|-
|ARGOL HS 100
|approx. 9.0
|90 - 120
|99.9% Ag
|-
|ARGOL 2000
|approx. 12.0
|
|
|-
|ARGOL 400
|
|160 - 180
|
|}
</figtable>

=====7.1.1.1.2 Non-Precious Metal Electrolytes=====

The most important non-precious metals that are deposited by electroplating are: Copper, nickel, tin, and zinc and their alloys. The deposition is performed in the form of pure metals with different electrolytes used <xr id="tab:Typical Electrolytes for the Deposition of Non-Precious Metals"/>(Table 7.4).

*Copper electrolytes Copper electrolytes are used for either depositing an intermediate layer on strips or parts, for building up a printed circuit board structure, or for the final strengthening during the production of printed circuit boards. 

*Tin electrolytes Pure tin and tin alloy deposits are used as dull or also bright surface layers on surfaces required for soldering. In the printed circuit board manufacturing they are also utilized as an etch resist for the conductive pattern design after initial copper electroplating. 

<figtable id="tab:Precious Metal Electrolytes for Decorative Applications">
'''Table 7.3: Precious Metal Electrolytes for Decorative Applications'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Bereich
!colspan="2" style="text-align:center"|Deposit Properties
!Areas of Application
|-
!
!
!Hardness HV
!Purity [kt]
!
|-
|colspan="5" |'''Gold electrolytes'''
|-
|DURAMET 1N14 DURAMET 2N18 DURAMET 3N DURAMET 265S DURAMET 333S DURAMET 386S
|3.4 - 3.8 3.4 - 3.8 3.4 - 3.8 3.4 - 3.8 3.2 - 3.6 3.4 - 3.8
|1N 2N 3N Hamilton 1N Hamilton
|23 23 23 23 23 23
|Jewelry, watches, writing instruments, frames for glasses, fixtures
|-
|HELODOR 630
|8.5 - 9.5
|rose colored
|22
|Frames for glasses, jewelry, watches, writing instruments
|-
|DODUPLAT Y18 DODUPLAT Y18HS
|9.5 - 10.5 9.5 - 11
|2N 2N
|18 16
|Jewelry, watches, writing instruments
|-
|AUROMET TN AUROMET 2 AUROMET 4
|3.2 - 4.2 3.2 - 4.0 3.2 - 4.2
|Pure Gold 2 - 3N 2 - 3N
|23 23 23
|Colored gold for jewelry, watches, writing instruments, fixtures, frames for glasses, etc.
|-
|colspan="5" |'''Platinum metal electrolytes'''
|-
|RHODIOR 2 RHODIOR 20 RHODIOR 25 RHODIOR 40
|< 1 < 1 < 1 < 1
|white white white white
|99.99%Rh 99.99%Rh 99.99%Rh 99.99%Rh
|Bright white rhodium coatings with high hardness for jewelry, watches, writing instruments, etc.
|-
|RUTHENIUMBAD
|strongly acidic
|grey/black
|99.0%Ru
|Very hard and luster retaining Ruthenium coating
|-
|PLATINBAD
|strongly acidic
|white
|99.9%Pt
|Jewelry, watches, etc.
|-
|DODUPAL 3
|7.0 - 7.6
|Pd - color
|95%Pd
|Thin Pd/Zn coating as Ni-free diffusion barrier
|-
|DODUPAL 10
|8.0 - 8.5
|white
|80%Pd
|Pd/Zn alloy for jewelry
|-
|DODUPAL 12
|7.0 - 8.0
|white
|95%Pd
|Pd/Zn alloy for decorations
|-
|colspan="5" |'''Silver electrolytes'''
|-
|ARGOL 2000
|11.5 - 12.5
|bright white
|99.9%Ag
|Jewelry, watches, decoration
|}
</figtable>

*Nickel electrolytes Nickel layers are mostly used as diffusion barriers during the gold plating of copper and copper alloys or as an intermediate layer for tinning 

*Bronze electrolytes Bronze coatings – in white or yellow color tones – are used either as an allergy free nickel replacement or as a surface layer for decorative purposes. For technical applications the bronze layers are utilized for their good corrosion resistance and good brazing and soldering properties. 

<figtable id="tab:Typical Electrolytes for the Deposition of Non-Precious Metals">
'''Table 7.4: Typical Electrolytes for the Deposition of Non-Precious Metals'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Range
!Electrolyte temperature [°C]
!Current density [A/dm²]
!Yield [%]
|-
|colspan="5" |'''Copper electrolytes'''
|-
|Cyanide copper
|10 - 13
|40 - 65
|0 .5 - 4
|70-95
|-
|Acidic copper
|<1
|20 - 35
|2 - 8
|<100
|-
|colspan="5" |'''Nickel electrolytes'''
|-
|Watts nickel (Sulfate)
|3 - 5
|40 - 70
|3 - 10
|95-97
|-
|Sulfamate nickel
|3 - 4
|30 - 60
|5 - 20
|95-97
|-
|colspan="5" |'''Tin electrolytes'''
|-
|Acidic tin (Sulfate)
|<1
|18 - 25
|1 - 3
|<100
|-
|Alkaline tin
|>10
|75 - 80
|2 - 17
|max.95
|-
|colspan="5" |'''Bronze electrolytes'''
|-
|DODUBRONCE W
|Strongly alkaline
|55 - 60
|0.5 - 1.5
|
|-
|DODUBRONCE G
|Strongly alkaline
|45 - 50
|2 - 3.5
|
|-
|DODUBRONCE AF
|Strongly alkaline
|58 - 62
|0.5 - 1.5
|
|}
</figtable>

==== Electroplating of Parts====
The complete or all-around electroplating of small mass produced parts like contact springs, rivets, or pins is usually done as mass plating in electroplating barrels of different shape. During the electroplating process the parts are continuously moved and mixed to reach a uniform coating.

Larger parts are frequently electroplated on racks either totally or by different masking techniques also partially. Penetrating the coating into the interior of drilled holes or tubes can be achieved with the use of special fixtures.

'''Electroplated Parts'''

[[File:Electroplated Parts.jpg|left|Electroplated Parts]]

<div class="clear"></div>
*'''Materials'''
{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
!colspan="2" style="text-align:center"|Coatings
|-
|Precious metals
|Pure gold, hard gold (HV 150 – 250), palladium, palladium-nickel, rhodium, pure silver, hard silver (HV 130 – 160)
|-
|Non-precious metals
|Copper, nickel, tin, tin alloys
|-
|Carrier materials
|Copper, copper alloys, nickel, nickel alloys, iron, steel, aluminum, aluminum alloys, composite materials such as aluminum – silicon carbide
|}

*'''Coating thickness'''

{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
|Precious metals:
|0.2 – 5 μm (typical layer thicknesses; for Ag also up to 25 μm)
|-
|Non-precious metals:
|Up to approx. 20 μm
|-
|Tungsten
|0.5 N
|-
|Tolerances:
|Strongly varying depending on the geometrical shape of parts(up to 50% at a defined measuring spot). It is recommended to specify a minimum value for the coating thickness at a defined measuring spot
|}

*'''Quality criteria'''
Besides others the following layer parameters are typically monitored in-process and documented:

*Coating thickness
*Adhesion strength
*Porosity
*Solderability
*Bonding property
*Contact resistance
These quality tests are performed according to industry standards, internal standards, and customer specifications resp.

==== Electroplating of Semi-finished Materials====
The process for overall electroplating of strips, profiles, and wires is mostly performed on continuously operating reel-to-reel equipment. The processing steps for the individual operations such as pre-cleaning, electroplating, rinsing are following the same principles as those employed in parts electroplating.

The overall coating is usually applied for silver plating and tin coating of strips and wires. Compared to hard gold or palladium these deposits are rather ductile, ensuring that during following stamping and forming operations no cracks are generated in the electroplated layers.

==== Selective Electroplating====
Since precious metals are rather expensive it is necessary to perform the electroplating most economically and coat only those areas that need the layers
for functional purposes. This leads from overall plating to selective electroplating of strip material in continuous reel-to-reel processes. Depending
on the final parts design and the end application the processes can be applied to solid strip material as well as pre-stamped and formed continuous strips or utilizing wire-formed or machined pins which have been arranged as bandoliers attached to conductive metal strips.

The core part of selective precious metal electroplating is the actual electroplating cell. In it the anode is arranged closely to the cathodic polarized
material strip. Cathode screens or masks may be applied between the two to focus the electrical field onto closely defined spots on the cathode strip.

Special high performance electrolytes are used in selective electroplating to reach short plating times and allow a high flow rate of the electrolyte for a fast electrolyte exchange in the actual coating area.

For a closely targeted electroplating of limited precious metal coating of contact springs so-called brush-electroplating cells are employed <xr id="fig:Brush Tampon plating cell"/> (Fig. 7.1). The “brush” or “tampon” consists of a roof shaped titanium metal part covered with a special felt-like material. The metal body has holes in defined spots through which the electrolyte reaches the felt. In the same spots is also the anode consisting of a fine platinum net. The pre-stamped and in the contact area pre-formed contact spring part is guided under a defined pressure over the electrolyte soaked felt material and gets wetted with the electrolyte. This allows the metal electroplating in highly selective spots.

<figure id="fig:Brush Tampon plating cell">
[[File:Brush Tampon plating cell.jpg|right|thumb|Brush (or “Tampon”) plating cell; 1 Strip; 2 Anode; 3 Electrolyte feed; 4 Felt covered cell]]
</figure>
For special applications, such as for example electronic component substrates, a dot shaped precious metal coating is required. This is achieved with two belt masks running synchronous to the carrier material. One of these two masks has windows which are open to the spot areas targeted for precious metal plating coverage.

'''Summary of the processes for selective electroplating'''

*'''Immersion electroplating'''
Overall or selective electroplating of both sides of solid strips or pre-stamped parts in strip form

*'''Stripe electroplating'''
Stripe electroplating on solid strips through wheel cells or using masking techniques

*'''Selective electroplating'''
One-sided selective coating of solid, pre-stamped, or metallically belt-linked strips by brush plating

*'''Spot electroplating'''
Electroplating in spots of solid strips with guide holes or pre-stamped parts in strip form

'''Typical examples of electroplated semi-finished materials'''
(overall or selectively)
[[File:Typical examples of electroplated semi finished materials.jpg|left|Typical examples of electroplated semi-finished materials (overall or selectively)]]

<div class="clear"></div>
*'''Materials'''
{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
!Type of Coatings
!Coating Thickness
!Remarks
|-
|colspan="3" |'''Gold electrolytes'''
|-
|Pure gold Hard gold (AuCo 0.3)
|0.1 - 3 μm
|In special cases up to 10 μm
|-
|Palladium-nickel (PdNi20)
|0.1 - 5 μm
|Frequently with additional 0.2 μm AuCo 0.3
|-
|Silver
|0.5 - 10 μm
|In special cases up to 40 μm
|-
|colspan="3" |'''Non-precious Metals'''
|-
|Nickel
|0.5 - 4 μm
|Diffusion barrier especially for gold layers
|-
|Copper
|1 - 5 μm
|Intermediate layer used in tinning of CuZn
|-
|Tin, tin alloys
|0.8 - 25 μm
|materials
|}

*'''Carrier Materials'''
Copper, copper alloys, nickel, nickel alloys, stainless steel

*'''Dimensions and Tolerances'''

[[File:Dimensions and Tolerances.jpg|left|Dimensions and Tolerances]]

*'''Tolerances'''

{| class="twocolortable" style="text-align: left; font-size: 12px;width:30%"
|-
|Coating thickness approx.
|± 10 %
|-
|Coating thickness and position
|± 0,5 mm
|}

*'''Quality Criteria'''
Mechanical properties and dimensional tolerances of the carrier materials follow the typical standards, i.e. DIN EN 1652 and 1654 for copper and copper alloys. Depending on the application the following parameters are tested and recorded (see also: Electroplating of parts):

*Coating thickness *Solderability
*Adhesion strength *Bonding property
*Porosity *Contact resistance

These quality tests are performed according to industry standards, internal standards, and customer specifications resp.

==References==
[[Surface Coating Technologies#References|References]]

Electroplating (or Galvanic Deposition)

2014-04-10T11:16:43Z

80.152.203.11: /* Selective Electroplating */

==== Electroplating Solutions – Electrolytes====
The actual metal deposition occurs in the electrolytic solution which contains the plating material as metal ions. Besides this basic ingredient, the electrolytes contain additional components depending on the processes used, such as for example conduction salts, brighteners, and organic additives which are codeposited into the coatings, influencing the final properties of the electroplating deposit.

===== Precious Metal Electrolytes=====
All precious metals can be electroplated with silver and gold by far the most widely used ones <xr id="tab:Precious Metal Electrolytes for Technical Applications"/> (Tab. 7.2) and <xr id="tab:Precious Metal Electrolytes for Decorative Applications"/> (Tab. 7.3).
The following precious metal electrolytes are the most important ones:

*Gold electrolytes For functional and decorative purposes pure gold, hard gold, low-karat gold, or colored gold coatings are deposited. Depending on the requirements, acidic, neutral, or cyanide electrolytes based on potassium gold cyanide or cyanide free and neutral electrolytes based on gold sulfite complexes are used. 

*Palladium and Platinum electrolytes Palladium is mostly deposited as a pure metal, for applications in electrical contacts however also as palladium nickel. For higher value jewelry allergy protective palladium intermediate layers are used as a diffusion barrier over copper alloy substrate materials. Platinum is mostly used as a surface layer on jewelry items. 

*Ruthenium electrolytes Ruthenium coatings are mostly used for decorative purposes creating a fashionable “grey” ruthenium color on the surface. An additional color variation is created by using “ruthenium-black” deposits which are mainly used in bi-color decorative articles. 

*Rhodium electrolytes Rhodium deposits are extremely hard (HV 700 – 1000) and wear resistant. They also excel in light reflection. Both properties are of value for technical as well as decorative applications. While technical applications mainly require hard, stress and crack free coatings, the jewelry industry takes advantage of the light whitish deposits with high corrosion resistance. 

*Silver electrolytes Silver electrolytes without additives generate dull soft deposits (HV ~ 80) which are mainly used as contact layers on connectors with limited insertion and withdrawal cycles. Properties required for decorative purposes such as shiny bright surfaces and higher wear resistance are achieved through various additives to the basic Ag electrolyte. 

<figtable id="tab:Precious Metal Electrolytes for Technical Applications">
'''Table 7.2: Precious Metal Electrolytes for Technical Applications'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Range
!colspan="2" style="text-align:center"|Deposit Properties Hardness
!Areas of Application
|-
!
!
!HV
!Purity [kt]
!
|-
|colspan="5" |'''Gold electrolytes'''
|-
|AUROMET TN
|3.2 - 4.2
|ca. 70
|99.99% Au
|Base-deposits
|-
|AUROMET XPH
|0.3 - 0.6
|160 - 180
|99.8% Au
|Base-deposits for stainless steel etc.
|-
|DODUREX COC
|4.6 - 4.9
|160 - 180
|99.6% Au
|Printed circuit boards, connectors, contact parts, etc.; hard gold coatings for rack and barrel plating
|-
|DODUREX HS 100
|4.3 - 4.6
|160 - 180
|99.6% Au
|High speed process for connectors and PCB plating
|-
|PURAMET 202 PURAMET 402
|5.5 - 6.5 7.0 - 7.5
|60 - 80 60 - 80
|99.99% Au 99.99% Au
|High purity gold coatings for electrical and electronic parts incl. semi conductors and PCBs; for demanding requirement on bonding properties
|-
|colspan="5" |'''Platinum metal electrolytes'''
|-
|RHODOPLAT T
|strongly acidic
|900
|99.0% Rh
|Ductile rhodium deposits for thicker layers, reed contacts, sliding contacts
|-
|RUTHENIUMBAD
|stronglyacidic
|900
|99.0% Ru
|Crack free thick ruthenium deposits
|-
|PLATINBAD 5
|stronglyacidic
|240 - 260
|99.9% Pt
|High temperature switching devices, etc
|-
|DODUPAL 3
|7.0 - 8.0
|220 - 250
|99.9% Pd
|Thin palladium layers as diffusion barrier
|-
|DODUPAL 5
|7.0 - 8.0
|220 - 250
|99.9% Pd
|Connectors and contact parts
|-
|DODUPAL 10
|8.0 - 8.5
|350 - 400
|80.0% Pd
|Pd/Ni for connectors and contact parts
|-
|colspan="5" |'''Silver electrolytes'''
|-
|ARGOL 30
|cyanidebased
|a pprox. 90
|99.9% Ag
|rowspan="4" |Contact parts, connectors
|-
|ARGOL HS 100
|approx. 9.0
|90 - 120
|99.9% Ag
|-
|ARGOL 2000
|approx. 12.0
|
|
|-
|ARGOL 400
|
|160 - 180
|
|}
</figtable>

=====7.1.1.1.2 Non-Precious Metal Electrolytes=====

The most important non-precious metals that are deposited by electroplating are: Copper, nickel, tin, and zinc and their alloys. The deposition is performed in the form of pure metals with different electrolytes used <xr id="tab:Typical Electrolytes for the Deposition of Non-Precious Metals"/>(Table 7.4).

*Copper electrolytes Copper electrolytes are used for either depositing an intermediate layer on strips or parts, for building up a printed circuit board structure, or for the final strengthening during the production of printed circuit boards. 

*Tin electrolytes Pure tin and tin alloy deposits are used as dull or also bright surface layers on surfaces required for soldering. In the printed circuit board manufacturing they are also utilized as an etch resist for the conductive pattern design after initial copper electroplating. 

<figtable id="tab:Precious Metal Electrolytes for Decorative Applications">
'''Table 7.3: Precious Metal Electrolytes for Decorative Applications'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Bereich
!colspan="2" style="text-align:center"|Deposit Properties
!Areas of Application
|-
!
!
!Hardness HV
!Purity [kt]
!
|-
|colspan="5" |'''Gold electrolytes'''
|-
|DURAMET 1N14 DURAMET 2N18 DURAMET 3N DURAMET 265S DURAMET 333S DURAMET 386S
|3.4 - 3.8 3.4 - 3.8 3.4 - 3.8 3.4 - 3.8 3.2 - 3.6 3.4 - 3.8
|1N 2N 3N Hamilton 1N Hamilton
|23 23 23 23 23 23
|Jewelry, watches, writing instruments, frames for glasses, fixtures
|-
|HELODOR 630
|8.5 - 9.5
|rose colored
|22
|Frames for glasses, jewelry, watches, writing instruments
|-
|DODUPLAT Y18 DODUPLAT Y18HS
|9.5 - 10.5 9.5 - 11
|2N 2N
|18 16
|Jewelry, watches, writing instruments
|-
|AUROMET TN AUROMET 2 AUROMET 4
|3.2 - 4.2 3.2 - 4.0 3.2 - 4.2
|Pure Gold 2 - 3N 2 - 3N
|23 23 23
|Colored gold for jewelry, watches, writing instruments, fixtures, frames for glasses, etc.
|-
|colspan="5" |'''Platinum metal electrolytes'''
|-
|RHODIOR 2 RHODIOR 20 RHODIOR 25 RHODIOR 40
|< 1 < 1 < 1 < 1
|white white white white
|99.99%Rh 99.99%Rh 99.99%Rh 99.99%Rh
|Bright white rhodium coatings with high hardness for jewelry, watches, writing instruments, etc.
|-
|RUTHENIUMBAD
|strongly acidic
|grey/black
|99.0%Ru
|Very hard and luster retaining Ruthenium coating
|-
|PLATINBAD
|strongly acidic
|white
|99.9%Pt
|Jewelry, watches, etc.
|-
|DODUPAL 3
|7.0 - 7.6
|Pd - color
|95%Pd
|Thin Pd/Zn coating as Ni-free diffusion barrier
|-
|DODUPAL 10
|8.0 - 8.5
|white
|80%Pd
|Pd/Zn alloy for jewelry
|-
|DODUPAL 12
|7.0 - 8.0
|white
|95%Pd
|Pd/Zn alloy for decorations
|-
|colspan="5" |'''Silver electrolytes'''
|-
|ARGOL 2000
|11.5 - 12.5
|bright white
|99.9%Ag
|Jewelry, watches, decoration
|}
</figtable>

*Nickel electrolytes Nickel layers are mostly used as diffusion barriers during the gold plating of copper and copper alloys or as an intermediate layer for tinning 

*Bronze electrolytes Bronze coatings – in white or yellow color tones – are used either as an allergy free nickel replacement or as a surface layer for decorative purposes. For technical applications the bronze layers are utilized for their good corrosion resistance and good brazing and soldering properties. 

<figtable id="tab:Typical Electrolytes for the Deposition of Non-Precious Metals">
'''Table 7.4: Typical Electrolytes for the Deposition of Non-Precious Metals'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Type of Electrolyte
!pH-Range
!Electrolyte temperature [°C]
!Current density [A/dm²]
!Yield [%]
|-
|colspan="5" |'''Copper electrolytes'''
|-
|Cyanide copper
|10 - 13
|40 - 65
|0 .5 - 4
|70-95
|-
|Acidic copper
|<1
|20 - 35
|2 - 8
|<100
|-
|colspan="5" |'''Nickel electrolytes'''
|-
|Watts nickel (Sulfate)
|3 - 5
|40 - 70
|3 - 10
|95-97
|-
|Sulfamate nickel
|3 - 4
|30 - 60
|5 - 20
|95-97
|-
|colspan="5" |'''Tin electrolytes'''
|-
|Acidic tin (Sulfate)
|<1
|18 - 25
|1 - 3
|<100
|-
|Alkaline tin
|>10
|75 - 80
|2 - 17
|max.95
|-
|colspan="5" |'''Bronze electrolytes'''
|-
|DODUBRONCE W
|Strongly alkaline
|55 - 60
|0.5 - 1.5
|
|-
|DODUBRONCE G
|Strongly alkaline
|45 - 50
|2 - 3.5
|
|-
|DODUBRONCE AF
|Strongly alkaline
|58 - 62
|0.5 - 1.5
|
|}
</figtable>

==== Electroplating of Parts====
The complete or all-around electroplating of small mass produced parts like contact springs, rivets, or pins is usually done as mass plating in electroplating barrels of different shape. During the electroplating process the parts are continuously moved and mixed to reach a uniform coating.

Larger parts are frequently electroplated on racks either totally or by different masking techniques also partially. Penetrating the coating into the interior of drilled holes or tubes can be achieved with the use of special fixtures.

'''Electroplated Parts'''

[[File:Electroplated Parts.jpg|left|Electroplated Parts]]

<div class="clear"></div>
*'''Materials'''
{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
!colspan="2" style="text-align:center"|Coatings
|-
|Precious metals
|Pure gold, hard gold (HV 150 – 250), palladium, palladium-nickel, rhodium, pure silver, hard silver (HV 130 – 160)
|-
|Non-precious metals
|Copper, nickel, tin, tin alloys
|-
|Carrier materials
|Copper, copper alloys, nickel, nickel alloys, iron, steel, aluminum, aluminum alloys, composite materials such as aluminum – silicon carbide
|}

*'''Coating thickness'''

{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
|Precious metals:
|0.2 – 5 μm (typical layer thicknesses; for Ag also up to 25 μm)
|-
|Non-precious metals:
|Up to approx. 20 μm
|-
|Tungsten
|0.5 N
|-
|Tolerances:
|Strongly varying depending on the geometrical shape of parts(up to 50% at a defined measuring spot). It is recommended to specify a minimum value for the coating thickness at a defined measuring spot
|}

*'''Quality criteria'''
Besides others the following layer parameters are typically monitored in-process and documented:

*Coating thickness
*Adhesion strength
*Porosity
*Solderability
*Bonding property
*Contact resistance
These quality tests are performed according to industry standards, internal standards, and customer specifications resp.

==== Electroplating of Semi-finished Materials====
The process for overall electroplating of strips, profiles, and wires is mostly performed on continuously operating reel-to-reel equipment. The processing steps for the individual operations such as pre-cleaning, electroplating, rinsing are following the same principles as those employed in parts electroplating.

The overall coating is usually applied for silver plating and tin coating of strips and wires. Compared to hard gold or palladium these deposits are rather ductile, ensuring that during following stamping and forming operations no cracks are generated in the electroplated layers.

==== Selective Electroplating====
Since precious metals are rather expensive it is necessary to perform the electroplating most economically and coat only those areas that need the layers
for functional purposes. This leads from overall plating to selective electroplating of strip material in continuous reel-to-reel processes. Depending
on the final parts design and the end application the processes can be applied to solid strip material as well as pre-stamped and formed continuous strips or utilizing wire-formed or machined pins which have been arranged as bandoliers attached to conductive metal strips.

The core part of selective precious metal electroplating is the actual electroplating cell. In it the anode is arranged closely to the cathodic polarized
material strip. Cathode screens or masks may be applied between the two to focus the electrical field onto closely defined spots on the cathode strip.

Special high performance electrolytes are used in selective electroplating to reach short plating times and allow a high flow rate of the electrolyte for a fast electrolyte exchange in the actual coating area.

For a closely targeted electroplating of limited precious metal coating of contact springs so-called brush-electroplating cells are employed <xr id="fig:Brush Tampon plating cell"/> (Fig. 7.1). The “brush” or “tampon” consists of a roof shaped titanium metal part covered with a special felt-like material. The metal body has holes in defined spots through which the electrolyte reaches the felt. In the same spots is also the anode consisting of a fine platinum net. The pre-stamped and in the contact area pre-formed contact spring part is guided under a defined pressure over the electrolyte soaked felt material and gets wetted with the electrolyte. This allows the metal electroplating in highly selective spots.

<figure id="fig:Brush Tampon plating cell">
[[File:Brush Tampon plating cell.jpg|right|thumb|Brush (or “Tampon”) plating cell; 1 Strip; 2 Anode; 3 Electrolyte feed; 4 Felt covered cell]]
</figure>
For special applications, such as for example electronic component substrates, a dot shaped precious metal coating is required. This is achieved with two belt masks running synchronous to the carrier material. One of these two masks has windows which are open to the spot areas targeted for precious metal plating coverage.

'''Summary of the processes for selective electroplating'''

*'''Immersion electroplating'''
Overall or selective electroplating of both sides of solid strips or pre-stamped parts in strip form

*'''Stripe electroplating'''
Stripe electroplating on solid strips through wheel cells or using masking techniques

*'''Selective electroplating'''
One-sided selective coating of solid, pre-stamped, or metallically belt-linked strips by brush plating

*'''Spot electroplating'''
Electroplating in spots of solid strips with guide holes or pre-stamped parts in strip form

'''Typical examples of electroplated semi-finished materials'''
(overall or selectively)
[[File:Typical examples of electroplated semi finished materials.jpg|left|Typical examples of electroplated semi-finished materials (overall or selectively)]]

<div class="clear"></div>
*'''Materials'''
{| class="twocolortable" style="text-align: left; font-size: 12px;width:70%"
|-
!Type of Coatings
!Coating Thickness
!Remarks
|-
|colspan="3" |'''Gold electrolytes'''
|-
|Pure gold Hard gold (AuCo 0.3)
|0.1 - 3 μm
|In special cases up to 10 μm
|-
|Palladium-nickel (PdNi20)
|0.1 - 5 μm
|Frequently with additional 0.2 μm AuCo 0.3
|-
|Silver
|0.5 - 10 μm
|In special cases up to 40 μm
|-
|colspan="3" |'''Non-precious Metals'''
|-
|Nickel
|0.5 - 4 μm
|Diffusion barrier especially for gold layers
|-
|Copper
|1 - 5 μm
|Intermediate layer used in tinning of CuZn
|-
|Tin, tin alloys
|0.8 - 25 μm
|materials
|}

*'''Carrier Materials'''
Copper, copper alloys, nickel, nickel alloys, stainless steel

*'''Dimensions and Tolerances'''

[[File:Dimensions and Tolerances.jpg|left|Dimensions and Tolerances]]

*'''Tolerances'''

{| class="twocolortable" style="text-align: left; font-size: 12px;width:30%"
|-
|Coating thickness approx.
|± 10 %
|-
|Coating thickness and position
|± 0,5 mm
|}

*'''Quality Criteria'''
Mechanical properties and dimensional tolerances of the carrier materials follow the typical standards, i.e. DIN EN 1652 and 1654 for copper and copper alloys. Depending on the application the following parameters are tested and recorded (see also: Electroplating of parts):

*Coating thickness *Solderability
*Adhesion strength *Bonding property
*Porosity *Contact resistance

These quality tests are performed according to industry standards, internal standards, and customer specifications resp.

==References==
[[Surface Coating Technologies#References|References]]

Contact Materials for Electrical Engineering

2014-04-10T09:38:59Z

80.152.203.11:

The contact parts are important components in switching devices. They have to maintain their function from the new state until the end of the functional life of the devices.

The requirements on contacts are rather broad. Besides typical contact properties such as

*High arc erosion resistance
*High resistance against welding
*Low contact resistance
*Good arc moving properties
*Good arc extinguishing capability

they have to exhibit physical, mechanical, and chemical properties like high electrical and thermal conductivity, high hardness, high corrosion resistance, etc and besides this should have good mechanical workability, and also be suitable for good weld and brazing attachment to contact carriers. In addition they must be made from environmentally friendly materials.

Materials suited for use as electrical contacts can be divided into the following groups based on their composition and metallurgical structure:

*Pure metals
*Alloys
*Composite materials

*'''Pure metals'''

From this group silver has the greatest importance for switching devices in the higher energy technology. Other precious metals such as gold and platinum are only used in applications for the information technology in the form of thin surface layers. As a nonprecious metal tungsten is used for some special applications such as for example as automotive horn contacts. In some rarer cases pure copper is used but mainly paired to a silver-based contact material.

*'''Alloys'''

Besides these few pure metals a larger number of alloy materials made by melt technology are available for the use as contacts. An alloy is characterized by the fact that its components are completely or partially soluble in each other in the solid state. Phase diagrams for multiple metal compositions show the number and type of the crystal structure as a function of the temperature and composition of the alloying components.

They indicate the boundaries of liquid and solid phases and define the parameters of solidification.
Alloying allows to improve the properties of one material at the cost of changing them for the second material. As an example, the hardness of a base metal may be increased while at the same time the electrical conductivity decreases with even small additions of the second alloying component.

*'''Composite Materials'''

Composite materials are a material group whose properties are of great importance for electrical contacts that are used in switching devices for higher
electrical currents.

Those used in electrical contacts are heterogeneous materials composed of two or more uniformly dispersed components in which the largest volume portion consists of a metal.

The properties of composite materials are determined mainly independent from each other by the properties of their individual components. Therefore it is for example possible to combine the high melting point and arc erosion resistance of tungsten with the low melting and good electrical conductivity of copper, or the high conductivity of silver with the weld resistant metalloid graphite. <xr id="fig:fig2.1"/> shows the schematic manufacturing processes from powder blending to contact material. Three basic process variations are typically
applied:

*Sintering without liquid phase (Press-Sinter-Repress, PSR)
*Sintering with liquid phase
*Infiltration (Press-Sinter-Infiltrate, PSI)

<figure id="fig:fig2.1">
[[File:Powder metallurgical manufacturing of composite materials (schematic).jpg|thumb|<caption>Powder-metallurgical manufacturing of composite materials (schematic) Ts = Melting point of the lower melting component)</caption>]]
</figure>

During ''sintering without a liquid phase'' (left side of schematic) the powder mix is first densified by pressing, then undergoes a heat treatment (sintering), and eventually is re-pressed again to further increase the density. The sintering atmosphere depends on the material components and later application; a vacuum is used for example for the low gas content material Cu/Cr. This process is used for individual contact parts and also termed press-sinterrepress (PSR). For materials with high silver content the starting point at pressing is most a larger block (or billet) which is then after sintering hot extruded into wire, rod, or strip form. The extrusion further increases the density of these composite materials and contributes to higher arc erosion resistance. Materials such as Ag/Ni, Ag/MeO, and Ag/C are typically produced by this process.

''Sintering with liquid phase'' has the advantage of shorter process times due to the accelerated diffusion and also results in near-theoretical densities of the composite material. To ensure the shape stability during the sintering process it
is however necessary to limit the volume content of the liquid phase material.

As opposed to the liquid phase sintering which has limited use for electrical contact manufacturing, the ''Infiltration process'' as shown on the right side of the schematic has a broad practical range of applications. In this process the powder of the higher melting component sometimes also as a powder mix with a small amount of the second material is pressed into parts and after sintering the porous skeleton is infiltrated with liquid metal of the second material. The filling up of the pores happens through capillary forces. This process reaches after the infiltration near-theoretical density without subsequent pressing and is widely used for Ag- and Cu-refractory contacts. For Ag/W or Ag/WC contacts, controlling the amount or excess on the bottom side of the contact of the infiltration metal Ag results in contact tips that can be easily attached to their carriers by resistance welding. For larger Cu/W contacts additional machining is often used to obtain the final shape of the contact component.

==Gold Based Materials==

Pure Gold is besides Platinum the chemically most stable of all precious metals. In its pure form it is not very suitable for use as a contact material in electromechanical devices because of its tendency to stick and cold-weld at even low contact forces. In addition it is not hard or strong enough to resist mechanical wear and exhibits high materials losses under electrical arcing loads. This limits its use in form of thin electroplated or vacuum deposited layers.

Main Article: [[Gold Based Materials| Gold Based Materials]]

==Platinum Metal Based Materials==

The platinum group metals include the elements Pt, Pd, Rh, Ru, Ir, and Os (Table 2.6). For electrical contacts platinum and palladium have practical significance as base alloy materials and ruthenium and iridium are used as alloying components. Pt and Pd have similar corrosion resistance as gold but because of their catalytical properties they tend to polymerize adsorbed organic vapors on contact surfaces. During frictional movement between contact surfaces the polymerized compounds known as “brown powder” are formed which can lead to significantly increase in contact resistance. Therefore Pt and Pd are typically used as alloys and not in their pure form for electrical contact applications.

Main Article: [[Platinum Metal Based Materials| Platinum Metal Based Materials]]

==Silver Based Materials==
Pure Silver, Silver Alloys, Silver Composite Materials

Main Article: [[Silver Based Materials| Silver Based Materials]]

==Tungsten and Molybdenum Based Materials==

Tungsten and Molybdenum (Pure Metals), Silver–Tungsten (SIWODUR) Materials, Silver–Tungsten Carbide (SIWODUR C) Materials, Silver–Molybdenum (SILMODUR) Materials, Copper–Tungsten (CUWODUR) Materials

Main Article: [[Tungsten and Molybdenum Based Materials| Tungsten and Molybdenum Based Materials]]

==Special Contact Materials (VAKURIT) for Vacuum Switches==

Low Gas Content Materials Based on Refractory Metals, Low Gas Content Materials Based on Copper-Chromium

Main Article: [[Special Contact Materials (VAKURIT) for Vacuum Switches| Special Contact Materials (VAKURIT) for Vacuum Switches]]

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Manufacturing Equipment for Semi-Finished Materials
(Bild)

Contact Carrier Materials

2014-03-25T10:03:02Z

80.152.203.11: /* 5.2.2 Nickel Alloys */

The reliability and electrical life of contact systems in switching devices as well as in electromechanical and electronic components do not only depend on the contact material. The selection of the most suitable carrier material also plays an important role.

The most frequently used ones are copper based materials. Depending on the application also materials based on nickel or multi-layer composite materials,
such as thermo bimetals for example, are frequently used. For special applications in the medium and high voltage technology, as well as for springs
and snap discs for the information technology, iron or steel based materials are considered. These are however not included for the purpose of this data book.

Various requirements based on the enduse of the contact components have to be met by carrier materials. Copper materials have to exhibit high electrical and thermal conductivity, good mechanical strength even at elevated temperatures, and in addition a sufficient high resistance against corrosion. If used as springs the carrier materials also must have good elastic spring properties. Besides these, the materials must, depending on the manufacturing processes employed, also have good technological properties like ductility to allow warm and cold forming, suitability for cutting and stamping, and be capable to be welded, brazed or coated by electroplating.

==5.1 Copper and Copper Alloys==

===Standards Overview===

Copper and copper alloys to be used in electrical and electronic components are usually covered by national and international standards. DIN numbers the
materials by a prefix and/or a material number. The newer European standards (EN) refer to the material's usage products and also show a prefix and material number. For reference we also show in <xr id="tab:MaterialDesignations"/> the material designation according to UNS, the Unified Numbering System (USA). Other internationally used standard and material numbers include, among others, those issued by CDA (Copper Development Association, USA), and GB (Guo Biao – China).

The most important EN as well as the US based and widely used ASTM standards covering the use of flat rolled copper and copper alloys in electrical contacts are:

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Standard Designation
!Description
|-
|DIN EN 1652
|Copper and copper alloys in plate, sheet, strip, and discs for general applications
|-
|DIN EN 1654
|Copper and copper alloys for springs and connectors
|-
|DIN EN 1758
|Copper and copper alloys in strip form for system component carriers
|-
|ASTM B 103/B103M-10 ||Spec. for Phosphor Bronce Plate, Sheet, Strip, and Rolled Bar
|-
|ASTM B 36/B36M-95 || Spec. for Brass Plate, Sheet, Strip, and Rolled Bar
|-
|ASTM B 122/B122M-08 || Spec. for CuNiSn-, CuNiZn-, and CuNi-Alloy
|-
|ASTM B 465-09 || Spec. for Copper-Iron-Alloy Plate, Sheet, and Strip
|-
|ASTM B 194-08 || Standard Spec. for CuBe-Alloy Plate, Sheet, Strip and Rolled Bar
|-
|ASTM B 534-07 || Sec. for CuCoBe-Alloy and CuNiBe-Alloy Plate, Sheet, Strip, and Rolled Bar
|}
The above DIN EN standards replace in part or completely the older DIN standards DIN 1777,
DIN 17670, DIN 1751, DIN 1791.

===5.1.2 Pure Copper===

Copper is used in electrical engineering mostly because of its high electrical conductivity<ref>As units for electrical conductivity MS/m and m/Ω.mm2 are commonly used. Frequently – and mostly in North America – the % IACS value (International Annealed Copper Standard) is also used, where 100% is equivalent to 58 MS/m or m/Ωmm2 .For the description of mechanical strength properties the units of N/mm2 or MPa are most commonly used:
1 MS/m = 1 m/Ωmm2
1 MPa = 1 N/mm2</ref> which with 58 MS/m (or m/Ωmm²) is only slightly below that of silver. Other advantages of copper are its high thermal conductivity, corrosion resistance, and its good ductility. The work hardening properties of ETP copper is illustrated in <xr id="fig:Strain hardening of Cu-ETP by cold working" />. The increase in strength achieved by cold working can be reversed easily by subsequent annealing. The softening properties are strongly dependent on the preceding cold working percentage ''(<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working"/> and <xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working"/> 5.3)''.

The purity of technically pure and un-alloyed copper used for electrical applications depends on the type used and ranges between > 99.90 and 99.95
wt%. The copper types are designated mainly by their oxygen content as oxygen containing, oxygen-free, and de-oxidized with phosphorus as
described in DIN EN 1652 ''(<xr id="tab:MaterialDesignations"/> and <xr id="tab:tab5.2"/> 5.2)''. <xr id="tab:tab5.3"/> Tables 5.3. and <xr id="tab:tab5.4"/> 5.4 show the physical and mechanical properties of these copper materials. According to these, Cu-ETP, Cu-OFE, and Cu-HCP are the types of copper for which minimum values for the electrical conductivity are guaranteed.

Cu-ETP is less suitable for welding or for brazing in reducing atmosphere because of the oxygen content (danger of hydrogen embrittlement).

Cu-HCP, Cu-DLP, and Cu-DHP are oxygen free copper types de-oxidized with different phosphorus contents. With increasing phosphorus content the
electrical conductivity decreases. Cu-OFE, also called OFHC copper, is free of oxygen and also free of de-oxidizing compounds.

<figtable id="tab:MaterialDesignations">
'''Table 5.1: Material Designations of Some Copper Types'''

<table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse">
<caption> Material Designations of Some Copper Types</caption>
<tr>
<th>WerkstMaterialEN-Designation</th><th>EN-Number</th><th>DIN-Designation</th><th>DIN-Number</th><th>UNS</th></tr>
<tr><td>Cu-ETP</td><td>CW004A</td><td>E-Cu 58</td><td>2.0065</td><td>C11000</td></tr>
<tr><td>Cu-OF</td><td>CW008A</td><td>OF-Cu</td><td>2.0040</td><td>C10200</td></tr>
<tr><td>Cu-HCP</td><td>CW021A</td><td>SE-Cu</td><td>2.0070</td><td>C10300</td></tr>
<tr><td>Cu-DLP</td><td>CW023A</td><td>SW-Cu</td><td>2.0076</td><td>C12000</td></tr>
<tr><td>Cu-DHP</td><td>CW024A</td><td>F-Cu</td><td>2.0090</td><td>C12200</td></tr>
</table>

</figtable>

<div class="small">
:Cu- ETP: electrolytic tough-pitch copper
:Cu-OFE: Oxygen Free Electronic Copper
:Cu-HCP: High Conductivity Phosphorus Deoxidized Copper
:Cu-DLP: phosphorous-deoxidized copper
:Cu-DHP: Phosphorous Deoxidized High Conductivity Copper
</div>

<figtable id="tab:tab5.2">
'''Table 5.2: Composition of Some Pure Copper Types'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material
!colspan="6" style="text-align:center"| Composition (wt%)
|-
!EN Designation
!Cu
!Bi
!O
!P
!Pb
!Others
|-
|Cu-ETP
|>99.90
|bis 0.0005
|bis 0.040
|
|up to 0.005
|up to 0.03
|-
|Cu-OF
|>99.95
|bis 0.0005
|
|
|up to 0.005
|up to 0.03
|-
|Cu-HCP
|>99.90
|
|
|ca. 0.003
|
|
|-
|Cu-DLP
|>99.90
|bis 0.005
|
|0.005-0.013
|up to 0.005
|up to 0.03
|-
|Cu-DHP
|>99.90
|
|
|0.015-0.040
|
|
|}
</figtable>

<figtable id="tab:tab5.3">
'''Table 5.3: Physical Properties of Some Copper Types'''

<table class="twocolortable">
<tr><th>Material</th><th >Density</th><th colspan="2">ElectricalConductivityt</th><th >Electrical Conductivity</th><th>ThermalConductivity</th>
<th>Coeff. ofLinear Thermal Expansion</th>
<th>ModulusofElasticity</th><th>SofteningTemperatur (approx.10% loss in strength)</th><th>MeltingTemperature</th></tr>
<tr><th>EN- Designation</th>
<th >[g/cm³]</th><th>[MS/m]</th><th>[% IACS]</th><th>[μΩ· cm]</th><th>[W/(m· K)]</th>
<th>[10-6/K]</th><th>[GPa]</th><th>[°C]</th><th>[°C]</th></tr>
<tr><td>Cu-ETP</td><td>8.94</td>
<td>≥58</td>
<td>100</td><td>1.72</td><td>390</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-OF</td><td>8.94</td><td>≥58</td><td>100</td><td>1.72</td><td>394</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-HCP</td><td>8.94</td><td>≥54</td><td>93</td><td>1.85</td><td>380</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-DLP</td><td>8.94</td><td>52</td><td>90</td><td>1.92</td><td>350</td><td>17.7</td><td>132</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-DHP</td><td>8.94</td><td>≥46</td><td>80</td><td>2.17</td><td>310</td><td>17.6</td><td>132</td><td>ca. 220</td><td>1083</td></tr></table>
</figtable>

<figtable id="tab:tab5.4">
'''Table 5.4: Mechanical Properties of Some Copper Types'''
<table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse">

<tr>

<th>Material</th><th>Condition</th><th>Tensile StrengthRm[MPa]</th><th>0,2% YieldStrength Rp0,2[MPa]</th><th>ElongationA50[ %]</th><th>HardnessHV</th>
</tr><tr>
<td class="multirow" rowspan="4">
Cu-ETP Cu-OF Cu-HCP Cu-DLP Cu-DHP</td>
<td>R220</td><td>220 - 260</td>
<td>≤140</td><td>≥33</td><td>40 - 65</td>
</tr><tr>
<td>R240</td><td>240 - 300</td>
<td>≥180</td>
<td>≥8</td><td>65 - 95</td>
</tr><tr>
<td>R290</td><td>290 - 360</td><td>≥250</td><td>≥4</td><td>90 - 110</td>
</tr><tr>
<td>R360</td><td>≥360</td><td>≥320</td><td>≥2</td>
<td>≥110</td></tr>
</table>
</figtable>

<xr id="fig:Strain hardening of Cu-ETP by cold working"/> Fig. 5.1: Strain hardening of Cu-ETP by cold working

<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working"/> Fig. 5.2: Softening of Cu-ETP after annealing for 3hrs after 25% cold working

<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working"/> Fig. 5.3: Softening of Cu-ETP after annealing for 3hrs after 50% cold working

<div class="multiple-images">

<figure id="fig:Strain hardening of Cu-ETP by cold working">
[[File:Strain hardening of Cu ETP by cold working.jpg|left|thumb|<caption>Strain hardening of Cu-ETP by cold working</caption>]]
</figure>

<figure id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working">
[[File:Softening of Cu ETP after annealing.jpg|left|thumb|<caption>Softening of Cu-ETP after annealing for 3hrs after 25% cold working</caption>]]
</figure>

<figure id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working">
[[File:Softening of Cu ETP after annealing 50.jpg|left|thumb|<caption>Softening of Cu-ETP after annealing for 3hrs after 50% cold working</caption>]]
</figure>
</div>
<div class="clear"></div>

===5.1.3 High Cu Content Copper Alloys===

The high Cu content alloy materials are closest in their properties to pure copper materials. By defined addition of small amounts of alloying elements it is possible to increase the mechanical strength and especially the softening temperature of copper and at the same time decrease the electrical conductivity only insignificantly <xr id="fig:Influence of small additions on the electrical conductivity of copper"/> (Fig. 5.4). Silver, iron, tin, zinc, nickel, chromium, zirconium, silicon, and titanium are used. Usually the additive amounts are significantly below 3 wt%. This group of materials consists of mixed crystal as well as precipitation hardening alloys. The precipiytion hardening copper-beryllium and copper-chromium-zirconium materials are decribed later in a separate section.

<figure id="fig:Influence of small additions on the electrical conductivity of copper">
[[File:Influence of small additions on the electrical conductivity of copper.jpg|right|thumb|Influence of small additions on the electrical conductivity of copper]]
</figure>

From the large number of high-Cu alloys only the properties of selected ones are covered here <xr id="tab:tab5.5"/> (Tab. 5.5) and <xr id="tab:tab5.6"/> (Tab. 5.6). Some of these materials are not included in the EN standards system.

The low alloyed materials CuAg0.1 and CuCd1 are mostly used as overhead drive cables where they have to meet sustained loads at elevated temperatures without softening.

The materials CuFe0.1 and CuSn0.15 have a high electrical conductivity. The mechanical strength of both is relatively low but stays almost constant at temperatures up to 400°C. The are used as substrates for power semiconductors and also as carriers for stationary contacts in higher energy
switchgear.

CuFe2 is a material exhibiting high electrical conductivity and good formability. During an annealing process Fe-rich precipitations are formed in the " -Cu matrix which change the mechanical properties very little but increase the electrical conductivity significantly. Besides being used as a contact carrier material in switching devices, this material has broader applications in automotive connectors and as a substrate in the semiconductor technology.

CuNi2Si has high mechanical strength, good formability, and at the same time high electrical conductivity. This combination of advantageous properties is achieved by a defined finely dispersed precipitation of nickel silicides. CuNi2Si is used mainly in the form of stamped and formed parts in thermally stressed electromechanical components for automotive applications.

CuSn1CrNiTi and CuCrSiTi are advanced developments of the Cu-Cr-Ti precipitation materials with fine intermetallic dispersions. The material
CuNi1Co1Si also belongs into this family and has properties similar to the low alloyed CuBe materials.

<figtable id="tab:tab5.5">
'''Tab. 5.5 Physical Properties of Selected High Cu Content Copper Alloys'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material/ Designation EN UNS
!Composition
!Density [g/cm3]
!colspan="2" style="text-align:center"|Electrical Conductivity [MS/m] [% IACS]
!Electrical Resistivity [μΩ·cm]
!Thermal Conductivity [W/(m·K)]
!Coeff. of Linear Thermal Expansion [10-6/K]
!Modulus of Elasticity [GPa]
!Softening Temperature (approx. 10% loss in strength) [°C]
!Melting Temp Range [°C]
|-
|CuAg 0,1 CW 013A
|Ag 0.08-0.12 Cu Rest
|8.89
|56
|97
|1.8
|380
|17.7
|126
|
|1082
|-
|CuFe0,1P not standardized C19210
|Fe 0.05-0.015 P 0.025-0.04 Cu Rest
|8.89
|53
|91
|1.9
|350
|17.0
|130
|ca. 280
|1080
|-
|CuSn0,15 CW117C C14415
|Sn 0.1-0.15 Zn 0.1 Cu Rest
|8.93
|51
|88
|2.0
|350
|18.0
|130
|ca. 280
|1060
|-
|CuFe2P CW107C C19400
|Fe 2.1-2.6 P 0.015-0.15 Zn 0.05-0.2 Cu Rest
|8.91
|37
|64
|2.7
|260
|17.6
|125
|ca. 380
|1084 - 1090
|-
|CuNi2Si CW111C C70260
|Ni 1.6-2.5 Si 0.4-0.8 Fe 0.2 Cu Rest
|8.80
|23
|40
|4.3
|200
|17.0
|130
|ca. 430
|
|-
|CuSn1CrNiTi not standardized C18090
|Sn 0.6 Ni 0.4 Cr 0.3 Ti 0.3 Cu Rest
|8.87
|35
|60
|2.9
|240
|17.6
|133
|ca. 480
|1025 - 1074
|-
|CuNi1Co1Si not standardized C70350
|Ni 1.5 Co 1.1 Si 0.6 Cu Rest
|8.82
|29
|50
|3.4
|200
|17.6
|131
|ca. 400
|
|-
|CuCrSiTi not standardized C18070
|Cr 0.3 Ti 0.1 Si 0.02 Cu Rest
|8.88
|45
|78
|2.2
|310
|18.0
|138
|ca. 430
|
|}
</figtable>

<figtable id="tab:tab5.6">
'''Table 5.6; Mechanical Properties of Selected High Cu Content Copper Alloys'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material
!Hardness Condition
!Tensile Strength Rm [MPa]
!0,2% YieldStrength Rp02 [MPa]
!Elongation A50 [%]
!Vickers Hardness HV
!Bend Radius1) perpendicular to rolling direction
!Bend Radius1) parallel to rolling direction
!Spring Bending Limit σFB [MPa]
!Spring Fatigue Limit σBW [MPa]
|-
|CuAg0,10
|R 200 R 360
|200 - 250 360
|120 320
|> 40 > 3
|40 90
|0 x t 0.5 x t
|0 x t 0.5 x t
|240
|120
|-
|CuFe0,1P
|R 300 R 360 R 420
|300 - 380 360 - 440 420 - 500
|> 260 > 300 > 350
|> 10 > 3 > 2
|80 - 110 110 - 130 120 - 150
|0 x t 0.5 x t 1.5 x t
|0 x t 0.5 x t 1.5 x t
|250
|160
|-
|CuSn0,15
|R 250 R 300 R 360 R 420
|250 - 320 300 - 370 360 - 430 420 - 490
|> 200 > 250 > 300 > 350
|> 9 > 4 > 3 > 2
|60 - 90 85 - 110 105 - 130 120 - 140
|0 x t 0 x t 0 x t 1 x t
|0 x t 0 x t 0 x t 1 x t
|250
|160
|-
|CuFe2P
|R 370 R 420 R 470 R 520
|370 - 430 420 - 480 470 - 530 520 - 580
|> 300 > 380 > 430 > 470
|> 6 > 4 > 4 > 3
|115 - 135 130 - 150 140 - 160 150 - 170
|0 x t 0.5 x t 0.5 x t 1 x t
|0 x t 0.5 x t 0.5 x t 1 x t
|340
|200
|-
|CuNi2Si
|R 4302) R 5102) R 6002)
|430 - 520 510 - 600 600 - 680
|> 350 > 450 > 550
|> 10 > 7 > 5
|125 - 155 150 - 180 180 - 210
|0 x t 0 x t 1 x t
|0 x t 0 x t 1 x t
|500
|230
|-
|CuSn1CrNiTi
|R 450 R 540 R 620
|450 - 550 540 - 620 620 - 700
|> 350 > 450 > 520
|> 9 > 6 > 3
|130 - 170 160 - 200 180 - 220
|0.5 x t 1 x t 3 x t
|0.5 x t 2 x t 6 x t
|530
|250
|-
|CuNi1Co1Si
|R 800 R 850
|> 800 > 850
|> 760 > 830
|> 4 > 1
|> 260 > 275
|0.5 x t 1.5 x t
|1.5 x t 2.5 x t
|
|
|-
|CuCrSiTi
|R 400 R 460 R 530
|400 - 480 460 - 540 530 - 610
|> 300 > 370 > 460
|> 8 > 5 > 2
|120 - 150 140 - 170 150 - 190
|0 x t 0.5 x t 1 x t
|0 x t 0.5 x t 1 x t
|400
|220
|}
</figtable>
1) t: Strip thickness max. 0.5 mm

These newer copper based materials optimize properties such as electrical conductivity, mechanical strength, and relaxation, which are custom tailored to specific applications. Typical uses include contact springs for relays, switches, and connectors.

===5.1.4 Naturally Hard Copper Alloys===

Alloys like brasses (CuZn), tin bronzes (CuSN), and German silver (CuNiZn), for which the required hardness is achieved by cold working are defined as naturally hard alloys. Included in this group are also the silver bronzes (CuAg) with 2 – 6 wt% of Ag.

Main Articel: [[Naturally Hard Copper Alloys| Naturally Hard Copper Alloys]]

===5.1.5 Other Naturally Hard Copper Alloys===

Main Articel: [[Other Naturally Hard Copper Alloys| Other Naturally Hard Copper Alloys]]

===5.1.6 Precipitation Hardening Copper Alloys===

Besides the naturally hard copper materials precipitation hardening copper alloys play also an important role as carrier materials for electrical contacts. By means of a suitable heat treatment finely dispersed precipitations of a second phase can be achieved which increase the mechanical strength of these copper alloys significantly.

Main Articel: [[Precipitation Hardening Copper Alloys| Precipitation Hardening Copper Alloys]]

===5.1.7 Application Properties for the Selection of Copper Alloys===

Important for the usage as spring contact components are besides mechanical strength and electrical conductivity mainly the typical spring properties such as the maximum spring bending limit and the fatigue strength as well as the bendability. During severe thermal stressing the behavior of spring materials is determined by their softening and relaxation. The following briefly describes these material properties.

Main Articel: [[Application Properties for the Selection of Copper Alloys| Application Properties for the Selection of Copper Alloys]]

===5.1.8 Selection Criteria for Copper-Based Materials===

The selection of copper-based materials from the broad spectrum of available materials must be based on the requirements of the application. First an
application profile should be established which can be used to define the material properties. Usually there is however no single material that can fulfill all requirements to the same degree. A compromise must be found as for example between electrical conductivity and spring properties.

If current carrying capability is the key requirement, mechanical strength may have to be sacrificed as for example in carrier parts for stationary contacts. In this case, depending on the current level, pure copper or low alloyed copper materials such as CuSn0.15, or for economic reasons CuZn30, may be suitable.

For spring contact components the interdependent relations between electrical conductivity and fatigue strength, or electrical conductivity and relaxation behavior are of main importance. The first case is critical for higher load relay springs. CuAg2 plays an important role for these applications. The latter is critical for components that are exposed to continuing high mechanical stresses like for example in connectors. The spring force must stay close to constant over the expected life time of the parts even at elevated temperatures from the environment or current carrying. In this case the relaxation behavior of the copper materials which may cause a decrease in spring force over time must be considered. Besides this easy forming during manufacturing must be possible; this means that bending operations can also be performed at high mechanical strength values.

The increasing requirements on spring components in connectors, especially for use in automotive applications, such as higher surrounding temperatures, increased reliability, and the trend towards miniaturization led to a change of materials from traditionally CuZn30 and CuSn4 to CuNiSi alloys, for example. These CuNiSi alloys and the newer heavy duty copper alloys like CuNi1Co1 are significantly improved with regards to mechanical strength, relaxation behavior, and electrical conductivity.

==5.2 Nickel and Nickel Alloys==

===5.2.1 Technical Grade Pure Nickel===

Technical grade pure nickel commonly contains 99.0 to 99.8 wt% Ni and up to 1 wt% Co. Other ingredients are iron and manganese <xr id="tab:tab5.21"/> (Tab. 5.21) and <xr id="tab:tab5.22"/> (Tab. 5.22). Work hardening and softening behavior of nickel are shown in [[#figures11|(Figs. 5 – 6)]] Figs. 5.45 and 5.46.

One of the significant properties of nickel is its modulus of elasticity which is almost twice as high as that of copper. At temperatures up to 345°C nickel is ferro-magnetic.
Nickel has a high corrosion resistance, is very ductile, and easy to weld and clad. It is of great importance as a backing material for multiple layer weld profiles. In addition nickel is used as an intermediate layers for thin claddings, acting as an effective diffusion barrier between copper containing carrier materials and goldand palladium-based contact materials.

Because of the always present thin oxide layer on its surface, nickel is not suitable as a contact material for switching contacts.

<div id="figures11">
<xr id="fig:Strain hardening of technical pure nickel by cold working"/> Fig. 5.45: Strain hardening of technical pure nickel by cold working

<xr id="fig:Softening of technical grad nickel after annealing for 3 hrs"/> Fig. 5.46; Softening of technical grad nickel after annealing for 3 hrs after 50% cold working
</div>

<div class="multiple-images">
<figure id="fig:Strain hardening of technical pure nickel by cold working">
[[File:Strain hardening of technical pure nickel by cold working.jpg|right|thumb|Strain hardening of technical pure nickel by cold working]]
</figure>

<figure id="fig:Softening of technical grad nickel after annealing for 3 hrs">
[[File:Softening of technical grad nickel after annealing for 3 hrs.jpg|right|thumb|Softening of technical grad nickel after annealing for 3 hrs after 50% cold working]]
</figure>
</div>
<div class="clear"></div>

===5.2.2 Nickel Alloys===

Because of its low electrical conductivity NiCu30Fe is besides pure Ni and CuNi alloys the most widely used backing material for weldable contact components. With 1 – 2 wt% additives of Fe as well as 0.5 – 1 wt% Mn and Co the mechanical strength of the binary alloy NiCu30 can be increased.

The strength values of NiCu30Fe are significantly higher than those of the copper rich CuNi alloys [[#figures12|(Figs. 7 – 8)]] (Figs. 5.47 and 5.48). The good spring properties and thermal stability of NiCu30Fe make it a suitable material for the use as thermally stressed contact springs.

<div id="figures12">
<xr id="fig:Strain hardening of NiCu30Fe by cold working"/> Fig. 5.47: Strain hardening of NiCu30Fe by cold working

<xr id="fig:Softening of NiCu30Fe after annealing for 0.5 hrs"/> Fig. 5.48: Softening of NiCu30Fe after annealing for 0.5 hrs and after 80% cold working
</div>

<div class="multiple-images">
<figure id="fig:Strain hardening of NiCu30Fe by cold working">
[[File:Strain hardening of NiCu30Fe by cold working.jpg|right|thumb|Strain hardening of NiCu30Fe by cold working]]
</figure>

<figure id="fig:Softening of NiCu30Fe after annealing for 0.5 hrs">
[[File:Softening of NiCu30Fe after annealing for 0.5 hrs.jpg|right|thumb|Softening of NiCu30Fe after annealing for 0.5 hrs and after 80% cold working]]
</figure>
</div>
<div class="clear"></div>

<figtable id="tab:tab5.21">
'''Table 5.21: Physical Properties of Nickel and Nickel Alloys'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material Designation EN UNS
!Composition [wt%]
!Density [g/cm3]
!colspan="2" style="text-align:center"|Electrical Conductivity [MS/m] [% IACS]
!Electrical Resistivity [μΩ·cm]
!Thermal Conductivity [W/(m·K)]
!Coeff. of Linear Thermal Expansion [10-6/K]
!Modulus of Elasticity [GPa]
!Softening Temperature (approx. 10% loss in strength) [°C]
!Melting Temp Range [°C]
|-
|CuBe1.7 CW100C C17000
|Be 1.6 - 1.8 Co 0.3 Ni 0.3 Cu Rest
|8.4
|8 - 9a 12 - 13b 11c
|14 - 16 21 - 22 19
|11 - 12.5a 7.7 - 8.3b 9.1c
|110
|17
|125a 135b
|ca. 380
|890 - 1000
|-
|CuBe2 CW101C C17200
|Be 1.8 - 2.1 Co 0.3 Ni 0.3 Cu Rest
|8.3
|8 - 9a 12 - 13b 11c
|14 - 16 21 - 22 19
|11 - 12.5a 7.7 - 8.3b 9.1c
|110
|17
|125a 135b
|ca. 380
|870 - 980
|-
|CuCo2Be CW104C C17500
|Co 2.0 - 2.8 Be 0.4 - 0.7 Ni 0.3 Cu Rest
|8.8
|11 - 14a 25 - 27b 27 - 34c
|19 - 24 43 - 47 47 - 59
|7.1 - 9.1a 3.7 - 4.0b 2.9c
|210
|18
|131a 138b
|ca. 450
|1030 - 1070
|-
|CuNi2Be CW110C C17510
|Ni 1.4 - 2.2 Be 0.2 - 0.6 Co 0.3 Cu Rest
|8.8
|11 - 14a 25 - 27b 27 - 34c
|19 - 24 43 - 47 47 - 59
|7.1 - 9.1a 3.7 - 4.0b 2.9c
|230
|18
|131a 138b
|ca. 480
|1060 - 1100
|}
</figtable>

asolution annealed, and cold rolled 
bsolution annealed, cold rolled, and precipitation hardened 
csolution annealed, cold rolled, and precipitation hardened at mill (mill hardened)

'''Table 5.22: Mechanical Properties of Nickel and Nickel Alloys''' (2 Teile!)

===5.2.3 Nickel-Beryllium Alloys===

Because of decreasing solubility of beryllium in nickel with decreasing temperature NiBe can be precipitation hardened similar to CuBe <xr id="fig:Phase diagram of nickel beryllium"/> (Fig. 5.49). The maximum soluble amount of Be in Ni is 2.7 wt% at the eutectic temperature of 1150°C. to achieve a high hardness by precipitation hardening NiBe, similar to CuBe, is annealed at 970 - 1030°C and rapidly quenched to room temperature. Soft annealed material is easily cold formed and after stamping and forming an hardening anneal is performed at 480 to 500°C for 1 to 2 hours.

<figure id="fig:Phase diagram of nickel beryllium">
[[File:Phase diagram of nickel beryllium.jpg|right|thumb|Phase diagram of nickel-beryllium]]
</figure>

Commercial nickel-beryllium alloys contain 2 wt% Be. Compared to CuBe2 the NiBe2 materials have a significantly higher modulus of elasticity but a much lower electrical conductivity. The mechanical strength is higher than that of CuBe2 <xr id="fig:Precipitation hardening of NiBe2 soft at 480C"/> (Fig. 5.50), the spring bending force limit can exceed values of over 1400 MPa and the fatigue strength reaches approximately 400 MPa.

<figure id="fig:Precipitation hardening of NiBe2 soft at 480C">
[[File:Precipitation hardening of NiBe2 soft at 480C.jpg|right|thumb|Precipitation hardening of NiBe2 (soft) at 480°C]]
</figure>

A further advantage of NiBe2 is its high temperature stability. Cold worked and subsequently precipitation hardened NiBe2 can withstand sustained
temperatures of 400 - 650°C, depending on ist pre-treatment.

Similar to CuBe materials, NiBe alloys are available in mill hardened in various conditions or also already precipitation hardened at the manufacturer.

Nickel-beryllium alloys are recommended for mechanically and thermally highly stressed spring components. For some applications their ferro-magnetic properties can also be advantageous.

==5.3 Triple-Layer Carrier Materials==

Manufacturing of triple-layer carrier materials is usually performed by cold rollcladding. The three materials cover each other completely. The advantage of this composite material group is that the different mechanical and physical properties of the individual components can be combined with each other.

Depending on the intended application the following layer systems are utilized:

* Conduflex N CuSn6 - Cu - CuSn6 

The high electrical and thermal conductivity as well as the current carrying capacity of copper is combined with the spring properties of the tin bronze. Conduflex N strips are used in a thickness range of 0.1 – 1,5 mm in a maximum width of 140 mm.

* Cu - FeNi36 (Invar) - Cu

The high electrical conductivity and ductility of copperis combined with the low coefficient of thermal conductivity of the Invar alloy. The dimensionsional range is 0.2 – 1.8 mm in thickness with a maximum width of 140 mm.

* Cu – Fe or Steel – Cu

The high electrical conductivity and good arc mobility properties of copper are combined with the mechanical strength and magnetic properties of iron or steel. The thickness and width range of material strips are the same of the ones for Cu – Invar – Cu system.

The thickness ratios of the components can be selected according to the application requirements. The two outer layers usually have the same thickness.

==5.4 Thermostatic Bimetals==

Thermostatic bimetals are composite materials consisting of two or three layers of materials with different coefficients of thermal expansion. They are usually bonded together by cladding. If such a material part is heated either directly through current flow or indirectly through heat conduction or radiation, the different expansion between the active (strong expansion) and passive (low expansion) layer causes bending of the component part.

Directional or force effects on the free end of the thermostatic bimetal part is then used as a trigger or control mechanism in thermostats, protective switches, or in control circuits. Depending on the required function of the thermostatic bimetal component different design shapes are used:

*'''Straight or U-shaped strips''' for nearly linear motion
*'''Circular discs''' for small linear motions with high force
*'''Spirals and filament spring shapes''' for circular motion
*'''Stamped and formed parts''' for special designs and applications

The wide variety of thermostatic bimetal types is specified mostly through DIN 1715 and/or applicable ASTM standards <xr id="tab:tab5.23"/> (Table 5.23). The different types have varying material compositions for the active and passive side of the materials. The mostly used alloys are iron-nickel and manganese-copper-nickel. Mainly used in circuit protection switches (i.e. circuit breakers) some thermo-bimetals include an intermediate layer of copper or nickel which allows to design parts with a closely controlled electrical resistance.

<figtable id="tab:tab5.23">
'''Table 5.23: Partial Selection from the Wide Range of Available Thermo-Bimetals'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Designation DIN 1715
!Designation ASTM
!Specific Thermal Deflection [106/K]
!Sprecific Electrical Resistance k [μΩ·m]
!Typical Application Range [°C]
!Application Limit [°C]
!Composition
|-
|TB 20110 TB 1577A TB1170A 
|TM 2 TM 8 TM 1 TM 3 TM 4
|21.1 15.3 15.5 14.2 11.7 10.6 8.5
|1.12 1.41 0.79 0.78 0.70 0.71 0.66
| - 70 – + 260 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 425 - 70 – + 480 - 70 – + 425
|350 350 450 450 480 540 540
|Two components
|-
|TB 1517 TB 1511 TB 1303 TB 1109
| TM 28 TM 26 TM 25 TM 24 
|14.9 14.9 14.3 13.9 13.2 13.1 12.3 11.5
|0.17 0.11 0.15 0.08 0.03 0.05 0.03 0.09
| - 70 – + 260 - 70 – + 260 - 70 – + 315 - 70 – + 315 - 70 – + 260 - 70 – + 315 - 70 – + 315 - 70 – + 380
|400 400 350 350 300 350 350 400
|Three components with Cu intermediale layer
|-
|TB 1555 TB 1435 TB 1425 
| TM 17 TM 15 TM 13 TM 11 TM 9
|15.0 14.8 14.2 14.1 14.0 13.6 12.8 10.7
|0.55 0.40 0.66 0.50 0.25 0.33 0.25 0.17
| - 70 – + 260 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 370
|450 450 480 480 450 480 480 480
|Three components with Ni intermediale layer
|}
</figtable>

===5.4.1 Design Formulas===

For the design and calculation of the most important thermostatic-bimetal parts formulas are given in <xr id="tab:tab5.24"/> Table 5.24. The necessary properties can be extracted for the most common materials from <xr id="tab:tab5.23"/> Table 5.23. The values given are valid only for a temperature range up to approximately 150°C. For higher temperatures data can be obtained from the materials manufacturer.

<figtable id="tab:tab5.24">
'''Table 5.24: Design Formulas for Thermostatic Bimetal Components'''

{| class="twocolortable" style="font-size:1em;"
|-
|
|Shape of the Thermostatic Bimetal
|Deflection
|Mechanical Action Force
|Thermal Action Force
|-
|Cantilevered strip
|[[File:Contilevered strip.jpg|left|234px|]]
|<math>A =
\frac {\alpha \Delta TL^2}{s} </math>
|<math>P =
\frac {cA Bs^3}{L^3} </math>
|<math>P =
\frac {b \Delta T Bs^3}{L} </math>
|-
|Dual supported strip
|[[File:Dual supported strip.jpg|left|234px|]]
|<math>A =
\frac {\alpha \Delta T L^2}{4s} </math>
|<math>P =
\frac {16c AB s^3}{L^3} </math>
|<math>P =
\frac {4b \Delta TB s^2}{L} </math>
|-
|U-shaped element
|[[File:U shaped element.jpg|left|220px|]]
|<math>A =
\frac {\alpha \Delta T L^2}{2s} </math>
|<math>P =
\frac {4c AB s^3}{L^3} </math>
|<math>P =
\frac {2b \Delta TB s^2}{L} </math>
|-
|Spiral
|[[File:Spiral.jpg|left|220px|]]
|colspan="3" style="text-align:center"|<math>A =
\frac {\alpha \Delta T}{s} (f^2 - e^2 + 4 r^2 + 2 e f + 2 \pi r f) </math>
|-
|Helical spring
|[[File:Helical spring.jpg|left|220px|]]
|<math>\alpha =
\frac {\alpha_{1} \Delta TL}{s} </math>
|<math>P =
\frac {c_{1} \alpha Bs^3}{L \cdot r} </math>
|<math>P =
\frac {b_{1} \Delta TBs^2}{r} </math>
|-
|Disc
|[[File:Disc.jpg|left|220px|]]
|<math>A =
\frac {\alpha \Delta T (D^2 - d^2)}{5s} </math>
|<math>P =
\frac {16c A s^3}{D^2 - d^2} </math>
|<math>P = 3,2 b \Delta T s^2 </math>
|-
|Reversed strip
|[[File:Reversed strip.jpg|left|240px|]]
|<math>A =
\frac {\alpha \Delta T}{s} (y^2 - 2xy - x^2) </math>
|<math>P =
\frac {c ABs^2}{L^3} </math>
|<math>P =
\frac {b \Delta T Bs^2}{L^3} (y^2 - 2xy - x^2) </math>
|-
|Reversed U-shaped element
|[[File:Reserved u shaped element.jpg|left|228px|]]
|colspan="3" style="text-align:center"|<math>A =
\frac {\alpha \Delta T}{s} [f^2 + 4 r^2 + 2 \pi r f - (e^2 - 2ex^2 - x^2) + 2f (e - x)] </math>
|}
</figtable>

{| style="border-spacing: 20px"
|<math>A</math> || Deflection in mm
|<math>B</math> || Width in mm
| rowspan="2" |<math>a_{1} = \frac {360}{\pi} \cdot a</math>
|-
|<math>\alpha</math> || Turn angle in °
|<math>D,d</math> || Diameter in mm
|-
|<math>P</math> || Force in N
|<math>r</math> || Radius in mm
| rowspan="2" |<math>b_{1} = \frac {2}{3} \cdot b</math>
|-
|<math>\Delta T</math> || Temperature difference in K
|<math>a</math> || Specific therm. Deflection in 1/K
|-
|<math>s</math> ||Thickness in mm
|<math>b=ac</math> ||Thermal action force constant<math> N/(mm^2 \cdot K)</math>
| rowspan="2" | <math>c_{1} = \frac {\pi}{540} \cdot c</math>
|-
|<math>L</math> || Free moving length in mm
|<math>c</math> || Mechan. action force constant in <math>N/mm^2</math>
|}

===5.4.2 Stress Force Limitations===

For all calculations according to the formulas in <xr id="tab:tab5.24"/> Table 5.24 one should check if the thermally or mechanically induced stress forces stay below the allowed bending force limit. The following formulas are applicable for calculating the allowable load (Force Pmax or momentum Mmax):

{| class="gray-first"
|Single side fixed strip
|<math>P_{max} <
\frac {\sigma Bs^2}{6L} </math>
|-
|Both sides fixed strip
|<math>P_{max} <
\frac {\sigma Bs^2}{1,5L} </math>
|-
|Spiral or filament
|<math>M_{max} <
\frac {\sigma Bs^2}{6} </math>
|-
|Disc
|<math>P_{max} <
\frac {2 \sigma s^2}{3} </math>
|}

<math>\sigma</math> = bending stress

==Comments==
<references/>
==References==

ASM Handbuch Volume 2, 10th Edition: Properties and Selection of Nonferrous

Alloys and Special Purpose Materials, ASM International, Cleveland OH, USA 1990

Wieland-Kupferwerkstoffe. Wieland-Werke AG, Ulm 1999

Rau, G.: Metallische Verbundwerkstoffe. Werkstofftechnische

Verlagsgesellschaft, Karlsruhe 1977

Kayser, O., Pawlek, F., Reichel, K.: Die Beeinflussung der Leitfähigkeit reinsten

Kupfers durch Beimengungen. Metall 8 (1954) 532-537

Dies, K.: Kupfer und Kupferlegierungen in der Technik. Springer-Verlag, Berlin, Heidelberg, New York, 1967

Gerlach,U.; Kreye, H.: Gefüge und mechanische Eigenschaften der Legierung

CuNi9Sn2. Metall 32 (1978) 1112-1115

Beryvac, Firmenschrift Vakuumschmelze GmbH, Hanau 1974

Beryvac 520, Firmenschrift Vacuumschmelze GmbH, Hanau 1975

Kupfer-Beryllium, Firmenschrift Brush Wellman

Kreye, H.; Nöcker, H.; Terlinde, G.: Schrumpfung und Verzug beim Aushärten von Kupfer-Beryllium-Legierungen. Metall 29 (1975) 1118-1121

Contact Carrier Materials

2014-03-25T10:02:04Z

80.152.203.11: /* 5.2.1 Technical Grade Pure Nickel */

The reliability and electrical life of contact systems in switching devices as well as in electromechanical and electronic components do not only depend on the contact material. The selection of the most suitable carrier material also plays an important role.

The most frequently used ones are copper based materials. Depending on the application also materials based on nickel or multi-layer composite materials,
such as thermo bimetals for example, are frequently used. For special applications in the medium and high voltage technology, as well as for springs
and snap discs for the information technology, iron or steel based materials are considered. These are however not included for the purpose of this data book.

Various requirements based on the enduse of the contact components have to be met by carrier materials. Copper materials have to exhibit high electrical and thermal conductivity, good mechanical strength even at elevated temperatures, and in addition a sufficient high resistance against corrosion. If used as springs the carrier materials also must have good elastic spring properties. Besides these, the materials must, depending on the manufacturing processes employed, also have good technological properties like ductility to allow warm and cold forming, suitability for cutting and stamping, and be capable to be welded, brazed or coated by electroplating.

==5.1 Copper and Copper Alloys==

===Standards Overview===

Copper and copper alloys to be used in electrical and electronic components are usually covered by national and international standards. DIN numbers the
materials by a prefix and/or a material number. The newer European standards (EN) refer to the material's usage products and also show a prefix and material number. For reference we also show in <xr id="tab:MaterialDesignations"/> the material designation according to UNS, the Unified Numbering System (USA). Other internationally used standard and material numbers include, among others, those issued by CDA (Copper Development Association, USA), and GB (Guo Biao – China).

The most important EN as well as the US based and widely used ASTM standards covering the use of flat rolled copper and copper alloys in electrical contacts are:

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Standard Designation
!Description
|-
|DIN EN 1652
|Copper and copper alloys in plate, sheet, strip, and discs for general applications
|-
|DIN EN 1654
|Copper and copper alloys for springs and connectors
|-
|DIN EN 1758
|Copper and copper alloys in strip form for system component carriers
|-
|ASTM B 103/B103M-10 ||Spec. for Phosphor Bronce Plate, Sheet, Strip, and Rolled Bar
|-
|ASTM B 36/B36M-95 || Spec. for Brass Plate, Sheet, Strip, and Rolled Bar
|-
|ASTM B 122/B122M-08 || Spec. for CuNiSn-, CuNiZn-, and CuNi-Alloy
|-
|ASTM B 465-09 || Spec. for Copper-Iron-Alloy Plate, Sheet, and Strip
|-
|ASTM B 194-08 || Standard Spec. for CuBe-Alloy Plate, Sheet, Strip and Rolled Bar
|-
|ASTM B 534-07 || Sec. for CuCoBe-Alloy and CuNiBe-Alloy Plate, Sheet, Strip, and Rolled Bar
|}
The above DIN EN standards replace in part or completely the older DIN standards DIN 1777,
DIN 17670, DIN 1751, DIN 1791.

===5.1.2 Pure Copper===

Copper is used in electrical engineering mostly because of its high electrical conductivity<ref>As units for electrical conductivity MS/m and m/Ω.mm2 are commonly used. Frequently – and mostly in North America – the % IACS value (International Annealed Copper Standard) is also used, where 100% is equivalent to 58 MS/m or m/Ωmm2 .For the description of mechanical strength properties the units of N/mm2 or MPa are most commonly used:
1 MS/m = 1 m/Ωmm2
1 MPa = 1 N/mm2</ref> which with 58 MS/m (or m/Ωmm²) is only slightly below that of silver. Other advantages of copper are its high thermal conductivity, corrosion resistance, and its good ductility. The work hardening properties of ETP copper is illustrated in <xr id="fig:Strain hardening of Cu-ETP by cold working" />. The increase in strength achieved by cold working can be reversed easily by subsequent annealing. The softening properties are strongly dependent on the preceding cold working percentage ''(<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working"/> and <xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working"/> 5.3)''.

The purity of technically pure and un-alloyed copper used for electrical applications depends on the type used and ranges between > 99.90 and 99.95
wt%. The copper types are designated mainly by their oxygen content as oxygen containing, oxygen-free, and de-oxidized with phosphorus as
described in DIN EN 1652 ''(<xr id="tab:MaterialDesignations"/> and <xr id="tab:tab5.2"/> 5.2)''. <xr id="tab:tab5.3"/> Tables 5.3. and <xr id="tab:tab5.4"/> 5.4 show the physical and mechanical properties of these copper materials. According to these, Cu-ETP, Cu-OFE, and Cu-HCP are the types of copper for which minimum values for the electrical conductivity are guaranteed.

Cu-ETP is less suitable for welding or for brazing in reducing atmosphere because of the oxygen content (danger of hydrogen embrittlement).

Cu-HCP, Cu-DLP, and Cu-DHP are oxygen free copper types de-oxidized with different phosphorus contents. With increasing phosphorus content the
electrical conductivity decreases. Cu-OFE, also called OFHC copper, is free of oxygen and also free of de-oxidizing compounds.

<figtable id="tab:MaterialDesignations">
'''Table 5.1: Material Designations of Some Copper Types'''

<table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse">
<caption> Material Designations of Some Copper Types</caption>
<tr>
<th>WerkstMaterialEN-Designation</th><th>EN-Number</th><th>DIN-Designation</th><th>DIN-Number</th><th>UNS</th></tr>
<tr><td>Cu-ETP</td><td>CW004A</td><td>E-Cu 58</td><td>2.0065</td><td>C11000</td></tr>
<tr><td>Cu-OF</td><td>CW008A</td><td>OF-Cu</td><td>2.0040</td><td>C10200</td></tr>
<tr><td>Cu-HCP</td><td>CW021A</td><td>SE-Cu</td><td>2.0070</td><td>C10300</td></tr>
<tr><td>Cu-DLP</td><td>CW023A</td><td>SW-Cu</td><td>2.0076</td><td>C12000</td></tr>
<tr><td>Cu-DHP</td><td>CW024A</td><td>F-Cu</td><td>2.0090</td><td>C12200</td></tr>
</table>

</figtable>

<div class="small">
:Cu- ETP: electrolytic tough-pitch copper
:Cu-OFE: Oxygen Free Electronic Copper
:Cu-HCP: High Conductivity Phosphorus Deoxidized Copper
:Cu-DLP: phosphorous-deoxidized copper
:Cu-DHP: Phosphorous Deoxidized High Conductivity Copper
</div>

<figtable id="tab:tab5.2">
'''Table 5.2: Composition of Some Pure Copper Types'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material
!colspan="6" style="text-align:center"| Composition (wt%)
|-
!EN Designation
!Cu
!Bi
!O
!P
!Pb
!Others
|-
|Cu-ETP
|>99.90
|bis 0.0005
|bis 0.040
|
|up to 0.005
|up to 0.03
|-
|Cu-OF
|>99.95
|bis 0.0005
|
|
|up to 0.005
|up to 0.03
|-
|Cu-HCP
|>99.90
|
|
|ca. 0.003
|
|
|-
|Cu-DLP
|>99.90
|bis 0.005
|
|0.005-0.013
|up to 0.005
|up to 0.03
|-
|Cu-DHP
|>99.90
|
|
|0.015-0.040
|
|
|}
</figtable>

<figtable id="tab:tab5.3">
'''Table 5.3: Physical Properties of Some Copper Types'''

<table class="twocolortable">
<tr><th>Material</th><th >Density</th><th colspan="2">ElectricalConductivityt</th><th >Electrical Conductivity</th><th>ThermalConductivity</th>
<th>Coeff. ofLinear Thermal Expansion</th>
<th>ModulusofElasticity</th><th>SofteningTemperatur (approx.10% loss in strength)</th><th>MeltingTemperature</th></tr>
<tr><th>EN- Designation</th>
<th >[g/cm³]</th><th>[MS/m]</th><th>[% IACS]</th><th>[μΩ· cm]</th><th>[W/(m· K)]</th>
<th>[10-6/K]</th><th>[GPa]</th><th>[°C]</th><th>[°C]</th></tr>
<tr><td>Cu-ETP</td><td>8.94</td>
<td>≥58</td>
<td>100</td><td>1.72</td><td>390</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-OF</td><td>8.94</td><td>≥58</td><td>100</td><td>1.72</td><td>394</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-HCP</td><td>8.94</td><td>≥54</td><td>93</td><td>1.85</td><td>380</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-DLP</td><td>8.94</td><td>52</td><td>90</td><td>1.92</td><td>350</td><td>17.7</td><td>132</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-DHP</td><td>8.94</td><td>≥46</td><td>80</td><td>2.17</td><td>310</td><td>17.6</td><td>132</td><td>ca. 220</td><td>1083</td></tr></table>
</figtable>

<figtable id="tab:tab5.4">
'''Table 5.4: Mechanical Properties of Some Copper Types'''
<table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse">

<tr>

<th>Material</th><th>Condition</th><th>Tensile StrengthRm[MPa]</th><th>0,2% YieldStrength Rp0,2[MPa]</th><th>ElongationA50[ %]</th><th>HardnessHV</th>
</tr><tr>
<td class="multirow" rowspan="4">
Cu-ETP Cu-OF Cu-HCP Cu-DLP Cu-DHP</td>
<td>R220</td><td>220 - 260</td>
<td>≤140</td><td>≥33</td><td>40 - 65</td>
</tr><tr>
<td>R240</td><td>240 - 300</td>
<td>≥180</td>
<td>≥8</td><td>65 - 95</td>
</tr><tr>
<td>R290</td><td>290 - 360</td><td>≥250</td><td>≥4</td><td>90 - 110</td>
</tr><tr>
<td>R360</td><td>≥360</td><td>≥320</td><td>≥2</td>
<td>≥110</td></tr>
</table>
</figtable>

<xr id="fig:Strain hardening of Cu-ETP by cold working"/> Fig. 5.1: Strain hardening of Cu-ETP by cold working

<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working"/> Fig. 5.2: Softening of Cu-ETP after annealing for 3hrs after 25% cold working

<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working"/> Fig. 5.3: Softening of Cu-ETP after annealing for 3hrs after 50% cold working

<div class="multiple-images">

<figure id="fig:Strain hardening of Cu-ETP by cold working">
[[File:Strain hardening of Cu ETP by cold working.jpg|left|thumb|<caption>Strain hardening of Cu-ETP by cold working</caption>]]
</figure>

<figure id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working">
[[File:Softening of Cu ETP after annealing.jpg|left|thumb|<caption>Softening of Cu-ETP after annealing for 3hrs after 25% cold working</caption>]]
</figure>

<figure id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working">
[[File:Softening of Cu ETP after annealing 50.jpg|left|thumb|<caption>Softening of Cu-ETP after annealing for 3hrs after 50% cold working</caption>]]
</figure>
</div>
<div class="clear"></div>

===5.1.3 High Cu Content Copper Alloys===

The high Cu content alloy materials are closest in their properties to pure copper materials. By defined addition of small amounts of alloying elements it is possible to increase the mechanical strength and especially the softening temperature of copper and at the same time decrease the electrical conductivity only insignificantly <xr id="fig:Influence of small additions on the electrical conductivity of copper"/> (Fig. 5.4). Silver, iron, tin, zinc, nickel, chromium, zirconium, silicon, and titanium are used. Usually the additive amounts are significantly below 3 wt%. This group of materials consists of mixed crystal as well as precipitation hardening alloys. The precipiytion hardening copper-beryllium and copper-chromium-zirconium materials are decribed later in a separate section.

<figure id="fig:Influence of small additions on the electrical conductivity of copper">
[[File:Influence of small additions on the electrical conductivity of copper.jpg|right|thumb|Influence of small additions on the electrical conductivity of copper]]
</figure>

From the large number of high-Cu alloys only the properties of selected ones are covered here <xr id="tab:tab5.5"/> (Tab. 5.5) and <xr id="tab:tab5.6"/> (Tab. 5.6). Some of these materials are not included in the EN standards system.

The low alloyed materials CuAg0.1 and CuCd1 are mostly used as overhead drive cables where they have to meet sustained loads at elevated temperatures without softening.

The materials CuFe0.1 and CuSn0.15 have a high electrical conductivity. The mechanical strength of both is relatively low but stays almost constant at temperatures up to 400°C. The are used as substrates for power semiconductors and also as carriers for stationary contacts in higher energy
switchgear.

CuFe2 is a material exhibiting high electrical conductivity and good formability. During an annealing process Fe-rich precipitations are formed in the " -Cu matrix which change the mechanical properties very little but increase the electrical conductivity significantly. Besides being used as a contact carrier material in switching devices, this material has broader applications in automotive connectors and as a substrate in the semiconductor technology.

CuNi2Si has high mechanical strength, good formability, and at the same time high electrical conductivity. This combination of advantageous properties is achieved by a defined finely dispersed precipitation of nickel silicides. CuNi2Si is used mainly in the form of stamped and formed parts in thermally stressed electromechanical components for automotive applications.

CuSn1CrNiTi and CuCrSiTi are advanced developments of the Cu-Cr-Ti precipitation materials with fine intermetallic dispersions. The material
CuNi1Co1Si also belongs into this family and has properties similar to the low alloyed CuBe materials.

<figtable id="tab:tab5.5">
'''Tab. 5.5 Physical Properties of Selected High Cu Content Copper Alloys'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material/ Designation EN UNS
!Composition
!Density [g/cm3]
!colspan="2" style="text-align:center"|Electrical Conductivity [MS/m] [% IACS]
!Electrical Resistivity [μΩ·cm]
!Thermal Conductivity [W/(m·K)]
!Coeff. of Linear Thermal Expansion [10-6/K]
!Modulus of Elasticity [GPa]
!Softening Temperature (approx. 10% loss in strength) [°C]
!Melting Temp Range [°C]
|-
|CuAg 0,1 CW 013A
|Ag 0.08-0.12 Cu Rest
|8.89
|56
|97
|1.8
|380
|17.7
|126
|
|1082
|-
|CuFe0,1P not standardized C19210
|Fe 0.05-0.015 P 0.025-0.04 Cu Rest
|8.89
|53
|91
|1.9
|350
|17.0
|130
|ca. 280
|1080
|-
|CuSn0,15 CW117C C14415
|Sn 0.1-0.15 Zn 0.1 Cu Rest
|8.93
|51
|88
|2.0
|350
|18.0
|130
|ca. 280
|1060
|-
|CuFe2P CW107C C19400
|Fe 2.1-2.6 P 0.015-0.15 Zn 0.05-0.2 Cu Rest
|8.91
|37
|64
|2.7
|260
|17.6
|125
|ca. 380
|1084 - 1090
|-
|CuNi2Si CW111C C70260
|Ni 1.6-2.5 Si 0.4-0.8 Fe 0.2 Cu Rest
|8.80
|23
|40
|4.3
|200
|17.0
|130
|ca. 430
|
|-
|CuSn1CrNiTi not standardized C18090
|Sn 0.6 Ni 0.4 Cr 0.3 Ti 0.3 Cu Rest
|8.87
|35
|60
|2.9
|240
|17.6
|133
|ca. 480
|1025 - 1074
|-
|CuNi1Co1Si not standardized C70350
|Ni 1.5 Co 1.1 Si 0.6 Cu Rest
|8.82
|29
|50
|3.4
|200
|17.6
|131
|ca. 400
|
|-
|CuCrSiTi not standardized C18070
|Cr 0.3 Ti 0.1 Si 0.02 Cu Rest
|8.88
|45
|78
|2.2
|310
|18.0
|138
|ca. 430
|
|}
</figtable>

<figtable id="tab:tab5.6">
'''Table 5.6; Mechanical Properties of Selected High Cu Content Copper Alloys'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material
!Hardness Condition
!Tensile Strength Rm [MPa]
!0,2% YieldStrength Rp02 [MPa]
!Elongation A50 [%]
!Vickers Hardness HV
!Bend Radius1) perpendicular to rolling direction
!Bend Radius1) parallel to rolling direction
!Spring Bending Limit σFB [MPa]
!Spring Fatigue Limit σBW [MPa]
|-
|CuAg0,10
|R 200 R 360
|200 - 250 360
|120 320
|> 40 > 3
|40 90
|0 x t 0.5 x t
|0 x t 0.5 x t
|240
|120
|-
|CuFe0,1P
|R 300 R 360 R 420
|300 - 380 360 - 440 420 - 500
|> 260 > 300 > 350
|> 10 > 3 > 2
|80 - 110 110 - 130 120 - 150
|0 x t 0.5 x t 1.5 x t
|0 x t 0.5 x t 1.5 x t
|250
|160
|-
|CuSn0,15
|R 250 R 300 R 360 R 420
|250 - 320 300 - 370 360 - 430 420 - 490
|> 200 > 250 > 300 > 350
|> 9 > 4 > 3 > 2
|60 - 90 85 - 110 105 - 130 120 - 140
|0 x t 0 x t 0 x t 1 x t
|0 x t 0 x t 0 x t 1 x t
|250
|160
|-
|CuFe2P
|R 370 R 420 R 470 R 520
|370 - 430 420 - 480 470 - 530 520 - 580
|> 300 > 380 > 430 > 470
|> 6 > 4 > 4 > 3
|115 - 135 130 - 150 140 - 160 150 - 170
|0 x t 0.5 x t 0.5 x t 1 x t
|0 x t 0.5 x t 0.5 x t 1 x t
|340
|200
|-
|CuNi2Si
|R 4302) R 5102) R 6002)
|430 - 520 510 - 600 600 - 680
|> 350 > 450 > 550
|> 10 > 7 > 5
|125 - 155 150 - 180 180 - 210
|0 x t 0 x t 1 x t
|0 x t 0 x t 1 x t
|500
|230
|-
|CuSn1CrNiTi
|R 450 R 540 R 620
|450 - 550 540 - 620 620 - 700
|> 350 > 450 > 520
|> 9 > 6 > 3
|130 - 170 160 - 200 180 - 220
|0.5 x t 1 x t 3 x t
|0.5 x t 2 x t 6 x t
|530
|250
|-
|CuNi1Co1Si
|R 800 R 850
|> 800 > 850
|> 760 > 830
|> 4 > 1
|> 260 > 275
|0.5 x t 1.5 x t
|1.5 x t 2.5 x t
|
|
|-
|CuCrSiTi
|R 400 R 460 R 530
|400 - 480 460 - 540 530 - 610
|> 300 > 370 > 460
|> 8 > 5 > 2
|120 - 150 140 - 170 150 - 190
|0 x t 0.5 x t 1 x t
|0 x t 0.5 x t 1 x t
|400
|220
|}
</figtable>
1) t: Strip thickness max. 0.5 mm

These newer copper based materials optimize properties such as electrical conductivity, mechanical strength, and relaxation, which are custom tailored to specific applications. Typical uses include contact springs for relays, switches, and connectors.

===5.1.4 Naturally Hard Copper Alloys===

Alloys like brasses (CuZn), tin bronzes (CuSN), and German silver (CuNiZn), for which the required hardness is achieved by cold working are defined as naturally hard alloys. Included in this group are also the silver bronzes (CuAg) with 2 – 6 wt% of Ag.

Main Articel: [[Naturally Hard Copper Alloys| Naturally Hard Copper Alloys]]

===5.1.5 Other Naturally Hard Copper Alloys===

Main Articel: [[Other Naturally Hard Copper Alloys| Other Naturally Hard Copper Alloys]]

===5.1.6 Precipitation Hardening Copper Alloys===

Besides the naturally hard copper materials precipitation hardening copper alloys play also an important role as carrier materials for electrical contacts. By means of a suitable heat treatment finely dispersed precipitations of a second phase can be achieved which increase the mechanical strength of these copper alloys significantly.

Main Articel: [[Precipitation Hardening Copper Alloys| Precipitation Hardening Copper Alloys]]

===5.1.7 Application Properties for the Selection of Copper Alloys===

Important for the usage as spring contact components are besides mechanical strength and electrical conductivity mainly the typical spring properties such as the maximum spring bending limit and the fatigue strength as well as the bendability. During severe thermal stressing the behavior of spring materials is determined by their softening and relaxation. The following briefly describes these material properties.

Main Articel: [[Application Properties for the Selection of Copper Alloys| Application Properties for the Selection of Copper Alloys]]

===5.1.8 Selection Criteria for Copper-Based Materials===

The selection of copper-based materials from the broad spectrum of available materials must be based on the requirements of the application. First an
application profile should be established which can be used to define the material properties. Usually there is however no single material that can fulfill all requirements to the same degree. A compromise must be found as for example between electrical conductivity and spring properties.

If current carrying capability is the key requirement, mechanical strength may have to be sacrificed as for example in carrier parts for stationary contacts. In this case, depending on the current level, pure copper or low alloyed copper materials such as CuSn0.15, or for economic reasons CuZn30, may be suitable.

For spring contact components the interdependent relations between electrical conductivity and fatigue strength, or electrical conductivity and relaxation behavior are of main importance. The first case is critical for higher load relay springs. CuAg2 plays an important role for these applications. The latter is critical for components that are exposed to continuing high mechanical stresses like for example in connectors. The spring force must stay close to constant over the expected life time of the parts even at elevated temperatures from the environment or current carrying. In this case the relaxation behavior of the copper materials which may cause a decrease in spring force over time must be considered. Besides this easy forming during manufacturing must be possible; this means that bending operations can also be performed at high mechanical strength values.

The increasing requirements on spring components in connectors, especially for use in automotive applications, such as higher surrounding temperatures, increased reliability, and the trend towards miniaturization led to a change of materials from traditionally CuZn30 and CuSn4 to CuNiSi alloys, for example. These CuNiSi alloys and the newer heavy duty copper alloys like CuNi1Co1 are significantly improved with regards to mechanical strength, relaxation behavior, and electrical conductivity.

==5.2 Nickel and Nickel Alloys==

===5.2.1 Technical Grade Pure Nickel===

Technical grade pure nickel commonly contains 99.0 to 99.8 wt% Ni and up to 1 wt% Co. Other ingredients are iron and manganese <xr id="tab:tab5.21"/> (Tab. 5.21) and <xr id="tab:tab5.22"/> (Tab. 5.22). Work hardening and softening behavior of nickel are shown in [[#figures11|(Figs. 5 – 6)]] Figs. 5.45 and 5.46.

One of the significant properties of nickel is its modulus of elasticity which is almost twice as high as that of copper. At temperatures up to 345°C nickel is ferro-magnetic.
Nickel has a high corrosion resistance, is very ductile, and easy to weld and clad. It is of great importance as a backing material for multiple layer weld profiles. In addition nickel is used as an intermediate layers for thin claddings, acting as an effective diffusion barrier between copper containing carrier materials and goldand palladium-based contact materials.

Because of the always present thin oxide layer on its surface, nickel is not suitable as a contact material for switching contacts.

<div id="figures11">
<xr id="fig:Strain hardening of technical pure nickel by cold working"/> Fig. 5.45: Strain hardening of technical pure nickel by cold working

<xr id="fig:Softening of technical grad nickel after annealing for 3 hrs"/> Fig. 5.46; Softening of technical grad nickel after annealing for 3 hrs after 50% cold working
</div>

<div class="multiple-images">
<figure id="fig:Strain hardening of technical pure nickel by cold working">
[[File:Strain hardening of technical pure nickel by cold working.jpg|right|thumb|Strain hardening of technical pure nickel by cold working]]
</figure>

<figure id="fig:Softening of technical grad nickel after annealing for 3 hrs">
[[File:Softening of technical grad nickel after annealing for 3 hrs.jpg|right|thumb|Softening of technical grad nickel after annealing for 3 hrs after 50% cold working]]
</figure>
</div>
<div class="clear"></div>

===5.2.2 Nickel Alloys===

Because of its low electrical conductivity NiCu30Fe is besides pure Ni and CuNi alloys the most widely used backing material for weldable contact components. With 1 – 2 wt% additives of Fe as well as 0.5 – 1 wt% Mn and Co the mechanical strength of the binary alloy NiCu30 can be increased.

The strength values of NiCu30Fe are significantly higher than those of the copper rich CuNi alloys [[#figures12|(Figs. 7 – 8)]] (Figs. 5.47 and 5.48). The good spring properties and thermal stability of NiCu30Fe make it a suitable material for the use as thermally stressed contact springs.

<div id="figures12">
<xr id="fig:Strain hardening of NiCu30Fe by cold working"/> Fig. 5.47: Strain hardening of NiCu30Fe by cold working

<xr id="fig:Softening of NiCu30Fe after annealing for 0.5 hrs"/> Fig. 5.48: Softening of NiCu30Fe after annealing for 0.5 hrs and after 80% cold working
</div>

<div class="multiple-images">
<figure id="fig:Strain hardening of NiCu30Fe by cold working">
[[File:Strain hardening of NiCu30Fe by cold working.jpg|right|thumb|Strain hardening of NiCu30Fe by cold working]]
</figure>

<figure id="fig:Softening of NiCu30Fe after annealing for 0.5 hrs">
[[File:Softening of NiCu30Fe after annealing for 0.5 hrs.jpg|right|thumb|Softening of NiCu30Fe after annealing for 0.5 hrs and after 80% cold working]]
</figure>
</div>
<div class="clear"></div>

'''Table 5.21: Physical Properties of Nickel and Nickel Alloys''' (2 Teile!)

'''Table 5.22: Mechanical Properties of Nickel and Nickel Alloys''' (2 Teile!)

===5.2.3 Nickel-Beryllium Alloys===

Because of decreasing solubility of beryllium in nickel with decreasing temperature NiBe can be precipitation hardened similar to CuBe <xr id="fig:Phase diagram of nickel beryllium"/> (Fig. 5.49). The maximum soluble amount of Be in Ni is 2.7 wt% at the eutectic temperature of 1150°C. to achieve a high hardness by precipitation hardening NiBe, similar to CuBe, is annealed at 970 - 1030°C and rapidly quenched to room temperature. Soft annealed material is easily cold formed and after stamping and forming an hardening anneal is performed at 480 to 500°C for 1 to 2 hours.

<figure id="fig:Phase diagram of nickel beryllium">
[[File:Phase diagram of nickel beryllium.jpg|right|thumb|Phase diagram of nickel-beryllium]]
</figure>

Commercial nickel-beryllium alloys contain 2 wt% Be. Compared to CuBe2 the NiBe2 materials have a significantly higher modulus of elasticity but a much lower electrical conductivity. The mechanical strength is higher than that of CuBe2 <xr id="fig:Precipitation hardening of NiBe2 soft at 480C"/> (Fig. 5.50), the spring bending force limit can exceed values of over 1400 MPa and the fatigue strength reaches approximately 400 MPa.

<figure id="fig:Precipitation hardening of NiBe2 soft at 480C">
[[File:Precipitation hardening of NiBe2 soft at 480C.jpg|right|thumb|Precipitation hardening of NiBe2 (soft) at 480°C]]
</figure>

A further advantage of NiBe2 is its high temperature stability. Cold worked and subsequently precipitation hardened NiBe2 can withstand sustained
temperatures of 400 - 650°C, depending on ist pre-treatment.

Similar to CuBe materials, NiBe alloys are available in mill hardened in various conditions or also already precipitation hardened at the manufacturer.

Nickel-beryllium alloys are recommended for mechanically and thermally highly stressed spring components. For some applications their ferro-magnetic properties can also be advantageous.

==5.3 Triple-Layer Carrier Materials==

Manufacturing of triple-layer carrier materials is usually performed by cold rollcladding. The three materials cover each other completely. The advantage of this composite material group is that the different mechanical and physical properties of the individual components can be combined with each other.

Depending on the intended application the following layer systems are utilized:

* Conduflex N CuSn6 - Cu - CuSn6 

The high electrical and thermal conductivity as well as the current carrying capacity of copper is combined with the spring properties of the tin bronze. Conduflex N strips are used in a thickness range of 0.1 – 1,5 mm in a maximum width of 140 mm.

* Cu - FeNi36 (Invar) - Cu

The high electrical conductivity and ductility of copperis combined with the low coefficient of thermal conductivity of the Invar alloy. The dimensionsional range is 0.2 – 1.8 mm in thickness with a maximum width of 140 mm.

* Cu – Fe or Steel – Cu

The high electrical conductivity and good arc mobility properties of copper are combined with the mechanical strength and magnetic properties of iron or steel. The thickness and width range of material strips are the same of the ones for Cu – Invar – Cu system.

The thickness ratios of the components can be selected according to the application requirements. The two outer layers usually have the same thickness.

==5.4 Thermostatic Bimetals==

Thermostatic bimetals are composite materials consisting of two or three layers of materials with different coefficients of thermal expansion. They are usually bonded together by cladding. If such a material part is heated either directly through current flow or indirectly through heat conduction or radiation, the different expansion between the active (strong expansion) and passive (low expansion) layer causes bending of the component part.

Directional or force effects on the free end of the thermostatic bimetal part is then used as a trigger or control mechanism in thermostats, protective switches, or in control circuits. Depending on the required function of the thermostatic bimetal component different design shapes are used:

*'''Straight or U-shaped strips''' for nearly linear motion
*'''Circular discs''' for small linear motions with high force
*'''Spirals and filament spring shapes''' for circular motion
*'''Stamped and formed parts''' for special designs and applications

The wide variety of thermostatic bimetal types is specified mostly through DIN 1715 and/or applicable ASTM standards <xr id="tab:tab5.23"/> (Table 5.23). The different types have varying material compositions for the active and passive side of the materials. The mostly used alloys are iron-nickel and manganese-copper-nickel. Mainly used in circuit protection switches (i.e. circuit breakers) some thermo-bimetals include an intermediate layer of copper or nickel which allows to design parts with a closely controlled electrical resistance.

<figtable id="tab:tab5.23">
'''Table 5.23: Partial Selection from the Wide Range of Available Thermo-Bimetals'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Designation DIN 1715
!Designation ASTM
!Specific Thermal Deflection [106/K]
!Sprecific Electrical Resistance k [μΩ·m]
!Typical Application Range [°C]
!Application Limit [°C]
!Composition
|-
|TB 20110 TB 1577A TB1170A 
|TM 2 TM 8 TM 1 TM 3 TM 4
|21.1 15.3 15.5 14.2 11.7 10.6 8.5
|1.12 1.41 0.79 0.78 0.70 0.71 0.66
| - 70 – + 260 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 425 - 70 – + 480 - 70 – + 425
|350 350 450 450 480 540 540
|Two components
|-
|TB 1517 TB 1511 TB 1303 TB 1109
| TM 28 TM 26 TM 25 TM 24 
|14.9 14.9 14.3 13.9 13.2 13.1 12.3 11.5
|0.17 0.11 0.15 0.08 0.03 0.05 0.03 0.09
| - 70 – + 260 - 70 – + 260 - 70 – + 315 - 70 – + 315 - 70 – + 260 - 70 – + 315 - 70 – + 315 - 70 – + 380
|400 400 350 350 300 350 350 400
|Three components with Cu intermediale layer
|-
|TB 1555 TB 1435 TB 1425 
| TM 17 TM 15 TM 13 TM 11 TM 9
|15.0 14.8 14.2 14.1 14.0 13.6 12.8 10.7
|0.55 0.40 0.66 0.50 0.25 0.33 0.25 0.17
| - 70 – + 260 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 370
|450 450 480 480 450 480 480 480
|Three components with Ni intermediale layer
|}
</figtable>

===5.4.1 Design Formulas===

For the design and calculation of the most important thermostatic-bimetal parts formulas are given in <xr id="tab:tab5.24"/> Table 5.24. The necessary properties can be extracted for the most common materials from <xr id="tab:tab5.23"/> Table 5.23. The values given are valid only for a temperature range up to approximately 150°C. For higher temperatures data can be obtained from the materials manufacturer.

<figtable id="tab:tab5.24">
'''Table 5.24: Design Formulas for Thermostatic Bimetal Components'''

{| class="twocolortable" style="font-size:1em;"
|-
|
|Shape of the Thermostatic Bimetal
|Deflection
|Mechanical Action Force
|Thermal Action Force
|-
|Cantilevered strip
|[[File:Contilevered strip.jpg|left|234px|]]
|<math>A =
\frac {\alpha \Delta TL^2}{s} </math>
|<math>P =
\frac {cA Bs^3}{L^3} </math>
|<math>P =
\frac {b \Delta T Bs^3}{L} </math>
|-
|Dual supported strip
|[[File:Dual supported strip.jpg|left|234px|]]
|<math>A =
\frac {\alpha \Delta T L^2}{4s} </math>
|<math>P =
\frac {16c AB s^3}{L^3} </math>
|<math>P =
\frac {4b \Delta TB s^2}{L} </math>
|-
|U-shaped element
|[[File:U shaped element.jpg|left|220px|]]
|<math>A =
\frac {\alpha \Delta T L^2}{2s} </math>
|<math>P =
\frac {4c AB s^3}{L^3} </math>
|<math>P =
\frac {2b \Delta TB s^2}{L} </math>
|-
|Spiral
|[[File:Spiral.jpg|left|220px|]]
|colspan="3" style="text-align:center"|<math>A =
\frac {\alpha \Delta T}{s} (f^2 - e^2 + 4 r^2 + 2 e f + 2 \pi r f) </math>
|-
|Helical spring
|[[File:Helical spring.jpg|left|220px|]]
|<math>\alpha =
\frac {\alpha_{1} \Delta TL}{s} </math>
|<math>P =
\frac {c_{1} \alpha Bs^3}{L \cdot r} </math>
|<math>P =
\frac {b_{1} \Delta TBs^2}{r} </math>
|-
|Disc
|[[File:Disc.jpg|left|220px|]]
|<math>A =
\frac {\alpha \Delta T (D^2 - d^2)}{5s} </math>
|<math>P =
\frac {16c A s^3}{D^2 - d^2} </math>
|<math>P = 3,2 b \Delta T s^2 </math>
|-
|Reversed strip
|[[File:Reversed strip.jpg|left|240px|]]
|<math>A =
\frac {\alpha \Delta T}{s} (y^2 - 2xy - x^2) </math>
|<math>P =
\frac {c ABs^2}{L^3} </math>
|<math>P =
\frac {b \Delta T Bs^2}{L^3} (y^2 - 2xy - x^2) </math>
|-
|Reversed U-shaped element
|[[File:Reserved u shaped element.jpg|left|228px|]]
|colspan="3" style="text-align:center"|<math>A =
\frac {\alpha \Delta T}{s} [f^2 + 4 r^2 + 2 \pi r f - (e^2 - 2ex^2 - x^2) + 2f (e - x)] </math>
|}
</figtable>

{| style="border-spacing: 20px"
|<math>A</math> || Deflection in mm
|<math>B</math> || Width in mm
| rowspan="2" |<math>a_{1} = \frac {360}{\pi} \cdot a</math>
|-
|<math>\alpha</math> || Turn angle in °
|<math>D,d</math> || Diameter in mm
|-
|<math>P</math> || Force in N
|<math>r</math> || Radius in mm
| rowspan="2" |<math>b_{1} = \frac {2}{3} \cdot b</math>
|-
|<math>\Delta T</math> || Temperature difference in K
|<math>a</math> || Specific therm. Deflection in 1/K
|-
|<math>s</math> ||Thickness in mm
|<math>b=ac</math> ||Thermal action force constant<math> N/(mm^2 \cdot K)</math>
| rowspan="2" | <math>c_{1} = \frac {\pi}{540} \cdot c</math>
|-
|<math>L</math> || Free moving length in mm
|<math>c</math> || Mechan. action force constant in <math>N/mm^2</math>
|}

===5.4.2 Stress Force Limitations===

For all calculations according to the formulas in <xr id="tab:tab5.24"/> Table 5.24 one should check if the thermally or mechanically induced stress forces stay below the allowed bending force limit. The following formulas are applicable for calculating the allowable load (Force Pmax or momentum Mmax):

{| class="gray-first"
|Single side fixed strip
|<math>P_{max} <
\frac {\sigma Bs^2}{6L} </math>
|-
|Both sides fixed strip
|<math>P_{max} <
\frac {\sigma Bs^2}{1,5L} </math>
|-
|Spiral or filament
|<math>M_{max} <
\frac {\sigma Bs^2}{6} </math>
|-
|Disc
|<math>P_{max} <
\frac {2 \sigma s^2}{3} </math>
|}

<math>\sigma</math> = bending stress

==Comments==
<references/>
==References==

ASM Handbuch Volume 2, 10th Edition: Properties and Selection of Nonferrous

Alloys and Special Purpose Materials, ASM International, Cleveland OH, USA 1990

Wieland-Kupferwerkstoffe. Wieland-Werke AG, Ulm 1999

Rau, G.: Metallische Verbundwerkstoffe. Werkstofftechnische

Verlagsgesellschaft, Karlsruhe 1977

Kayser, O., Pawlek, F., Reichel, K.: Die Beeinflussung der Leitfähigkeit reinsten

Kupfers durch Beimengungen. Metall 8 (1954) 532-537

Dies, K.: Kupfer und Kupferlegierungen in der Technik. Springer-Verlag, Berlin, Heidelberg, New York, 1967

Gerlach,U.; Kreye, H.: Gefüge und mechanische Eigenschaften der Legierung

CuNi9Sn2. Metall 32 (1978) 1112-1115

Beryvac, Firmenschrift Vakuumschmelze GmbH, Hanau 1974

Beryvac 520, Firmenschrift Vacuumschmelze GmbH, Hanau 1975

Kupfer-Beryllium, Firmenschrift Brush Wellman

Kreye, H.; Nöcker, H.; Terlinde, G.: Schrumpfung und Verzug beim Aushärten von Kupfer-Beryllium-Legierungen. Metall 29 (1975) 1118-1121

Contact Carrier Materials

2014-03-11T13:02:39Z

80.152.203.11: /* 5.4.2 Stress Force Limitations */

The reliability and electrical life of contact systems in switching devices as well as in electromechanical and electronic components do not only depend on the contact material. The selection of the most suitable carrier material also plays an important role.

The most frequently used ones are copper based materials. Depending on the application also materials based on nickel or multi-layer composite materials,
such as thermo bimetals for example, are frequently used. For special applications in the medium and high voltage technology, as well as for springs
and snap discs for the information technology, iron or steel based materials are considered. These are however not included for the purpose of this data book.

Various requirements based on the enduse of the contact components have to be met by carrier materials. Copper materials have to exhibit high electrical and thermal conductivity, good mechanical strength even at elevated temperatures, and in addition a sufficient high resistance against corrosion. If used as springs the carrier materials also must have good elastic spring properties. Besides these, the materials must, depending on the manufacturing processes employed, also have good technological properties like ductility to allow warm and cold forming, suitability for cutting and stamping, and be capable to be welded, brazed or coated by electroplating.

==5.1 Copper and Copper Alloys==

===Standards Overview===

Copper and copper alloys to be used in electrical and electronic components are usually covered by national and international standards. DIN numbers the
materials by a prefix and/or a material number. The newer European standards (EN) refer to the material's usage products and also show a prefix and material number. For reference we also show in <xr id="tab:MaterialDesignations"/> the material designation according to UNS, the Unified Numbering System (USA). Other internationally used standard and material numbers include, among others, those issued by CDA (Copper Development Association, USA), and GB (Guo Biao – China).

The most important EN as well as the US based and widely used ASTM standards covering the use of flat rolled copper and copper alloys in electrical contacts are:

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Standard Designation
!Description
|-
|DIN EN 1652
|Copper and copper alloys in plate, sheet, strip, and discs for general applications
|-
|DIN EN 1654
|Copper and copper alloys for springs and connectors
|-
|DIN EN 1758
|Copper and copper alloys in strip form for system component carriers
|-
|ASTM B 103/B103M-10 ||Spec. for Phosphor Bronce Plate, Sheet, Strip, and Rolled Bar
|-
|ASTM B 36/B36M-95 || Spec. for Brass Plate, Sheet, Strip, and Rolled Bar
|-
|ASTM B 122/B122M-08 || Spec. for CuNiSn-, CuNiZn-, and CuNi-Alloy
|-
|ASTM B 465-09 || Spec. for Copper-Iron-Alloy Plate, Sheet, and Strip
|-
|ASTM B 194-08 || Standard Spec. for CuBe-Alloy Plate, Sheet, Strip and Rolled Bar
|-
|ASTM B 534-07 || Sec. for CuCoBe-Alloy and CuNiBe-Alloy Plate, Sheet, Strip, and Rolled Bar
|}
The above DIN EN standards replace in part or completely the older DIN standards DIN 1777,
DIN 17670, DIN 1751, DIN 1791.

===5.1.2 Pure Copper===

Copper is used in electrical engineering mostly because of its high electrical conductivity<ref>As units for electrical conductivity MS/m and m/Ω.mm2 are commonly used. Frequently – and mostly in North America – the % IACS value (International Annealed Copper Standard) is also used, where 100% is equivalent to 58 MS/m or m/Ωmm2 .For the description of mechanical strength properties the units of N/mm2 or MPa are most commonly used:
1 MS/m = 1 m/Ωmm2
1 MPa = 1 N/mm2</ref> which with 58 MS/m (or m/Ωmm²) is only slightly below that of silver. Other advantages of copper are its high thermal conductivity, corrosion resistance, and its good ductility. The work hardening properties of ETP copper is illustrated in <xr id="fig:Strain hardening of Cu-ETP by cold working" />. The increase in strength achieved by cold working can be reversed easily by subsequent annealing. The softening properties are strongly dependent on the preceding cold working percentage ''(<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working"/> and <xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working"/> 5.3)''.

The purity of technically pure and un-alloyed copper used for electrical applications depends on the type used and ranges between > 99.90 and 99.95
wt%. The copper types are designated mainly by their oxygen content as oxygen containing, oxygen-free, and de-oxidized with phosphorus as
described in DIN EN 1652 ''(<xr id="tab:MaterialDesignations"/> and <xr id="tab:tab5.2"/> 5.2)''. <xr id="tab:tab5.3"/> Tables 5.3. and <xr id="tab:tab5.4"/> 5.4 show the physical and mechanical properties of these copper materials. According to these, Cu-ETP, Cu-OFE, and Cu-HCP are the types of copper for which minimum values for the electrical conductivity are guaranteed.

Cu-ETP is less suitable for welding or for brazing in reducing atmosphere because of the oxygen content (danger of hydrogen embrittlement).

Cu-HCP, Cu-DLP, and Cu-DHP are oxygen free copper types de-oxidized with different phosphorus contents. With increasing phosphorus content the
electrical conductivity decreases. Cu-OFE, also called OFHC copper, is free of oxygen and also free of de-oxidizing compounds.

<figtable id="tab:MaterialDesignations">
'''Table 5.1: Material Designations of Some Copper Types'''

<table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse">
<caption> Material Designations of Some Copper Types</caption>
<tr>
<th>WerkstMaterialEN-Designation</th><th>EN-Number</th><th>DIN-Designation</th><th>DIN-Number</th><th>UNS</th></tr>
<tr><td>Cu-ETP</td><td>CW004A</td><td>E-Cu 58</td><td>2.0065</td><td>C11000</td></tr>
<tr><td>Cu-OF</td><td>CW008A</td><td>OF-Cu</td><td>2.0040</td><td>C10200</td></tr>
<tr><td>Cu-HCP</td><td>CW021A</td><td>SE-Cu</td><td>2.0070</td><td>C10300</td></tr>
<tr><td>Cu-DLP</td><td>CW023A</td><td>SW-Cu</td><td>2.0076</td><td>C12000</td></tr>
<tr><td>Cu-DHP</td><td>CW024A</td><td>F-Cu</td><td>2.0090</td><td>C12200</td></tr>
</table>

</figtable>

<div class="small">
:Cu- ETP: electrolytic tough-pitch copper
:Cu-OFE: Oxygen Free Electronic Copper
:Cu-HCP: High Conductivity Phosphorus Deoxidized Copper
:Cu-DLP: phosphorous-deoxidized copper
:Cu-DHP: Phosphorous Deoxidized High Conductivity Copper
</div>

<figtable id="tab:tab5.2">
'''Table 5.2: Composition of Some Pure Copper Types'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material
!colspan="6" style="text-align:center"| Composition (wt%)
|-
!EN Designation
!Cu
!Bi
!O
!P
!Pb
!Others
|-
|Cu-ETP
|>99.90
|bis 0.0005
|bis 0.040
|
|up to 0.005
|up to 0.03
|-
|Cu-OF
|>99.95
|bis 0.0005
|
|
|up to 0.005
|up to 0.03
|-
|Cu-HCP
|>99.90
|
|
|ca. 0.003
|
|
|-
|Cu-DLP
|>99.90
|bis 0.005
|
|0.005-0.013
|up to 0.005
|up to 0.03
|-
|Cu-DHP
|>99.90
|
|
|0.015-0.040
|
|
|}
</figtable>

<figtable id="tab:tab5.3">
'''Table 5.3: Physical Properties of Some Copper Types'''

<table border="1" cellspacing="0" style="border-collapse:collapse">
<tr><td>MaterialEN- Desig- nation</td><td>Density[g/cm³]</td><td>ElectricalConductivityt</td><td>Electrical Conduc- tivity[µS · cm]</td><td>ThermalConduc- tivity[W/(m.K)]</td>
<td>Coeff. ofLinear Thermal Expan- sion[10-6/K]</td>
<td>ModulusofElasticity[GPa]</td><td>SofteningTempera- tur (approx.10% loss instrength) [°C]</td><td>MeltingTempera- ture[°C]</td></tr><tr><td>MaterialEN- Desig- nation</td>
<td>Density[g/cm³]</td><td>[MS/m]</td>
<td>[% IACS]</td><td>Electrical Conduc- tivity[µS · cm]</td>
<td>ThermalConduc- tivity[W/(m.K)]</td><td>Coeff. ofLinear Thermal Expan- sion[10-6/K]</td><td>ModulusofElasticity[GPa]</td><td>SofteningTempera- tur (approx.10% loss instrength) [°C]</td><td>MeltingTempera- ture[°C]</td></tr>
<tr><td>Cu-ETP</td><td>8.94</td>
<td>≥58</td>
<td>100</td><td>1.72</td><td>390</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-OF</td><td>8.94</td><td>≥58</td><td>100</td><td>1.72</td><td>394</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-HCP</td><td>8.94</td><td>≥54</td><td>93</td><td>1.85</td><td>380</td><td>17.7</td><td>127</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-DLP</td><td>8.94</td><td>52</td><td>90</td><td>1.92</td><td>350</td><td>17.7</td><td>132</td><td>ca. 220</td><td>1083</td></tr><tr><td>Cu-DHP</td><td>8.94</td><td>≥46</td><td>80</td><td>2.17</td><td>310</td><td>17.6</td><td>132</td><td>ca. 220</td><td>1083</td></tr></table>
</figtable>

<figtable id="tab:tab5.4">
'''Table 5.4: Mechanical Properties of Some Copper Types'''
<table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse">

<tr>

<th>Material</th><th>Condition</th><th>Tensile StrengthRm[MPa]</th><th>0,2% YieldStrength Rp0,2[MPa]</th><th>ElongationA50[ %]</th><th>HardnessHV</th>
</tr><tr>
<td class="multirow" rowspan="4">
Cu-ETP Cu-OF Cu-HCP Cu-DLP Cu-DHP</td>
<td>R220</td><td>220 - 260</td>
<td>≤140</td><td>≥33</td><td>40 - 65</td>
</tr><tr>
<td>R240</td><td>240 - 300</td>
<td>≥180</td>
<td>≥8</td><td>65 - 95</td>
</tr><tr>
<td>R290</td><td>290 - 360</td><td>≥250</td><td>≥4</td><td>90 - 110</td>
</tr><tr>
<td>R360</td><td>≥360</td><td>≥320</td><td>≥2</td>
<td>≥110</td></tr>
</table>
</figtable>

<xr id="fig:Strain hardening of Cu-ETP by cold working"/> Fig. 5.1: Strain hardening of Cu-ETP by cold working

<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working"/> Fig. 5.2: Softening of Cu-ETP after annealing for 3hrs after 25% cold working

<xr id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working"/> Fig. 5.3: Softening of Cu-ETP after annealing for 3hrs after 50% cold working

<div class="multiple-images">

<figure id="fig:Strain hardening of Cu-ETP by cold working">
[[File:Strain hardening of Cu ETP by cold working.jpg|left|thumb|<caption>Strain hardening of Cu-ETP by cold working</caption>]]
</figure>

<figure id="fig:Softening of Cu-ETP after annealing for 3hrs after 25% cold working">
[[File:Softening of Cu ETP after annealing.jpg|left|thumb|<caption>Softening of Cu-ETP after annealing for 3hrs after 25% cold working</caption>]]
</figure>

<figure id="fig:Softening of Cu-ETP after annealing for 3hrs after 50% cold working">
[[File:Softening of Cu ETP after annealing 50.jpg|left|thumb|<caption>Softening of Cu-ETP after annealing for 3hrs after 50% cold working</caption>]]
</figure>
</div>
<div class="clear"></div>

===5.1.3 High Cu Content Copper Alloys===

The high Cu content alloy materials are closest in their properties to pure copper materials. By defined addition of small amounts of alloying elements it is possible to increase the mechanical strength and especially the softening temperature of copper and at the same time decrease the electrical conductivity only insignificantly <xr id="fig:Influence of small additions on the electrical conductivity of copper"/> (Fig. 5.4). Silver, iron, tin, zinc, nickel, chromium, zirconium, silicon, and titanium are used. Usually the additive amounts are significantly below 3 wt%. This group of materials consists of mixed crystal as well as precipitation hardening alloys. The precipiytion hardening copper-beryllium and copper-chromium-zirconium materials are decribed later in a separate section.

<figure id="fig:Influence of small additions on the electrical conductivity of copper">
[[File:Influence of small additions on the electrical conductivity of copper.jpg|right|thumb|Influence of small additions on the electrical conductivity of copper]]
</figure>

From the large number of high-Cu alloys only the properties of selected ones are covered here ''(Tables 5.5 and 5.6)''. Some of these materials are not included in the EN standards system.

The low alloyed materials CuAg0.1 and CuCd1 are mostly used as overhead drive cables where they have to meet sustained loads at elevated temperatures without softening.

The materials CuFe0.1 and CuSn0.15 have a high electrical conductivity. The mechanical strength of both is relatively low but stays almost constant at temperatures up to 400°C. The are used as substrates for power semiconductors and also as carriers for stationary contacts in higher energy
switchgear.

CuFe2 is a material exhibiting high electrical conductivity and good formability. During an annealing process Fe-rich precipitations are formed in the " -Cu matrix which change the mechanical properties very little but increase the electrical conductivity significantly. Besides being used as a contact carrier material in switching devices, this material has broader applications in automotive connectors and as a substrate in the semiconductor technology.

CuNi2Si has high mechanical strength, good formability, and at the same time high electrical conductivity. This combination of advantageous properties is achieved by a defined finely dispersed precipitation of nickel silicides. CuNi2Si is used mainly in the form of stamped and formed parts in thermally stressed electromechanical components for automotive applications.

CuSn1CrNiTi and CuCrSiTi are advanced developments of the Cu-Cr-Ti precipitation materials with fine intermetallic dispersions. The material
CuNi1Co1Si also belongs into this family and has properties similar to the low alloyed CuBe materials.

'''Tab. 5.5 Physical Properties of Selected High Cu Content Copper Alloys'''

2 teile!

'''Table 5.6; Mechanical Properties of Selected High Cu Content Copper Alloys'''

2 teile!

These newer copper based materials optimize properties such as electrical conductivity, mechanical strength, and relaxation, which are custom tailored to specific applications. Typical uses include contact springs for relays, switches, and connectors.

===5.1.4 Naturally Hard Copper Alloys===

Alloys like brasses (CuZn), tin bronzes (CuSN), and German silver (CuNiZn), for which the required hardness is achieved by cold working are defined as naturally hard alloys. Included in this group are also the silver bronzes (CuAg) with 2 – 6 wt% of Ag.

Main Articel: [[Naturally Hard Copper Alloys| Naturally Hard Copper Alloys]]

===5.1.5 Other Naturally Hard Copper Alloys===

Main Articel: [[Other Naturally Hard Copper Alloys| Other Naturally Hard Copper Alloys]]

===5.1.6 Precipitation Hardening Copper Alloys===

Besides the naturally hard copper materials precipitation hardening copper alloys play also an important role as carrier materials for electrical contacts. By means of a suitable heat treatment finely dispersed precipitations of a second phase can be achieved which increase the mechanical strength of these copper alloys significantly.

Main Articel: [[Precipitation Hardening Copper Alloys| Precipitation Hardening Copper Alloys]]

===5.1.7 Application Properties for the Selection of Copper Alloys===

Important for the usage as spring contact components are besides mechanical strength and electrical conductivity mainly the typical spring properties such as the maximum spring bending limit and the fatigue strength as well as the bendability. During severe thermal stressing the behavior of spring materials is determined by their softening and relaxation. The following briefly describes these material properties.

Main Articel: [[Application Properties for the Selection of Copper Alloys| Application Properties for the Selection of Copper Alloys]]

===5.1.8 Selection Criteria for Copper-Based Materials===

The selection of copper-based materials from the broad spectrum of available materials must be based on the requirements of the application. First an
application profile should be established which can be used to define the material properties. Usually there is however no single material that can fulfill all requirements to the same degree. A compromise must be found as for example between electrical conductivity and spring properties.

If current carrying capability is the key requirement, mechanical strength may have to be sacrificed as for example in carrier parts for stationary contacts. In this case, depending on the current level, pure copper or low alloyed copper materials such as CuSn0.15, or for economic reasons CuZn30, may be suitable.

For spring contact components the interdependent relations between electrical conductivity and fatigue strength, or electrical conductivity and relaxation behavior are of main importance. The first case is critical for higher load relay springs. CuAg2 plays an important role for these applications. The latter is critical for components that are exposed to continuing high mechanical stresses like for example in connectors. The spring force must stay close to constant over the expected life time of the parts even at elevated temperatures from the environment or current carrying. In this case the relaxation behavior of the copper materials which may cause a decrease in spring force over time must be considered. Besides this easy forming during manufacturing must be possible; this means that bending operations can also be performed at high mechanical strength values.

The increasing requirements on spring components in connectors, especially for use in automotive applications, such as higher surrounding temperatures, increased reliability, and the trend towards miniaturization led to a change of materials from traditionally CuZn30 and CuSn4 to CuNiSi alloys, for example. These CuNiSi alloys and the newer heavy duty copper alloys like CuNi1Co1 are significantly improved with regards to mechanical strength, relaxation behavior, and electrical conductivity.

==5.2 Nickel and Nickel Alloys==

===5.2.1 Technical Grade Pure Nickel===

Technical grade pure nickel commonly contains 99.0 to 99.8 wt% Ni and up to 1 wt% Co. Other ingredients are iron and manganese (Tables 5.21 and 5.22). Work hardening and softening behavior of nickel are shown in [[#figures11|(Figs. 5 – 6)]] Figs. 5.45 and 5.46.

One of the significant properties of nickel is its modulus of elasticity which is almost twice as high as that of copper. At temperatures up to 345°C nickel is ferro-magnetic.
Nickel has a high corrosion resistance, is very ductile, and easy to weld and clad. It is of great importance as a backing material for multiple layer weld profiles. In addition nickel is used as an intermediate layers for thin claddings, acting as an effective diffusion barrier between copper containing carrier materials and goldand palladium-based contact materials.

Because of the always present thin oxide layer on its surface, nickel is not suitable as a contact material for switching contacts.

<div id="figures11">
<xr id="fig:Strain hardening of technical pure nickel by cold working"/> Fig. 5.45: Strain hardening of technical pure nickel by cold working

<xr id="fig:Softening of technical grad nickel after annealing for 3 hrs"/> Fig. 5.46; Softening of technical grad nickel after annealing for 3 hrs after 50% cold working
</div>

<div class="multiple-images">
<figure id="fig:Strain hardening of technical pure nickel by cold working">
[[File:Strain hardening of technical pure nickel by cold working.jpg|right|thumb|Strain hardening of technical pure nickel by cold working]]
</figure>

<figure id="fig:Softening of technical grad nickel after annealing for 3 hrs">
[[File:Softening of technical grad nickel after annealing for 3 hrs.jpg|right|thumb|Softening of technical grad nickel after annealing for 3 hrs after 50% cold working]]
</figure>
</div>
<div class="clear"></div>

===5.2.2 Nickel Alloys===

Because of its low electrical conductivity NiCu30Fe is besides pure Ni and CuNi alloys the most widely used backing material for weldable contact components. With 1 – 2 wt% additives of Fe as well as 0.5 – 1 wt% Mn and Co the mechanical strength of the binary alloy NiCu30 can be increased.

The strength values of NiCu30Fe are significantly higher than those of the copper rich CuNi alloys [[#figures12|(Figs. 7 – 8)]] (Figs. 5.47 and 5.48). The good spring properties and thermal stability of NiCu30Fe make it a suitable material for the use as thermally stressed contact springs.

<div id="figures12">
<xr id="fig:Strain hardening of NiCu30Fe by cold working"/> Fig. 5.47: Strain hardening of NiCu30Fe by cold working

<xr id="fig:Softening of NiCu30Fe after annealing for 0.5 hrs"/> Fig. 5.48: Softening of NiCu30Fe after annealing for 0.5 hrs and after 80% cold working
</div>

<div class="multiple-images">
<figure id="fig:Strain hardening of NiCu30Fe by cold working">
[[File:Strain hardening of NiCu30Fe by cold working.jpg|right|thumb|Strain hardening of NiCu30Fe by cold working]]
</figure>

<figure id="fig:Softening of NiCu30Fe after annealing for 0.5 hrs">
[[File:Softening of NiCu30Fe after annealing for 0.5 hrs.jpg|right|thumb|Softening of NiCu30Fe after annealing for 0.5 hrs and after 80% cold working]]
</figure>
</div>
<div class="clear"></div>

'''Table 5.21: Physical Properties of Nickel and Nickel Alloys''' (2 Teile!)

'''Table 5.22: Mechanical Properties of Nickel and Nickel Alloys''' (2 Teile!)

===5.2.3 Nickel-Beryllium Alloys===

Because of decreasing solubility of beryllium in nickel with decreasing temperature NiBe can be precipitation hardened similar to CuBe <xr id="fig:Phase diagram of nickel beryllium"/> (Fig. 5.49). The maximum soluble amount of Be in Ni is 2.7 wt% at the eutectic temperature of 1150°C. to achieve a high hardness by precipitation hardening NiBe, similar to CuBe, is annealed at 970 - 1030°C and rapidly quenched to room temperature. Soft annealed material is easily cold formed and after stamping and forming an hardening anneal is performed at 480 to 500°C for 1 to 2 hours.

<figure id="fig:Phase diagram of nickel beryllium">
[[File:Phase diagram of nickel beryllium.jpg|right|thumb|Phase diagram of nickel-beryllium]]
</figure>

Commercial nickel-beryllium alloys contain 2 wt% Be. Compared to CuBe2 the NiBe2 materials have a significantly higher modulus of elasticity but a much lower electrical conductivity. The mechanical strength is higher than that of CuBe2 <xr id="fig:Precipitation hardening of NiBe2 soft at 480C"/> (Fig. 5.50), the spring bending force limit can exceed values of over 1400 MPa and the fatigue strength reaches approximately 400 MPa.

<figure id="fig:Precipitation hardening of NiBe2 soft at 480C">
[[File:Precipitation hardening of NiBe2 soft at 480C.jpg|right|thumb|Precipitation hardening of NiBe2 (soft) at 480°C]]
</figure>

A further advantage of NiBe2 is its high temperature stability. Cold worked and subsequently precipitation hardened NiBe2 can withstand sustained
temperatures of 400 - 650°C, depending on ist pre-treatment.

Similar to CuBe materials, NiBe alloys are available in mill hardened in various conditions or also already precipitation hardened at the manufacturer.

Nickel-beryllium alloys are recommended for mechanically and thermally highly stressed spring components. For some applications their ferro-magnetic properties can also be advantageous.

==5.3 Triple-Layer Carrier Materials==

Manufacturing of triple-layer carrier materials is usually performed by cold rollcladding. The three materials cover each other completely. The advantage of this composite material group is that the different mechanical and physical properties of the individual components can be combined with each other.

Depending on the intended application the following layer systems are utilized:

* Conduflex N CuSn6 - Cu - CuSn6 

The high electrical and thermal conductivity as well as the current carrying capacity of copper is combined with the spring properties of the tin bronze. Conduflex N strips are used in a thickness range of 0.1 – 1,5 mm in a maximum width of 140 mm.

* Cu - FeNi36 (Invar) - Cu

The high electrical conductivity and ductility of copperis combined with the low coefficient of thermal conductivity of the Invar alloy. The dimensionsional range is 0.2 – 1.8 mm in thickness with a maximum width of 140 mm.

* Cu – Fe or Steel – Cu

The high electrical conductivity and good arc mobility properties of copper are combined with the mechanical strength and magnetic properties of iron or steel. The thickness and width range of material strips are the same of the ones for Cu – Invar – Cu system.

The thickness ratios of the components can be selected according to the application requirements. The two outer layers usually have the same thickness.

==5.4 Thermostatic Bimetals==

Thermostatic bimetals are composite materials consisting of two or three layers of materials with different coefficients of thermal expansion. They are usually bonded together by cladding. If such a material part is heated either directly through current flow or indirectly through heat conduction or radiation, the different expansion between the active (strong expansion) and passive (low expansion) layer causes bending of the component part.

Directional or force effects on the free end of the thermostatic bimetal part is then used as a trigger or control mechanism in thermostats, protective switches, or in control circuits. Depending on the required function of the thermostatic bimetal component different design shapes are used:

*'''Straight or U-shaped strips''' for nearly linear motion
*'''Circular discs''' for small linear motions with high force
*'''Spirals and filament spring shapes''' for circular motion
*'''Stamped and formed parts''' for special designs and applications

The wide variety of thermostatic bimetal types is specified mostly through DIN 1715 and/or applicable ASTM standards <xr id="tab:tab5.23"/> (Table 5.23). The different types have varying material compositions for the active and passive side of the materials. The mostly used alloys are iron-nickel and manganese-copper-nickel. Mainly used in circuit protection switches (i.e. circuit breakers) some thermo-bimetals include an intermediate layer of copper or nickel which allows to design parts with a closely controlled electrical resistance.

<figtable id="tab:tab5.23">
'''Table 5.23: Partial Selection from the Wide Range of Available Thermo-Bimetals'''

{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Designation DIN 1715
!Designation ASTM
!Specific Thermal Deflection [106/K]
!Sprecific Electrical Resistance k [μΩ·m]
!Typical Application Range [°C]
!Application Limit [°C]
!Composition
|-
|TB 20110 TB 1577A TB1170A 
|TM 2 TM 8 TM 1 TM 3 TM 4
|21.1 15.3 15.5 14.2 11.7 10.6 8.5
|1.12 1.41 0.79 0.78 0.70 0.71 0.66
| - 70 – + 260 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 425 - 70 – + 480 - 70 – + 425
|350 350 450 450 480 540 540
|Two components
|-
|TB 1517 TB 1511 TB 1303 TB 1109
| TM 28 TM 26 TM 25 TM 24 
|14.9 14.9 14.3 13.9 13.2 13.1 12.3 11.5
|0.17 0.11 0.15 0.08 0.03 0.05 0.03 0.09
| - 70 – + 260 - 70 – + 260 - 70 – + 315 - 70 – + 315 - 70 – + 260 - 70 – + 315 - 70 – + 315 - 70 – + 380
|400 400 350 350 300 350 350 400
|Three components with Cu intermediale layer
|-
|TB 1555 TB 1435 TB 1425 
| TM 17 TM 15 TM 13 TM 11 TM 9
|15.0 14.8 14.2 14.1 14.0 13.6 12.8 10.7
|0.55 0.40 0.66 0.50 0.25 0.33 0.25 0.17
| - 70 – + 260 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 260 - 70 – + 370 - 70 – + 370 - 70 – + 370
|450 450 480 480 450 480 480 480
|Three components with Ni intermediale layer
|}
</figtable>

===5.4.1 Design Formulas===

For the design and calculation of the most important thermostatic-bimetal parts formulas are given in Table 5.24. The necessary properties can be extracted for the most common materials from <xr id="tab:tab5.23"/> Table 5.23. The values given are valid only for a temperature range up to approximately 150°C. For higher temperatures data can be obtained from the materials manufacturer.

'''Table 5.24: Design Formulas for Thermostatic Bimetal Components''' (ganz große Tabelle!)

===5.4.2 Stress Force Limitations===

For all calculations according to the formulas in Table 5.24 one should check if the thermally or mechanically induced stress forces stay below the allowed bending force limit. The following formulas are applicable for calculating the allowable load (Force Pmax or momentum Mmax):

{| class="gray-first"
|Single side fixed strip
|<math>P_{max} <
\frac {\sigma Bs^2}{6L} </math>
|-
||
|-
|}

==Comments==
<references/>
==References==

ASM Handbuch Volume 2, 10th Edition: Properties and Selection of Nonferrous

Alloys and Special Purpose Materials, ASM International, Cleveland OH, USA 1990

Wieland-Kupferwerkstoffe. Wieland-Werke AG, Ulm 1999

Rau, G.: Metallische Verbundwerkstoffe. Werkstofftechnische

Verlagsgesellschaft, Karlsruhe 1977

Kayser, O., Pawlek, F., Reichel, K.: Die Beeinflussung der Leitfähigkeit reinsten

Kupfers durch Beimengungen. Metall 8 (1954) 532-537

Dies, K.: Kupfer und Kupferlegierungen in der Technik. Springer-Verlag, Berlin, Heidelberg, New York, 1967

Gerlach,U.; Kreye, H.: Gefüge und mechanische Eigenschaften der Legierung

CuNi9Sn2. Metall 32 (1978) 1112-1115

Beryvac, Firmenschrift Vakuumschmelze GmbH, Hanau 1974

Beryvac 520, Firmenschrift Vacuumschmelze GmbH, Hanau 1975

Kupfer-Beryllium, Firmenschrift Brush Wellman

Kreye, H.; Nöcker, H.; Terlinde, G.: Schrumpfung und Verzug beim Aushärten von Kupfer-Beryllium-Legierungen. Metall 29 (1975) 1118-1121

Precipitation Hardening Copper Alloys

2014-03-11T10:11:40Z

80.152.203.11: /* 5.1.6.2.1 Copper-Chromium Alloys */

====5.1.6.1 Copper-Beryllium Alloys (Beryllium Bronze)====

The cause for precipitation hardening of CuBe materials is the rapidly diminishing solubility of beryllium in copper as temperature decrease. As the
phase diagram for CuBe shows, 2.4 wt% of Be are soluble in Cu at 780°C <xr id="fig:Phase diagram of copperberyllium with temperature ranges for brazing and annealing treatments"/> (Fig. 5.28). In this temperature range annealed CuBe alloys are homogeneous(solution annealing). The homogeneous state can be frozen through rapid cooling to room temperature (quenching). Through a subsequent annealing at 325°C the desired precipitation hardening is achieved which results in a significant increase in mechanical strength and electrical conductivity of CuBe ''(Table 5.17)''. The final strength and hardness values depend on the annealing temperature and time as well as on the initial degree of cold working ''(Table 5.18)'' and [[#figures7|(Figs. 43 – 75)]](Figs. 5.29 - 5.31).

<figure id="fig:Phase diagram of copperberyllium with temperature ranges for brazing and annealing treatments">
Fig. 5.28: Phase diagram of copperberyllium with temperature ranges for brazing and annealing treatments
[[File:Phase diagram of copper beryllium with temperature ranges.jpg|right|thumb|Phase diagram of copper- beryllium with temperature ranges for brazing and annealing treatments]]
</figure>

As precipitation hardening alloys CuBe materials, mainly CuBe2 and CuBe1.7 have gained broad usage as current carrying contact springs because of their outstanding mechanical properties. Besides these CuCo2Be and CuNi2Be, which have medium mechanical strength and a relatively high electrical
conductivity, are also used as contact carrier materials. After stamping and forming into desired contact configurations these CuBe materials are then precipitation hardened. CuBe alloys are available as semi-finished materials in a variety of cold work conditions. They can also be supplied and used in the already precipitation hardened condition without significant strength losses. In this case the hardening was already performed at the alloy producer.

Since Beryllium is rated as a carcinogen by the European regulation EU-67/548, it has been tried to reach the application properties of the well established CuBe1.7 and CuBe2 alloys with a lower Be content. The development efforts for alternate precipitation hardening materials without toxic and declaration requiring additive materials, for example CuNiCoSi, are aimed at the replacement of CuBe.

<div id="figures7">
<xr id="fig:Precipitation hardening of CuBe2 at 325°C after different cold working"/> Fig. 5.29: Precipitation hardening of CuBe2 at 325°C after different cold working

<xr id="fig:Precipitation hardening of CuBe2 (soft) at 325°C"/> Fig. 5.30: Precipitation hardening of CuBe2 (soft) at 325°C

<xr id="fig:Precipitation hardening of CuBe2 (half hard) at different annealing temperatures"/> Fig. 5.31: Precipitation hardening of CuBe2 (half hard) at different annealing temperatures
</div>

<div class="multiple-images">
<figure id="fig:Precipitation hardening of CuBe2 at 325°C after different cold working">
[[File:Precipitation hardening of CuBe2 at 325C.jpg|right|thumb|Precipitation hardening of CuBe2 at 325°C after different cold working]]
</figure>

<figure id="fig:Precipitation hardening of CuBe2 (soft) at 325°C">
[[File:Precipitation hardening of CuBe2 (soft) at 325C.jpg|right|thumb|Precipitation hardening of CuBe2 (soft) at 325°C]]
</figure>

<figure id="fig:Precipitation hardening of CuBe2 (half hard) at different annealing temperatures">
[[File:Precipitation hardening of CuBe2 half hard.jpg|right|thumb|Precipitation hardening of CuBe2 (half hard) at different annealing temperatures]]
</figure>
</div>
<div class="clear"></div>

'''Table 5.17: Physical Properties of Selected Copper-Beryllium Alloys''' (2 Teile!)

'''Table 5.18: Mechanical Properties of Selected Copper-Beryllium Alloys''' (2 Teile!)

====5.1.6.2 Other Precipitation Hardening Copper Alloys====

=====5.1.6.2.1 Copper-Chromium Alloys=====

As the phase diagram shows, copper-chromium has a similar hardening profile compared to CuBe <xr id="fig:Copper corner of the copper-chromium phase diagram for up to 0.8 wt% chromium"/>(Fig. 5.32). In the hardened stage CuCr has limitations to work hardening. Compared to copper it has a better temperature stability with good electrical conductivity. Hardness and electrical conductivity as a function of cold working and precipitation hardening conditions are illustrated in [[#figures8|(Figs. 3 – 7)]] Figs. 5.33-5.35, <xr id="tab:tab5.19"/> (Tables 5.19) and <xr id="tab:tab5.20"/> (Tab. 5.20).

Copper-chromium materials are especially suitable for use as electrodes for resistance welding. During brazing the loss in hardness is limited if low melting brazing alloys and reasonably short heating times are used.

<figure id="fig:Copper corner of the copper-chromium phase diagram for up to 0.8 wt% chromium">
Fig. 5.32: Copper corner of the copper-chromium phase diagram for up to 0.8 wt% chromium
[[File:Copper corner of the copper chromium phase diagram.jpg|right|thumb|Copper corner of the copper-chromium phase diagram for up to 0.8 wt% chromium]]
</figure>

<div id="figures5">
<xr id="fig:Softening of precipitation hardened and subsequently cold worked CuCr1"/> Fig. 5.33: Softening of precipitation-hardened and subsequently cold worked CuCr1 after 4hrs annealing

<xr id="fig:Electrical conductivity of precipitation hardened CuCr 0.6"/> Fig. 5.34 a: Electrical conductivity of precipitation hardened CuCr 0.6 as a function of annealing conditions

<xr id="fig:Hardness of precipitation hardened CuCr 0.6"/> Fig. 5.34 b: Hardness of precipitation hardened CuCr 0.6 as a function of annealing conditions

<xr id="fig:Electrical conductivity and hardness of precipitation hardened CuCr 0.6"/> Fig. 5.35: Electrical conductivity and hardness of precipitation hardened CuCr 0.6 after cold working
</div>

<div class="multiple-images">
<figure id="fig:Softening of precipitation hardened and subsequently cold worked CuCr1">
[[File:Softening of precipitation hardened and subsequently cold worked CuCr1.jpg|right|thumb|Softening of precipitation-hardened and subsequently cold worked CuCr1 after 4hrs annealing]]
</figure>

<figure id="fig:Electrical conductivity of precipitation hardened CuCr 0.6">
[[File:Electrical conductivity of precipitation hardened CuCr 0.6.jpg|right|thumb|Electrical conductivity of precipitation hardened CuCr 0.6 as a function of annealing conditions]]
</figure>

<figure id="fig:Hardness of precipitation hardened CuCr 0.6">
[[File:Hardness of precipitation hardened CuCr 0.6.jpg|right|thumb|Hardness of precipitation hardened CuCr 0.6 as a function of annealing conditions]]
</figure>

<figure id="fig:Electrical conductivity and hardness of precipitation hardened CuCr 0.6">
[[File:Electrical conductivity and hardness of precipitation hardened CuCr 0.6.jpg|right|thumb|Electrical conductivity and hardness of precipitation hardened CuCr 0.6 after cold working]]
</figure>
</div>
<div class="clear"></div>

'''Table 5.19: Physical Properties of Other Precipitation Hardening Copper Alloys''' (2 Teile!)

'''Table 5.20: Mechanical Properties of Other Precipitation Hardening Copper Alloys'''

<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td>Material</td><td>HardnessCondi- tion</td><td>TensileStrength Rm[MPa]</td><td>0,2% YieldStrength Rp02[MPa]</td><td>ElongationA50[%]</td><td>VickersHardnessHV</td><td>Spring BendingLimit FFB [MPa]</td></tr><tr><td>CuCr</td><td>R 230aR 400a R 450b R 550b</td><td>> 230> 400> 450> 550</td><td>> 80> 295> 325> 440</td><td>3010108</td><td>> 55> 120> 130> 150</td><td>350</td></tr><tr><td>CuZr</td><td>R 260aR 370a R 400b R 420b</td><td>> 260> 370> 400> 420</td><td>> 100> 270> 280> 400</td><td>35121210</td><td>> 55> 100> 105> 115</td><td>280</td></tr><tr><td>CuCr1Zr</td><td>R 200aR 400bR 450b</td><td>> 200> 400> 450</td><td>> 60> 210> 360</td><td>301210</td><td>> 70> 140> 155</td><td>420</td></tr></table>

=====5.1.6.2.2 Copper-Zirconium Alloys=====

The solubility of Zirconium in copper is 0.15 wt% Zr at the eutectic temperature of 980°C ''(Fig. 5.36)''. Copper-zirconium materials have a similar properties spectrum compared to the one for copper-chromium materials. At room temperature the mechanical properties of copper-zirconium are less suitable than those of copper chromium, its temperature stability is however at least the same.

=====5.1.6.2.3 Copper-Chromium-Zirconium Alloys=====

The earlier used CuCr and CuZr materials have been partially replaced over the years by the capitation hardening three materials alloy CuCr1Zr. This material exhibits high mechanical strength at elevated temperatures and good oxidation resistance as well as high softening temperatures. In its hardened condition CuCr1Zr has also a high electrical conductivity (Bild 5.37). Their usage extends from mechanically and thermally highly stressed parts such as contact tulips in high voltage switchgear to electrodes for resistance welding.

Fig. 5.36: Copper corner of the copperzirconium for up to 0.5 wt% zirconium
[[File:Copper corner of the copper zirconium for up to 0.5-wt zirconium.jpg|right|thumb|Copper corner of the copper- zirconium for up to 0.5 wt% zirconium]]

Fig. 5.37: Softening of CuCr1Zr after 1 hr annealing and after 90% cold working
[[File:Softening of CuCr1Zr after 1hr annealing.jpg|right|thumb|Softening of CuCr1Zr after 1 hr annealing and after 90% cold working]]

==References==
[[Contact Carrier Materials#References|References]]

Switching Contacts

2014-03-11T08:59:32Z

80.152.203.11:

===6.4.4 Switching Contacts===

*'''Effects during switching operations'''

Fig. 6.7 Contact opening with arc formation (schematic)

*'''Influence of out-gasing from plastics'''
Fig. 6.9:
Histogram of the contact
resistance R of an electroplated K
palladium layer (3 μm) with and
without hard gold flash plating
(0.2 μm) after exposure with
different plastic materials

Fig. 6.10: Contact resistance with exposure to out-gasing from plastics as a function of numbers of
operations at 6 V ,100 mA: 1 Silicon containing plastic; 2 Plastics with strongly out-gasing DC
components; 3 Plastics with minimal out-gasing components

*'''Influence of corrosive gases on the contact resistance'''

Fig. 6.11: Distribution of cumulative frequency H of the contact resistance for solid contact rivets
after 10 days exposure in a three-component test environment with 400 ppb each of H2S, SO2 and
NO2 at 25°C, 75% RH; Contact force 10cN; Measuring parameters: ≤ 40 mVDC,10 mA; Probing
contact: Gold rivet

Fig. 6.8: Influences on contact areas in relays

*'''Contact Phenomena under the influence of arcing Matertia'''
*'''Material transfer'''
Fig. 6.12: Material transfer under DC load a) Cathode; b) Anode.
6 Material: AgNi0.15; Switching parameters: 12VDC, 3 A, 2x10 operations

*'''Arc erosion'''

Fig. 6.13 Arc erosion of a Ag/SnO2 contact pair after extreme arcing conditions
a) Overall view; b) Partial detail view

*'''Contact welding'''
Fig. 6.14: Micro structure of a welded contact pair (Ag/SnO2 88/12 - Ag/CdO88/12)
after extremely high current load. a) Ag/SnO2 88/12; b) Ag/CdO88/12

==References==
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]

Switching Contacts

2014-03-11T08:59:20Z

80.152.203.11:

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===6.4.4 Switching Contacts===

*'''Effects during switching operations'''

Fig. 6.7 Contact opening with arc formation (schematic)

*'''Influence of out-gasing from plastics'''
Fig. 6.9:
Histogram of the contact
resistance R of an electroplated K
palladium layer (3 μm) with and
without hard gold flash plating
(0.2 μm) after exposure with
different plastic materials

Fig. 6.10: Contact resistance with exposure to out-gasing from plastics as a function of numbers of
operations at 6 V ,100 mA: 1 Silicon containing plastic; 2 Plastics with strongly out-gasing DC
components; 3 Plastics with minimal out-gasing components

*'''Influence of corrosive gases on the contact resistance'''

Fig. 6.11: Distribution of cumulative frequency H of the contact resistance for solid contact rivets
after 10 days exposure in a three-component test environment with 400 ppb each of H2S, SO2 and
NO2 at 25°C, 75% RH; Contact force 10cN; Measuring parameters: ≤ 40 mVDC,10 mA; Probing
contact: Gold rivet

Fig. 6.8: Influences on contact areas in relays

*'''Contact Phenomena under the influence of arcing Matertia'''
*'''Material transfer'''
Fig. 6.12: Material transfer under DC load a) Cathode; b) Anode.
6 Material: AgNi0.15; Switching parameters: 12VDC, 3 A, 2x10 operations

*'''Arc erosion'''

Fig. 6.13 Arc erosion of a Ag/SnO2 contact pair after extreme arcing conditions
a) Overall view; b) Partial detail view

*'''Contact welding'''
Fig. 6.14: Micro structure of a welded contact pair (Ag/SnO2 88/12 - Ag/CdO88/12)
after extremely high current load. a) Ag/SnO2 88/12; b) Ag/CdO88/12

==References==
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]