稍微搜尋了一下 rhodium plating:
Rhodium is a precious metal of the Platinum group with properties of wear and corrosion resistance that make it ideally suitable as a final finish for all types of jewellery whether real jewellery made from other precious metals such as gold or silver or fashion (costume) jewellery made from a variety of materials such as copper,brass,cast pewter or cast zinc.
Rhodium is a white bright metal as plated and has many advantages over other white metal finishes such as silver or tin in that it is very hard so as to provide good wearing ability but also rhodium is almost impervious to attack by most naturally occurring chemical compounds and so the finish
Does not tarnish