PRODUCTION OF ANTIQUED EXTERNAL PARTS FOR TIMEPIECE

摘要

PURPOSE:To obtain antiqued external parts for a timepiece having superior wear resistance over a long period by successively forming an Ni (alloy) layer, a Pd (alloy) layer and Rh plating as an intermediate layer on the surface of a Cu alloy, etc., further forming a Ti-based black hard film as a finishing layer by ion plating, and removing the film by barrel machining. CONSTITUTION:For example, an Ni layer as a first underlayer is formed on a brass watchcase by electroplating or other method and Pd plating as a second underlayer is formed on the first underlayer by electroplating. Rh plating as an intermediate layer is further formed on the second underlayer by electroplating and coated with a dark-gray hard film of a Ti-C-N compd. as a finishing layer by ion plating. The hard film is then polished with a rotating barrel to obtain an antiqued watchcase having uniform gold color as the base color.