| 摘要 |
PROBLEM TO BE SOLVED: To improve the strength and the heat transmissivity by achieving the silver plating or nickel-boron plating on a copper alloy bush to be cast in a pin hole of a piston for an internal combustion engine to keep the cast-in interface of a metallic bonded condition. SOLUTION: Copper plating and silver plating are successively achieved on an outer surface of a copper alloy bush 10 to form a composite plated layer having a silver plated layer of 3μm in thickness on an electrolytic copper plated layer of 3μm in thickness. The bush 10 is arranged in a casting mold after the heating at 300 deg.C in the atmosphere, and cast in with aluminum alloy 28 of high strength. The wettability to aluminum alloy of the bush 10 is improved, a diffusion layer and a compound layer 32 of CuAl2 and Cu9 Al4 are formed in the metallic bonded condition without generating any discontinuous layer on the bonded interface. Then kind of the plating need not be limited to the combination of copper with silver, and other combination of other metals, such as the combination of nickel with boron may be acceptable.
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