| 摘要 |
PURPOSE:To harden the surface of a metallic case for a wrist watch at a low cost by successively forming an Ni-P alloy layer and a Pd layer on the case by plating, coating the Pd layer with TiN, and age-hardening the Ni-P alloy layer at the same time. CONSTITUTION:A case for a wrist watch is made of a metal such as stainless steel, brass or German silver, and the case is successively plated with an Ni-P alloy contg. 0.5-20% P to 10-60mum thickness and Pd to about 1mum thickness. The plated case is coated with TiN by a PVD method under the conditions of 300-450 deg.C for 30min-2hr, and at the same time, the Ni-P alloy layer is age- hardened. By this treatment the abrasion resistance and corrosion resistance of the surface of the case are improved at a low cost. |
