| 摘要 |
PURPOSE:To maintain a high anticorrosion property and a high quality by applying a nickel plating as a foundation layer, a nickel plating including silver as an intermediate layer over the foundation layer, and finally a gold plating as the uppermost layer. CONSTITUTION:On the surface of a basic material 13 of a copper alloy or the like punched in the form of a specific contact piece, a relatively thick nickel 14 plating is applied as a foundation layer, over which a nickel plating including silver is applied in the same thickness or thinner as an intermediate layer, and a very thin gold 16 or a gold alloy plating is applied as the uppermost layer, to form a conductive membrane 17. The intermediate layer of the nickel 15 plating including silver in the threefold plating layers is much harder than the nickel 14 plating, with finer particles, and its electrodeposition property is excellent. In such a composition, when a corrosion is generated, it hardly progresses up to the outer surface of the gold 16, the lubrication is further improved owing to the difference in hardness, and the abrasion resistance property is excellent. |
