Difference between revisions of "Platinum Metal Based Materials"

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The platinum group metals include the elements Pt, Pd, Rh, Ru, Ir, and Os ''(Table 2.6)''. For electrical contacts platinum and palladium have practical significance as base alloy materials and ruthenium and iridium are used as alloying components. Pt and Pd have similar corrosion resistance as gold but because of their catalytical properties they tend to polymerize adsorbed organic vapors on contact surfaces. During frictional movement between contact surfaces the polymerized compounds known as “brown powder” are formed which can lead to significantly increase in contact resistance. Therefore Pt and Pd are typically used as alloys and not in their pure form for electrical contact applications.
+
The platinum group metals include the elements Pt, Pd, Rh, Ru, Ir and Os (<xr id="tab:Properties_Production_Processes_and_Application_Forms_for_Platinum_Metals"/><!--(Tab. 2.6)-->). For electrical contacts, platinum and palladium have practical significance as base alloy materials and ruthenium and iridium are used as alloying components. Pt and Pd have similar corrosion resistance as gold but for the reason of their catalytical properties, they tend to polymerize adsorbed organic vapors on contact surfaces. During frictional movement between contact surfaces, the polymerized compounds known as “brown powder” are formed, which can lead to a significant increase in contact resistance. Therefore Pt and Pd are typically used as alloys and not in their pure form for electrical contact applications.
 +
 
 +
<figtable id="tab:Properties_Production_Processes_and_Application_Forms_for_Platinum_Metals">
 +
<caption>'''<!--Table 2.6:-->Properties, Production Processes, and Application Forms for Platinum Metals'''</caption>
 +
 
 +
{| 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 presence of oxygen resistant to acids,<br />oxidizes during heating in air
 +
|Vapor deposition, sputtering, powder metallurgy,<br />warm-forming only possible at 1200 – 1500°C
 +
|Powder; in sheet form, as coatings,<br />and as wire mostly as alloying component
 +
|-
 +
|Rh<br />Rhodium
 +
|Almost silvery white, very hard and brittle, not soluble in acids,<br />oxidizes in air during red anneal
 +
|Electroplating, vapor deposition, sputtering,<br />after warm-forming at 800 – 1000°C cold working is possible
 +
|Coatings (electroplated), alloying component,<br />in limited form as sheet and wire
 +
|-
 +
|Pd<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>
 +
 
  
 
Rhodium is not used as a solid contact material but is applied for example as a electroplated layer in sliding contact systems. Ruthenium is mostly used as an alloying component in the material PdRu15. The metals osmium and iridium have no practical applications in electrical contacts.
 
Rhodium is not used as a solid contact material but is applied for example as a electroplated layer in sliding contact systems. Ruthenium is mostly used as an alloying component in the material PdRu15. The metals osmium and iridium have no practical applications in electrical contacts.
  
Since Pd was for the longest time rather stable in price it was looked at as a substitute for the more expensive gold. This was followed by a steep increase in the Pd price which caused a significant reduction in its use in electrical contacts. Today (2011) the Pd price again is lower than that of gold.
+
Since Pd was for the longest time rather stable in price, it was seen as a substitute for the more expensive gold. This was followed by a steep increase in the Pd price, which caused a significant reduction in its use in electrical contacts. Today (Dec. 2021) the palladium price is around 2600 Euro/oz.
  
Alloys of Pt with Ru, Ir, Ni, and W were widely used in electromechanical components in the telecommunication industry and in heavy duty automotive breaker points ''(Table 2.7)''. Today these components have been replaced in many applications by solid state technology and the usage of these materials is greatly reduced. Pd alloys however have a more significant importance. PdCu15 is widely used for example in automotive flasher relays. Because of their resistance to sulfide formation PdAg alloys are applied in various relay designs. The ability to thermally precipitation harden some
+
Alloys of Pt with Ru, Ir, Ni and W were widely used in electromechanical components in the telecommunication industry and in heavy duty automotive breaker points (<xr id="tab:Physical Properties of the Platinum Metals an their Alloys/>).
multi component alloys based on PdAgAuPt they find special usage in wear resistant sliding contact applications. Pd44Ag38Cu15PtAuZn is a standard alloy in this group.
 
  
Platinum and palladium alloys are mainly used similar to the gold based materials in the form of welded wire and profile segments but rarely as contact rivets. Because of the high precious metal prices joining technologies are used that allow the most economic application of the contact alloy in the area where functionally needed. Because of their resistance to material transfer they are used for DC applications and due to their higher arc erosion resistance they are applied for medium electrical loads up to about 30W in relays and switches ''(Table 2.10)''. Multi-component alloys based on Pd with higher hardness and wear resistance are mainly used as spring arms in sliding contact systems and DC miniature motors.
+
<figtable id="tab:Physical Properties of the Platinum Metals an their Alloys">
 +
<caption>'''<!--Table 2.7:-->Physical Properties of the Platinum Metals an their Alloys'''</caption> 
  
Table 2.6: Properties, Production Processes, and Application Forms for Platinum Metals
+
{| class="twocolortable" style="text-align: left; font-size: 12px"
[[File:Properties production platinum metals.jpg|right|thumb|Properties, Production Processes, and Application Forms for Platinum Metals]]
+
|-
Table 2.7: Physical Properties of the Platinum Metals and their Alloys
+
!Material
 +
!Platin/Palladium<br/>Content<br/>[wt.%]
 +
!Density<br/>[g/cm<sup>3</sup>]
 +
!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/>[10<sup>3</sup>/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. 1800
 +
|33,3
 +
|3,0
 +
|
 +
|0,83
 +
|235
 +
|-
 +
|PtNi6
 +
|92
 +
|19,2
 +
|1670 - 1710
 +
|30
 +
|3,3
 +
|
 +
|1,5
 +
|180
 +
|-
 +
|PtW5
 +
|95
 +
|21,3
 +
|1830 - 1860
 +
|43,4
 +
|2,3
 +
|
 +
|0,7
 +
|185
 +
|-
 +
|Pd (99,95)
 +
| >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>
  
'''Table 2.8: Mechanical Properties of the Platinum Metals and their Alloys'''
 
  
<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><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">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></table>
+
Today these components have been replaced in many applications by solid state technology and the usage of these materials is greatly reduced. Pd alloys however have a more significant importance. PdCu15 is widely used, for example in automotive flasher relays. Because of their resistance to sulfide formation PdAg alloys are applied in various relay designs. 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 2.8)--> and <xr id="tab:Contact_and_Switching_Properties_of_the_Platinum_Metals_and_their_Alloys"/><!--(Tab. 2.9)-->).
  
Fig. 2.25:
+
Platinum and palladium alloys are mainly used similar to the gold based materials in the form of welded wire and profile segments but rarely as contact rivets. 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 2.10)-->). Multi-component alloys based on Pd with higher hardness and wear resistance are mainly used as spring arms in sliding contact systems and DC miniature motors.
Influence of 1-20 atom% of different additive metals on the electrical resistivity p of platinum (Degussa)
 
[[File:Influence of platinum degussa.jpg|right|thumb|Influence of 1- 20 atom% of different additive metals on the electrical resistivity p of platinum (Degussa)]]
 
  
Fig. 2.26:
+
<figtable id="tab:Mechanical_Properties_of_the_Platinum_Metals_and_their_Alloys">
Influence of 1-22 atom% of different additive metals on the electrical resistivity p of palladium
+
<caption>'''<!--Table 2.8:-->Mechanical Properties of the Platinum Metals and their Alloys'''</caption>
[[File:Influence of palladium.jpg|right|thumb|Influence of 1-22 atom% of different additive metals on the electrical resistivity p of palladium]]
+
<table class="twocolortable">
 +
<tr>
 +
<th rowspan="2">Material</th><th colspan="2">Tensile Strength [MPa]</th><th colspan="2">Elongation A [%]</th><th colspan="2">Vickers Hardness HV 1</th></tr>
 +
<tr><th>soft</th><th>70% cold worket</th><th>soft</th><th>70% cold worket</th><th>soft</th><th>70% cold worket</th></tr>
 +
<tr><td>Pt (99,95)</td><td>150</td><td>360</td><td>40</td><td>3</td><td>40</td><td>120</td></tr>
 +
<tr><td>PtIr5</td><td>260</td><td>550</td><td>25</td><td>2</td><td>85</td><td>160</td></tr>
 +
<tr><td>PtIr10</td><td>340</td><td>570</td><td>24</td><td>2</td><td>105</td><td>210</td></tr>
 +
<tr><td>PtRu10</td><td>650</td><td>1000</td><td>24</td><td>2</td><td>195</td><td>320</td></tr>
 +
<tr><td>PtNi8</td><td>640</td><td>950</td><td>22</td><td>2</td><td>200</td><td>320</td></tr>
 +
<tr><td>PtW5</td><td>530</td><td>860</td><td>21</td><td>2</td><td>150</td><td>270</td></tr>
 +
<tr><td>Pd (99,95)</td><td>200</td><td>420</td><td>42</td><td>2</td><td>40</td><td>90</td></tr>
 +
<tr><td>PdCu15</td><td>400</td><td>780</td><td>38</td><td>2</td><td>90</td><td>220</td></tr>
 +
<tr><td>PdCu40</td><td>550</td><td>950</td><td>35</td><td>2</td><td>120</td><td>260</td></tr>
 +
<tr><td>PdNi5</td><td>340</td><td>700</td><td>25</td><td>2</td><td>95</td><td>200</td></tr>
 +
<tr><td>Pd35AuAgPt</td><td></td><td></td><td></td><td></td><td></td><td>420*</td></tr>
 +
<tr><td>Pd44Ag38Cu15 PtAuZn</td><td/><td/><td/><td/><td/><td>405*</td></tr>
 +
<tr><td>Pd40Co40W20</td><td/><td/><td/><td/><td/><td>680*</td></tr>
 +
</table>
 +
</figtable>
  
Fig. 2.27:
+
*maximum hardness
Phase diagram of platinum-iridium
 
[[File:Phase diagram of platinum iridium.jpg|right|thumb|Phase diagram of platinum-iridium]]
 
  
Fig. 2.28:
+
<figtable id="tab:Contact_and_Switching_Properties_of_the_Platinum_Metals_and_their_Alloys">
Phase diagram of
+
<table class="twocolortable">
platinum-nickel
+
<caption> '''<!--Table 2.9:-->Contact and Switching Properties of the Platinum Metals and their Alloys'''</caption>
 +
<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</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>
 +
</figtable>
  
Fig. 2.29:
 
Phase diagram
 
of platinum-tungsten
 
  
Fig. 2.30:
 
Phase diagram of
 
palladium-copper
 
  
Fig. 2.31:
+
<figtable id="fig:Application_Examples_and_Form_of_Supply_for_Platinum_Metals_and_their_Alloys">
Strain
+
<table class="twocolortable">
hardening
+
<caption>'''<!--Table 2.10:-->Application Examples and Form of Supply for Platinum Metals and their Alloys'''</caption>
of Pt by cold
+
<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</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>
working
+
</figtable>
  
Fig. 2.32:
 
Softening of Pt after
 
annealing for 0.5 hrs
 
after 80%
 
cold working
 
  
Fig. 2.33:
+
<div class="multiple-images">
Strain hardening of PtIr5
 
by cold working
 
  
Fig. 2.34:
+
<figure id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum_(Degussa)">
Softening of PtIr5 after annealing for 1 hr
+
[[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>]]
after different degrees of cold working
+
</figure>
  
Fig. 2.35:
+
<figure id="fig:Influence_of_1-20_atom%_of_different_additive_metals_on_the_electrical_resistivit_ p_of_platinum">
Strain hardening
+
[[File:Influence of palladium.jpg|left|thumb|<caption>Influence of 1-22 atom% of different additive metals on the electrical resistivity p of palladium</caption>]]
of PtNi8 by cold working
+
</figure>
  
Fig. 2.36:
+
<figure id="fig:Phase_diagram_of_platinum-iridium">
Softening of PtNi8 after
+
[[File:Phase diagram of platinum iridium.jpg|left|thumb|<caption>Fig. 2.27:Phase diagram of platinum-iridium</caption>]]
annealing
+
</figure>
for 1 hr after
 
80% cold working
 
  
Fig. 2.37:
+
<figure id="fig:Phase_diagram_of_platinum-nickel">
Strain hardening
+
[[File:Phase diagram of platinum nickel.jpg|left|thumb|<caption>Fig. 2.28:Phase diagram of platinum-nickel</caption>]]
of PtW5 by cold working
+
</figure>
  
Fig. 2.38:
+
<figure id="fig:Phase_diagram_of_platinum-tungsten">
Softening
+
[[File:Phase diagram of palladium copper.jpg|left|thumb|<caption>Fig. 2.29:Phase diagram of platinum-tungsten</caption>]]
of PtW5 after
+
</figure>
annealing for 1hr
 
after 80% cold
 
working
 
  
Fig. 2.39:
+
<figure id="fig:Phase_diagram_of_platinum-copper">
Strain hardening
+
[[File:Phase diagram of palladium copper2.jpg|left|thumb|<caption>Fig. 2.30: Phase diagram of palladium-copper</caption>]]
of Pd 99.99 by cold working
+
</figure>
  
Fig. 2.40:
+
<figure id="fig:Strain_hardening_of_Pt_by_cold_working">
Strain hardening
+
[[File:Strain hardening of Pt by cold working.jpg|left|thumb|<caption>Fig. 2.31: Strain hardening of Pt by cold working</caption>]]
of PdCu15 by cold working
+
</figure>
  
Fig. 2.41:
+
<figure id="fig:Softening_of_Pt_after_annealing_for_0.5_hrs_after_80%_cold_working">
Softening
+
[[File:Softening of Pt after annealing.jpg|left|thumb|<caption>Fig. 2.32: Softening of Pt after annealing for 0.5 hrs after 80% cold working</caption>]]
of PdCu15 after
+
</figure>
annealing
 
for 0.5 hrs
 
  
Fig. 2.42:
+
<figure id="fig:Strain_hardening_of_PtIr5_by_cold_working">
Strain hardening
+
[[File:Strain hardening of PtIr5 by cold working.jpg|left|thumb|<caption>Fig. 2.33: Strain hardening of PtIr5 by cold working</caption>]]
of PdCu40 by cold working
+
</figure>
  
Fig. 2.43:
+
<figure id="fig:Softening_of_PtIr5_after_annealing_for_1_hr_after_different degrees_of_cold_working">
Softening
+
[[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>]]
of PdCu40
+
</figure>
after annealing
 
for 0.5 hrs after 80%
 
cold working
 
  
Fig. 2.44:
+
<figure id="fig:Strain_hardening_of_PtNi8_by_cold_working">
Electrical resistivity p
+
[[File:Strain hardening of PtNi8 by cold working.jpg|left|thumb|<caption>Fig. 2.35: Strain hardening of PtNi8 by cold working</caption>]]
of PdCu alloys with and without an
+
</figure>
annealing step for forming an ordered
 
phase
 
  
'''Table 2.9: Contact and Switching Properties of the Platinum Metals and their Alloys'''
+
<figure id="fig:Softening_of_PtNi8_after_annealing_for_1_hr_after_80%_cold_working">
<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s11">Material</p></td><td><p class="s12">Properties</p></td></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</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>
+
[[File:Softening of PtNi8 after annealing.jpg|left|thumb|<caption>Fig. 2.36: Softening of PtNi8 after annealing for 1 hr after 80% cold working</caption>]]
 +
</figure>
 +
 
 +
<figure id="fig:Strain_hardening_of_PtW5_by_cold_working">
 +
[[File:Strain hardening of PtW5 by cold working.jpg|left|thumb|<caption>Fig. 2.37: Strain hardening of PtW5 by cold working</caption>]]
 +
</figure>
 +
 
 +
<figure id="fig:Softening_of_PtW5_after_annealing_for_1_hr_after_80%_cold_working">
 +
[[File:Softening of PtW5 after annealing.jpg|left|thumb|<caption>Fig. 2.38: Softening of PtW5 after annealing for 1 hr after 80% cold working</caption>]]
 +
</figure>
 +
 
 +
<figure id="fig:Strain_hardening_of_Pd_99.99_by_cold_working">
 +
[[File:Strain hardening of Pd-99 99by cold working.jpg|left|thumb|<caption>Fig. 2.39:  Strain hardening of Pd 99.99 by cold working</caption>]]
 +
</figure>
 +
 
 +
<figure id="fig:Strain_hardening_of_PdCu15_by_cold_working">
 +
[[File:Strain hardening of PdCu15 by cold working.jpg|left|thumb|<caption>Fig. 2.40:  Strain hardening of PdCu15 by cold working</caption>]]
 +
</figure>
 +
 
 +
<figure id="fig:Softening_of_PdCu15_after_annealing_for_0.5_hrs">
 +
[[File:Softening of PdCu15 after annealing.jpg|left|thumb|<caption>Softening of PdCu15 after annealing for 0.5 hrs</caption>]]
 +
</figure>
 +
 
 +
<figure id="fig:Strain_hardening_of_PdCu40_by_cold_working">
 +
[[File:Strain hardening of PdCu40 by cold working.jpg|left|thumb|<caption>Strain hardening of PdCu40 by cold working</caption>]]
 +
</figure>
 +
 
 +
<figure id="fig:Softening_of_PdCu40_after_annealing_for_0.5_hrs_after_80%_cold_working">
 +
[[File:Softening of PdCu40 after annealing.jpg|left|thumb|<caption>Softening of PdCu40 after annealing for 0.5 hrs after 80% cold working</caption>]]
 +
</figure>
 +
 
 +
<figure id="fig:Electrical_resistivity_p_of_PdCu_alloys">
 +
[[File:Electrical resistivity p of PdCu alloys.jpg|left|thumb|<caption>Electrical resistivity p of PdCu alloys with and without an annealing step for forming an ordered phase</caption>]]
 +
</figure>
 +
 
 +
</div>
 +
<div class="clear"></div>
  
'''Table 2.10: Application Examples and Form of Supply for Platinum Metals and their Alloys'''
 
<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s11">Material</p></td><td><p class="s12">Application Examples</p></td><td><p class="s12">Forms of Supply</p></td></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</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>
 
 
==References==
 
==References==
 
[[Contact Materials for Electrical Engineering#References|References]]
 
[[Contact Materials for Electrical Engineering#References|References]]
 +
 +
[[de:Werkstoffe_aus_Platin-Metallen]]

Latest revision as of 09:24, 4 January 2023

The platinum group metals include the elements Pt, Pd, Rh, Ru, Ir and Os (Table 1). For electrical contacts, platinum and palladium have practical significance as base alloy materials and ruthenium and iridium are used as alloying components. Pt and Pd have similar corrosion resistance as gold but for the reason of their catalytical properties, they tend to polymerize adsorbed organic vapors on contact surfaces. During frictional movement between contact surfaces, the polymerized compounds known as “brown powder” are formed, which can lead to a significant increase in contact resistance. Therefore Pt and Pd are typically used as alloys and not in their pure form for electrical contact applications.

Table 1: Properties, Production Processes, and Application Forms for Platinum Metals
Element Properties Processing Forms of Application
Ru
Ruthenium
Dull grey to silvery white, very hard and brittle,
in the presence of oxygen resistant to acids,
oxidizes during heating in air
Vapor deposition, sputtering, powder metallurgy,
warm-forming only possible at 1200 – 1500°C
Powder; in sheet form, as coatings,
and as wire mostly as alloying component
Rh
Rhodium
Almost silvery white, very hard and brittle, not soluble in acids,
oxidizes in air during red anneal
Electroplating, vapor deposition, sputtering,
after warm-forming at 800 – 1000°C cold working is possible
Coatings (electroplated), alloying component,
in limited form as sheet and wire
Pd
Palladium
Dull white, resistant to most acids,
oxidizes at red anneal
Electroplating, vapor deposition,
sputtering, cold working
Sheet, strip, tubing, wire,
rivets, and coatings
Os
Osmium
Bluish white, hardest platinum metal,
very brittle, resistant against non-oxidizing acids,
oxidizes easily on air
Powder metallurgy Powder, alloying component
Ir
Iridium
Almost silvery white, very hard and brittle,
acid resistant, oxidizes at red anneal
Vapor deposition, sputtering, powder metallurgy,
warm-forming possible at 1200 – 1500°C
Powder, alloying component,
in limited amounts as sheet
Pt
Platinum
Grey white, ductile, acid resistant except for aqua regia,
HBr, and HJ, oxidation resistant at red anneal
Electroplating, vapor deposition,
sputtering, cold working
Sheet, strip, tubing, wire, rivets, coatings


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

Since Pd was for the longest time rather stable in price, it was seen as a substitute for the more expensive gold. This was followed by a steep increase in the Pd price, which caused a significant reduction in its use in electrical contacts. Today (Dec. 2021) the palladium price is around 2600 Euro/oz.

Alloys of Pt with Ru, Ir, Ni and W were widely used in electromechanical components in the telecommunication industry and in heavy duty automotive breaker points (Table 2).

Table 2: Physical Properties of the Platinum Metals an their Alloys
Material Platin/Palladium
Content
[wt.%]
Density
[g/cm3]
Melting Point or Range
[°C]
Electrical
Resistivity
[µΩ*cm]
Electrical
Conductivity
[MS/m]
Thermal
Conductivity
[W/m*K]
Temp. Coefficient of the
Electrical Resistance
[103/K]
modulus of
Elasticity
[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. 1800 33,3 3,0 0,83 235
PtNi6 92 19,2 1670 - 1710 30 3,3 1,5 180
PtW5 95 21,3 1830 - 1860 43,4 2,3 0,7 185
Pd (99,95) >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


Today these components have been replaced in many applications by solid state technology and the usage of these materials is greatly reduced. Pd alloys however have a more significant importance. PdCu15 is widely used, for example in automotive flasher relays. Because of their resistance to sulfide formation PdAg alloys are applied in various relay designs. 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 (Table 3 and Table 4).

Platinum and palladium alloys are mainly used similar to the gold based materials in the form of welded wire and profile segments but rarely as contact rivets. 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 (Table 5). Multi-component alloys based on Pd with higher hardness and wear resistance are mainly used as spring arms in sliding contact systems and DC miniature motors.

Table 3: Mechanical Properties of the Platinum Metals and their Alloys
MaterialTensile Strength [MPa]Elongation A [%]Vickers Hardness HV 1
soft70% cold worketsoft70% cold worketsoft70% cold worket
Pt (99,95)15036040340120
PtIr526055025285160
PtIr10340570242105210
PtRu106501000242195320
PtNi8640950222200320
PtW5530860212150270
Pd (99,95)2004204224090
PdCu1540078038290220
PdCu40550950352120260
PdNi534070025295200
Pd35AuAgPt420*
Pd44Ag38Cu15 PtAuZn405*
Pd40Co40W20680*
  • maximum hardness

Table 4: Contact and Switching Properties of the Platinum Metals and their Alloys

Material

Properties

Pt

Very high corrosion resistance

PtIr5 - 10

Very high corrosion resistance, low contact resistance

High arc erosion resistance, high hardness

PtRu10

Very high corrosion resistance, low welding tendency

Low contact resistance, very

high hardness

PtNi8

Low material transfer tendency

Very high hardness

PtW5

Low material transfer tendency

High hardness

Pd

Strong tendency to “Brown Powder” formation

Less arc erosion resistant than Pt

PdCu15

PdCu40

Tendency to “Brown Powder” formation

Mostly resistant to material

transfer, high hardness

PdNi5

Strong tendency to “Brown Powder” formation

Low welding tendency

Pd44Ag38Cu15

PtAuZn

High mechanical wear resistance

Standard material for sliding

contact brushes


Table 5: Application Examples and Form of Supply for Platinum Metals and their Alloys

Material

Application Examples

Forms of Supply

Pt (99,95)

Relays

Contact rivets, welded contact parts

PtIr5

PtIr10

PtRu10

PtNi8

PtW5

Relays, sliding contact systems,

automotive ignition breaker points

Semi-finished Contact Materials:

Wire, seam-welded contact profiles

Contact Parts:

Tips, wire-formed parts, solid and composite contact rivets, welded contact parts

Pd (99,95)

PdNi5

Relays

Micro-profiles (weld tapes), contact rivets, welded contact parts

PdCu15

PdCu40

Automotive flasher relays

Micro-profiles, composite contact rivets

Pd35AuAgPt

Pd44Ag38Cu15

PtAuZn

Pd40Co40W20

Potentiometers, slip rings, miniature

DC motors

Wire-formed parts, welded wire segments, multi-arm sliding contact brushes


Figure 1: Influence of 1- 20 atom% of different additive metals on the electrical resistivity p of platinum (Degussa)
Figure 2: Influence of 1-22 atom% of different additive metals on the electrical resistivity p of palladium
Figure 3: Fig. 2.27:Phase diagram of platinum-iridium
Figure 4: Fig. 2.28:Phase diagram of platinum-nickel
Figure 5: Fig. 2.29:Phase diagram of platinum-tungsten
Figure 6: Fig. 2.30: Phase diagram of palladium-copper
Figure 7: Fig. 2.31: Strain hardening of Pt by cold working
Figure 8: Fig. 2.32: Softening of Pt after annealing for 0.5 hrs after 80% cold working
Figure 9: Fig. 2.33: Strain hardening of PtIr5 by cold working
Figure 10: Fig. 2.34: Softening of PtIr5 after annealing for 1 hr after different degrees of cold working
Figure 11: Fig. 2.35: Strain hardening of PtNi8 by cold working
Figure 12: Fig. 2.36: Softening of PtNi8 after annealing for 1 hr after 80% cold working
Figure 13: Fig. 2.37: Strain hardening of PtW5 by cold working
Figure 14: Fig. 2.38: Softening of PtW5 after annealing for 1 hr after 80% cold working
Figure 15: Fig. 2.39: Strain hardening of Pd 99.99 by cold working
Figure 16: Fig. 2.40: Strain hardening of PdCu15 by cold working
Figure 17: Softening of PdCu15 after annealing for 0.5 hrs
Figure 18: Strain hardening of PdCu40 by cold working
Figure 19: Softening of PdCu40 after annealing for 0.5 hrs after 80% cold working
Figure 20: Electrical resistivity p of PdCu alloys with and without an annealing step for forming an ordered phase

References

References