| 摘要 |
PROBLEM TO BE SOLVED: To prevent oxidation of base nickel plating by (1) sticking displacement gold plating on a reduction nickel plating, sticking a reduction nickel plating on the gold plating, (2) sticking displacement gold plating on the nickel plating, (3) alternately repeating (1) and (2) n-times, and specifying the thickness of the surface gold plating. SOLUTION: An oxide film on the sintered metallized 8 surface is eliminated by chemical treatment. By using alkali displacement palladium activation solution, Pd is stuck on the sintered metallized 8 surface. Reduction nickel plating 9 is deposited. In order to ensure adhesion of the nickel plating 9 and the metallized base, heating is performed in a reducing atmosphere. Displacement gold plating 10 is deposited to be about 2μm thick. By using the phenomenon that gold turns to catalyst of reduction nickel plating 9, it is deposited to be about 0.1-0.2μm thick. The displacement gold 10 is again deposited to be about 0.2μm thick. By repeating the above process n-times, the gold plating 10 is stuck thicker than 0.2μm.
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