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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 resist mechanical wear and exhibits high materials losses under electrical arcing loads <xr id="tab:tab2.4Contact and Switching Properties of Gold and Gold Alloys"/>(Tab. 2.4). This limits its use in form of thin electroplated or vacuum deposited layers.
For most electrical contact applications gold alloys are used. Depending on the alloying metal the melting is performed either under in a reducing atmosphere or in a vacuum. The choice of alloying metals depends on the intended use of the resulting contact material. The binary Au alloys with typically <10 wt% of other precious metals such as Pt, Pd, or Ag or non-precious metals like Ni, Co, and Cu are the more commonly used ones <xr id="tab:tab2.2Physical Properties of Gold and Gold-Alloys"/> ''(Table Tab. 2.2)''.On one hand these alloy additions improve the mechanical strength and electrical switching properties but on the other hand reduce the electrical conductivity and chemical corrosion resistance <xr id="fig:fig2.2Influence of 1-10 atomic of different"/>''(Fig. 2.2)'' to varying degrees.
Under the aspect of reducing the gold content ternary alloys with a gold content of approximately 70 wt% and additions of Ag and Cu or Ag and Ni resp., for example AuAg25Cu5 or AuAg20Cu10 are used which exhibit for many applications good mechanical stability while at the same time have sufficient
resistance against the formation of corrosion layers <xr id="tab:tab2.3Mechanical Properties of Gold and Gold-Alloys"/>''(Table 2.3)''.
<div class="multiple-images">
<figtable id="tab:tab2.2Physical Properties of Gold and Gold-Alloys">
[[File:Physical Properties of Gold and Gold-Alloys.jpg|left|thumb|<caption>Tab 2.2 Physical Properties of Gold and Gold-Alloys</caption>]]
</figtable>
<figure id="fig:fig2.2Influence of 1-10 atomic of different">
[[File:Influence of 1-10 atomic of different.jpg|left|thumb|<caption>Fig 2.2 Influence of 1-10 atomic% of different alloying metals on the electrical resistivity of gold (according to J. O. Linde)</caption>]]
</figure>
'''Tab.2.3: Mechanical Properties of Gold and Gold-Alloys'''
<figtable id="tab:tab2.3Mechanical Properties of Gold and Gold-Alloys">
{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
</figtable>
Other ternary alloys based on the AuAg system are AuAg26Ni3 and AuAg25Pt6. These alloys are mechanically similar to the AuAgCu alloys but have significantly higher oxidation resistance at elevated temperatures <xr id="tab:tab2.4Contact and Switching Properties of Gold and Gold Alloys"/>''(Table 2.4)''.
<figtable id="tab:tab2.4Contact and Switching Properties of Gold and Gold Alloys">
'''Table 2.4: Contact and Switching Properties of Gold and Gold Alloys'''
<table class="twocolortable">
least possible amount of the expensive precious metal component.
Besides being used as switching contacts in relays and pushbuttons, gold alloys are also applied in the design of connectors as well as sliding contacts for potentiometers, sensors, slip rings, and brushes in miniature DC motors <xr id="tab:tab2.5Application Examples and Forms of Gold and Gold Alloys"/>''(Table 2.5)''.
<figtable id="tab:tab2.5Application Examples and Forms of Gold and Gold Alloys">
'''Table 2.5: Application Examples and Forms of Gold and Gold Alloys'''
