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===2.1 Introduction===
The contact parts are important components in switching devices. They have to
maintain their function from the new state until the end of the functional life of the
often 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.
Table 2.5: Application Examples and Forms of Gold and Gold Alloys
===2.3 Platinum Metal Based Materials===
The platinum group metals include the elements Pt, Pd, Rh, Ru, Ir, and Os ''(Table
of Supply for Platinum Metals and their Alloys
===2.4 Silver Based Materials===
===2.4.1 = Pure Silver====
Pure silver (also called fine silver) exhibits the highest electrical and thermal
conductivity of all metals. It is also resistant against oxidation. Major disadvantages
degrees of strain hardening
===2.4.2 =Silver Alloys====
To improve the physical and contact properties of fine silver melt-metallurgical
produced silver alloys are used ''(Table 2.13)''. By adding metal components the
resistance can be negatively impacted by alloying ''(Figs. 2.47 and 2.48)''.
===2.4.2.1 ==Fine-Grain Silver=====
Fine-Grain Silver (ARGODUR-Spezial) is defined as a silver alloy with an addition
of 0.15 wt% of Nickel. Silver and nickel are not soluble in each other in solid
properties fine grain silver has replaced pure silver in many applications.
===2.4.2.2 ==Hard-Silver Alloys=====
Using copper as an alloying component increases the mechanical stability of
silver significantly. The most important among the binary AgCu alloys is that of
Table 2.20: Application Examples and Forms of Suppl for Silver-Palladium Alloys
===2.4.3 =Silver Composite Materials====
===2.4.3.1 ==Silver-Nickel (SINIDUR) Materials=====
Since silver and nickel are not soluble in each other in solid form and in the liquid
phase have only very limited solubility silver nickel composite materials with
for Silver-Nickel (SINIDUR) Materials
===2.4.3.2: == Silver-Metal Oxide Materials Ag/CdO, Ag/SnO<sub>2</sub>, Ag/ZnO=====
The family of silver-metal oxide contact materials includes the material groups:
silver-cadmium oxide (DODURIT CdO), silver-tin oxide (SISTADOX), and silverzinc
Table 2.31: Application Examples of Silver–Metal Oxide Materials
===2.4.3.3 ==Silver–Graphite (GRAPHOR)-Materials=====
Ag/C (GRAPHOR) contact materials are usually produced by powder metallurgy
with graphite contents of 2 – 5 wt% ''(Table 2.32)''. The earlier typical
(Bild)
===2.5 Tungsten and Molybdenum Based Materials===
===2.5.1 =Tungsten and Molybdenum (Pure Metals)====
Tungsten is characterized by its advantageous properties of high melting and
boiling points, sufficient electrical and thermal conductivity and high hardness
