The platinum group metals include the elements Pt, Pd, Rh, Ru, Ir, and Os ''(Table<xr id="tab:Properties_Production_Processes_and_Application_Forms_for_Platinum_Metals"/><!--(Tab. 2.6)''-->). For electrical contacts , platinum and palladium have practical significanceas base alloy materials and ruthenium and iridium are used as alloying components.Pt and Pd have similar corrosion resistance as gold but because for the reason of theircatalytical properties , they tend to polymerize adsorbed organic vapors on contactsurfaces. During frictional movement between contact surfaces , the polymerizedcompounds known as “brown powder” are formed , which can lead to significantlya significant increase in contact resistance. Therefore Pt and Pd are typically used as alloys andnot in their pure form for electrical contact applications.

Rhodium is not used as a solid contact material but is applied for example as aelectroplated layer in sliding contact systems. Ruthenium is mostly used as an alloying<figtable id="tab:Properties_Production_Processes_and_Application_Forms_for_Platinum_Metals">component in the material PdRu15<caption>'''<!--Table 2. The metals osmium 6:-->Properties, Production Processes, and iridium have no practicalapplications in electrical contacts.Application Forms for Platinum Metals'''</caption>

Since Pd was for {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Element !Properties!Processing!Forms of Application|-|Ru<br />Ruthenium|Dull grey to silvery white, very hard and brittle,<br />in the longest time rather stable presence of oxygen resistant to acids,<br />oxidizes during heating in price it was looked air|Vapor deposition, sputtering, powder metallurgy,<br />warm-forming only possible at 1200 – 1500°C|Powder; in sheet form, as a substitutecoatings,<br />and as wire mostly as alloying component|-for the more expensive gold. This was followed by a steep increase in the Pd price|Rh<br />Rhodium which caused a significant reduction |Almost silvery white, very hard and brittle, not soluble in its use acids,<br />oxidizes in electrical contacts. Today air during red anneal|Electroplating, vapor deposition, sputtering,<br />after warm-forming at 800 – 1000°C cold working is possible|Coatings (2011electroplated) the, alloying component,<br />in limited form as sheet and wire|-|Pd price again is lower than that of gold.<br />Palladium|Dull white, resistant to most acids,<br />oxidizes at red anneal|Electroplating, vapor deposition,<br />sputtering, cold working|Sheet, strip, tubing, wire,<br />rivets, and coatings|-|Os<br />Osmium|Bluish white, hardest platinum metal,<br />very brittle, resistant against non-oxidizing acids,<br />oxidizes easily on air|Powder metallurgy|Powder, alloying component|-|Ir<br />Iridium|Almost silvery white, very hard and brittle,<br />acid resistant, oxidizes at red anneal|Vapor deposition, sputtering, powder metallurgy,<br />warm-forming possible at 1200 – 1500°C|Powder, alloying component,<br />in limited amounts as sheet|-|Pt<br />Platinum|Grey white, ductile, acid resistant except for aqua regia,<br />HBr, and HJ, oxidation resistant at red anneal|Electroplating, vapor deposition,<br />sputtering, cold working|Sheet, strip, tubing, wire, rivets, coatings|}</figtable>

Platinum and palladium alloys are mainly Rhodium is not used similar to the gold based materials inthe form of welded wire and profile segments as a solid contact material but rarely is applied for example as a electroplated layer in sliding contact rivetssystems. Because ofthe high precious metal prices joining technologies are Ruthenium is mostly used that allow the mosteconomic application of the contact alloy as an alloying component in the area where functionally needed.Because of their resistance to material transfer they are used for DC applications anddue to their higher arc erosion resistance they are applied for medium electrical loadsup to about 30W in relays and switches ''(Table 2PdRu15.10)''. Multi-component alloys basedon Pd with higher hardness The metals osmium and wear resistance are mainly used as spring arms iridium have no practical applications insliding contact systems and DC miniature motorselectrical contacts.

Table 2.6: PropertiesSince Pd was for the longest time rather stable in price, Production Processes, and Application Forms it was seen as a substitute for Platinum Metals[[File:Properties production platinum metalsthe more expensive gold.jpg|right|thumb|PropertiesThis was followed by a steep increase in the Pd price, Production Processes, and Application Forms for Platinum Metals]]Table 2which caused a significant reduction in its use in electrical contacts. Today (Dec.7: Physical Properties of 2021) the Platinum Metals and their Alloyspalladium price is around 2600 Euro/oz.

'''Table 2.8Alloys of Pt with Ru, Ir, Ni and W were widely used in electromechanical components in the telecommunication industry and in heavy duty automotive breaker points (<xr id="tab: Mechanical Physical Properties of the Platinum Metals and an their Alloys'''/>).

<table borderfigtable id="1" cellspacing="0" style="border-collapsetab:collapsePhysical Properties of the Platinum Metals an their Alloys"><trcaption>'''<td/><td><p class="s11">soft</p></td><td><p class="s11">70% cold worket</p></td><td><p class="s11">soft</p></td><td><p class="s11">70% cold</p><p class="s11">worket</p></td><td><p class="s11">soft</p></td><td><p class="s11">70% cold</p><p class="s11">worket</p></td></tr><tr><td><p class="s11">Pt (99,95)</p></td><td><p class="s11">150</p></td><td><p class="s11">360</p></td><td><p class="s11">40</p></td><td><p class="s11">3</p></td><td><p class="s11">40</p></td><td><p class="s11">120</p></td></tr><tr><td><p class="s11">PtIr5</p></td><td><p class="s11">260</p></td><td><p class="s11">550</p></td><td><p class="s11">25</p></td><td><p class="s11">!--Table 2</p></td><td><p class="s11">85</p></td><td><p class="s11">160</p></td></tr><tr><td><p class="s11">PtIr10</p></td><td><p class="s11">340</p></td><td><p class="s11">570</p></td><td><p class="s11">24</p></td><td><p class="s11">2</p></td><td><p class="s11">105</p></td><td><p class="s11">210</p></td></tr><tr><td><p class="s11">PtRu10</p></td><td><p class="s11">650</p></td><td><p class="s11">1000</p></td><td><p class="s11">24</p></td><td><p class="s11">2</p></td><td><p class="s11">195</p></td><td><p class="s11">320</p></td></tr><tr><td><p class="s11">PtNi8</p></td><td><p class="s11">640</p></td><td><p class="s11">950</p></td><td><p class="s11">22</p></td><td><p class="s11">2</p></td><td><p class="s11">200</p></td><td><p class="s11">320</p></td></tr><tr><td><p class="s11">PtW5</p></td><td><p class="s11">530</p></td><td><p class="s11">860</p></td><td><p class="s11">21</p></td><td><p class="s11">2</p></td><td><p class="s11">150</p></td><td><p class="s11">270</p></td></tr><tr><td><p class="s11">Pd (99,95)</p></td><td><p class="s11">200</p></td><td><p class="s11">420</p></td><td><p class="s11">42</p></td><td><p class="s11">2</p></td><td><p class="s11">40</p></td><td><p class="s11">90</p></td></tr><tr><td><p class="s11">PdCu15</p></td><td><p class="s11">400</p></td><td><p class="s11">780</p></td><td><p class="s11">38</p></td><td><p class="s11">2</p></td><td><p class="s11">90</p></td><td><p class="s11">220</p></td></tr><tr><td><p class="s11">PdCu40</p></td><td><p class="s11">550</p></td><td><p class="s11">950</p></td><td><p class="s11">35</p></td><td><p class="s11">2</p></td><td><p class="s11">120</p></td><td><p class="s11">260</p></td></tr><tr><td><p class="s11">PdNi5</p><p class="s11">Pd35AuAgPt</p></td><td><p class="s11">340</p></td><td><p class="s11">700</p></td><td><p class="s11">25</p></td><td><p class="s11">2</p></td><td><p class="s11">95</p></td><td><p class="s11">200</p><p class="s11">420*</p></td></tr><tr><td><p class="s11">Pd44Ag38Cu15</p></td><td/><td/><td/><td/><td/><td><p class="s11">405*</p></td></tr><tr><td><p class="s11">PtAuZn</p><p class="s11">Pd40Co40W20</p></td><td/><td/><td/><td/><td/><td><p class="s11">680*</p></td></tr><tr><td><p class="s31">*maximum hardness</p></td><td/><td/><td/><td/><td/><td/></tr.7:-->Physical Properties of the Platinum Metals an their Alloys'''</tablecaption>

Fig{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material!Platin/Palladium<br/>Content<br/>[wt. %]!Density<br/>[g/cm³]!Melting Point or Range<br/>[°C]!Electrical<br/>Resistivity<br/>[µΩ*cm]!Electrical<br/>Conductivity<br/>[MS/m]!Thermal<br/>Conductivity<br/>[W/m*K]!Temp. Coefficient of the<br/>Electrical Resistance<br/>[10³/K]!modulus of<br/>Elasticity<br/>[Gpa]|-|Pt (99,95)| >99,95|21,5|1772|10,6|9,5|72|3,9|173|-|PtIr5|95|21,5|1774 - 1776|22,2|4,5|42||190|-|PtIr10|90|21,6|1780 - 1785|17,9|5,6|29|2,0|220|-|PtRu10|90|20,6|ca.25:1800|33,3|3,0||0,83|235|-|PtNi6|92|19,2|1670 - 1710|30|3,3|Influence of |1,5|180|-20 atom% of|PtW5|95|21,3|1830 - 1860different additive|43,4metals on the|2,3electrical|resistivity p of|0,7platinum|185|-|Pd (Degussa99,95)| >99,95|12,0|1554|10,8|9,3|72|3,8|124|-|PdCu15|85|11,3|1370 - 1400|38,5|2,6|17|0,49|175|-|PdCu40|60|10,5|1200 - 1230|33,3|3,0|38|0,28|175|-|PdNi5|95|11,8|1455 - 1485|16,9|5,9||2,47|175|-|}</figtable>

FigToday these components have been replaced in many applications by solid state technology and the usage of these materials is greatly reduced. Pd alloys however have a more significant importance. PdCu15 is widely used, for example in automotive flasher relays. Because of their resistance to sulfide formation PdAg alloys are applied in various relay designs. With the ability to thermally precipitation harden some multi component alloys based on PdAgAuPt, they find special usage in wear resistant sliding contact applications. Pd44Ag38Cu15PtAuZn is a standard alloy in this group (<xr id="tab:Mechanical_Properties_of_the_Platinum_Metals_and_their_Alloys"/><!--(Tab 2.278)--> and <xr id="tab:Phase diagram ofplatinumContact_and_Switching_Properties_of_the_Platinum_Metals_and_their_Alloys"/><!--(Tab. 2.9)--iridium>).

FigPlatinum and palladium alloys are mainly used similar to the gold based materials in the form of welded wire and profile segments but rarely as contact rivets. Due to the high precious metal prices, joining technologies are used, that allow the most economic application of the contact alloy in the area where functionally needed. For reason of their resistance to material transfer they are used for DC applications and due to their higher arc erosion resistance, they are applied for medium electrical loads up to about 30W in relays and switches (<xr id="fig:Application_Examples_and_Form_of_Supply_for_Platinum_Metals_and_their_Alloys"/><!--(Table 2.28:Phase diagram ofplatinum10)-->). Multi-nickelcomponent alloys based on Pd with higher hardness and wear resistance are mainly used as spring arms in sliding contact systems and DC miniature motors.

Fig. <figtable id="tab:Mechanical_Properties_of_the_Platinum_Metals_and_their_Alloys"><caption>'''<!--Table 2.298:-->Mechanical Properties of the Platinum Metals and their Alloys'''</caption><table class="twocolortable"><tr><th rowspan="2">Material</th><th colspan="2">Tensile Strength [MPa]</th><th colspan="2">Elongation A [%]</th><th colspan="2">Vickers Hardness HV 1</th></tr><tr><th>soft</th><th>70% cold worket</th><th>soft</th><th>70% cold worket</th><th>soft</th><th>70% cold worket</th></tr><tr><td>Pt (99,95)</td><td>150</td><td>360</td><td>40</td><td>3</td><td>40</td><td>120</td></tr><tr><td>PtIr5</td><td>260</td><td>550</td><td>25</td><td>2</td><td>85</td><td>160</td></tr><tr><td>PtIr10</td><td>340</td><td>570</td><td>24</td><td>2</td><td>105</td><td>210</td></tr><tr><td>PtRu10</td><td>650</td><td>1000</td><td>24</td><td>2</td><td>195</td><td>320</td></tr><tr><td>PtNi8</td><td>640</td><td>950</td><td>22</td><td>2</td><td>200</td><td>320</td></tr><tr><td>PtW5</td><td>530</td><td>860</td><td>21</td><td>2</td><td>150</td><td>270</td></tr><tr><td>Pd (99,95)</td><td>200</td><td>420</td><td>42</td><td>2</td><td>40</td><td>90</td></tr><tr><td>PdCu15</td><td>400</td><td>780</td><td>38</td><td>2</td><td>90</td><td>220</td></tr><tr><td>PdCu40</td><td>550</td><td>950</td><td>35</td><td>2</td><td>120</td><td>260</td></tr><tr><td>PdNi5</td><td>340</td><td>700</td><td>25</td><td>2</td><td>95</td><td>200</td></tr><tr><td>Pd35AuAgPt</td><td></td><td></td><td></td><td></td><td></td><td>420*</td></tr>Phase diagram<tr><td>Pd44Ag38Cu15 PtAuZn</td><td/><td/><td/><td/><td/><td>405*</td></tr>of platinum-tungsten<tr><td>Pd40Co40W20</td><td/><td/><td/><td/><td/><td>680*</td></tr></table></figtable>

Fig. <figtable id="tab:Contact_and_Switching_Properties_of_the_Platinum_Metals_and_their_Alloys"><table class="twocolortable"><caption> '''<!--Table 2.319:-->Contact and Switching Properties of the Platinum Metals and their Alloys'''</caption>Strainhardeningof <tr><th><p class="s11">Material</p></th><th><p class="s12">Properties<th colspan="2"></p></th></tr><tr><td><p class="s11">Pt</p></td><td><p class="s12">Very high corrosion resistance</p></td><td/></tr><tr><td><p class="s11">PtIr5 - 10</p></td><td><p class="s12">Very high corrosion resistance, low contact resistance</p></td><td><p class="s12">High arc erosion resistance, high hardness</p></td></tr><tr><td><p class="s11">PtRu10</p></td><td><p class="s12">Very high corrosion resistance, low welding tendency</p></td><td><p class="s12">Low contact resistance, very</p><p class="s12">high hardness</p></td></tr><tr><td><p class="s11">PtNi8</p></td><td><p class="s12">Low material transfer tendency</p></td><td><p class="s12">Very high hardness</p></td></tr><tr><td><p class="s11">PtW5</p></td><td><p class="s12">Low material transfer tendency</p></td><td><p class="s12">High hardness</p></td></tr><tr><td><p class="s11">Pd</p></td><td><p class="s12">Strong tendency to “Brown Powder” formation</p></td><td><p class="s12">Less arc erosion resistant than Pt by cold</p></td></tr><tr><td><p class="s11">PdCu15</p><p class="s11">PdCu40</p></td><td><p class="s12">Tendency to “Brown Powder” formation</p></td><td><p class="s12">Mostly resistant to material</p><p class="s12">transfer, high hardness</p></td></tr><tr><td><p class="s11">PdNi5</p></td><td><p class="s12">Strong tendency to “Brown Powder” formation</p></td><td><p class="s12">Low welding tendency</p></td></tr><tr><td><p class="s11">Pd44Ag38Cu15</p><p class="s11">PtAuZn</p></td><td><p class="s12">High mechanical wear resistance</p></td><td><p class="s12">Standard material for sliding</p><p class="s12">contact brushes</p></td></tr></table>working</figtable>

Fig. <figtable id="fig:Application_Examples_and_Form_of_Supply_for_Platinum_Metals_and_their_Alloys"><table class="twocolortable"><caption>'''<!--Table 2.3410:-->Application Examples and Form of Supply for Platinum Metals and their Alloys'''</caption>Softening <tr><th><p class="s11">Material</p></th><th><p class="s12">Application Examples</p></th><th><p class="s12">Forms of Supply</p></th></tr><tr><td><p class="s11">Pt (99,95)</p></td><td><p class="s12">Relays</p></td><td><p class="s12">Contact rivets, welded contact parts</p></td></tr><tr><td><p class="s11">PtIr5 after annealing for 1 hr</p><p class="s11">PtIr10</p><p class="s11">PtRu10</p><p class="s11">PtNi8</p><p class="s11">PtW5</p></td><td><p class="s12">Relays, sliding contact systems,</p><p class="s12">automotive ignition breaker points</p></td><td><p class="s12">'''Semi-finished Contact Materials''':</p><p class="s12">Wire, seam-welded contact profiles</p><p class="s12">'''Contact Parts:'''</p><p class="s12">Tips, wire-formed parts, solid and composite contact rivets, welded contact parts</p></td></tr><tr><td><p class="s11">Pd (99,95)</p><p class="s11">PdNi5</p></td><td><p class="s12">Relays</p></td><td><p class="s12">Micro-profiles (weld tapes), contact rivets, welded contact parts</p></td></tr><tr><td><p class="s11">PdCu15</p><p class="s11">PdCu40</p></td><td><p class="s12">Automotive flasher relays</p></td><td><p class="s12">Micro-profiles, composite contact rivets</p></td></tr><tr><td><p class="s11">Pd35AuAgPt</p><p class="s11">Pd44Ag38Cu15</p><p class="s11">PtAuZn</p><p class="s11">Pd40Co40W20</p></td><td><p class="s12">Potentiometers, slip rings, miniature</p><p class="s12">DC motors</p></td><td><p class="s12">Wire-formed parts, welded wire segments, multi-arm sliding contact brushes</p></td></tr></table>after different degrees of cold working</figtable>

Fig. 2.37<figure id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum_(Degussa)">Strain hardening[[File:Influence of platinum degussa.jpg|left|thumb|<caption>Influence of 1- 20 atom% of different additive metals on the electrical resistivity p of platinum (Degussa)</caption>]]of PtW5 by cold working</figure>

Fig. 2.38<figure id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum">Softening[[File:Influence of palladium.jpg|left|thumb|<caption>Influence of PtW5 afterannealing for 1hrafter 801-22 atom% coldof different additive metals on the electrical resistivity p of palladium</caption>]]working</figure>

<figure id="fig:Phase_diagram_of_platinum-iridium">[[File:Phase diagram of platinum iridium.jpg|left|thumb|<caption>Fig. 2.3927:Phase diagram of platinum-iridium</caption>]]Strain hardeningof Pd 99.99 by cold working</figure>

<figure id="fig:Phase_diagram_of_platinum-nickel">[[File:Phase diagram of platinum nickel.jpg|left|thumb|<caption>Fig. 2.4028:Phase diagram of platinum-nickel</caption>]]Strain hardeningof PdCu15 by cold working</figure>

<figure id="fig:Phase_diagram_of_platinum-tungsten">[[File:Phase diagram of palladium copper.jpg|left|thumb|<caption>Fig. 2.4129:SofteningPhase diagram of PdCu15 afterannealingplatinum-tungsten</caption>]]for 0.5 hrs</figure>

<figure id="fig:Phase_diagram_of_platinum-copper">[[File:Phase diagram of palladium copper2.jpg|left|thumb|<caption>Fig. 2.4230:Phase diagram of palladium-copper</caption>]]Strain hardeningof PdCu40 by cold working</figure>

<figure id="fig:Strain_hardening_of_Pt_by_cold_working">[[File:Strain hardening of Pt by cold working.jpg|left|thumb|<caption>Fig. 2.4331:SofteningStrain hardening of PdCu40after annealingfor 0.5 hrs after 80%Pt by cold working</caption>]]</figure>

<figure id="fig:Softening_of_Pt_after_annealing_for_0.5_hrs_after_80%_cold_working">[[File:Softening of Pt after annealing.jpg|left|thumb|<caption>Fig. 2.4432:Electrical resistivity pSoftening of PdCu alloys with and without anPt after annealing step for forming an ordered0.5 hrs after 80% cold working</caption>]]phase</figure>

Table <figure id="fig:Strain_hardening_of_PtIr5_by_cold_working">[[File:Strain hardening of PtIr5 by cold working.jpg|left|thumb|<caption>Fig. 2.933: Contact and Switching PropertiesStrain hardening of PtIr5 by cold working</caption>]]of the Platinum Metals and their Alloys</figure>

Table <figure id="fig:Softening_of_PtIr5_after_annealing_for_1_hr_after_different degrees_of_cold_working">[[File:Softening of PtIr5 after annealing.jpg|left|thumb|<caption>Fig. 2.34: Softening of PtIr5 after annealing for 1 hr after different degrees of cold working</caption>]]</figure> <figure id="fig:Strain_hardening_of_PtNi8_by_cold_working">[[File:Strain hardening of PtNi8 by cold working.jpg|left|thumb|<caption>Fig. 2.35: Strain hardening of PtNi8 by cold working</caption>]]</figure> <figure id="fig:Softening_of_PtNi8_after_annealing_for_1_hr_after_80%_cold_working">[[File:Softening of PtNi8 after annealing.jpg|left|thumb|<caption>Fig. 2.36: Softening of PtNi8 after annealing for 1 hr after 80% cold working</caption>]]</figure> <figure id="fig:Strain_hardening_of_PtW5_by_cold_working">[[File:Strain hardening of PtW5 by cold working.jpg|left|thumb|<caption>Fig. 2.37: Strain hardening of PtW5 by cold working</caption>]]</figure> <figure id="fig:Softening_of_PtW5_after_annealing_for_1_hr_after_80%_cold_working">[[File:Softening of PtW5 after annealing.jpg|left|thumb|<caption>Fig. 2.38: Softening of PtW5 after annealing for 1 hr after 80% cold working</caption>]]</figure> <figure id="fig:Strain_hardening_of_Pd_99.99_by_cold_working">[[File:Strain hardening of Pd-99 99by cold working.jpg|left|thumb|<caption>Fig. 2.39: Strain hardening of Pd 99.99 by cold working</caption>]]</figure> <figure id="fig:Strain_hardening_of_PdCu15_by_cold_working">[[File:Strain hardening of PdCu15 by cold working.jpg|left|thumb|<caption>Fig. 2.1040: Strain hardening of PdCu15 by cold working</caption>]]</figure> <figure id="fig:Softening_of_PdCu15_after_annealing_for_0.5_hrs">[[File:Softening of PdCu15 after annealing.jpg|left|thumb|<caption>Softening of PdCu15 after annealing for 0.5 hrs</caption>]]</figure> <figure id="fig: Application Examples and FormStrain_hardening_of_PdCu40_by_cold_working">[[File:Strain hardening of PdCu40 by cold working.jpg|left|thumb|<caption>Strain hardening of PdCu40 by cold working</caption>]]</figure> <figure id="fig:Softening_of_PdCu40_after_annealing_for_0.5_hrs_after_80%_cold_working">[[File:Softening of PdCu40 after annealing.jpg|left|thumb|<caption>Softening of Supply PdCu40 after annealing for Platinum Metals 0.5 hrs after 80% cold working</caption>]]</figure> <figure id="fig:Electrical_resistivity_p_of_PdCu_alloys">[[File:Electrical resistivity p of PdCu alloys.jpg|left|thumb|<caption>Electrical resistivity p of PdCu alloys with and their Alloyswithout an annealing step for forming an ordered phase</caption>]]</figure> </div><div class="clear"></div>