PROCEDIMIENTO MEJORADO PARA ELECTRODEPOSITAR CROMO SOBRE SUPERFICIES METALICAS

A very low concentration (below 0.03 M) trivalent chromium plating bath in which the source of chromium is an equilibrated aqueous solution of a chromium (III) - thiocyanate complex gives a deposit of unexpectedly light color. Such a bath is employed to produce thin overcoatings of light colored chromium for decorative applications. The bath and process is also used to plate the initial layer of a thick (greater than 5 micron) deposit for engineering applications, the major part of which is plated from a higher chromium concentration bath. Such thick deposits from a higher concentration bath are more cohesive and smoother when plated over an initial layer from the low concentration bath.