We have parts plated with decorative and black chromium. The decorative chromium finish holds up well, but the black chromium parts scratch. Why? Is there anything that can be done to prevent this? S.A.
You are faced with a basic difference between decorative and black chromium deposits. The decorative deposit is metallic and hard. The black chromium deposit is a mixture of oxides, which tends to be soft and easily damaged. There are a couple of things you might consider. Try a different type of finish such as black nickel or black oxide, or try coating the black chromium with some type of topcoat. Waxes and various organic materials are used for this purpose.