aqueous, acid bath for the galvanic deposition of gold and method for galvanic deposition of hartgold in its use

摘要

A bath for electroplating hard gold deposits at relatively high current efficiencies comprises an aqueous solution of an alkali metal dihydrogen phosphate, nitrilotris(methylene) triphosphonic acid, a nickel and/or cobalt phosphate compound, triethanolamine borate, alkali metal gold cyanide and a small amount of free alkali metal cyanide. The bath is maintained at a pH of 3.8-4.5 and operated at a current density of 0.1-20 amperes per square decimeter.