| 摘要 |
PURPOSE:To produce silver alloy decorative parts having excellent corrosion resistance by coating silver on the surface of the silver alloy parts contg. a specific amt. of copper, subjecting said parts to a thermal diffusion treatment then to a heating and quick cooling treatment and a mechanical surface removing treatment thereby forming the inside phase and the outside phase into the specific two-phase state. CONSTITUTION:Silver is stuck by electroplating, etc. on silver alloy parts solutionized therein with 2-8wt% copper and the silver alloy parts are maintained at the temp. in the alpha phase region of said alloy and the region where the stuck silver and the alloy diffuse thermally, thereby providing certain gradient to the concn. of the copper from the surface. The alloy is then maintained at the lower temp. at which the alloy beta phase deposits. After the beta phase is deposited, the alloy is cooled quickly to obtain the alloy having the single phase in which the copper changes with a positive concn. gradient down to certain depth from the surface and the two phases of (alpha+beta) in the part deeper than the same. Such surface is removed by polishing, etc., by which the decorative parts consisting of the alpha single phase solutionized therein with >=0.5wt% copper on the outermost surface and the two phases of the hardened (alpha+beta) phase in the inside are obtd. |
