NICKEL SILVER HAVING EXCELLENT HEATING DISCOLORATION RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide nickel silver which is hard to be discolored even when subjected to thermal hysteresis in a process where a metallic material for electronic parts is worked and packaged from a bar stock into parts. SOLUTION: The nickel silver having excellent heating discoloration resistance can be obtained by controlling its surface properties to the following: (1) the concentration of zinc in the outermost surface is controlled to >=1.2 times that in the bulk, (2) the difference in the zinc concentration between a dezincification layer and the bulk is controlled to <7 mass%, and (3) the thickness of the dezincification layer is controlled to <=0.5μm.