| 摘要 |
PROBLEM TO BE SOLVED: To attain plating excellent in corrosion resistance with respect to a casing part for a watch, which is made of zinc or zinc alloy cast. SOLUTION: Cu is formed to have 10-23μm thickness as a 1st plating layer on a zinc or zinc alloy cast base material, Cu-Sn or Cu-Sn-Zn alloy is formed to have 2-4μm thickness as a 2nd plating layer on the 1st plating layer and further Au or one kind of Au-Fe, Au-Fe-In and Au-In alloy is formed to have 0.05-2μm thickness on the 2nd plating layer as a 3rd plating layer.
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