| 摘要 |
PURPOSE:To partially change the color tone of the same part by increasing or decreasing the gold phase of exterior decoration parts of a watch, e.g. an edge, a body, a back cover, a band and a crown by diffusion cementation. CONSTITUTION:Resist film 13 is formed on base metal 11 such as Au-Ag-Cu type 18K yellow gold, and metal layer 12 is coated onto the film-free portion. After removing film 13 metal 11 is heated to form diffusion layer 14. By carrying out perfect diffusion a metal layer is formed having a concn. gradient from the surface of metal 11 to the interior. Thus, the color tone is changed to easily form a portion with a partially different color tone and wear resistance. For example, by electrodepositing Pd on 18K yellow gold or Au on 18K white gold the color tone can be changed partially. |
