Electrical Contacts - User contributions [en]

Platinum Metal Based Materials

2014-02-13T11:55:05Z

192.168.254.104: /* DEVELOP:ImageLIst */

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.

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 ''(Table 2.7)''. 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.

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 ''(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.

==DEVELOP:ImageLIst==
===BEGIN====

<xr id="fig:Properties,_Production_Processes,_and_Application_Forms_for_Platinum Metals"/> Properties, Production Processes, and Application Forms for Platinum Metals

<xr id="fig:Physical_Properties_of_the_Platinum_Metals_and_their_Alloys"/>
Physical Properties of the Platinum Metals and their Alloys

<xr id="fig:Mechanical_Properties_of_the_Platinum_Metals_and_their_Alloys"/>
Table 2.8: Mechanical Properties of the Platinum Metals and their Alloys

<xr id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum_(Degussa)"/>
Fig. 2.25: 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"/>
Fig. 2.26: 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:"/>
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:"/>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:"/>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:"/>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:"/>Fig. 2.43: Softening of PdCu40 after annealing for 0.5 hrs after 80% cold working

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

<xr id="fig:"/>'''Table 2.9: Contact and Switching Properties of the Platinum Metals and their Alloys'''

<xr id="fig:"/>'''Table 2.10: Application Examples and Form of Supply for Platinum Metals and their Alloys'''

===END====
Table 2.6: Properties, Production Processes, and Application Forms for Platinum Metals
<figtable id="fig:Properties,_Production_Processes,_and_Application_Forms_for_Platinum Metals">
[[File:Properties production platinum metals.jpg|left|thumb|<caption>Properties, Production Processes and Application Forms for Platinum Metals</caption>]]
</figtable>
<figtable id="fig:Physical_Properties_of_the_Platinum_Metals_and_their_Alloys">
Table 2.7: Physical Properties of the Platinum Metals and their Alloys
</figtable>
<figtable id="fig:Mechanical_Properties_of_the_Platinum_Metals_and_their_Alloys">
'''Table 2.8: Mechanical Properties of the Platinum Metals and their Alloys'''

<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td/><td>soft</td><td>70% cold worket</td><td>soft</td><td>70% coldworket</td><td>soft</td><td>70% coldworket</td></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>PdNi5Pd35AuAgPt</td><td>340</td><td>700</td><td>25</td><td>2</td><td>95</td><td>200420*</td></tr><tr><td>Pd44Ag38Cu15</td><td/><td/><td/><td/><td/><td>405*</td></tr><tr><td>PtAuZnPd40Co40W20</td><td/><td/><td/><td/><td/><td>680*</td></tr><tr><td>*maximum hardness</td><td/><td/><td/><td/><td/><td/></tr></table>
</figtable>

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

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

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

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

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

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

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

<figure id="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
[[File:Softening of Pt after annealing.jpg|right|thumb|Softening of Pt after annealing for 0.5 hrs after 80% cold working]]
</figure>

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

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

<figure id="">
Fig. 2.35: Strain hardening of PtNi8 by cold working
[[File:Strain hardening of PtNi8 by cold working.jpg|right|thumb|Strain hardening of PtNi8 by cold working]]

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

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

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

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

<figure id="">
Fig. 2.40: Strain hardening of PdCu15 by cold working
[[File:Strain hardening of PdCu15 by cold working.jpg|right|thumb|Strain hardening of PdCu15 by cold working]]
</figure>
<figure id="">
Fig. 2.41: Softening of PdCu15 after annealing for 0.5 hrs
[[File:Softening of PdCu15 after annealing.jpg|right|thumb|Softening of PdCu15 after annealing for 0.5 hrs]]
</figure>

<figure id="">
Fig. 2.42: Strain hardening of PdCu40 by cold working
[[File:Strain hardening of PdCu40 by cold working.jpg|right|thumb|Strain hardening of PdCu40 by cold working]]
</figure>

<figure id="">
Fig. 2.43: Softening of PdCu40 after annealing for 0.5 hrs after 80% cold working
[[File:Softening of PdCu40 after annealing.jpg|right|thumb|Softening of PdCu40 after annealing for 0.5 hrs after 80% cold working]]
</figure>

<figure id="">
Fig. 2.44: Electrical resistivity p of PdCu alloys with and without an annealing step for forming an ordered phase
[[File:Electrical resistivity p of PdCu alloys.jpg|right|thumb|Electrical resistivity p of PdCu alloys with and without an annealing step for forming an ordered phase]]
</figure>

<figtable id="">
'''Table 2.9: Contact and Switching Properties of the Platinum Metals and their Alloys'''
<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td>Material</td><td>Properties</td></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="">
'''Table 2.10: Application Examples and Form of Supply for Platinum Metals and their Alloys'''
<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td>Material</td><td>Application Examples</td><td>Forms of Supply</td></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>

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

2014-01-30T11:55:30Z

192.168.254.104:

Soon after it's founding in 1922 Electrical Contacts became the focal world for DODUCO. In
the previous two editions of the DODUCO Data Book this world was mostly limited to
Europe. Since expanding its reach globally from the 1970s through the 1990s, including the
start-up of manufacturing operations in China, the employees of DODUCO have
concentrated on solving electrical contact problems around the world as the main task of
their daily work.

Ever increasing requirements on the performance of contacts in electrical switching devices,
the need for highly reliable interconnections between electro-mechanics and electronics, the
minimizing of precious metal usage, and the call for more environmentally compatible
materials and manufacturing processes, defined in the past years the development of
materials and technologies related to electrical contacts. These latest developments and
repeated requests from our customers were the motivation to publish a new edition of the
well known DODUCO Data Book. It includes now also materials whose properties and
applications are mostly relevant in the North American and Asian markets. We also included
materials which are needed for the manufacturing of contact parts and assemblies, but are
outside of AMI DODUCO's product offerings. These include contact carrier materials such as
copper and nickel alloys, as well as thermostatic materials and brazing alloys.

Even so we felt it necessary to add more detailed descriptive passages about products
and technologies, which expanded the original focus on mostly data tables and
diagrams, we continue to keep the name Data Book. We updated and re-wrote most
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The third edition was published in English in 2010 under the name AMI DODUCO.
Since later in that year our company is owned by the investment groups Tinicum
Capital Partners II and JP Asia Partners and again is registered under the former name
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the reason to again revise the Data Book and publish the latest version under the well
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This new DODUCO Data Book again is meant to be a handy reference and data source
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can however not be a full substitute for personal discussions with experts in electrical
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ready to answer your questions.

Please challenge us with your unique problems or special requests; because our
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The Editors
DODUCO
Pforzheim, Germany, May 2012

#[[Physical Properties of the Most Important Metals|Physical Properties of the Most Important Metals ]]
#[[Contact Materials for Electrical Engineering| Contact Materials for Electrical Engineering ]]
#[[Manufacturing Technologies for Contact Parts|Manufacturing Technologies for Contact Parts ]]
#[[Brazing Alloys and Fluxes|Brazing Alloys and Fluxes ]]
#[[Contact Carrier Materials|Contact Carrier Materials ]]
#[[Application Tables and Guideline Data for Use of Electrical Contact Design |Application Tables and Guideline Data for Use of Electrical Contact Design ]]
#[[Surface Coating Technologies| Surface Coating Technologies ]]
#[[ Precious Metal Powders and Preparations|Precious Metal Powders and Preparations ]]
#[[Applications for Bonding Technologies|Applications for Bonding Technologies ]]
#[[Electromechaninal Components | Electromechaninal Components ]]
#[[Precious Metal Refining| Precious Metal Refining ]]
#[[Environmental Aspects| Environmental Aspects ]]
#[[Testing Procedures| Testing Procedures ]]

Physical Properties of the Most Important Metals

2014-01-28T12:48:47Z

192.168.254.104:

bubledipup
<onlyinclude>The following tables list the physical properties of the most technically significant pure metals as well as carbon. The values given may vary considerably depending on the degree of purity and sometimes they are also difficult to determine. In compiling the data from the available literature we selected those that are currently the most probable. Some properties are anisotropic and vary with the crystalline structure of the metal.</onlyinclude> In those cases, whenever possible, we listed the value applicable to the poly-crystalline stage. 

'''Tab. Mechanical Properties of the Most Important Metals'''

[[File:Mechanical-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Mechanical Properties of the Most Important Metals]]

'''Tab. Atomic Properties of the Most Important Metals'''

[[File:Atomic-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Atomic Properties of the Most Important Metals]]

'''Tab. Thermal Properties of the Most Important Metals'''

[[File:Thermal-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Thermal Properties of the Most Important Metals]]

'''Tab. Electrical Properties of the Most Important Metals'''

[[File:Electrical-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Electrical Properties of the Most Important Metals]]

===References===

Metals Handbook, Desk Edition: Chicago, IL, American Society of Metal, 1985

Landolt-Börnstein: Zahlenwerte und Funktionen. Springer-Verlag, Berlin-Göttingen-Heidelberg, 1959

Handbook of Chemistry and Physics, 70th Edition: CRC Press., Inc. Boca Raton, Florida, 1989 - 1990

Fluck, E.; Heumann, K., G.: Periodensystem der Elemente. Weinheim: VCH-Verlagsgesellschaft, 1986

Kieffer, R.; Jangg, G.; Ettmayer, P.: Sondermetalle. Springer- Verlag, Wien-New York, 1963

Hering, E.; Schulz, W.: Physik für Ingenieure (Periodensystem der Elemente). Düsseldorf: VDI-Verlag, 1988

Degussa AG (Hrsg.): Edelmetall-Taschenbuch. Hüthig-Verlag, Heidelberg, 1995

Slade, P.; G. (editor): Electrical Contacts Principles and Applications. Marcel Dekker, Inc., New York-Basel, 1999

Gerritsen, A.; N.: Metallic Conductivity in: Flügge, S.: Handbuch der Physik, Bd. 19, Springer-Verlag, Berlin-Göttingen-Heidelberg, 1956

Köster, W.; Franz, H.: Poisson,s Ratio for Metals and Alloys. Metallurg. Reviews 6 (1961)

Nesmeyanow, A., N.: Vapor Pressure of the Chemical Elements: Elsevier, Amsterdam-London-New York, 1963

Wyckoff, R., W., G.: Crystal Structures. Vol 1,New York, 1963

[[Category:Metal Powders|Category]]
[[Category:Thermal conductivity|Category]]

Physical Properties of the Most Important Metals

2014-01-28T11:41:15Z

192.168.254.104: Undo revision 1059 by 192.168.254.104 (talk)

<onlyinclude>The following tables list the physical properties of the most technically significant pure metals as well as carbon. The values given may vary considerably depending on the degree of purity and sometimes they are also difficult to determine. In compiling the data from the available literature we selected those that are currently the most probable. Some properties are anisotropic and vary with the crystalline structure of the metal.</onlyinclude> In those cases, whenever possible, we listed the value applicable to the poly-crystalline stage. 

'''Tab. Mechanical Properties of the Most Important Metals'''

[[File:Mechanical-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Mechanical Properties of the Most Important Metals]]

'''Tab. Atomic Properties of the Most Important Metals'''

[[File:Atomic-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Atomic Properties of the Most Important Metals]]

'''Tab. Thermal Properties of the Most Important Metals'''

[[File:Thermal-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Thermal Properties of the Most Important Metals]]

'''Tab. Electrical Properties of the Most Important Metals'''

[[File:Electrical-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Electrical Properties of the Most Important Metals]]

===References===

Metals Handbook, Desk Edition: Chicago, IL, American Society of Metal, 1985

Landolt-Börnstein: Zahlenwerte und Funktionen. Springer-Verlag, Berlin-Göttingen-Heidelberg, 1959

Handbook of Chemistry and Physics, 70th Edition: CRC Press., Inc. Boca Raton, Florida, 1989 - 1990

Fluck, E.; Heumann, K., G.: Periodensystem der Elemente. Weinheim: VCH-Verlagsgesellschaft, 1986

Kieffer, R.; Jangg, G.; Ettmayer, P.: Sondermetalle. Springer- Verlag, Wien-New York, 1963

Hering, E.; Schulz, W.: Physik für Ingenieure (Periodensystem der Elemente). Düsseldorf: VDI-Verlag, 1988

Degussa AG (Hrsg.): Edelmetall-Taschenbuch. Hüthig-Verlag, Heidelberg, 1995

Slade, P.; G. (editor): Electrical Contacts Principles and Applications. Marcel Dekker, Inc., New York-Basel, 1999

Gerritsen, A.; N.: Metallic Conductivity in: Flügge, S.: Handbuch der Physik, Bd. 19, Springer-Verlag, Berlin-Göttingen-Heidelberg, 1956

Köster, W.; Franz, H.: Poisson,s Ratio for Metals and Alloys. Metallurg. Reviews 6 (1961)

Nesmeyanow, A., N.: Vapor Pressure of the Chemical Elements: Elsevier, Amsterdam-London-New York, 1963

Wyckoff, R., W., G.: Crystal Structures. Vol 1,New York, 1963

[[Category:Metal Powders|Category]]
[[Category:Thermal conductivity|Category]]

Physical Properties of the Most Important Metals

2014-01-28T11:40:17Z

192.168.254.104:

blub
<onlyinclude>The following tables list the physical properties of the most technically significant pure metals as well as carbon. The values given may vary considerably depending on the degree of purity and sometimes they are also difficult to determine. In compiling the data from the available literature we selected those that are currently the most probable. Some properties are anisotropic and vary with the crystalline structure of the metal.</onlyinclude> In those cases, whenever possible, we listed the value applicable to the poly-crystalline stage. 

'''Tab. Mechanical Properties of the Most Important Metals'''

[[File:Mechanical-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Mechanical Properties of the Most Important Metals]]

'''Tab. Atomic Properties of the Most Important Metals'''

[[File:Atomic-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Atomic Properties of the Most Important Metals]]

'''Tab. Thermal Properties of the Most Important Metals'''

[[File:Thermal-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Thermal Properties of the Most Important Metals]]

'''Tab. Electrical Properties of the Most Important Metals'''

[[File:Electrical-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Electrical Properties of the Most Important Metals]]

===References===

Metals Handbook, Desk Edition: Chicago, IL, American Society of Metal, 1985

Landolt-Börnstein: Zahlenwerte und Funktionen. Springer-Verlag, Berlin-Göttingen-Heidelberg, 1959

Handbook of Chemistry and Physics, 70th Edition: CRC Press., Inc. Boca Raton, Florida, 1989 - 1990

Fluck, E.; Heumann, K., G.: Periodensystem der Elemente. Weinheim: VCH-Verlagsgesellschaft, 1986

Kieffer, R.; Jangg, G.; Ettmayer, P.: Sondermetalle. Springer- Verlag, Wien-New York, 1963

Hering, E.; Schulz, W.: Physik für Ingenieure (Periodensystem der Elemente). Düsseldorf: VDI-Verlag, 1988

Degussa AG (Hrsg.): Edelmetall-Taschenbuch. Hüthig-Verlag, Heidelberg, 1995

Slade, P.; G. (editor): Electrical Contacts Principles and Applications. Marcel Dekker, Inc., New York-Basel, 1999

Gerritsen, A.; N.: Metallic Conductivity in: Flügge, S.: Handbuch der Physik, Bd. 19, Springer-Verlag, Berlin-Göttingen-Heidelberg, 1956

Köster, W.; Franz, H.: Poisson,s Ratio for Metals and Alloys. Metallurg. Reviews 6 (1961)

Nesmeyanow, A., N.: Vapor Pressure of the Chemical Elements: Elsevier, Amsterdam-London-New York, 1963

Wyckoff, R., W., G.: Crystal Structures. Vol 1,New York, 1963

[[Category:Metal Powders|Category]]
[[Category:Thermal conductivity|Category]]

Physical Properties of the Most Important Metals

2014-01-27T12:45:00Z

192.168.254.104:

ters
<onlyinclude>The following tables list the physical properties of the most technically significant pure metals as well as carbon. The values given may vary considerably depending on the degree of purity and sometimes they are also difficult to determine. In compiling the data from the available literature we selected those that are currently the most probable. Some properties are anisotropic and vary with the crystalline structure of the metal.</onlyinclude> In those cases, whenever possible, we listed the value applicable to the poly-crystalline stage. 

'''Tab. Mechanical Properties of the Most Important Metals'''

[[File:Mechanical-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Mechanical Properties of the Most Important Metals]]

'''Tab. Atomic Properties of the Most Important Metals'''

[[File:Atomic-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Atomic Properties of the Most Important Metals]]

'''Tab. Thermal Properties of the Most Important Metals'''

[[File:Thermal-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Thermal Properties of the Most Important Metals]]

'''Tab. Electrical Properties of the Most Important Metals'''

[[File:Electrical-Properties-of-the-Most-Important-Metals.jpg|right|thumb|Electrical Properties of the Most Important Metals]]

===References===

<onlyinclude>
[[Category:Metal Powders|Category]]
[[Category:Thermal conductivity|Category]]
</onlyinclude>

Metals Handbook, Desk Edition: Chicago, IL, American Society of Metal, 1985

Landolt-Börnstein: Zahlenwerte und Funktionen. Springer-Verlag, Berlin-Göttingen-Heidelberg, 1959

Handbook of Chemistry and Physics, 70th Edition: CRC Press., Inc. Boca Raton, Florida, 1989 - 1990

Fluck, E.; Heumann, K., G.: Periodensystem der Elemente. Weinheim: VCH-Verlagsgesellschaft, 1986

Kieffer, R.; Jangg, G.; Ettmayer, P.: Sondermetalle. Springer- Verlag, Wien-New York, 1963

Hering, E.; Schulz, W.: Physik für Ingenieure (Periodensystem der Elemente). Düsseldorf: VDI-Verlag, 1988

Degussa AG (Hrsg.): Edelmetall-Taschenbuch. Hüthig-Verlag, Heidelberg, 1995

Slade, P.; G. (editor): Electrical Contacts Principles and Applications. Marcel Dekker, Inc., New York-Basel, 1999

Gerritsen, A.; N.: Metallic Conductivity in: Flügge, S.: Handbuch der Physik, Bd. 19, Springer-Verlag, Berlin-Göttingen-Heidelberg, 1956

Köster, W.; Franz, H.: Poisson,s Ratio for Metals and Alloys. Metallurg. Reviews 6 (1961)

Nesmeyanow, A., N.: Vapor Pressure of the Chemical Elements: Elsevier, Amsterdam-London-New York, 1963

Wyckoff, R., W., G.: Crystal Structures. Vol 1,New York, 1963

Testing Procedures

2014-01-24T12:51:40Z

192.168.254.104:

The procedures and standards for testing electrical contacts described below are mostly concentrated on contact applications in electromechanical devices. Since the range of applications for electrical contacts is very broad, a complete description of all relevant test procedures would extend the scope of this chapter of the Data Book. Therefore we limited the content here to contact coatings and switching contacts for information and power engineering. Because of the ongoing miniaturization of electromechanical devices the testing for effects of corrosive influences by the environment play an important role. Special testing procedures, such as these for brazed, soldered, and welded contact joints are covered already in chapter 3.

==13.1 Terms and Definitions==

Every technical device has to fulfill a series of requirements. Some of those which are important for agreement between contact manufacturer and user are part of DIN 40042 standard and described here in a summarized version:

*Availability (Ready-for-Use) and Reliabilty

Availability (for use) defines the probability of a system or switching device to be in a functional stage at a given time

Reliability describes the system's ability to fulfill at any time the requirements of an application within pre-defined limitations.

Both, availability and reliability, are guaranteed for a pre-determined time span and/or a specific number of switching operations. This means they warrant the life expectancy of a switching device. At the end of the live span the failure rate exceeds pre-defined limit values.

*Electrical Life

Electrical life is the number of operations reached under a given electrical load under specified operating conditions.
Since the criteria which determine the electrical life of switching contacts depend on the type of switching devices they are used in, they are described in more detail under the testing procedures in information and power engineering.

==13.2 Testing of Contact Surface Layers==

For applications at low switching loads contact layers with thicknesses in the range of just a few micrometers are widely used. For testing such thin layers the actual coating properties must be distinguished from the functional properties. Coating properties include, besides others, porosity, hardness, and ductility.
Depending on the application, the most important function properties are for example frictional wear, contact resistance, material transfer, or contact welding behavior. Besides these other technological properties such as adhesion strength, and solderability, maybe of importance for special applications like those for electronic components.

The following descriptions are mainly applicable to electroplated contact coatings which are of the most economical importance in contact applications. They also apply however in similar form to surface layers which have been created by mechanical cladding or by sputtering.

Main Articel: [[Testing of Contact Surface Layers| Testing of Contact Surface Layers]]

==13.3 Test Procedures for the Communications Technology==

Testing of the contact behavior in the communications technology is usually performed on the actual devices such as for example in relays. Experience has shown that the interaction between all design and functional parameters such as contact forces, relative movement, and electrical loads, are determining the failure mode. Therefore only statistical performance tests on a larger number of switching devices lead to meaningful results.

One must differentiate between static tests (for ex. contact resistance) and dynamic ones (for ex. electrical life). In certain electromechanical components and switching devices the contacts can be exposed to both, static and dynamic stresses (for ex. connectors, relays, switches, pushbuttons, circuit breakers). For statically stressed components the life expectancy is usually expressed as a time period, i.e. hours, while for dynamically stressed ones the expected functional life is defined as numbers of operations or switching cycles.

Main Articel: [[Test Procedures for the Communications Technology| Test Procedures for the Communications Technology]]

==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.

Main Articel: [[Testing Procedures for Power Engineering| Testing Procedures for Power Engineering]]

==13.5 Corrosion Testing==

===13.5.1 Definition of “Corrosion”===

The definition of corrosion can be found in DIN 500900 Part 1 as follows: Reaction of a metallic material with its environment, which produces a
measurable change in the material and can lead to corrosion damage. This reaction is in most cases an electrochemical one. It can however also be based on chemical and metal-physics effects.

During corrosive influences metal is dissolved. This metal loss can be uniformly spread out over a certain area or be limited to locally smaller spots. This process usually proceeds with constant speed up to the total material loss, or after certain reaction times a natural corrosion limiting surface layer can be formed (i.e. on aluminum).

===13.5.2 Special Types of Corrosion===

*Contact corrosion: Corrosion of a metal object after coming into physical contact with another metallic body. This can occur also on metallic impurities in alloys, on chemically and physically heterogeneous surfaces and on heterogeneous solutions on homogeneous surfaces, as well as through contacting a metal object by non-metallic materials through formation of corrosion compounds. 

*Hole corrosion (pitting corrosion): Local narrowly limited corrosion growing by dissolving material in small pin holes or craters to a depth that can lead to holes all the way through the material. 

*Inter-crystalline corrosion: Corrosion along the grain boundaries with the danger for the material to lose all its mechanical strength by decomposition (for example: at weld seams in austenitic stainless steels). 

*Selective corrosion: Preferred corrosion in specific microstructure areas (for example: loss of zinc in brasses with formation of copper enrichments). 

*Air access corrosion: Through differences in the amount of exposure to air or oxygen surface areas of a metal are becoming cathodes at the more exposed spots and therefore corrode less than those protected (for example: gap corrosion in screw or press connections). 

*Tension stress corrosion: Crack formation of stress corrosion sensitive materials which are under mechanical pull stresses while exposed to corrosive media. Especially affected are zinc containing copper alloys (brasses) under the influence of ammonia or nitrates. 

*Oxygen corrosion: Cathodic reaction in aqueous solutions forms reduced molecular, in water dissolved oxygen. Corrosion occurs when the electrochemical potential of the metal is below that of oxygen. 

*Hydrogen corrosion: Cathodic reduction of H to H2 (in acidic solutions) under conditions where the potential of the metal is less precious. 

*Fretting (frictional) corrosion: Enrichment of oxide particles of non-precious metal (especially tinned) surfaces during relative movements at small ampliyudes (< 100 μm). They occur through transfer of oscillation ot thermal displacement energy because of the difference in thermal expansion of the two contacting metals. This effect can be especially detrimental in connectors with tin plated surfaces, such as for example in automotive applications. 

*Fatigue corrosion: Fatigue fracture during repeated mechanical stresses in corrosive environments. This effect is often observed on brittle electroplated surface coatings that are exposed to repeated cycling between mechanical stresses and corrosive chemicals. Air access corrosion: Through differences in the amount of exposure to air or oxygen surface areas of a metal are becoming cathodes at the more exposed spots and therefore corrode less than those protected (for example: gap corrosion in screw or press connections). 

===13.5.3 Electrochemical Potentials===

Corrosion effects are mainly governed by the electrode potential of the respective metals. The electrochemical potential table provides a measure for corrosion resistance. Non-precious (corrosion prone) metals are characterized by a negative, precious (corrosion resistant) metals by a positive normal potential against hydrogen.

Table 13.3: Electrode Potential of Metals

===13.5.4 Corrosion Testing===

The following pages describe test methods and procedures which are mainly related to the effects of environmental exposure of electrical contacts which are used in contact components for the telecommunication and information technology.
Corrosion products on the surface of electrical contacts can reduce the reliability of contact making significantly by, for example, higher contact
resistance, which will negatively affect the transmission of current and data signals. This can cause major problems in electromechanical contact
components used in the information processing technology. Causes for the formation of tarnish film on electrical contacts include for example the presence of corrosive gases such as H2S, SO2, NOx, O3, Cl2, and NH3 ''(Table 13.4)'' in industrial environments.

Table 13.4: Typical Corrosive Gas Concentrations (ppm) Near Industrial Facilities

Corrosion tests – also called environmental – on electrical contacts in natural environments must be critically evaluated, because they are the rather time consuming.

During different times of the year temperature and relative humidity changes as well as changes in the concentration of corrosive gases can have significant influences on the formation of corrosion products.

Therefore research and quality assurance efforts have centered for many years on developing test methods for electrical contacts which can predict in an accelerated time frame the corrosion behavior of electrical contacts in different corrosive atmospheres with reasonable accuracy.

Single components corrosive test atmospheres and testing with two gas exposures following each other provide only limited validity. Flowing gas test
atmospheres with four components have proven to be the most likely ones to realistically simulate long term natural corrosive gas exposure ''(Table 13.4)''.

Table 13.5: Some Standardized Corrosion Tests for Electrical Contacts

The differences in the corrosive gas concentrations and the test durations are dependent on the end application of the contact components and the
assessment of the exposure parameters.
Battelle (the Battelle Institute) has, for different applications, defined four climate classes which reflect the corrosion behavior of porous electroplated gold surfaces. Such gold layers are often used in connectors for the telecommunications and information technology ''(Table 13.5, Fig. 13.14)''.

Table 13.5: Classification of Corrosion Effects According to Battelle

The dominant corrosion effects for thin gold coatings are pore corrosion and at higher gas concentrations creep corrosion from the base materials onto the coating starting at the boundary line between non-precious base metal and contact layer.

Fig. 13.14:
Influence of the corrosive gas
concentration for four classes ( – )
on the contact resistance of a porous
gold layer as a function of the exposure
time (Battelle)

The measurement of contact resistance allows an indirect classification of corrosion product layers. While the analysis of thicker corrosive product layers in the range of 0.1 – 1 μm can be performed by classic methods such as SEM and X-ray microprobe, thinner layers of 10 – 100 nm require the use of ionoptical analysis equipment.

==References==

Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer-Verlag, Berlin, Heidelberg, New York 2002

Nobel, F.J.; Ostrow, B.D.; Thomson, D.W.: Porosity Testing of Gold Deposits. Plating 52 (1965) 1001-1008

Bedetti, F.V.; Chiarenzelli, R.V.: Porosity Testing of Electroplated Gold. Plating 53 (1966) 305-308

Antler, M.: Gold-plated Contacts: Effect of Substrate Roughness on Reliability. Plating 56 (1969) 1139-1144

Huck, M.; Mayer, U.: Korrosionsbeständigkeit und Werkstoffeigenschaften galvanischer Legierungsniederschläge für die Elektroindustrie. Metalloberfläche 10, (1984) 427-434

Wund, K.; Schnabl, R.: Gold und seine Legierungen in der Galvanotechnik. Galvanotechnik 77(2) (1986) 312-324

DIN EN ISO 6507: Metallic materials - Vickers hardness test - Part 1: Test method

DIN ISO 4516: Metallic and other inorganic coating - Vickers and Knoop hardness test

Dengel, D.: Wichtige Gesichtspunkte für die Härtemessung nach Vickers und nach Knoop im Bereich der Kleinlast und Mikrolast.

Z. Werkstofftechnik 4 (1973) 292-298

Schnabl, R.: Herstellverfahren und Prüfungen für Kontaktschichten in der Nachrichtentechnik. Buchreihe „Kontakt & Studium“, Bd. 366: Werkstoffe für elektrische Kontakte und ihre Anwendungen, Expert-Verlag, Renningen,Bd

366, (1997) 279-310

Bogenschütz, A.F.; Jostan, J.L.; Mussinger, W.: Galvanische

Korrosionsschutzschichten für elektronische Anwendungen. Metalloberfläche
34 (1980) 45-53, 93-136, 163-168, 187-194 (mit J. Ruf), 229-235, 261-269

Huck, M.: Kontaktzuverlässigkeit von Steckverbindern. Metall 37 (1983) H.7,

685-690

Kaspar, F.: Drahtbonden zur Kontaktierung auf elektronischen Baugruppen, 13

Werkstoffen und Beschichtungen. VDE-Fachbericht 55, (1999) 97-103

Weiser,J.: Prüfverfahren in der Informationstechnik. In Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer Verlag, Berlin, Heidelberg, New York (2002) 600 - 609

I Data Book I Testing Procedures I

Schäfer, E.: Zuverlässigkeit, Verfügbarkeit und Sicherheit in der Elektronik, Vogel-Verlag, (1979)

Siepmann, R.: Elektronische Lastnachbildung, Siemens Comp., (1990) 28

Johler, W.: Untere und obere Einsatzgrenzen von Signalrelais. VDE-Fachbericht 63 (2007) 31-40

IEC/EN 61810-2: Electromechanical elementary relays - Part 2: Reliability

IEC/EN 61810-7: Electromechanical elementary relays - Part 7: Test and measurement procedures

Braumann, P.; Koffler, A.: Einfluss von Herstellungsverfahren, Metalloxidgehalt und Wirkzusätzen auf das Schaltverhalten von AgSnO2 in Relais (1).
VDE-Fachbericht 59 (2003) 133-142
Braumann, P.; Koffler, A.: Einfluss von Herstellungsverfahren, Metalloxidgehalt und Wirkzusätzen auf das Schaltverhalten von AgSnO2 in Relais (2).
VDE-Fachbericht 61 (2005) 149-154

Schöpf, Th.: Silber/Zinnoxid und andere Silber/Metalloxidwerkstoffe in

Netzrelais. VDE-Fachbericht 51 (1997) 41-50

Behrens, V.; Honig, Th.; Kraus, A.; Michal, R.: Schalteigenschaften von verschiedenen Silber/Zinnoxid-Werkstoffen in Kfz-Relais.

VDE-Fachbericht 51 (1997) 51-57

Braumann, P.: Prüfung der elektrischen Lebensdauer von Kfz-Relais. VDE-Fachbericht 55 (1999) 49-59

Schröder, K.-H.: Prüfverfahren in der Energietechnik. In Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer-Verlag, Berlin, Heidelberg, New York (2002) 609-633

IEC/EN 60947-4-1: Low-voltage switchgear and controlgear - Part 4-1: Contactors and motor-starters-Electromechanical contactors and motor starters

IEC/EN 60947-5-1: Low-voltage switchgear and controlgear - Part 5-1: Control circuit devices and switching elements- Electromechanical control circuit devices

IEC/EN 60947-2: Low-voltage switchgear and controlgear - Part 2: Circuitbreakers

UL 489: „Molded Case Circuit Breakers, Molded Case Switches and Circuit Breaker enclosures“

Braumann, P.; Koffler, A.; Schröder, K.-H.: Analysis of Interrelation Between Mechanical and Eletrical Phenomena During Making Operations of Contacts: Proc. 17th Int. Conf. on Electrical Contacts, Nagoya, Japan, 1994

Braumann, P.; Koffler, A.: The Importance of Characterizing the Make and Break Operations to Allow Effective Contact Material Development. 19. ITK Nürnberg, VDE-Verlag, Berlin, Offenbach, (1998) 325-333

EN ISO 8044: Corrosion of metals and alloys - Basic terms and definitions. Berlin, Beuth-Verlag 1999

Abbott, W.H.: Contact Corrosion. in Slade, P.: Electrical Contacts, Principles and Applications: Marcel Dekker, Inc., New York, Basel, (1999) 113 - 154

Slade, P.: Introduction to Contact Tarnishing and Corrosion. in Slade, P.: Electrical Contacts, Principles and Applications: Marcel Dekker, Inc., New York, Basel, (1999) 89 - 112

Cosack, U.: Survey of Corrosion Tests with Pollutant Gases and their Relevance for Contact Material. Proc. of the 13th Intern. Conf. on Electr. Contacts, Lausanne, Switzerland, (1986) 316-325

Schnabl, R.; Paulsen, R.: Korrosionserscheinungen an Edelmetallen und

Trägerwerkstoffen. Metall 7 (1987) 696-701

Abbott, W.H.: The Development and Performance Characteristics of Flowing Mixed Gas Test Environments. IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 2, No. 1, (1988) 22-35

Hienomen, R.; Rakkolainen, J.; Saarinen, T.; Aberg, M.: Nordic Project on Corrosion in Electronics. A Comparative Study on Field and Laboratory Test Results of Various Electronic Contacts. Proc. 14th Int. Conf. on Electric Contacts, Paris, (1988) 271-275

Leygraf, Ch.: Indoor Athmosperic Corrosion. VDE-Fachbericht 63 (2007) 39-52

ASTM Designation B 845-97: Standard Guide for Mixed Flowing Gas (MFG) Tests for Electrical Contacts, 1997

IEC Standard 68-2-60, Environmental Testing Part 2: Tests Flowing-Mixed Gas

Corrosion Test, 1995

Telcordia GR-63-CORE Issue 2, Section 5.5 : Airborne Contaminants Test

Methods, Nov. 2000

Testing Procedures

2014-01-24T12:51:28Z

192.168.254.104:

Test
The procedures and standards for testing electrical contacts described below are mostly concentrated on contact applications in electromechanical devices. Since the range of applications for electrical contacts is very broad, a complete description of all relevant test procedures would extend the scope of this chapter of the Data Book. Therefore we limited the content here to contact coatings and switching contacts for information and power engineering. Because of the ongoing miniaturization of electromechanical devices the testing for effects of corrosive influences by the environment play an important role. Special testing procedures, such as these for brazed, soldered, and welded contact joints are covered already in chapter 3.

==13.1 Terms and Definitions==

Every technical device has to fulfill a series of requirements. Some of those which are important for agreement between contact manufacturer and user are part of DIN 40042 standard and described here in a summarized version:

*Availability (Ready-for-Use) and Reliabilty

Availability (for use) defines the probability of a system or switching device to be in a functional stage at a given time

Reliability describes the system's ability to fulfill at any time the requirements of an application within pre-defined limitations.

Both, availability and reliability, are guaranteed for a pre-determined time span and/or a specific number of switching operations. This means they warrant the life expectancy of a switching device. At the end of the live span the failure rate exceeds pre-defined limit values.

*Electrical Life

Electrical life is the number of operations reached under a given electrical load under specified operating conditions.
Since the criteria which determine the electrical life of switching contacts depend on the type of switching devices they are used in, they are described in more detail under the testing procedures in information and power engineering.

==13.2 Testing of Contact Surface Layers==

For applications at low switching loads contact layers with thicknesses in the range of just a few micrometers are widely used. For testing such thin layers the actual coating properties must be distinguished from the functional properties. Coating properties include, besides others, porosity, hardness, and ductility.
Depending on the application, the most important function properties are for example frictional wear, contact resistance, material transfer, or contact welding behavior. Besides these other technological properties such as adhesion strength, and solderability, maybe of importance for special applications like those for electronic components.

The following descriptions are mainly applicable to electroplated contact coatings which are of the most economical importance in contact applications. They also apply however in similar form to surface layers which have been created by mechanical cladding or by sputtering.

Main Articel: [[Testing of Contact Surface Layers| Testing of Contact Surface Layers]]

==13.3 Test Procedures for the Communications Technology==

Testing of the contact behavior in the communications technology is usually performed on the actual devices such as for example in relays. Experience has shown that the interaction between all design and functional parameters such as contact forces, relative movement, and electrical loads, are determining the failure mode. Therefore only statistical performance tests on a larger number of switching devices lead to meaningful results.

One must differentiate between static tests (for ex. contact resistance) and dynamic ones (for ex. electrical life). In certain electromechanical components and switching devices the contacts can be exposed to both, static and dynamic stresses (for ex. connectors, relays, switches, pushbuttons, circuit breakers). For statically stressed components the life expectancy is usually expressed as a time period, i.e. hours, while for dynamically stressed ones the expected functional life is defined as numbers of operations or switching cycles.

Main Articel: [[Test Procedures for the Communications Technology| Test Procedures for the Communications Technology]]

==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.

Main Articel: [[Testing Procedures for Power Engineering| Testing Procedures for Power Engineering]]

==13.5 Corrosion Testing==

===13.5.1 Definition of “Corrosion”===

The definition of corrosion can be found in DIN 500900 Part 1 as follows: Reaction of a metallic material with its environment, which produces a
measurable change in the material and can lead to corrosion damage. This reaction is in most cases an electrochemical one. It can however also be based on chemical and metal-physics effects.

During corrosive influences metal is dissolved. This metal loss can be uniformly spread out over a certain area or be limited to locally smaller spots. This process usually proceeds with constant speed up to the total material loss, or after certain reaction times a natural corrosion limiting surface layer can be formed (i.e. on aluminum).

===13.5.2 Special Types of Corrosion===

*Contact corrosion: Corrosion of a metal object after coming into physical contact with another metallic body. This can occur also on metallic impurities in alloys, on chemically and physically heterogeneous surfaces and on heterogeneous solutions on homogeneous surfaces, as well as through contacting a metal object by non-metallic materials through formation of corrosion compounds. 

*Hole corrosion (pitting corrosion): Local narrowly limited corrosion growing by dissolving material in small pin holes or craters to a depth that can lead to holes all the way through the material. 

*Inter-crystalline corrosion: Corrosion along the grain boundaries with the danger for the material to lose all its mechanical strength by decomposition (for example: at weld seams in austenitic stainless steels). 

*Selective corrosion: Preferred corrosion in specific microstructure areas (for example: loss of zinc in brasses with formation of copper enrichments). 

*Air access corrosion: Through differences in the amount of exposure to air or oxygen surface areas of a metal are becoming cathodes at the more exposed spots and therefore corrode less than those protected (for example: gap corrosion in screw or press connections). 

*Tension stress corrosion: Crack formation of stress corrosion sensitive materials which are under mechanical pull stresses while exposed to corrosive media. Especially affected are zinc containing copper alloys (brasses) under the influence of ammonia or nitrates. 

*Oxygen corrosion: Cathodic reaction in aqueous solutions forms reduced molecular, in water dissolved oxygen. Corrosion occurs when the electrochemical potential of the metal is below that of oxygen. 

*Hydrogen corrosion: Cathodic reduction of H to H2 (in acidic solutions) under conditions where the potential of the metal is less precious. 

*Fretting (frictional) corrosion: Enrichment of oxide particles of non-precious metal (especially tinned) surfaces during relative movements at small ampliyudes (< 100 μm). They occur through transfer of oscillation ot thermal displacement energy because of the difference in thermal expansion of the two contacting metals. This effect can be especially detrimental in connectors with tin plated surfaces, such as for example in automotive applications. 

*Fatigue corrosion: Fatigue fracture during repeated mechanical stresses in corrosive environments. This effect is often observed on brittle electroplated surface coatings that are exposed to repeated cycling between mechanical stresses and corrosive chemicals. Air access corrosion: Through differences in the amount of exposure to air or oxygen surface areas of a metal are becoming cathodes at the more exposed spots and therefore corrode less than those protected (for example: gap corrosion in screw or press connections). 

===13.5.3 Electrochemical Potentials===

Corrosion effects are mainly governed by the electrode potential of the respective metals. The electrochemical potential table provides a measure for corrosion resistance. Non-precious (corrosion prone) metals are characterized by a negative, precious (corrosion resistant) metals by a positive normal potential against hydrogen.

Table 13.3: Electrode Potential of Metals

===13.5.4 Corrosion Testing===

The following pages describe test methods and procedures which are mainly related to the effects of environmental exposure of electrical contacts which are used in contact components for the telecommunication and information technology.
Corrosion products on the surface of electrical contacts can reduce the reliability of contact making significantly by, for example, higher contact
resistance, which will negatively affect the transmission of current and data signals. This can cause major problems in electromechanical contact
components used in the information processing technology. Causes for the formation of tarnish film on electrical contacts include for example the presence of corrosive gases such as H2S, SO2, NOx, O3, Cl2, and NH3 ''(Table 13.4)'' in industrial environments.

Table 13.4: Typical Corrosive Gas Concentrations (ppm) Near Industrial Facilities

Corrosion tests – also called environmental – on electrical contacts in natural environments must be critically evaluated, because they are the rather time consuming.

During different times of the year temperature and relative humidity changes as well as changes in the concentration of corrosive gases can have significant influences on the formation of corrosion products.

Therefore research and quality assurance efforts have centered for many years on developing test methods for electrical contacts which can predict in an accelerated time frame the corrosion behavior of electrical contacts in different corrosive atmospheres with reasonable accuracy.

Single components corrosive test atmospheres and testing with two gas exposures following each other provide only limited validity. Flowing gas test
atmospheres with four components have proven to be the most likely ones to realistically simulate long term natural corrosive gas exposure ''(Table 13.4)''.

Table 13.5: Some Standardized Corrosion Tests for Electrical Contacts

The differences in the corrosive gas concentrations and the test durations are dependent on the end application of the contact components and the
assessment of the exposure parameters.
Battelle (the Battelle Institute) has, for different applications, defined four climate classes which reflect the corrosion behavior of porous electroplated gold surfaces. Such gold layers are often used in connectors for the telecommunications and information technology ''(Table 13.5, Fig. 13.14)''.

Table 13.5: Classification of Corrosion Effects According to Battelle

The dominant corrosion effects for thin gold coatings are pore corrosion and at higher gas concentrations creep corrosion from the base materials onto the coating starting at the boundary line between non-precious base metal and contact layer.

Fig. 13.14:
Influence of the corrosive gas
concentration for four classes ( – )
on the contact resistance of a porous
gold layer as a function of the exposure
time (Battelle)

The measurement of contact resistance allows an indirect classification of corrosion product layers. While the analysis of thicker corrosive product layers in the range of 0.1 – 1 μm can be performed by classic methods such as SEM and X-ray microprobe, thinner layers of 10 – 100 nm require the use of ionoptical analysis equipment.

==References==

Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer-Verlag, Berlin, Heidelberg, New York 2002

Nobel, F.J.; Ostrow, B.D.; Thomson, D.W.: Porosity Testing of Gold Deposits. Plating 52 (1965) 1001-1008

Bedetti, F.V.; Chiarenzelli, R.V.: Porosity Testing of Electroplated Gold. Plating 53 (1966) 305-308

Antler, M.: Gold-plated Contacts: Effect of Substrate Roughness on Reliability. Plating 56 (1969) 1139-1144

Huck, M.; Mayer, U.: Korrosionsbeständigkeit und Werkstoffeigenschaften galvanischer Legierungsniederschläge für die Elektroindustrie. Metalloberfläche 10, (1984) 427-434

Wund, K.; Schnabl, R.: Gold und seine Legierungen in der Galvanotechnik. Galvanotechnik 77(2) (1986) 312-324

DIN EN ISO 6507: Metallic materials - Vickers hardness test - Part 1: Test method

DIN ISO 4516: Metallic and other inorganic coating - Vickers and Knoop hardness test

Dengel, D.: Wichtige Gesichtspunkte für die Härtemessung nach Vickers und nach Knoop im Bereich der Kleinlast und Mikrolast.

Z. Werkstofftechnik 4 (1973) 292-298

Schnabl, R.: Herstellverfahren und Prüfungen für Kontaktschichten in der Nachrichtentechnik. Buchreihe „Kontakt & Studium“, Bd. 366: Werkstoffe für elektrische Kontakte und ihre Anwendungen, Expert-Verlag, Renningen,Bd

366, (1997) 279-310

Bogenschütz, A.F.; Jostan, J.L.; Mussinger, W.: Galvanische

Korrosionsschutzschichten für elektronische Anwendungen. Metalloberfläche
34 (1980) 45-53, 93-136, 163-168, 187-194 (mit J. Ruf), 229-235, 261-269

Huck, M.: Kontaktzuverlässigkeit von Steckverbindern. Metall 37 (1983) H.7,

685-690

Kaspar, F.: Drahtbonden zur Kontaktierung auf elektronischen Baugruppen, 13

Werkstoffen und Beschichtungen. VDE-Fachbericht 55, (1999) 97-103

Weiser,J.: Prüfverfahren in der Informationstechnik. In Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer Verlag, Berlin, Heidelberg, New York (2002) 600 - 609

I Data Book I Testing Procedures I

Schäfer, E.: Zuverlässigkeit, Verfügbarkeit und Sicherheit in der Elektronik, Vogel-Verlag, (1979)

Siepmann, R.: Elektronische Lastnachbildung, Siemens Comp., (1990) 28

Johler, W.: Untere und obere Einsatzgrenzen von Signalrelais. VDE-Fachbericht 63 (2007) 31-40

IEC/EN 61810-2: Electromechanical elementary relays - Part 2: Reliability

IEC/EN 61810-7: Electromechanical elementary relays - Part 7: Test and measurement procedures

Braumann, P.; Koffler, A.: Einfluss von Herstellungsverfahren, Metalloxidgehalt und Wirkzusätzen auf das Schaltverhalten von AgSnO2 in Relais (1).
VDE-Fachbericht 59 (2003) 133-142
Braumann, P.; Koffler, A.: Einfluss von Herstellungsverfahren, Metalloxidgehalt und Wirkzusätzen auf das Schaltverhalten von AgSnO2 in Relais (2).
VDE-Fachbericht 61 (2005) 149-154

Schöpf, Th.: Silber/Zinnoxid und andere Silber/Metalloxidwerkstoffe in

Netzrelais. VDE-Fachbericht 51 (1997) 41-50

Behrens, V.; Honig, Th.; Kraus, A.; Michal, R.: Schalteigenschaften von verschiedenen Silber/Zinnoxid-Werkstoffen in Kfz-Relais.

VDE-Fachbericht 51 (1997) 51-57

Braumann, P.: Prüfung der elektrischen Lebensdauer von Kfz-Relais. VDE-Fachbericht 55 (1999) 49-59

Schröder, K.-H.: Prüfverfahren in der Energietechnik. In Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer-Verlag, Berlin, Heidelberg, New York (2002) 609-633

IEC/EN 60947-4-1: Low-voltage switchgear and controlgear - Part 4-1: Contactors and motor-starters-Electromechanical contactors and motor starters

IEC/EN 60947-5-1: Low-voltage switchgear and controlgear - Part 5-1: Control circuit devices and switching elements- Electromechanical control circuit devices

IEC/EN 60947-2: Low-voltage switchgear and controlgear - Part 2: Circuitbreakers

UL 489: „Molded Case Circuit Breakers, Molded Case Switches and Circuit Breaker enclosures“

Braumann, P.; Koffler, A.; Schröder, K.-H.: Analysis of Interrelation Between Mechanical and Eletrical Phenomena During Making Operations of Contacts: Proc. 17th Int. Conf. on Electrical Contacts, Nagoya, Japan, 1994

Braumann, P.; Koffler, A.: The Importance of Characterizing the Make and Break Operations to Allow Effective Contact Material Development. 19. ITK Nürnberg, VDE-Verlag, Berlin, Offenbach, (1998) 325-333

EN ISO 8044: Corrosion of metals and alloys - Basic terms and definitions. Berlin, Beuth-Verlag 1999

Abbott, W.H.: Contact Corrosion. in Slade, P.: Electrical Contacts, Principles and Applications: Marcel Dekker, Inc., New York, Basel, (1999) 113 - 154

Slade, P.: Introduction to Contact Tarnishing and Corrosion. in Slade, P.: Electrical Contacts, Principles and Applications: Marcel Dekker, Inc., New York, Basel, (1999) 89 - 112

Cosack, U.: Survey of Corrosion Tests with Pollutant Gases and their Relevance for Contact Material. Proc. of the 13th Intern. Conf. on Electr. Contacts, Lausanne, Switzerland, (1986) 316-325

Schnabl, R.; Paulsen, R.: Korrosionserscheinungen an Edelmetallen und

Trägerwerkstoffen. Metall 7 (1987) 696-701

Abbott, W.H.: The Development and Performance Characteristics of Flowing Mixed Gas Test Environments. IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 2, No. 1, (1988) 22-35

Hienomen, R.; Rakkolainen, J.; Saarinen, T.; Aberg, M.: Nordic Project on Corrosion in Electronics. A Comparative Study on Field and Laboratory Test Results of Various Electronic Contacts. Proc. 14th Int. Conf. on Electric Contacts, Paris, (1988) 271-275

Leygraf, Ch.: Indoor Athmosperic Corrosion. VDE-Fachbericht 63 (2007) 39-52

ASTM Designation B 845-97: Standard Guide for Mixed Flowing Gas (MFG) Tests for Electrical Contacts, 1997

IEC Standard 68-2-60, Environmental Testing Part 2: Tests Flowing-Mixed Gas

Corrosion Test, 1995

Telcordia GR-63-CORE Issue 2, Section 5.5 : Airborne Contaminants Test

Methods, Nov. 2000

Testing Procedures

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TEST
The procedures and standards for testing electrical contacts described below are mostly concentrated on contact applications in electromechanical devices. Since the range of applications for electrical contacts is very broad, a complete description of all relevant test procedures would extend the scope of this chapter of the Data Book. Therefore we limited the content here to contact coatings and switching contacts for information and power engineering. Because of the ongoing miniaturization of electromechanical devices the testing for effects of corrosive influences by the environment play an important role. Special testing procedures, such as these for brazed, soldered, and welded contact joints are covered already in chapter 3.

==13.1 Terms and Definitions==

Every technical device has to fulfill a series of requirements. Some of those which are important for agreement between contact manufacturer and user are part of DIN 40042 standard and described here in a summarized version:

*Availability (Ready-for-Use) and Reliabilty

Availability (for use) defines the probability of a system or switching device to be in a functional stage at a given time

Reliability describes the system's ability to fulfill at any time the requirements of an application within pre-defined limitations.

Both, availability and reliability, are guaranteed for a pre-determined time span and/or a specific number of switching operations. This means they warrant the life expectancy of a switching device. At the end of the live span the failure rate exceeds pre-defined limit values.

*Electrical Life

Electrical life is the number of operations reached under a given electrical load under specified operating conditions.
Since the criteria which determine the electrical life of switching contacts depend on the type of switching devices they are used in, they are described in more detail under the testing procedures in information and power engineering.

==13.2 Testing of Contact Surface Layers==

For applications at low switching loads contact layers with thicknesses in the range of just a few micrometers are widely used. For testing such thin layers the actual coating properties must be distinguished from the functional properties. Coating properties include, besides others, porosity, hardness, and ductility.
Depending on the application, the most important function properties are for example frictional wear, contact resistance, material transfer, or contact welding behavior. Besides these other technological properties such as adhesion strength, and solderability, maybe of importance for special applications like those for electronic components.

The following descriptions are mainly applicable to electroplated contact coatings which are of the most economical importance in contact applications. They also apply however in similar form to surface layers which have been created by mechanical cladding or by sputtering.

Main Articel: [[Testing of Contact Surface Layers| Testing of Contact Surface Layers]]

==13.3 Test Procedures for the Communications Technology==

Testing of the contact behavior in the communications technology is usually performed on the actual devices such as for example in relays. Experience has shown that the interaction between all design and functional parameters such as contact forces, relative movement, and electrical loads, are determining the failure mode. Therefore only statistical performance tests on a larger number of switching devices lead to meaningful results.

One must differentiate between static tests (for ex. contact resistance) and dynamic ones (for ex. electrical life). In certain electromechanical components and switching devices the contacts can be exposed to both, static and dynamic stresses (for ex. connectors, relays, switches, pushbuttons, circuit breakers). For statically stressed components the life expectancy is usually expressed as a time period, i.e. hours, while for dynamically stressed ones the expected functional life is defined as numbers of operations or switching cycles.

Main Articel: [[Test Procedures for the Communications Technology| Test Procedures for the Communications Technology]]

==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.

Main Articel: [[Testing Procedures for Power Engineering| Testing Procedures for Power Engineering]]

==13.5 Corrosion Testing==

===13.5.1 Definition of “Corrosion”===

The definition of corrosion can be found in DIN 500900 Part 1 as follows: Reaction of a metallic material with its environment, which produces a
measurable change in the material and can lead to corrosion damage. This reaction is in most cases an electrochemical one. It can however also be based on chemical and metal-physics effects.

During corrosive influences metal is dissolved. This metal loss can be uniformly spread out over a certain area or be limited to locally smaller spots. This process usually proceeds with constant speed up to the total material loss, or after certain reaction times a natural corrosion limiting surface layer can be formed (i.e. on aluminum).

===13.5.2 Special Types of Corrosion===

*Contact corrosion: Corrosion of a metal object after coming into physical contact with another metallic body. This can occur also on metallic impurities in alloys, on chemically and physically heterogeneous surfaces and on heterogeneous solutions on homogeneous surfaces, as well as through contacting a metal object by non-metallic materials through formation of corrosion compounds. 

*Hole corrosion (pitting corrosion): Local narrowly limited corrosion growing by dissolving material in small pin holes or craters to a depth that can lead to holes all the way through the material. 

*Inter-crystalline corrosion: Corrosion along the grain boundaries with the danger for the material to lose all its mechanical strength by decomposition (for example: at weld seams in austenitic stainless steels). 

*Selective corrosion: Preferred corrosion in specific microstructure areas (for example: loss of zinc in brasses with formation of copper enrichments). 

*Air access corrosion: Through differences in the amount of exposure to air or oxygen surface areas of a metal are becoming cathodes at the more exposed spots and therefore corrode less than those protected (for example: gap corrosion in screw or press connections). 

*Tension stress corrosion: Crack formation of stress corrosion sensitive materials which are under mechanical pull stresses while exposed to corrosive media. Especially affected are zinc containing copper alloys (brasses) under the influence of ammonia or nitrates. 

*Oxygen corrosion: Cathodic reaction in aqueous solutions forms reduced molecular, in water dissolved oxygen. Corrosion occurs when the electrochemical potential of the metal is below that of oxygen. 

*Hydrogen corrosion: Cathodic reduction of H to H2 (in acidic solutions) under conditions where the potential of the metal is less precious. 

*Fretting (frictional) corrosion: Enrichment of oxide particles of non-precious metal (especially tinned) surfaces during relative movements at small ampliyudes (< 100 μm). They occur through transfer of oscillation ot thermal displacement energy because of the difference in thermal expansion of the two contacting metals. This effect can be especially detrimental in connectors with tin plated surfaces, such as for example in automotive applications. 

*Fatigue corrosion: Fatigue fracture during repeated mechanical stresses in corrosive environments. This effect is often observed on brittle electroplated surface coatings that are exposed to repeated cycling between mechanical stresses and corrosive chemicals. Air access corrosion: Through differences in the amount of exposure to air or oxygen surface areas of a metal are becoming cathodes at the more exposed spots and therefore corrode less than those protected (for example: gap corrosion in screw or press connections). 

===13.5.3 Electrochemical Potentials===

Corrosion effects are mainly governed by the electrode potential of the respective metals. The electrochemical potential table provides a measure for corrosion resistance. Non-precious (corrosion prone) metals are characterized by a negative, precious (corrosion resistant) metals by a positive normal potential against hydrogen.

Table 13.3: Electrode Potential of Metals

===13.5.4 Corrosion Testing===

The following pages describe test methods and procedures which are mainly related to the effects of environmental exposure of electrical contacts which are used in contact components for the telecommunication and information technology.
Corrosion products on the surface of electrical contacts can reduce the reliability of contact making significantly by, for example, higher contact
resistance, which will negatively affect the transmission of current and data signals. This can cause major problems in electromechanical contact
components used in the information processing technology. Causes for the formation of tarnish film on electrical contacts include for example the presence of corrosive gases such as H2S, SO2, NOx, O3, Cl2, and NH3 ''(Table 13.4)'' in industrial environments.

Table 13.4: Typical Corrosive Gas Concentrations (ppm) Near Industrial Facilities

Corrosion tests – also called environmental – on electrical contacts in natural environments must be critically evaluated, because they are the rather time consuming.

During different times of the year temperature and relative humidity changes as well as changes in the concentration of corrosive gases can have significant influences on the formation of corrosion products.

Therefore research and quality assurance efforts have centered for many years on developing test methods for electrical contacts which can predict in an accelerated time frame the corrosion behavior of electrical contacts in different corrosive atmospheres with reasonable accuracy.

Single components corrosive test atmospheres and testing with two gas exposures following each other provide only limited validity. Flowing gas test
atmospheres with four components have proven to be the most likely ones to realistically simulate long term natural corrosive gas exposure ''(Table 13.4)''.

Table 13.5: Some Standardized Corrosion Tests for Electrical Contacts

The differences in the corrosive gas concentrations and the test durations are dependent on the end application of the contact components and the
assessment of the exposure parameters.
Battelle (the Battelle Institute) has, for different applications, defined four climate classes which reflect the corrosion behavior of porous electroplated gold surfaces. Such gold layers are often used in connectors for the telecommunications and information technology ''(Table 13.5, Fig. 13.14)''.

Table 13.5: Classification of Corrosion Effects According to Battelle

The dominant corrosion effects for thin gold coatings are pore corrosion and at higher gas concentrations creep corrosion from the base materials onto the coating starting at the boundary line between non-precious base metal and contact layer.

Fig. 13.14:
Influence of the corrosive gas
concentration for four classes ( – )
on the contact resistance of a porous
gold layer as a function of the exposure
time (Battelle)

The measurement of contact resistance allows an indirect classification of corrosion product layers. While the analysis of thicker corrosive product layers in the range of 0.1 – 1 μm can be performed by classic methods such as SEM and X-ray microprobe, thinner layers of 10 – 100 nm require the use of ionoptical analysis equipment.

==References==

Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer-Verlag, Berlin, Heidelberg, New York 2002

Nobel, F.J.; Ostrow, B.D.; Thomson, D.W.: Porosity Testing of Gold Deposits. Plating 52 (1965) 1001-1008

Bedetti, F.V.; Chiarenzelli, R.V.: Porosity Testing of Electroplated Gold. Plating 53 (1966) 305-308

Antler, M.: Gold-plated Contacts: Effect of Substrate Roughness on Reliability. Plating 56 (1969) 1139-1144

Huck, M.; Mayer, U.: Korrosionsbeständigkeit und Werkstoffeigenschaften galvanischer Legierungsniederschläge für die Elektroindustrie. Metalloberfläche 10, (1984) 427-434

Wund, K.; Schnabl, R.: Gold und seine Legierungen in der Galvanotechnik. Galvanotechnik 77(2) (1986) 312-324

DIN EN ISO 6507: Metallic materials - Vickers hardness test - Part 1: Test method

DIN ISO 4516: Metallic and other inorganic coating - Vickers and Knoop hardness test

Dengel, D.: Wichtige Gesichtspunkte für die Härtemessung nach Vickers und nach Knoop im Bereich der Kleinlast und Mikrolast.

Z. Werkstofftechnik 4 (1973) 292-298

Schnabl, R.: Herstellverfahren und Prüfungen für Kontaktschichten in der Nachrichtentechnik. Buchreihe „Kontakt & Studium“, Bd. 366: Werkstoffe für elektrische Kontakte und ihre Anwendungen, Expert-Verlag, Renningen,Bd

366, (1997) 279-310

Bogenschütz, A.F.; Jostan, J.L.; Mussinger, W.: Galvanische

Korrosionsschutzschichten für elektronische Anwendungen. Metalloberfläche
34 (1980) 45-53, 93-136, 163-168, 187-194 (mit J. Ruf), 229-235, 261-269

Huck, M.: Kontaktzuverlässigkeit von Steckverbindern. Metall 37 (1983) H.7,

685-690

Kaspar, F.: Drahtbonden zur Kontaktierung auf elektronischen Baugruppen, 13

Werkstoffen und Beschichtungen. VDE-Fachbericht 55, (1999) 97-103

Weiser,J.: Prüfverfahren in der Informationstechnik. In Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer Verlag, Berlin, Heidelberg, New York (2002) 600 - 609

I Data Book I Testing Procedures I

Schäfer, E.: Zuverlässigkeit, Verfügbarkeit und Sicherheit in der Elektronik, Vogel-Verlag, (1979)

Siepmann, R.: Elektronische Lastnachbildung, Siemens Comp., (1990) 28

Johler, W.: Untere und obere Einsatzgrenzen von Signalrelais. VDE-Fachbericht 63 (2007) 31-40

IEC/EN 61810-2: Electromechanical elementary relays - Part 2: Reliability

IEC/EN 61810-7: Electromechanical elementary relays - Part 7: Test and measurement procedures

Braumann, P.; Koffler, A.: Einfluss von Herstellungsverfahren, Metalloxidgehalt und Wirkzusätzen auf das Schaltverhalten von AgSnO2 in Relais (1).
VDE-Fachbericht 59 (2003) 133-142
Braumann, P.; Koffler, A.: Einfluss von Herstellungsverfahren, Metalloxidgehalt und Wirkzusätzen auf das Schaltverhalten von AgSnO2 in Relais (2).
VDE-Fachbericht 61 (2005) 149-154

Schöpf, Th.: Silber/Zinnoxid und andere Silber/Metalloxidwerkstoffe in

Netzrelais. VDE-Fachbericht 51 (1997) 41-50

Behrens, V.; Honig, Th.; Kraus, A.; Michal, R.: Schalteigenschaften von verschiedenen Silber/Zinnoxid-Werkstoffen in Kfz-Relais.

VDE-Fachbericht 51 (1997) 51-57

Braumann, P.: Prüfung der elektrischen Lebensdauer von Kfz-Relais. VDE-Fachbericht 55 (1999) 49-59

Schröder, K.-H.: Prüfverfahren in der Energietechnik. In Vinaricky, E. (Hrsg.): Elektrische Kontakte, Werkstoffe und Anwendungen. Springer-Verlag, Berlin, Heidelberg, New York (2002) 609-633

IEC/EN 60947-4-1: Low-voltage switchgear and controlgear - Part 4-1: Contactors and motor-starters-Electromechanical contactors and motor starters

IEC/EN 60947-5-1: Low-voltage switchgear and controlgear - Part 5-1: Control circuit devices and switching elements- Electromechanical control circuit devices

IEC/EN 60947-2: Low-voltage switchgear and controlgear - Part 2: Circuitbreakers

UL 489: „Molded Case Circuit Breakers, Molded Case Switches and Circuit Breaker enclosures“

Braumann, P.; Koffler, A.; Schröder, K.-H.: Analysis of Interrelation Between Mechanical and Eletrical Phenomena During Making Operations of Contacts: Proc. 17th Int. Conf. on Electrical Contacts, Nagoya, Japan, 1994

Braumann, P.; Koffler, A.: The Importance of Characterizing the Make and Break Operations to Allow Effective Contact Material Development. 19. ITK Nürnberg, VDE-Verlag, Berlin, Offenbach, (1998) 325-333

EN ISO 8044: Corrosion of metals and alloys - Basic terms and definitions. Berlin, Beuth-Verlag 1999

Abbott, W.H.: Contact Corrosion. in Slade, P.: Electrical Contacts, Principles and Applications: Marcel Dekker, Inc., New York, Basel, (1999) 113 - 154

Slade, P.: Introduction to Contact Tarnishing and Corrosion. in Slade, P.: Electrical Contacts, Principles and Applications: Marcel Dekker, Inc., New York, Basel, (1999) 89 - 112

Cosack, U.: Survey of Corrosion Tests with Pollutant Gases and their Relevance for Contact Material. Proc. of the 13th Intern. Conf. on Electr. Contacts, Lausanne, Switzerland, (1986) 316-325

Schnabl, R.; Paulsen, R.: Korrosionserscheinungen an Edelmetallen und

Trägerwerkstoffen. Metall 7 (1987) 696-701

Abbott, W.H.: The Development and Performance Characteristics of Flowing Mixed Gas Test Environments. IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 2, No. 1, (1988) 22-35

Hienomen, R.; Rakkolainen, J.; Saarinen, T.; Aberg, M.: Nordic Project on Corrosion in Electronics. A Comparative Study on Field and Laboratory Test Results of Various Electronic Contacts. Proc. 14th Int. Conf. on Electric Contacts, Paris, (1988) 271-275

Leygraf, Ch.: Indoor Athmosperic Corrosion. VDE-Fachbericht 63 (2007) 39-52

ASTM Designation B 845-97: Standard Guide for Mixed Flowing Gas (MFG) Tests for Electrical Contacts, 1997

IEC Standard 68-2-60, Environmental Testing Part 2: Tests Flowing-Mixed Gas

Corrosion Test, 1995

Telcordia GR-63-CORE Issue 2, Section 5.5 : Airborne Contaminants Test

Methods, Nov. 2000

Template:MainArticles

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{{:Brazing Alloys and Fluxes}} 
[[Physical Properties of the Most Important Metals]] 
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Brazing Alloys and Fluxes

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=== 4.1 Brazing Alloys ===
For the joining of contact materials with carrier substrates brazing alloys with working temperatures > 600 °C are used exclusively. The working temperature is defined as the lowest surface temperature by which the brazing material wets the materials to be joined. This temperature is within the melting range and between the solidus (temperature at which melting starts) and liquidus (temperature at complete liquid state) point of the brazing alloy. Silver-based brazing alloys have good electrical conductivity and a sufficient mechanical
strength which allows a bonding process without significant changes in the 4
microstructure of the material to be joined.
For electrical contacts usually low-melting alloys with a minimum of 20 wt-% silver and additions of cadmium, zinc or tin to lower the melting point are used (Table 4.1). Because of the toxicity of cadmium most cadmium containing brazing alloys have been replaced by zinc and tin containing brazing alloys. For higher requirements on corrosion resistance or for easier wetting of stainless steel nickel and manganese containing alloys are also used. Using any of these brazing alloys in an air environment is only possible with the addition of oxide reducing fluxes.
For high temperature brazing in vacuum or protective atmosphere vacuum melted silver-copper eutectic brazing alloys are used. These also allow subsequent forming operations due to their higher ductility.
For the brazing of contacts with a silver bottom layer to copper backings phosphorous containing brazing alloys which eliminate the need for a flux application are widely used.
The brazing alloy is typically introduced into the joint area in the form of wire segments, foil, shims, or as powder or paste. For larger production volumes it is economically advantageous to pre-coat contact tips with a thin layer (< 100 µm) of brazing alloy.
=== 4.2 Fluxes ===
Brazing fluxes consist of non-metallic materials, mostly salt mixtures of boron and halogen compounds (Table 4.2). Their purpose is to remove oxides from
the brazing surfaces and prevent their new build-up in order to allow a thorough wetting of these surfaces by the liquefied brazing alloy. Fluxes have to be activated already at a temperature below the working range of the brazing alloy. They are selected mainly according to the working temperature of the brazing alloy and the base material to be joined.

{| class="twocolortable"
|+ Table 4.1: Commonly Used Brazing Alloys for Electrical Contacts
!Designation
!Designation
!Designation
!Composition
! colspan="2" style="" |Melting range
!Working
!Electrical
Conductivity
!Density
!Application
|-
!DIN EN 1044
!US (equivalent or closest
similar brazing alloy)
!DIN EN ISO 3677
!wt%
!
!
!Temperature
[°C]
![MS/m]
![g/m³]
!
|-
|-
|AG 304*) || BAg-1 || B-Ag40ZnCdCu-
595/630
| Ag39 - 41
Cd18 - 22
Cu18 - 20
Zn19 - 23
| 595 || 630 || 610 || 14.0 || 9.3 || Cu,Cu alloys,
Ag materials, Fe, Ni
|-
|AG 306*) || BAg-2a
|B-Ag30CuCdZn-
600/765
| Ag30 - 32
Cu28 - 30
Cd21 - 25
Zn21 - 25
| 600 || 690 || 680 || 13.0 ||9.2 || Cu, Cu alloys,
Ag materials, Fe, Ni

|}

Since the residues of fluxes are hygroscopic and can cause corrosion they have to be removed completely after the brazing process in very hot or boiling water. Depending on the type and process used, fluxes are being applied in liquid form or as powders or pastes.

Table 4.2: Fluxes for the Brazing of Heavy Metals

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Electrical Contacts - User contributions [en]

Platinum Metal Based Materials

Table of Contents

Physical Properties of the Most Important Metals

Physical Properties of the Most Important Metals

Physical Properties of the Most Important Metals

Physical Properties of the Most Important Metals

Testing Procedures

Testing Procedures

Testing Procedures

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Data Book of Electrical Contacts

Data Book of Electrical Contacts

Data Book of Electrical Contacts

Data Book of Electrical Contacts

Data Book of Electrical Contacts

Brazing Alloys and Fluxes

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