ELECTRODEPOSITION OF CHROMIUM AND ITS ALLOYS

摘要

A chromium electroplating electrolyte comprising a source of trivalent chromium ions, a complexant, a buffer agent and a sulphur species selected from sulphites and dithionites, the complexant being selected so that the stability constant K1 of the chromium complex as defined herein is in the range 10<6> < K1 < 10<1><2> M<-><1> preferably the chromium ions have a molar concentration lower than 0.01M. Complexants within this range include aspartic acid, iminodiacetic acid, nitrilotriacetic acid, 5-sulphosalicylic acid and citric acid.