TREATMENT OF CHROMIUM ELECTRODEPOSIT

摘要

A method whereby a surface of chromium metal electrodeposited on a zinc substrate from a trivalent chromium electrolyte is treated by contacting the surface with an aqueous solution at a pH of from 5 to 12 and containing a dissolved metal salt of a weak acid which does not form a soluble complex with zinc. Preferred salts are carbonates, phosphates and silicates of an alkali metal, e.g. sodium or potassium. Also disclosed is the product of said process comprising an article having a zinc substrate, a microporous electrodeposited chromium coating from 0.025 to 2.5 microns in thickness on said substrate, and a water-insoluble basic salt of zinc within the micropores.