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→Fine-Grain Silver
====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 form. In liquid silver only a small amount of nickel is soluble as the phase diagram ''(Fig. 2.51)'' illustrates. During solidification of the melt this nickel addition gets finely dispersed in the silver matrix and eliminates the pronounce coarse grain growth after prolonged influence of elevated temperatures ''(Figs. 2.49 and 2.50)''.
[[File:Coarse grain micro structure of Ag.jpg|right|thumb|Coarse grain micro structure of Ag 99.97 after 80% cold working and 1 hr annealing at 600°C]]
Fine-grain silver has almost the same chemical corrosion resistance as fine silver. Compared to pure silver it exhibits a slightly increased hardness and
tensile strength ''(Table 2.14)''. The electrical conductivity is just slightly decreased by this low nickel addition. Because of its significantly improved contact properties fine grain silver has replaced pure silver in many applications.
