Changes

===2.1 Introduction===The contact parts are important components in switching devices. They have tomaintain their function from the new state until the end of the functional life of thedevices.

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

they They have to exhibit physical, mechanical, and chemical properties like high electricaland thermal conductivity, high hardness, high corrosion resistance, etc . and besidesthis , should have good mechanical workability, and also be suitable for good weld andbrazing attachment to contact carriers. In addition they must be made fromenvironmentally friendly materials.

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

*'''Pure metals''' Within this group, silver has the greatest importance for switching devices in the higher energy technology. Other precious metals such as gold and platinum are only used in applications for the information technology in the form of thin surface layers. As a nonprecious metal, tungsten is used for some special applications such as, for example, automotive horn contacts. In some rarer cases, pure copper is used, but mainly paired to a silver-based contact material. '''Alloys''' Besides these few pure metals, a larger number of alloy materials made by melt technology are available for the use as contacts. An alloy is characterized by the fact, that its components are completely or partially soluble in each other in the solid state. Phase diagrams for multiple metal compositions show the number and type of the crystal structure as a function of the temperature and composition of the alloying components.

Besides these few pure metals a larger number They indicate the boundaries of liquid and solid phases and define the parameters of alloy materials made by meltsolidification.technology are available for Alloying allows to improve the use as contacts. An alloy is characterized by properties of one material at the factthat its components are completely or partially soluble in each other in cost of changing them for the solid statesecond material.Phase diagrams for multiple metal compositions show As an example, the number and type hardness of a base metal may be increased while at thecrystal structure as a function of same time the temperature and composition electrical conductivity decreases with even small additions of the second alloying componentscomponent.

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

Composite materials are a material group whose properties are of greatimportance for electrical contacts that are used in switching devices for higherelectrical currents.Those used in electrical contacts are heterogeneous materials , composed of twoor more uniformly dispersed components , in which the largest volume portionconsists of a metal.The properties of composite materials are determined mainly independent fromeach other by the properties of their individual components. Therefore it is forexample possible to combine the high melting point and arc erosion resistanceof tungsten with the low melting and good electrical conductivity of copper, orthe high conductivity of silver with the weld resistant metalloid graphite.

Figure 2The properties of composite materials are determined mainly independent from each other by the properties of their individual components.1 Therefore it is, for example, possible to combine the high melting point and arc erosion resistance of tungsten with the low melting and good electrical conductivity of copper or the high conductivity of silver with the weld resistant metalloid graphite. <xr id="fig:Powder metallurgical manufacturing of composite materials (schematic)"/> shows the schematic manufacturing processes from powderblending to contact material. Three basic process variations are typicallyapplied:

During sintering without a liquid phase <figure id="fig:Powder metallurgical manufacturing of composite materials (left side of schematic) the powder mix is">first densified by pressing, then undergoes a heat treatment [[File:Powder metallurgical manufacturing of composite materials (sinteringschematic), andeventually is re-pressed again to further increase the density. The sinteringatmosphere depends on the material components and later application; avacuum is used for example for the low gas content material Cu/Cr. Thisprocess is used for individual contact parts and also termed pressjpg|thumb|<caption>Powder-sinterrepressmetallurgical manufacturing of composite materials (PSRschematic). For materials with high silver content T_s = Melting point of the starting point atpressing is most a larger block (or billetlower melting component) which is then after sintering hotextruded into wire, rod, or strip form. The extrusion further increases the density</caption>]]of these composite materials and contributes to higher arc erosion resistance.Materials such as Ag</Ni, Ag/MeO, and Ag/C are typically produced by thisprocess. Sintering with liquid phase has the advantage of shorter process times due tothe accelerated diffusion and also results in near-theoretical densities of thefigure>

FigDuring ''sintering without a liquid phase'' (left side of schematic), the powder mix is first densified by pressing, then undergoes a heat treatment (sintering) and eventually is re-pressed again to further increase the density. 2The sintering atmosphere depends on the material components and later application; a vacuum is used for example for the low gas content material Cu/Cr.1: PowderThis process is used for individual contact parts and also termed press-metallurgical manufacturing of composite sinter-repress (PSR). For materials with high silver content, the starting point before pressing is mostly a large block (schematicor billet)T = Melting point which is then, after sintering, hot extruded into wire, rod or strip form. The extrusion further increases the density of the lower melting componentthese composite materials and contributes to higher arc erosion resistance. Materials such as Ag/Ni, Ag/MeO and Ag/C are typically produced by this process.

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

As opposed to the liquid phase sintering , which has limited use for electricalcontact manufacturing, the ''Infiltration process '' as shown on the right side of theschematic , has a broad practical range of applications. In this process thepowder of the higher melting component , sometimes also as a powder mix witha small amount of the second material , is pressed into parts and . Then, right after sintering, the porous skeleton is infiltrated with liquid metal of the second material. Thefilling fill-up process of the pores happens through capillary forces. This process reaches, after the infiltration , near-theoretical density without subsequent pressing and iswidely used for Ag- and Cu-refractory contacts. For Ag/W or Ag/WC contacts,controlling the amount or excess on the bottom side of the contact of theinfiltration metal Ag , results in contact tips that can be easily attached to theircarriers by resistance welding. For larger Cu/W contacts , additional machining isoften used to obtain the final shape of the contact component. ===2.2 Gold Based Materials=== Pure Gold is besides Platinum the chemically most stable of all precious metals.In its pure form it is not very suitable for use as a contact material in electromechanical devices because of its tendency to stick and cold-weld at even low contact forces. In addition it is not hard or strong enough to resistmechanical wear and exhibits high materials losses under electrical arcingloads. This limits its use in form of thin electroplated or vacuum deposited layers. For most electrical contact applications gold alloys are used. Depending on thealloying metal the melting is performed either under in a reducing atmosphere orin a vacuum. The choice of alloying metals depends on the intended use of theresulting contact material. The binary Au alloys with typically <10 wt% of otherprecious metals such as Pt, Pd, or Ag or non-precious metals like Ni, Co, andCu are the more commonly used ones (Table 2.2). On one hand these alloyadditions improve the mechanical strength and electrical switching propertiesbut on the other hand reduce the electrical conductivity and chemical corrosionresistance (Fig. 2.2) to varying degrees. Under the aspect of reducing the gold content ternary alloys with a gold contentof approximately 70 wt% and additions of Ag and Cu or Ag and Ni resp., forexample AuAg25Cu5 or AuAg20Cu10 are used which exhibit for manyapplications good mechanical stability while at the same time have sufficientresistance against the formation of corrosion layers (Table 2.3). Other ternaryalloys based on the AuAg system are AuAg26Ni3 and AuAg25Pt6. These alloysare mechanically similar to the AuAgCu alloys but have significantly higheroxidation resistance at elevated temperatures (Table 2.4). Caused by higher gold prices over the past years the development of alloys withfurther reduced gold content had a high priority. The starting point has been theAuPd system which has continuous solubility of the two components. Besidesthe binary alloy of AuPd40 and the ternary one AuPd35Ag9 other multiplecomponent alloys were developed. These alloys typically have < 50 wt% Au andoften can be solution hardened in order to obtain even higher hardness andtensile strength. They are mostly used in sliding contact applications. Gold alloys are used in the form of welded wire or profile (also called weldtapes),segments, contact rivets, and stampings produced from clad stripmaterials. The selection of the bonding process is based on the cost for thejoining process, and most importantly on the economical aspect of using theleast possible amount of the expensive precious metal component. Besides being used as switching contacts in relays and pushbuttons, goldalloys are also applied in the design of connectors as well as sliding contacts forpotentiometers, sensors, slip rings, and brushes in miniature DC motors(Table 2.5). Table 2.3: Mechanical Properties of Gold and Gold-Alloys Table 2.1: Commonly Used Grades of Gold Table 2.2: Physical Properties of Gold and Gold-Alloys Fig. 2.2:Influence of 1-10 atomic% of differentalloying metals on the electrical resistivity of gold(according to J. O. Linde) Fig. 2.3:Phase diagramof goldplatinum Fig. 2.4:Phase diagramof gold-silver Fig. 2.5:Phase diagramof gold-copper Fig. 2.6: Phase diagram of gold-nickel Fig. 2.7: Phase diagram of gold-cobalt Fig. 2.8:Strain hardeningof Au by cold working Fig. 2.9:Softening of Au after annealingfor 0.5 hrs after 80%cold working Fig. 2.10:Strain hardening ofAuPt10 by cold working Fig. 2.11:Strain hardeningof AuAg20 by cold working Fig. 2.12:Strain hardening ofAuAg30 by cold working Fig. 2.13:Strain hardening of AuNi5by cold working Fig. 2.14:Softeningof AuNi5 after annealingfor 0.5 hrs after 80%cold working Fig. 2.15:Strain hardeningof AuCo5 by cold working Fig. 2.16:Precipitation hardening ofAuCo5 at 400°C hardeningtemperature Fig. 2.17:Strain hardeningof AuAg25Pt6 by cold working Fig. 2.18:Strain hardeningof AuAg26Ni3 by cold working Fig. 2.19:Softeningof AuAg26Ni3 afterannealing for 0.5 hrsafter 80% coldworking Fig. 2.20:Strain hardening ofAuAg25Cu5by cold working Fig. 2.21:Strain hardening ofAuAg20Cu10by cold working Fig. 2.22:Softeningof AuAg20Cu10 afterannealing for 0.5 hrsafter 80% cold working Fig. 2.23:Strain hardening ofAuCu14Pt9Ag4by cold working Fig. 2.24:Precipitationhardening ofAuCu14Pt9Ag4at differenthardeningtemperaturesafter 50%cold working Table 2.4: Contact and Switching Properties of Gold and Gold Alloys

Table 2.5: Application Examples and Forms of ==Gold and Gold AlloysBased Materials==

===2Pure Gold is besides Platinum the chemically most stable of all precious metals. In its pure form, it is not very suitable for use as a contact material in electromechanical devices because of its tendency to stick and cold-weld at even low contact forces. In addition, it is not hard or strong enough to resist mechanical wear and exhibits high material losses under electrical arcing loads. This limits its use in form of thin electroplated or vacuum deposited layers.3 Platinum Metal Based Materials===

Since The platinum group metals include the elements Pt, Pd was for the longest time rather stable in price it was looked at , Rh, Ru, Ir and Os ([[Platinum_Metal_Based_Materials|Table 1]]<!--(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 a substitutefor the more expensive goldbut due to their catalytical properties, they tend to polymerize adsorbed organic vapors on contact surfaces. This was followed by a steep increase in During frictional movement between contact surfaces, the Pd pricepolymerized compounds known as “brown powder” are formed, which caused can lead to a significant reduction increase in its use contact resistance. Therefore Pt and Pd are typically used as alloys and are rather not used in their pure form for electrical contacts. Today (2011) thePd price again is lower than that of goldcontact applications.

Table 2.6Main Article: Properties, Production Processes, and Application Forms for Platinum Metals[[Silver Based Materials| Silver Based Materials]]

Table 2.7: Physical Properties of the Platinum Metals ==Tungsten and their AlloysMolybdenum Based Materials==

Table 2.8Main Article: Mechanical Properties of the Platinum Metals [[Tungsten and their AlloysMolybdenum Based Materials| Tungsten and Molybdenum Based Materials]]

FigThe low gas content contact materials are developed for the use in vacuum switching devices. 2.26:Influence of 1-22 atom% of differentadditive metals on the electricalresistivityp of palladium

Fig. 2.27Main Article:Phase diagram ofplatinum-iridium[[Contact Materials for Vacuum Switches| Contact Materials for Vacuum Switches]]

FigVinaricky, E. 2(Hrsg.29):Elektrische Kontakte, Werkstoffe und Anwendungen.Phase diagramof platinumSpringer-tungstenVerlag, Berlin, Heidelberg etc. 2002

FigLindmayer, M. 2: Schaltgeräte-Grundlagen, Aufbau, Wirkungsweise.30:Phase diagram ofpalladiumSpringer-copperVerlag, Berlin, Heidelberg, New York, Tokio, 1987

FigRau, G. 2: Metallische Verbundwerkstoffe.31:Strainhardeningof Pt by coldWerkstofftechnischeworkingVerlagsgesellschaft, Karlsruhe 1977

FigSchreiner, H. 2.32:Softening of Pt afterannealing for 0Pulvermetallurgie elektrischer Kontakte.5 hrsafter 80%Springer-Verlagcold workingBerlin, Göttingen, Heidelberg, 1964

FigHansen. 2M.; Anderko, K.33:Strain hardening Constitution of PtIr5Binary Alloys. New York:by cold workingMc Graw-Hill, 1958

FigShunk, F. 2A.34:Softening Constitution of PtIr5 after annealing for 1 hrafter different degrees of cold workingBinary Alloy. 2 Suppl. New York; Mc Graw-Hill, 1969

FigEdelmetall-Taschenbuch. 2( Herausgeber Degussa AG, Frankfurt a.35:Strain hardeningM.),of PtNi8 by cold workingHeidelberg, Hüthig-Verlag, 1995

FigRau, G. 2: Elektrische Kontakte-Werkstoffe und Technologie. Eigenverlag G.36:RauSoftening of PtNi8 afterannealingfor 1 hr after80% cold workingGmbH & Co., Pforzheim, 1984

FigHeraeus, W. 2C.37:Strain hardeningof PtW5 by cold workingWerkstoffdaten. Eigenverlag W.C. Heraeus, Hanau, 1978

FigLinde, J. 2O.38:Elektrische Widerstandseigenschaften der verdünnten LegierungenSofteningof PtW5 afterannealing for 1hrafter 80% coldworkingdes Kupfers, Silbers und Goldes. Lund: Hakan Ohlsson, 1938

FigGroßmann, H. 2Saeger, K. E.; Vinaricky, E.40:Gold and Gold Alloys in ElectricalStrain hardeningEngineering. in: Gold, Progress in Chemistry, Biochemistry and Technology. Johnof PdCu15 by cold workingWiley & Sons, Chichester etc, (1999) 199-236

FigGehlert, B. 2: Edelmetall-Legierungen für elektrische Kontakte.41:Softeningof PdCu15 afterannealingfor 0Metall 61 (2007) H.5 hrs6, 374-379

FigAldinger, F. 2; Schnabl, R.42:Edelmetallarme Kontakte für kleine Ströme.Strain hardeningof PdCu40 by cold workingMetall 37 (1983) 23-29

FigBischoff, A. 2; Aldinger, F.43:Einfluss geringer Zusätze auf die mechanischenSofteningof PdCu40after annealingfor 0Eigenschaften von Au-Ag-Pd-Legierungen.5 hrs after 80%cold workingMetall 36 (1982) 752-765

FigWise, E. 2M.44:Electrical resistivity pof PdCu alloys with Palladium, Recovery, Properties and without anannealing step for forming an orderedUses. New York, London:phaseAcademic Press 1968

Table 2Savitskii, E.M.; Polyakova, V.P.; Tylina, M.A.9: Contact and Switching PropertiesPalladium Alloys, Primary Sources.of the Platinum Metals and their AlloysNew York: Publishers 1969

Table 2Gehlert, B.10: Application Examples and FormLebensdaueruntersuchungen von Edelmetall Kontaktwerkstoff-of Supply for Platinum Metals and their AlloysKombinationen für Schleifringübertrager. VDE-Fachbericht 61, (2005) 95-100

===2Holzapfel,C.4 Silver Based Materials===: Verschweiß und elektrische Eigenschaften vonSchleifringübertragern. VDE-Fachbericht 67 (2011) 111-120

===2.4.1 Pure Silver===Pure silver (also called fine silver) exhibits the highest electrical and thermalconductivity of all metals. It is also resistant against oxidation. Major disadvantagesare its low mechanical wear resistanceSchnabl, the low softening temperature,and especially its strong affinity to sulfur and sulfur compounds. In the presenceof sulfur and sulfur containing compounds brownish to black silver sulfide layerare formed on its surfaceR. These can cause increased contact resistance oreven total failure of a switching device if they are not mechanically; Gehlert, electrically,or thermally destroyedB. Other weaknesses of silver contacts are the tendency toweld under the influence of over: Lebensdauerprüfungen von Edelmetall-currents and the low resistance againstmaterial transfer when switching DC loadsSchleifkontaktwerkstoffen für Gleichstrom Kleinmotoren. In humid environments and underthe influence of an electrical field silver can creep Feinwerktechnik & Messtechnik (silver migration1984) and causeelectrical shorting between adjacent current paths.8, 389-393

Table 2Kobayashi, T.11 shows the typically available quality grades of silver; Koibuchi, K. In certaineconomic areas; Sawa, iK.e; Endo, K. China; Hagino, there are additional grades with varying amounts H.: A Study ofLifetimeimpurities available on the market. In powder form silver is used of Au-plated Slip-Ring and AgPd Brush System for a widevariety of silver based composite contact materialsPower Supply. Different manufacturingprocesses result in different grades of Ag powder as shown in Table 2th Proc.1224 Int.additional properties of silver powders and their usage are describedin chapter 8Conf.1on Electr.Semi-finished silver materials can easily be warm or cold formed and can beclad to the usual base materials. For attachment of silver to contact carriermaterials welding of wire or profile cutContacts, Saint Malo, France 2008, 537-offs and brazing are most widely applied.Besides these mechanical processes such as wire insertion (wire staking) andthe riveting (staking) of solid or composite contact rivets are used in themanufacture of contact components.542

Contacts made from fine silver are applied in various electrical switchingdevices such as relaysHarmsen, pushbuttons, appliance and control switches forcurrents < 2 A (Table 2U.; Saeger K.16)E. Electroplated silver coatings are widely used toreduce the contact resistance and improve the brazing behavior of other contact: Über das Entfestigungsverhalten von Silbermaterials and componentsverschiedener Reinheiten.Metall 28 (1974) 683-686

Table 2Behrens, V.; Michal, R.; Minkenberg, J.N.; Saeger, K.E.11: Overview of the Most Widely Used Silver GradesAbbrand undKontaktwiderstandsverhalten von Kontaktwerkstoffen auf Basis von Silber-Nickel. e.& i. 107. Jg. (1990), 2, 72-77

Table 2Behrens, V.12: Quality Criteria of Differently Manufactured Silver PowdersSilber/Nickel und Silber/Grafit- zwei Spezialisten auf dem Gebietder Kontaktwerkstoffe. Metall 61 (2007) H.6, 380-384

FigRieder, W. 2.45:Silber / Metalloxyd-Werkstoffe für elektrische Kontakte,Strain hardeningof Ag 99.95 by cold workingVDE - Fachbericht 42 (1991) 65-81

FigHarmsen,U. 2.46:Die innere Oxidation von AgCd-Legierungen unterSoftening of Ag 99Sauerstoffdruck.95after annealing for 1 hr after differentdegrees of strain hardeningMetall 25 (1991), H.2, 133-137

===2Muravjeva, E.4M.2 Silver Alloys===To improve the physical and contact properties of fine silver melt-metallurgicalproduced silver alloys are used (Table 2; Povoloskaja, M.13)D. By adding metal components the: Verbundwerkstoffe Silber-Zinkoxid undmechanical properties such as hardness and tensile strength as well as typicalcontact properties such as erosion resistanceSilber-Zinnoxid, and resistance against materialtransfer in DC circuits are increased (Table 2hergestellt durch Oxidationsglühen.14). On the other hand however,other properties such as electrical conductivity and chemical corrosionresistance can be negatively impacted by alloying Elektrotechnika 3 (Figs. 2.47 and 2.481965).37-39

===2Behrens, V.; Honig Th.; Kraus, A.4; Michal, R.2; Saeger, K.1 Fine-Grain Silver===Fine-Grain Silver (ARGODUR-Spezial) is defined as a silver alloy with an additionof 0.15 wt% of NickelE. Silver and nickel are not soluble in each other in solidform; Schmidberger, R. In liquid silver only a small amount of nickel is soluble as the phase diagram;(FigStaneff, Th. : Eine neue Generation von AgSnO₂ -Kontaktwerkstoffen.51) illustrates. During solidification of the melt this nickel addition getsfinely dispersed in the silver matrix and eliminates the pronounce coarse graingrowth after prolonged influence of elevated temperatures VDE-Fachbericht 44, (Figs. 2.49 and 2.50.1993) 99-114

FineBraumann, P.; Lang, J.: Kontaktverhalten von Ag-grain silver has almost the same chemical corrosion resistance as fineMetalloxiden für den Bereichsilverhoher Ströme. Compared to pure silver it exhibits a slightly increased hardness andtensile strength VDE-Fachbericht 42, (Table 2.141991). The electrical conductivity is just slightly decreasedby this low nickel addition. Because of its significantly improved contactproperties fine grain silver has replaced pure silver in many applications.89-94

===2Hauner, F.; Jeannot, D.4; Mc Neilly, U.2; Pinard, J.: Advanced AgSnO Contact 2 Hard-Silver Alloys===Using copper as an alloying component increases the mechanical stability ofsilver significantlyth Materials for High Current Contactors. Proc. 20 Int. Conf. The most important among the binary AgCu alloys is that ofAgCu3, known in europe also under the name of hard-silveron Electr. This material stillContacthas a chemical corrosion resistance close to that of fine silverPhenom. In comparison topure silver and fine, Stockholm 2000, 193-grain silver AgCu3 exhibits increased mechanical strengthas well as higher arc erosion resistance and mechanical wear resistance(Table 2.14).198

Increasing Wintz, J.-L.; Hardy, S.; Bourda, C.: Influence on the Cu content further also increases the mechanical strength Electrical Performances ofAgCu alloys Assembly Process, Supports Materials and improves arc erosion resistance and resistance againstmaterial transfer while at the same time however the tendency to oxide formationbecomes detrimentalProduction Means for AgSnO₂ . This causes during switching under arcing conditions anincrease in contact resistance with rising numbers of operationProc. In specialapplications where highest mechanical strength is recommended and a reducedchemical resistance can be tolerated, the eutectic AgCu alloy with 28 wt% ofcopper (Fig24_th Int. 2Conf.52) is usedon Electr. AgCu10 also known as coin silver has beenreplaced in many applications by composite silverContacts, Saint Malo, France 2008, 75-based materials while sterlingsilver (AgCu7.5) has never extended its important usage from decorative tablewear and jewelry to industrial applications in electrical contacts.81

Besides these binary alloysBehrens, ternary AgCuNi alloys are used in electrical contactapplicationsV. From this group the material ARGODUR 27; Honig, an alloy of 98 wt% Agwith a 2 wt% Cu and nickel addition has found practical importance close to thatof AgCu3Th. This material is characterized by high resistance to oxidation and lowtendency to re-crystallization during exposure to high temperatures; Kraus, A. Besideshigh mechanical stability this AgCuNi alloy also exhibits a strong resistanceagainst arc erosion; Michal, R. Because of its high resistance against material transfer the: Schalteigenschaften vonalloy AgCu24.5Ni0.5 has been used verschiedenen Silber-Zinnoxidwerkstoffen in the automotive industry for an extendedtime in the North American marketKfz-Relais. Caused by miniaturization and the relatedVDE-Fachbericht 51reduction in available contact forces in relays and switches this material hasbeen replaced widely because of its tendency to oxide formation.(1997) 51-57

The attachment methods used for the hard silver materials are mostly close toSchöpf, Th.: Silber/Zinnoxid und andere Silber-Metalloxidwerkstoffe inthose applied for fine silver and fine grain silverNetzrelais.VDE-Fachbericht 51 (1997) 41-50

Hard-silver alloys are widely used for switching applications in the informationSchöpf, Th.; Behrens, V.; Honig, Th.; Kraus, A.: Development of Silver Zincand energy technology th Oxide for currents up to 10 AGeneral-Purpose Relays. Proc. 20 Int. Conf. on Electr. Contacts, in special cases also for highercurrent ranges (Table 2.16).Stockholm 2000, 187-192

Dispersion hardened alloys of silver with 0Braumann, P.5 wt% MgO and NiO (ARGODUR 32); Koffler, A.: Einfluss von Herstellverfahren, Metalloxidgehalt undare produced by internal oxidationWirkzusätzen auf das Schaltverhalten von Ag/SnO in Relais. While the melt-metallurgical alloy is easy to2coldVDE-work and form the material becomes very hard and brittle after dispersionhardening. Compared to fine silver and hardFachbericht 59, (2003) 133-silver this material has a greatlyimproved temperature stability and can be exposed to brazing temperatures upto 800°C without decreasing its hardness and tensile strength.Because of these mechanical properties and its high electrical conductivity142

Table 2Kempf, B.13; Braumann, P.; Böhm, C.; Fischer-Bühner, J.: Silber-Zinnoxid-Werkstoffe: Physical Properties of Silver and Silver AlloysHerstellverfahren und Eigenschaften. Metall 61(2007) H. 6, 404-408

ARGODUR 32 is mainly used Lutz, O.; Behrens, V.; Finkbeiner, M.; Honig, T.; Späth, D.: Ag/CdO-Ersatz in the form of contact springs that are exposed tohigh thermal and mechanical stresses in relaysLichtschaltern. VDE-Fachbericht 61, and contactors for aeronauticapplications.(2005) 165-173

FigLutz, O. 2; Behrens, V.; Wasserbäch, W.; Franz, S.; Honig, Th.; Späth,D.; Heinrich, J.47:Improved Silver/Tin Oxide Contact Materials for AutomotiveInfluence of 1-10 atom% of differentalloying metals th Applications. Proc.24 Int. Conf. on the electrical resistivity ofElectr. Contacts, Saint Malo, France 2008,silver88-93

FigLeung, C. 2; Behrens, V.48:Electrical resistivity pA Review of AgCu alloys with 0-20 weight% Cuin the soft annealedAg/SnO Contact Materials and tempered stageArc Erosion. 2a) Annealed and quenchedb) Tempered at 280°Cth Proc.24 Int. Conf. on Electr. Contacts, Saint Malo, France 2008, 82-87

FigChen, Z. 2K.; Witter, G.J.49: Coarse grain micro structureComparison in Performance for Silver–Tin–Indiumof Ag 99Oxide Materials Made by Internal Oxidation and Powder Metallurgy.97 after 80% cold workingand 1 hr annealing at 600°Cth Proc. 55 IEEE Holm Conf. on Electrical Contacts, Vancouver, BC, Canada,(2009) 167 – 176

FigRoehberg, J. 2; Honig, Th.; Witulski, N.; Finkbeiner, M.; Behrens, V.50: Fine grain microstructurePerformanceof AgNi0Different Silver/Tin Oxide Contact Materials for Applications in Low Voltageth Circuit Breakers. Proc. 55 IEEE Holm Conf.15 after 80% cold workingon Electrical Contacts, Vancouver,and 1 hr annealing at 600°CBC, Canada, (2009) 187 – 194

FigMuetzel, T. 2; Braumann, P.; Niederreuther, R.51:Temperature Rise Behavior ofPhase diagramth Ag/SnO Contact Materials for Contactor Applications. Proc. 55 IEEE Holm 2of silver-nickelConf. on Electrical Contacts, Vancouver, BC, Canada, (2009) 200 – 205

FigLutz, O. 2et al.52:Silber/Zinnoxid – Kontaktwerkstoffe auf Basis der InnerenPhase diagramOxidation fuer AC – und DC – Anwendungen.of silver-copperVDE Fachbericht 65 (2009) 167 – 176

FigHarmsen, U. 2; Meyer, C.L.53:Mechanische Eigenschaften stranggepresster Silber-Phase diagram ofsilverGraphit-Verbundwerkstoffe. Metall 21 (1967), 731-cadmium733

Table 2Behrens, V.14: Mechanical Properties of Mahle, E.; Michal, R.; Saeger, K.E.: An Advanced Silver and Silver Alloys/Graphiteth Contact Material Based on Graphite Fibre. Proc. 16 Int. Conf. on Electr.Contacts, Loghborough 1992, 185-189

FigSchröder, K. 2-H.; Schulz, E.-D.54:Über den Einfluss des HerstellungsverfahrensStrain hardeningth auf das Schaltverhalten von Kontaktwerkstoffen der Energietechnik. Proc. 7 Int.of AgCu3by cold workingConf. on Electr. Contacts, Paris 1974, 38-45

FigMützel, T. 2: Niederreuther, R.55:Kontaktwerkstoffe für Hochleistungsanwendungen.Softening of AgCu3after annealing for 1 hrafter 80% cold workingVDE-Bericht 67 (2011) 103-110

FigLambert, C. 2; Cambon, G.56:The Influence of Manufacturing Conditions andStrain hardening Metalurgical Characteristics on the Electrical Behaviour of AgCu5 by coldSilver-Graphiteth Contact Materials. Proc. 9 Int. Conf.on Electr. Contacts,workingChicago 1978, 401-406

FigVinaricky, E. 2.57:Grundsätzliche Untersuchungen zum Abbrand- undSoftening of AgCu5 afterannealing for 1 hr after 80% coldSchweißverhalten von Ag/C-Kontaktwerkstoffen. VDE-Fachbericht 47 (1995)working159-169

FigAgte, C. 2; Vacek, J.58:Strain hardening of AgCu 10by cold workingWolfram und Molybdän. Berlin: Akademie-Verlag 1959

FigKeil, A. 2; Meyer, C.-L.59:Der Einfluß des Faserverlaufes auf die elektrischeSoftening of AgCu10 afterannealing for 1 hr after 80% coldworkingVerschleißfestigkeit von Wolfram-Kontakten. ETZ 72, (1951) 343-346

FigSlade, P. 2G.60:Electric Contacts for Power Interruption. A Review. Proc. 19 Int.Strain hardening of AgCu28 bycold workingConf. on Electric Contact Phenom. Nuremberg (Germany) 1998, 239-245

FigSlade, P. 2G.61:Variations in Contact Resistance Resulting from Oxide FormationSoftening of AgCu28and Decomposition in AgW and Ag-WC-C Contacts Passing Steady Currentsafter annealing for Long Time Periods. IEEE Trans. Components, Hybrids and Manuf. Technol.CHMT-9,1 hr after80% cold working(1986) 3-16

FigSlade, P. 2G.62:Effect of the Electric Arc and the Ambient Air on the ContactStrain hardening Resistance of AgNi0Silver, Tungsten and Silver-Tungsten Contacts.15by cold workingJ.Appl.Phys. 47, 8 (1976) 3438-3443

FigLindmayer, M. 2; Roth, M.63:Contact Resistance and Arc-Erosion of W-Ag andSoftening of AgNi0WC-Ag. IEEE Trans components, Hybrids and Manuf. Technol.15after annealing for CHMT-2, 1 hr after 80%cold working(1979) 70-75

FigLeung, C. 2-H.; Kim, H.J.64:Strain hardening A Comparison ofAg/W, Ag/WC and Ag/Mo ElectricalARGODUR 27Contacts. IEEE Trans. Components, Hybrids, Manuf. Technol.,by cold workingVol. CHMT-7, 1 (1984) 69-75

FigAllen, S. 2E.; Streicher, E.65:The Effect of Microstructure on the ElectricalSofteningth Performance of ARGODUR 27 after annealingAg-WC-C Contact Materials. Proc. 44 IEEE Holm Conf. on Electr.for 1 hr after 80% cold workingContacts, Arlington, VA, USA (1998), 276-285

Table 2Haufe, W.; Reichel, W.; Schreiner H.15: Contact and Switching Properties of Silver and Silver AlloysAbbrand verschiedener W/Cu-Sinter-Tränkwerkstoffe an Luft bei hohen Strömen. Z. Metallkd. 63 (1972) 651-654

Table 2Althaus, B.; Vinaricky, E.16: Application Examples and Forms of Supply for Silver and Silver AlloysDas Abbrandverhalten verschieden hergestellterWolfram-Kupfer-Verbundwerkstoffe im Hochstromlichtbogen.Metall 22 (1968) 697-701

===2Gessinger, G.4H.2; Melton, K.3 SilverN.: Burn-Palladium Alloys===The addition off Behaviour of 30 wt% Pd increases the mechanical properties as well as theWCu Contact Materials in anresistance of silver against the influence of sulfur and sulfur containingcompounds significantly (Tables 2Electric Arc. Powder Metall.17 and 2Int.189 (1977).Alloys with 4067-60 wt% Pd have an even higher resistance against silver sulfideformation. At these percentage ranges however the catalytic properties ofpalladium can influence the contact resistance behavior negatively. Theformability also decreases with increasing Pd contents.72

AgPd alloys are hardMagnusson, arc erosion resistant, and have a lower tendency towardsM.: Abbrandverhalten und Rißbildung bei WCu-Tränkwerkstoffenmaterial transfer under DC loads unterschiedlicher Wolframteilchengröße. ETZ-A 98 (Table 2.191977). On the other hand the electricalconductivity is decreased at higher Pd contents. The ternary alloy AgPd30Cu5has an even higher hardness which makes it suitable for use in sliding contactsystems.681-683

AgPd alloys are mostly used in relays for the switching of medium to higher loads(>60VHeitzinger, F.; Kippenberg, H.; Saeger, >2A) as shown in Table 2K.20E. Because of the high palladium price theseformerly solid contacts have been widely replaced by multi-layer designs suchas AgNi0; Schröder, K.15 or AgNi10 with a thin Au surface layerH. A broader field of application: Contact Materials forfor AgPd alloys remains in the wear resistant sliding contact systemsVacuum Switching Devices. Proc.XVth ISDEIV, Darmstadt 1992, 273-278

FigGrill, R. 2; Müller, F.66: Phase diagram of silverVerbundwerkstoffe auf Wolframbasis fürHochspannungsschaltgeräte. Metall 61 (2007) H. 6, 390-palladium393

FigSlade, P. 2: G.67:The Vacuum Interrupter- Theory; Design; and Application. CRCStrain hardeningof AgPd30 by cold workingPress, Boca Raton, FL (USA), 2008

FigFrey, P. 2; Klink, N.; Saeger, K.E.68:Untersuchungen zum Abreißstromverhalten vonStrain hardeningof AgPd50 by cold workingKontaktwerkstoffen für Vakuumschütze. Metall 38 (1984) 647-651

FigFrey, P. 2; Klink, N.; Michal, R.; Saeger, K.E.69:Metallurgical Aspects of ContactStrain hardeningof AgPd30Cu5Materials for Vacuum Switching Devices. IEEE Trans. Plasma Sc. 17, (1989) 743-by cold working740

FigSlade, P. 2.70:Advances in Material Development for High Power Vacuum InterrupterSoftening of AgPd30th Contacts. Proc.16 Int. Conf. on Electr. Contact Phenom., AgPd50Loughborough 1992,and AgPd30Cu5 after annealing of 1 hrafter 80% cold working-10

Table 2Behrens, V.; Honig, Th.; Kraus, A.; Allen, S.17: Physical Properties Comparison of SilverDifferent Contactth Materials for Low Voltage Vacuum Applications. Proc.19 Int. Conf. on Electr.Contact Phenom., Nuremberg 1998, 247-Palladium Alloys251

Table 2Rolle, S.; Lietz, A.; Amft, D.; Hauner, F.18: Mechanical Properties of SilverCuCr Contact Material for Low Voltageth Vacuum Contactors. Proc. 20 int. Conf. on Electr. Contact. Phenom. Stockholm2000, 179-Palladium Alloys186

Table 2Kippenberg, H.19: CrCu as a Contact and Switching Properties of SilverMaterial for Vacuum Interrupters.th Proc.13 Int. Conf. on Electr. Contact Phenom. Lausanne 1986, 140-Palladium Alloys144

Table 2Hauner, F.; Müller, R.; Tiefel, R.20: Application Examples and Forms of Suppl for SilverCuCr für Vakuumschaltgeräte-Herstellungsverfahren, Eigenschaften und Anwendung.Metall 61 (2007) H. 6, 385-Palladium Alloys389

===2.4.3 Silver Composite Manufacturing Equipment for Semi-Finished Materials===(Bild)