Besides manufacturing contact materials from the solid phase, i.e. by melt orpowder metallurgy, the production starting in the liquid or gaseous phase isgenerally preferred when thin layers in within the μm range are required , which cannotbe obtained economically by conventional cladding methods(<xr id="tab:Overview_of_Important_Properties_of_Electroplated_Coatings_and_their_Applications"/><!--(Tab. 7.1)-->). Such coatingsfulfill different requirements depending on their composition and thickness.They can serve as corrosion or wear protection or can fulfill the need for thincontact layers for certain technical applications. In addition they serve fordecorative purposes as a pleasing and wear resistant surface coating.

<figtable id="tab:Overview_of_Important_Properties_of_Electroplated_Coatings_and_their_Applications"><caption>'''<!--Table 7.1: -->Overview of Important Properties of Electroplated Coatingsand their Applications'''</caption>

{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Properties!Applications!Examples|-|Color|Pleasing appearance|Brass plated lamps and furniture hardware|-|Luster|Decorative appearance, Light reflection|Chrome plated fixtures, silver coated mirrors|-|Hardness / Wear Resistance|Prolonging of mechanical wear life|Hard chrome plated tools|-|Sliding properties|Improvement of dry sliding wear|Lead-tin-copper alloys for slide bearings|-|Chemical stability|Protection against chemical effects|Lead-Tin coatings as etch resist on PC boards|-|Corrosion resistance|Protection against environmental corrosion|Zinc coatings on steel parts|-|Electrical conductivity|Surface conduction of electrical current|Conductive path on PC boards|-|Thermal conductivity|Improved heat conduction on the surface|Copper plated bottoms for cookware|-|Machining capability|Shaping through machining|Copper coatings on low pressure cylinders|-|Magnetic properties|Increase of coercive force [[#text-reference|^*)]] |Cobalt-nickel layers on magnetic storage media|-|Brazing and soldering|Brazing without aggressive fluxes|Tin-Lead coatings on PC board paths|-|Adhesion strength|Improvement of adhesion|Brass coating on reinforcement steel wires in tires|-|Lubricating properties|Improvement of formability|Copper plating for wire drawing|}</figtable><div id="text-reference">*) Coercive force= force to retaim the adopted magnetisation</div>  To reduce the mechanical wear of thin surface layers on sliding and connectorcontacts , additional lubricants in liquid form are often used. On silver contacts, passivation coatings are applied as protection against silver sulfide formation.

For thin coatings starting from the liquid phase , two processes are useddifferentiated by the metallic deposition being performed either with or withoutthe use of an external electrical current source. The first one is electroplating, while the second one is a chemical deposition process.

For electroplating of metals, especially precious metals, water based solutions(electrolytes) are used , which contain the metals to be deposited as ions (i.e.dissolved metal salts). An electric field between the anode and the work piecesas the cathode , forces the positively charged metal ions to move to the cathodewhere they give up their charge and deposit themselves as metal on the surfaceof the work piece.Depending on the application, for electric and electronic or decorative end use,different electrolytic bath solutions (electrolytes) are used. The electroplatingequipment used for precious metal plating and its complexity varies widely, depending on the process technologies employed.Electroplating processes are encompassing , besides the pure metal deposition, also preparative and post treatments of the goods to be coated. An importantparameter for creating strongly adhering deposits is that the surface of the goods has tobe metallic clean without oily or oxide film residues. This is achieved throughvarious pre-treatment processes , specifically developed for the types of materialand surface conditions of the goods to be plated.In the following segments , electrolytes – both precious and non-precious – aswell as the most widely used electroplating processes are described.

==== Main Articel: [[Electroplating Solutions – Electrolytes====The actual metal deposition occurs in the electrolytic solution which containsthe plating material as metal ions. Besides this basic ingredient, the electrolytescontain additional components depending on the processes used, such as forexample conduction salts, brighteners, and organic additives which are codepositedinto the coatings, influencing the final properties of the electroplatingdeposit.(or Galvanic Deposition)| Electroplating (or Galvanic Deposition)]]

===== Precious Metal Electrolytes=====All precious metals can be electroplated with silver and gold by far the mostwidely used ones ''(Tables <!--7.1 and 7.2)''.The following precious metal electrolytes are the most important ones:-->Electroless Plating===

*'''Gold electrolytes''' For functional and decorative purposes pure goldElectroless plating is defined as a coating process which is performed without the use of an external current source. It allows a uniform metal coating, hard goldindependent of the geometrical shape of the parts, low-karat gold, or colored gold coatings are depositedto be coated. Depending on Because of the requirementsvery good dispersion capability of the used electrolytes, acidicalso cavities and the inside of drilled holes in parts can be coated for example.In principal, neutral, or cyanide electrolytes based on potassium gold cyanide or cyanide free two different mechanisms are employed for electroless plating: processes in which the carrier material serves as a reduction agent (Immersion processes) and neutral electrolytes based on gold sulfite complexes are usedthose in which a reduction agent is added to the electrolyte (Electroless processes).

*'''Ruthenium electrolytes''' Ruthenium coatings ==<!--7.2-->Coatings from the Gaseous Phase (Vacuum Deposition)==The term PVD (physical vapor deposition) defines processes of metal, metal alloys and chemical compounds deposition in a vacuum by adding thermal and kinetic energy by particle bombardment. The main processes are mostly used for decorative purposes creating a fashionable “grey” ruthenium color on the surfacefollowing four coating variations (<xr id="tab:Characteristics of the Most Important PVD Processes"/><!--(Table 7. An additional color variation is created by using “ruthenium6-black” deposits which are mainly used in bi-color decorative articles.>):

*'''Rhodium electrolytes''' Rhodium deposits are extremely hard Vapor deposition *Sputtering (HV 700 – 1000Cathode atomization) 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.*Arc vaporizing *Ion implantation

*'''Silver electrolytes''' Silver electrolytes without additives generate dull soft deposits (HV ~ 80) which are mainly used as contact layers In all four processes, the coating material is transported in its atomic form to the substrate and deposited on connectors with limited insertion and withdrawal cycles. Properties required for decorative purposes such it as shiny bright surfaces and higher wear resistance are achieved through various additives a thin layer (a few nm to the basic Ag electrolyteapprox.10 μm)

<table borderfigtable id="1" cellspacing="0" style="border-collapsetab:collapse"><tr><td><p class="s8">AUROMET TN</p></td><td><p class="s8">3.2 - 4.2</p></td><td><p class="s8">ca. 70</p></td><td><p class=Characteristics of the Most Important PVD Processes"s8">99.99% Au</p></td><tdcaption>'''<p class="s8">Base!-deposits</p></td></tr><tr><td><p class="s8">AUROMET XPH</p></td><td><p class="s8">0.3 - 0Table 7.6</p></td><td><p class="s8">160 - 180</p></td><td><p class="s8">99.8% Au</p></td><td><p class="s8">Base-deposits for stainless steel etc.</p></td></tr><tr><td><p class="s8">DODUREX COC</p></td><td><p class="s8">4.6 - 4.9</p></td><td><p class="s8">160 - 180</p></td><td><p class="s8">99.6% Au</p></td><td><p class="s8">Printed circuit boards, connectors, contact parts, etc.; hard gold coatings for rack and barrel plating</p></td></tr><tr><td><p class="s8">DODUREX HS 100</p></td><td><p class="s8">4.3 - 4.6</p></td><td><p class="s8">160 - 180</p></td><td><p class="s8">99.6% Au</p></td><td><p class="s8">High speed process for connectors and</p><p class="s8">PCB plating</p></td></tr><tr><td><p class="s8">PURAMET 202</p><p class="s8">PURAMET 402</p></td><td><p class="s8">5.5 :- 6.5</p><p class="s8">7.0 - 7.5</p></td><td><p class="s8">60 - 80</p><p class="s8">60 - 80</p></td><td><p class="s8">99.99% Au</p><p class="s8">99.99% Au</p></td><td><p class="s8">High purity gold coatings for electrical</p><p class="s8">and electronic parts incl. semi conductors and PCBs; for demanding requirement on bonding properties</p></td></tr>Characteristics of the Most Important PVD Processes'''</tablecaption>

{| class="twocolortable" style==== Non"text-align: left; font-size: 12px"|-Precious Metal Electrolytes=====The most important non!Process!Principle!Process Gas Pressure!Particle Energy!Remarks|-precious metals that are deposited by electroplatingare: Copper, nickel, tin, and zinc and their alloys. The |Vapor deposition is performed |Vaporizing ina crucible <br />(electron beam or resistance heating)|10^-3 Pa|< 2eV|Separation of alloy components may occur|-|Arc vaporizing|Vaporizing of the form target <br />plate in an electrical arc|10^-1 Pa-1Pa|80eV-300eV|Very good adhesion due to ion bombardement|-|Sputtering|Atomizing of pure metals with different electrolytes used ''the target plate<br />(Table 7.4cathode).''in a gas discharge|10^-1 Pa-1Pa|10eV-100eV|Sputtering of non-conductive materials possible through RF operation|-|Ion implantation|Combination of vapor <br />deposition and sputtering|10^-1 Pa-1Pa|80eV-300eV|Very good adhesion from ion bombardment but also heating of the substrate material|}</figtable>

*'''Tin electrolytes''' Pure tin and tin alloy deposits are used as dull or also bright surface layers on surfaces required for solderingThe sputtering process has gained the economically most significant usage. In the printed circuit board manufacturing they are also utilized as an etch resist for the conductive pattern design after initial copper electroplatingIts process principle is illustrated in (<xr id="fig:Principle of sputtering"/><!--(Fig. 7.5)-->).

Table 7<figure id="fig:Principle of sputtering">[[File:Principle of sputtering.3jpg|right|thumb|Figure 1: Precious Principle of sputtering Ar = Argon atoms; e = Electrons; M = Metal Electrolytes for Decorative Applicationsatoms]]</figure>Initially, a gas discharge is ignited in a low pressure (10^-1 -1 Pa) argon atmosphere. The argon ions generated, are accelerated in an electric field and impact the target of material to be deposited with high energy. Caused by this energy, atoms are released from the target material which condensate on the oppositely arranged anode (the substrate) and form a layer with high adhesion strength. Through an overlapping magnetic field at the target location, the deposition rate can be increased, making the process more economical.

*'''Nickel electrolytes''' Nickel layers are mostly used as diffusion barriers during The advantages of the gold plating of copper PVD processes and copper alloys or as an intermediate layer especially sputtering for tinningelectrical contact applications are:

*'''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 High purity of the bronze deposit layers are utilized for their good corrosion resistance and good brazing and soldering properties. *Low thermal impact on the substrate *Almost unlimited coating materials *Low coating thickness tolerance *Excellent adhesion (also by using additional intermediate layers)

Table 7.2: Typical Electrolytes Coatings produced by PVD processes are used for contact applications, for example on miniature-profiles, in electrical engineering and for electronic components, for solderability in joining processes, for the Deposition metalizing of Nonnonconductive materials, as well as in semiconductors, opto-Precious Metalselectronics, optics and medical technology applications.

==== Electroplating There are few limitations regarding the geometrical shape of Parts====The complete or all-around electroplating substrate parts. Only the interior coating of drilled holes and small mass produced parts likecontact springs, rivetsdiameter tubing can be more problematic (ratio of depth to diameter should be < 2:1). Profile wires, strips and foils can be coated from one side or pins is usually done both; formed parts can be coated selectively by using masking fixtures that at the same time serve as mass plating in electroplatingbarrels holding fixtures (<xr id="fig:Examples of different shape. During the electroplating process the vacuum coated semi finished materials and parts arecontinuously moved and mixed to reach a uniform coating"/>).

Larger <figure id="fig:Examples of vacuum coated semi finished materials and parts are frequently electroplated on racks either totally or by different">masking techniques also partially[[File:Examples of vacuum coated semi finished materials and parts. Penetrating the coating into the interior jpg|left|Figure 2: Examples ofvacuum coated semi finished materials and parts]]drilled holes or tubes can be achieved with the use of special fixtures. '''Electroplated Parts'''bild</figure>

<table borderclass="1twocolortable" cellspacing><tr><th rowspan="02" style><p class="border-collapse:collapses8">Substrate Materials</p><tr/th><tdth colspan="12"><p class="s9s8">CoatingsCoating Materials</p></th></tr><tr><th><p><span>Ag</span></p></tdth><th><p><span>Au</span></p></th><th><p><span>Pt</span></p></th><th><p><span>Pd</span></p></th><th><p><span>Cu</span></p></th><th><p><span>Ni</span></p></th><th><p><span>Ti</span></p></th><th><p><span>Cr</span></p></th><th><p><span>Mo</span></p></th><th><p><span>W</span></p></th><th><p><span>Ai</span></p></th><th><p><span>Si</span></p></th></tr><tr><td><p class="s9s8">Precious metalsmetal / alloys</p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p class="s9">Pure gold, hard gold (HV 150 – 250), palladium, palladium<span>[[File:K7-nickel, rhodium,gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p class="s9">pure silver, hard silver (HV 130 – 160)</td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s9s8">NonNF metals / alloys</p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-precious metalsgef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p class="s9">Copper, nickel, tin, tin alloys<span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s9s8">Carrier materialsFe alloys / stainless steel</p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s9s8">CopperSpecial metals (Ti, copper alloys, nickel, nickel alloys, iron, steelMo,W)</p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p class="s9">aluminum, aluminum alloys, composite materials<span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s9s8">such as aluminum – silicon carbideCarbide steels (WC-Co)</p></td><td><p><span>[[File:K7-leer.png]]</trspan></p></tabletd><td><p><span>  *'''Coating thickness''' Precious metals[[File: 0K7-gef.2 – 5 μm (typical layer thicknesses; for Ag also up to 25 μm)Nonpng]]</span></p></td><td><p><span>[[File:K7-precious metalsgef.png]]</span></p></td><td><p><span>[[File: Up to approxK7-gef. 20 μmTolerancespng]]</span></p></td><td><p><span>[[File: Strongly varying depending on the geometrical shape ofparts (up to 50% at a defined measuring spot)K7-gef.It is recommended to specify a minimum value for thecoating thickness at a defined measuring spot als Bild? *'''Quality criteria''' Besides others the following layer parameters are typically monitored inpng]]</span></p></td><td><p><span>[[File:K7-process and documentedgef.png]]</span></p></td><td><p><span>[[File: *Coating thickness *Solderability*Adhesion strength *Bonding property*Porosity Contact *resistance These quality tests are performed according to industry standards, internalstandards, and customer specifications respK7-gef. ==== Electroplating of Semipng]]</span></p></td><td><p><span>[[File:K7-finished Materials====The process for overall electroplating of strips, profiles, and wires is mostlyperformed on continuously operating reelgef.png]]</span></p></td><td><p><span>[[File:K7-togef.png]]</span></p></td><td><p><span>[[File:K7-reel equipmentgef. The processingsteps for the individual operations such as prepng]]</span></p></td><td><p><span>[[File:K7-cleaning, electroplating, rinsingare following the same principles as those employed in parts electroplatingleer. The overall coating is usually applied for silver plating and tin coating of stripsand wirespng]]</span></p></td><td><p><span>[[File:K7-gef. Compared to hard gold or palladium these deposits are ratherductile, ensuring that during following stamping and forming operations nocracks are generated in the electroplated layers. png]]</span></p></td></tr><tr><td><p class="s8">Ceramics (Al<span class="s16">2</span>O<span class== Selective Electroplating====Since precious metals are rather expensive it is necessary to perform theelectroplating most economically and coat only those areas that need the layersfor functional purposes"s16">3</span>, AlN)</p></td><td><p><span>[[File:K7-leer. This leads from overall plating to selectiveelectroplating of strip material in continuous reelpng]]</span></p></td><td><p><span>[[File:K7-toleer.png]]</span></p></td><td><p><span>[[File:K7-reel processesgef. Dependingon the final parts design and the end application the processes can be appliedto solid strip material as well as prepng]]</span></p></td><td><p><span>[[File:K7-stamped and formed continuous strips orutilizing wiregef.png]]</span></p></td><td><p><span>[[File:K7-formed or machined pins which have been arranged as bandoliersattached to conductive metal stripsgef. The core part of selective precious metal electroplating is the actualelectroplating cellpng]]</span></p></td><td><p><span>[[File:K7-gef. In it the anode is arranged closely to the cathodic polarizedmaterial strippng]]</span></p></td><td><p><span>[[File:K7-gef. Cathode screens or masks may be applied between the two tofocus the electrical field onto closely defined spots on the cathode strippng]]</span></p></td><td><p><span>[[File:K7-gef. Special high performance electrolytes are used in selective electroplating toreach short plating times and allow a high flow rate of the electrolyte for a fastelectrolyte exchange in the actual coating areapng]]</span></p></td><td><p><span>[[File:K7-gef. For a closely targeted electroplating of limited precious metal coating of contactsprings sopng]]</span></p></td><td><p><span>[[File:K7-called brushgef.png]]</span></p></td><td><p><span>[[File:K7-electroplating cells are employed ''leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">Glasses (FigSiO<span class="s16">2</span>, CaF)</p></td><td><p><span>[[File:K7-leer. 7png]]</span></p></td><td><p><span>[[File:K7-leer.1)''png]]</span></p></td><td><p><span>[[File:K7-gef. The “brush”or “tampon” consists of a roof shaped titanium metal part covered with a specialfeltpng]]</span></p></td><td><p><span>[[File:K7-like materialgef. The metal body has holes in defined spots through which theelectrolyte reaches the feltpng]]</span></p></td><td><p><span>[[File:K7-gef. In the same spots is also the anode consisting of afine platinum netpng]]</span></p></td><td><p><span>[[File:K7-gef. The prepng]]</span></p></td><td><p><span>[[File:K7-stamped and in the contact area pregef.png]]</span></p></td><td><p><span>[[File:K7-formed contactspring part is guided under a defined pressure over the electrolyte soaked feltmaterial and gets wetted with the electrolytegef. This allows the metalelectroplating in highly selective spotspng]]</span></p></td><td><p><span>[[File:K7-gef. Figpng]]</span></p></td><td><p><span>[[File:K7-gef. 7png]]</span></p></td><td><p><span>[[File:K7-leer.1png]]</span></p></td><td><p><span>[[File:Brush K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">Plastics (or “Tampon”PA, PPS) plating cell;1 Strip; 2 Anode; 3 Electrolyte feed;4 Felt covered cell For special applications, such as for example electronic component substrates,a dot shaped precious metal coating is required</p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef. This is achieved with two beltmasks running synchronous to the carrier materialpng]]</span></p></td><td><p><span>[[File:K7-gef. One of these two masks haswindows which are open to the spot areas targeted for precious metal platingcoveragepng]]</span></p></td><td><p><span>[[File:K7-gef. '''Summary of the processes for selective electroplating''' *'''Immersion electroplating'''Overall or selective electroplating of both sides of solid strips or prepng]]</span></p></td><td><p><span>[[File:K7-stampedparts in strip form *'''Stripe electroplating'''Stripe electroplating on solid strips through wheel cells or using maskingtechniques *'''Selective electroplating'''Onegef.png]]</span></p></td><td><p><span>[[File:K7-sided selective coating of solid, pregef.png]]</span></p></td><td><p><span>[[File:K7-stamped, or metallically beltgef.png]]</span></p></td><td><p><span>[[File:K7-linkedstrips by brush plating *'''Spot electroplating'''Electroplating in spots of solid strips with guide holes or pregef.png]]</span></p></td><td><p><span>[[File:K7-stamped parts instrip form '''Typical examples of electroplated semigef.png]]</span></p></td><td><p><span>[[File:K7-finished materials'''(overall or selectively)bild *'''Materials'''gef.png]]</span></p></td></tr></table>

<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s8">Type of Coatings</p></td><td><p class="s8">Coating Thickness</p></td><td><p class="s8">Remarks</p></td></tr><tr><td><p class="s8">Precious Metals</p></td><td/><td/></tr><tr><td><p class="s8">Pure gold</p><p class="s8">Hard gold (AuCo 0.3)</p></td><td><p class="s8">0.1 - 3 µm</p></td><td><p class="s8">In special cases up to 10 µm</p></td></tr><tr><td><p class="s8">Palladium-nickel (PdNi20)</p></td><td><p class="s8">0.1 - 5 µm</p></td><td><p class="s8">Frequently with additional 0.2 µm AuCo 0.3</p></td></tr><tr><td><p class="s8">Silver</p></td><td><p class="s8">0.5 - 10 µm</p></td><td><p class="s8">In special cases up to 40 µm</p></td></tr><tr><td><p class="s8">Non-precious Metals</p></td><td/><td/></tr><tr><td><p class="s8">Nickel</p></td><td><p class="s8">0.5 - 4 µm</p></td><td><p class="s8">Diffusion barrier especially for gold layers</p></td></tr><tr><td><p class="s8">Copper</p></td><td><p class="s8">1 - 5 µm</p></td><td><p class="s8">Intermediate layer used in tinning of CuZn</p></td></tr><tr><td><p class="s8">Tin, tin alloys</p></td><td><p class="s8">0.8 - 25 µm</p></td><td><p class="s8">materials</p></td></tr></table> *'''Carrier Materials'''Copper, copper alloys, nickel, nickel alloys, stainless steel *'''Dimensions and Tolerances''' Bild  DimensionsCarrier thickness d= 0.1 - 1 mmCarrier width B= 6 - 130 mmDistance b > 2 mmCoating width a= 2 - 30mmCoating thickness s = 0.2 - 5 μm(typical range)Distance from edge b > 0.5 mmdepending on the carrier thicknessand the plating process *'''Tolerances'''Coating thickness approx. 10 %Coating thickness and position + 0,5 mm *'''Quality Criteria'''Mechanical properties and dimensional tolerances of the carrier materials followthe typical standards, i.e. DIN EN 1652 and 1654 for copper and copper alloys.Depending on the application the following parameters are tested andrecorded (see also: Electroplating of parts): *Coating thickness *Solderability*Adhesion strength *Bonding property *Porosity *Contact resistance These quality tests are performed according to industry standards, internalstandards, and customer specifications resp. ===7.1.2 Electroless Plating=== ====7.1.2.1 Introduction====Electroless plating is defined as a coating process which is performed withoutthe use of an external current source. It allows a uniform metal coatingindependent of the geometrical shape of the parts to be coated. Because of thevery good dispersion capability of the used electrolytes also cavities and theinside of drilled holes in parts can be coated for example.In principal two different mechanisms are employed for electroless plating:processes in which the carrier material serves as a reduction agent (Immersionprocesses) and those in which a reduction agent is added to the electrolyte(Electroless processes). ====7.1.2.2 Immersion Processes====The immersion processes are usually applied in the plating of the metals gold,silver, and tin. If the material to be coated is less precious, i.e. exhibits anegative standard potential against the metal ions in the surrounding solution, itgoes into solution releasing electrons while the more precious metal ions arereduced by absorbing electrons and being deposited on the electrode. Thisprocess can continue until the complete surface of the substrate is coveredwith a thin layer of the more precious metal. This limits the maximum achievablelayer thickness to approx. 0.1 μm ''(Table 7.5)''. Table 7.5: Immersion Gold Electrolytes<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s8">Type of Electrolyte</p></td><td><p class="s8">pH-Range</p></td><td><p class="s8">Coating Properties</p></td><td><p class="s8">Application Ranges</p></td></tr><tr><td><p class="s8">Type of Electrolyte</p></td><td><p class="s8">pH-Range</p></td><td><p class="s8">Hardness</p><p class="s8">HV 0.025</p></td><td><p class="s8">Punity</p></td><td><p class="s8">Application Ranges</p></td></tr><tr><td><p class="s8">Immersion Gold electrolytes</p></td><td/><td/><td/><td/></tr><tr><td><p class="s8">AUROL 4</p><p class="s8">AUROL 16</p><p class="s8">AUROL 20</p></td><td><p class="s8">3.8 - 4.2</p><p class="s8">5.8 - 6.2</p><p class="s8">5.8 - 6.2</p><p class="s8">5.8 - 6.2</p></td><td><p class="s8">60 - 80</p><p class="s8">60 - 80</p><p class="s8">60 - 80</p><p class="s8">60 - 80</p></td><td><p class="s8">99.99% Au</p><p class="s8">99.99% Au</p><p class="s8">99.99% Au</p><p class="s8">99.99% Au</p></td><td><p class="s8">Thin gold layers on Ni, Ni alloys,</p><p class="s8">Fe and Fe alloys for PCB technology and technical applications</p></td></tr></table> ====7.1.2.3 Electroless Processes====The electroless metal plating with adding reduction agents to the electrolyte isbased on the oxidation of the reducing agent with release of electrons whichthen in turn reduce the metal ions. To achieve a controlled deposition from suchsolutions the metal deposition has to happen through the catalytic influence ofthe substrate surface. Otherwise a “wild” uncontrollable deposition would occur. In most casespalladium containing solutions are used for the activation which seed thesurfaces with palladium and act as catalysts in the copper and nickelelectrolytes. The electrolytes contain besides the complex ion compounds of the metals tobe deposited also stabilizers, buffer and accelerator chemicals, and a suitablereduction agent. These electrolytes are usually operating at elevated temperatures (50° – 90°C).The deposits contain besides the metals also process related foreign inclusionssuch as for example decomposition products of the reduction agents.The electroless processes are used mainly for copper, nickel, and golddeposits. ====7.1.2.4 Electroless Deposition of Nickel/Gold==== Electroless deposited nickel coatings with an additional immersion layer of goldare seeing increased importance in the coating of printed circuit boards (PCBs).The process sequence is shown in ''(Fig. 7.2)'' using the example of theDODUCHEM process. Tabelle After the pre-cleaning (degreasing and etching) a palladium sulfate activator isused which activates the exposed copper surfaces on the printed circuit boardand thus facilitates the nickel deposition. The electroless working chemicalnickel electrolyte contains – besides other ingredients – Sodium-hypophosphite,which is reduced to phosphorus in a parallel occurring process andincorporated into the nickel deposit. At the temperature of 87 – 89°C a veryhomogeneous nickel-phosphorus alloy layer with approx. 9 wt% P is depositedwith layer thicknesses > 5 μm possible. During a consecutive processing stepa very thin and uniform layer (< 0.1 μm) of gold is added in an immersionelectrolyte. This protects the electroless nickel layer against corrosion achievinga solderable and well bondable surface for thick or fine aluminum bond wires. It is possible to enhance this layer combination further by adding a immersionpalladium layer between the electroless nickel and the gold coating(DODUBOND process). This Pd layer acts as a diffusion barrier and allows theusage of this surface combination also for gold wire bonding. As an alternative, for gold wire bonding applications a thicker gold layer of 0.2 –0.5 μm can be applied using an electroless process. Typical electrolytes work ata temperature of approx. 80°C with deposition rates of 0.3 – 0.4 μm per 30minutes. There are however limitations with these electroless electrolytesconcerning their stability and the robustness of the process compared to otherelectroplating processes which reduces their wider usage ''(Fig. 7.3)''. Fig. 7.3:Coating compositionof a printed circuit board withreductively enhanced gold ====7.1.2.5 Immersion Deposition of Tin====A tin coating by ion exchange is usually not possible since copper is the moreprecious metal. By adding thio-urea the electro-chemical potential of copper isreduced to a level (approx. 450 mV, significantly lower than tin) that allows theexchange reaction. Using a suitable electrolyte composition and enhancersolutions like with the DODUSTAN process ''(Fig. 7.4)'' tin coatings can beproduced that, even under usually unfavorable conditions of copperconcentrations of 7 g/l in the electrolyte, are well solderable. Fig. 7.4: Process flow for electroless tin deposition using the DODUSTAN process The immersion tin deposition is suitable for the production of a well solderablesurface on printed circuit boards and electronic components. It is also used asan etch resist against ammonia based solutions or as corrosion and oxidationprotection of copper surfaces. ==7.2 Coatings from the Gaseous Phase (Vacuum Deposition)==The term PVD (physical vapor deposition) defines processes of metal, metalalloys, and chemical compounds deposition in a vacuum by adding thermal andkinetic energy through particle bombardment. The main processes are thefollowing four coating variations ''(Table 7.6)'': *Vapor deposition *Sputtering (Cathode atomization)*Arc vaporizing *Ion implantation In all four processes the coating material is transported in its atomic form to thesubstrate and deposited on it as a thin layer (a few nm to approx. 10 μm) Table 7.6: Characteristics of the Most Important PVD Processes tabelle fehlt! The sputtering process has gained the economically most significant usage. Itsprocess principle is illustrated in ''(Fig. 7.5)''. Fig. 7.5: Principle of sputtering Ar = Argon atoms; e = Electrons; M = Metal atoms Initially a gas discharge is ignited in a low pressure (10 – 1 Pa) argonatmosphere. The argon ions generated are accelerated in an electric field andimpact the target of material to be deposited with high energy. Caused by thisenergy atoms are released from the target material which condensate on theoppositely arranged anode (the substrate) and form a layer with high adhesionstrength. Through an overlapping magnetic field at the target location thedeposition rate can be increased, making the process more economical. The advantages of the PVD processes and especially sputtering for electricalcontact applications are: *High purity of the deposit layers *Low thermal impact on the *Almost unlimited coating materials substrate*Low coating thickness tolerance *Excellent adhesion (also by using additional intermediate layers) Coatings produced by PVD processes are used for contact applications, forexample on miniature-profiles, in electrical engineering and for electroniccomponents, for solderability in joining processes, for metalizing of nonconductivematerials, as well as in semiconductors, opto-electronics, optics,and medical technology applications. There are few limitations regarding the geometrical shape of substrate parts.Only the interior coating of drilled holes and small diameter tubing can be moreproblematic (ratio of depth to diameter should be < 2:1). Profile wires, strips,and foils can be coated from one side or both; formed parts can be coatedselectively by using masking fixtures that at the same time serve as holdingfixtures. *'''Examples of vacuum coated semi-finished materials and parts'''bild *'''Materials'''Selection of possible combinations of coating and substrate materials <table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s8">Substrate Materials</p></td><td><p class="s8">Coating Materials</p></td></tr><tr><td><p class="s8">Substrate Materials</p></td><td><p><span>Ag</span></p></td><td><p><span>Au</span></p></td><td><p><span>Pt</span></p></td><td><p><span>Pd</span></p></td><td><p><span>Cu</span></p></td><td><p><span>Ni</span></p></td><td><p><span>Ti</span></p></td><td><p><span>Cr</span></p></td><td><p><span>Mo</span></p></td><td><p><span>W</span></p></td><td><p><span>Ai</span></p></td><td><p><span>Si</span></p></td></tr><tr><td><p class="s8">Precious metal / alloys</p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">NF metals / alloys</p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">Fe alloys / stainless steel</p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">Special metals (Ti, Mo, W)</p></td><td><p><span>can be produced[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">Carbide steels (WC-Co)</p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">Ceramics (Al<span class="s16">2</span>O<span class="s16">3</span>, AlN)</p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">Glasses (SiO<span class="s16">2</span>, CaF)</p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-leer.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr><tr><td><p class="s8">Plastics (PA, PPS)</p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td><td><p><span>[[File:K7-gef.png]]</span></p></td></tr></table>can be produced with intermediate layer

{| class="twocolortable" style="text-align: left; font-size: 12px;width:40%"|-!colspan="2" style="text-align:center"|'''Dimensions'''|-|Coating thickness: |10 nm - 15 μm|-|Coating thicknesses for contact applications: |0.1 - 10 μm|}

For the geometry of semi-finished products to be coated , there are fewrestrictions. Only the coating of the inside of machined holes and tubing has

Coating thickness +&#177;10 - 30 %, depending on the thickness

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, internalstandards, and customer specifications resp.

==<!--7.3 -->Comparison of Deposition Processes==The individual deposition processes have in part different performancecharacteristics. For each end application , the optimal process has to be chosen, considering all technical and economical factors. The main selection criteriashould be based on the electrical and mechanical requirements for the contactlayer and on the design characteristics of the contact component. <xr id="tab:Comparison of different coating processes"/><!--Table 7.7--> gives some indications for a comparative evaluation of the different coatingprocesses.

The electroless metal coating is not covered here because of the low thicknessof deposits , which makes them in most cases not suitable for contact

The main differences between the <figtable id="tab:Comparison of different coating processes are found in the "><caption>'''<!--Table 7.7:-->Comparison of different coatingprocesses'''</caption> {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Process / Coating Properties!Mechanical Processes (Cladding)!Electroplating!Vaccum Deposition (Sputtering)|-|Coating materialmaterials |formabe metal and thickness. While mechanical cladding and sputtering allow thealloysuse of almost any alloy material|metals, electroplating processes are alloys only limited to |metalsand selected alloys such as for example high|-|Coating thickness|> 1μm|0.1 -carat gold alloys with approx. 10 μm <br />(in special cases up to .3100 μm)wt% Co or Ni|0. Electroplated and sputtered surface layers have a technologicaland economical upper thickness limit of about 10μm. While mechanical claddinghas a minimum thickness of 1 approx. 1 10 μm|-|Coating configuration|selectively, electroplating stamping edges not coated|all around and sputteringselectively<br />stamping edges coated|mostly selectivity|-|Adhesion|good|goodcan also be easily applied in |very thin layers down to the range good|-|Ductility|good|limited|good|-|Purity|good|inclusions of 0.1 μmforeign materials|very good|-|Porosity|good|good for > approx.1μm|good|-|Temperature stability|goodvery good|good|very good|-|Mechanical wear|little|very little|little|-|Environmental impact|little|significant|none|}</figtable>

The properties of main differences between the coatings coating processes are closely related to found in the coating processmaterials and thickness.Starting materials for While mechanical cladding and sputtering targets precious allow the use of almost any alloy material, electroplating processes are limited to metals and theirselected alloys which in the case of , such as for example high-carat gold alloys with up to .3 wt% Co or Ni. Electroplated and palladium based materials are vacuummelted sputtered surface layers have a technological and therefore exhibit economical upper thickness limit of about 10μm. While mechanical cladding has a very high purityminimum thickness of approx. During 1 μm, electroplating, dependingon and sputtering can also be easily applied in very thin layers down to the type range of electrolytes and the deposition parameters, some electrolytecomponents such as carbon and organic compounds are incorporated intothe precious metal coating0. Layers deposited from the gaseous phase howeverare very pure1 μm.

==7The properties of the coatings are closely related to the coating process.4 Hot (-Dipped) Tin Coated Strip Materials==During hot-dip tinning pre-treated strip Starting materials for cladding and sputtering targets precious metals and their alloys, which in the case of gold and palladium based materials , are coated with pure tin or tinalloys from vacuum melted and therefore exhibit a liquid solder metalvery high purity. During overall (or all-around) tinning electroplating, depending on thestripsthrough a liquid metal melt. For strip tinning rotating rolls are partiallyimmersed into a liquid tin melt type of electrolytes and transport the liquid onto the strip which isguided above them. Through special wiping deposition parameters, some electrolyte components such as carbon and gas blowing procedures organic compounds are incorporated into thedeposited tin layer can be held within tight tolerances. Hot tinning is performeddirectly onto the base substrate material without any pre-precious metal coating with eithercopper or nickel. Special cast-on processes or Layers deposited from the melting of solder foils ontothe carrier strip allow also the production of thicker solder layers(> 15 μm)gaseous phase however are very pure.

The main advantage of ==<!--7.4-->Hot (-Dipped) Tin Coated Strip Materials==During hot -dip tinning of copper and copper alloys as compared to, pre-treated strip materials are coated with pure tin electroplating is the formation of an inter-metallic copper-or tin phase alloys from a liquid solder metal. During overall (Cu₃Sn,Cu₆ Sn₅or all-around) at tinning the boundary between strips through a liquid metal melt. For strip tinning, rotating rolls are partially immersed into a liquid tin melt and transport the carrier material and liquid onto the tin layer. This thin(0.3 – 0.5 μm) intermediate layerstrip, which is formed during the thermal tinningprocessguided above them. Through special wiping and gas blowing procedures, is rather hard and reduces in connectors the frictional force andmechanical weardeposited tin layer can be held within tight tolerances. Tin coatings produced by hot Hot tinning have a good adhesion tois performed directly onto the base substrate material and do not tend to tin whisker formationwithout any pre-coating with either copper or nickel. Special cast-on processes or the melting of solder foils onto the carrier strip, also allows the production of thicker solder layers ( > 15 μm).

A special process The main advantage of hot tinning of copper and copper alloys, compared to tin electroplating, is the “Reflow” process. After depositing a formation of an inter-metallic copper-tincoating by electroplating phase (Cu₃Sn, Cu₆Sn₅) at the boundary between the carrier material and the tin layer. This thin (0.3 – 0.5 μm) intermediate layer , which is formed during the thermal tinning process, is short-time melted rather hard and reduces the frictional force and mechanical wear in a continuous processconnectors.The properties of these reflow tin Tin coatings are comparable to those created produced byconventional hot tinninghave a good adhesion to the substrate material and do not tend to tin whisker formation.

Besides overall A special process of hot tinning is the “Reflow” process. After depositing a tin coating of strip material by electroplating, the hot tinning can also be applied layer is short-time melted inthe form of single or multiple stripes on both sides of a continuous substrateprocess.stripThe properties of these reflow tin coatings are comparable to those created by conventional hot tinning.

*'''Besides overall tin coating of strip material, the hot tinning can also be applied in the form of single or multiple stripes on both sides of a continuous substrate strip (<xr id="fig:Typical examples of hot tinned strip materials'''bild"/>).

Coating materials: Pure tin, tin alloys<br>Substrate materials: Cu, CuZn, CuNiZn, CuSn, CuBe and others<br />

{| class="twocolortable" style="text-align: left; font-size: 12px;width:40%"|-|Width of tinning: > |&#8805; 3 + &#177; 1 mm|-|Thickness of tinning: |1 - 15 μm|-|Tolerances (thickness): + |&#177; 1 - +&#177; 3 μm depending on tin thickness|}

Mechanical strength and dimensional tolerances of hot tinned strips are closelyrelated to the standard for Cu and Cu alloy strips according to DIN EN 1652 andDIN EN 1654.

==<!--7.5 -->Contact Lubricants==By using suitable lubricants , the mechanical wear and frictional oxidation ofsliding and connector contacts can be substantially reduced. In the electricalcontact technology , solid, as well as high and low viscosity liquid lubricants areused.

Solid lubricants include for example 0.05 – 0.2 μm thin hard gold layers , whichare added as surface layers on top of the actual contact material. Among the various contact lubricants offered on the market contact lubricationoils have shown performance advantages. They are mostly synthetic, chemically inert, and silicone-free oils such as for example the DODUCONTAcontact lubricants which differ in their chemical composition and viscosity. For sliding contact systems with contact forces < 50 cN and higher slidingspeeds oils with a lower viscosity (<50 mPa·s) are preferential. For applicationswith higher contact forces and operating at higher temperatures contact oilswith a higher viscosity are advantageous. Contact oils are mainly suited forapplications at low current loads. At higher loads and in situations wherecontact separation occurs during the sliding operation thermal decompositionmay be initiated which causes the lubricating properties to be lost. Most compatible with plastics are the contact oil varieties B5, B12K, and B25,which also over longer operating times do not lead to tension stress corrosion. For the optimum lubrication only a very thin layer of contact oil is required.Therefore it is for example recommended to dilute the oil in iso-propylenealcoholduring the application to contact parts. After evaporation of the alcohola thin and uniform layer of lubricant is retained on the contact surfaces.  *'''Properties of the Synthetic DODUCONTA Contact Lubricants'''

<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s8">Lubricant</p></td><td><p class="s8">DODUCONTA</p></td></tr><tr><td><p class="s8">Lubricant</p></td><td><p class="s8">B5</p></td><td><p class="s8">B9</p></td><td><p class="s8">B10</p></td><td><p class="s8">B12K</p></td><td><p class="s8">B25</p></td></tr><tr><td><p class="s8">Contact force</p></td><td><p class="s8">&gt;1N</p></td><td><p class="s8">0.1 - 2N</p></td><td><p class="s8">&lt; 0.2N</p></td><td><p class="s8">0Among the various contact lubricants offered on the market, contact lubrication oils have shown performance advantages.2 They are mostly synthetic, chemically inert and silicone- 5N</p></td><td><p class="s8">&lt;1N</p></td></tr><tr><td><p class="s8">Density (20°C)</p><p class="s8">[g/cm³]</p></td><td><p class="s8">1.9</p></td><td><p class="s8">1.0</p></td><td><p class="s8">0.92</p></td><td><p class="s8">1free oils which differ in their chemical composition and viscosity.0</p></td><td><p class="s8">1.0</p></td></tr><tr><td><p class="s8">Specificel. Resis-</p><p class="s8">tance [<span class="s9">S · </span>cm]</p></td><td/><td><p class="s8">2 x 10<span class="s18">10</span></p></td><td><p class="s8">10<span class="s18">10</span></p></td><td><p class="s8">6 x 10<span class="s18">9</span></p></td><td><p class="s8">5 x 10<span class="s18">8</span></p></td></tr><tr><td><p class="s8">Viscosity (20°C)</p><p class="s8">[mPa·s]</p></td><td><p class="s8">325</p></td><td><p class="s8">47</p></td><td><p class="s8">21</p></td><td><p class="s8">235</p></td><td><p class="s8">405</p></td></tr><tr><td><p class="s8">Congeal temp.[°C]</p></td><td/><td><p class="s8">-55</p></td><td><p class="s8">-60</p></td><td><p class="s8">-40</p></td><td><p class="s8">-35</p></td></tr><tr><td><p class="s8">Flash point[°C]</p></td><td/><td><p class="s8">247</p></td><td><p class="s8">220</p></td><td><p class="s8">238</p></td><td><p class="s8">230</p></td></tr><tr><td/><td><p class="s8">220</p></td><td/><td/></tr></table>

<table border="1" cellspacing="0" style="border<!--7.6--collapse:collapse"><tr><td><p classPassivation of Silver Surfaces="s8">Lubricant</p></td><td><p class="s8">Applications</p></td></tr><tr><td><p class="s8">DODUCONTA B5</p></td><td><p class="s8">Current collectors, connectors, slider switches</p></td></tr><tr><td><p class="s8">DODUCONTA B9</p></td><td><p class="s8">Wire potentiometers, slip ringsThe formation of silver sulfide during the shelf life of components with silver surface in sulfur containing environments, slider switchescan be significantly eliminated by coating them with an additional protective film layer (Passivation layer). For electrical contact use, measuring range selectorssuch thin layers should be chemically inert and sufficiently conductive, miniature connectorsotherwise they are easily broken by the applied contact force.</p></td></tr><tr><td><p classfigure id="s8fig:Typical process flow for the SILVERBRITE W ATPS process">DODUCONTA B10[[File:Typical process flow for the SILVERBRITE W ATPS process.jpg|right|thumb|Figure 4: Typical process flow for the SILVERBRITE W ATPS process]]</p></td><tdfigure>The passivation process SILVERBRITE W ATPS is a water-based tarnish preventer for silver (<p classxr id="s8">Precision wire potentiometers, miniature slip rings</p></td></tr><tr><td><p class="s8">DODUCONTA B12K</p></td><td><p class="s8">Wire potentiometers, slider switches, miniature slip rings, connectors</p></td></tr><tr><td><p class="s8fig:Typical process flow for the SILVERBRITE W ATPS process">DODUCONTA B25</p></td><td><p class="s8">Current collectors). It is free of chromium(VI) compounds and solvents. The passivating layer is applied by immersion, measuring range selectorswhich creates a transparent organic protective film which barely changes the appearance and only slightlyincreases the good electrical properties such as for example the contact resistance. The good solderability and bond properties of silver are notnegatively affected. Because of its chemical composition, this protective layer has some lubricating properties which reduce the insertion and withdrawal forces of connectors</p></td></tr></table>noticeably.

===7.6 Passivation of Silver Surfaces===The formation of silver sulfide during the shelf life of components with silversurface in sulfur containing environments can be significantly eliminated bycoating them with an additional protective film layer (Passivation layer). Forelectrical contact use such thin layers should be chemically inert andsufficiently conductive, or be easily broken by the applied contact force. The passivation process SILVERBRITE W ATPS is a water-based tarnishpreventer for silver. It is free of chromium(VI) compounds and solvents. Thepassivating layer is applied by immersion which creates a transparent organicprotective film which barely changes the appearance and only slightlyincreases the good electrical properties such as for example the contactresistance. The good solderability and bond properties of silver are notnegatively affected. Because of its chemical composition this protective layerhas some lubricating properties which reduce the insertion and withdrawalforces of connectors noticeably. Fig. 7.7: Typical process flow for the SILVERBRITE W ATPS process ===References===