Multilayer of precious metals for decorative items

摘要

#CMT# #/CMT# A decorative article has a palladium-containing bottom layer deposited electrochemically or reductively on a metallic substrate, and an electrolytically deposited alloy of ruthenium and an element chosen from platinum and rhodium, provided on the bottom layer. The platinum-ruthenium alloy has a platinum content of 55-80 wt.% and the rhodium-ruthenium alloy has a rhodium content of 60-85 wt.%. #CMT# : #/CMT# An independent claim is included for production process of decorative article. #CMT#USE : #/CMT# Decorative article e.g. jewelry case. #CMT#ADVANTAGE : #/CMT# The decorative article has high quality, excellent usability, excellent corrosion resistance, improved abrasion resistance, and uniform brightness and color. #CMT#METALLURGY : #/CMT# Preferred Composition: The platinum-ruthenium alloy has platinum content of 60-75 wt.%. The rhodium-ruthenium alloy has rhodium content of 70-80 wt.%. Preferred Layers: The metallic substrate has an outer copper layer on which the palladium-containing bottom layer is deposited. The article further has a layer of bonding gold provides between the palladium-containing bottom layer and the electrolytically deposited alloy. Preferred Method: The metallic substrate is subjected to preliminary copper plating using a cyanide-containing copper electrolyte, and then treated with an acidic copper electrolyte.