Process for chromating surfaces of zinc, cadmium and alloys thereof

An improved process for chromating a metal which comprises:

• immersing an article formed of a metal selected from the group consisting of zinc, cadmium and alloys thereof in a water solution of a soluble chromic oxalate complex at a pH of from 1.2 to 3.0, said soluble chromic oxalate complex being selected from the group consisting of:
• [Cr(C.sub.2 O.sub.4).sub.x (H.sub.2 O).sub.6-2x ].sub.n.sup.+(3-2x) . A.sub.3-2x.sup.-n
• wherein 0<x=<1.5, A is an anion selected from the group consisting of Cl.sup.-, Br.sup.-, I.sup.-, NO.sub.3 , SO.sub.4.sup.-2 and PO.sub.4.sup.-3 and n is the value of the anion of A, and
• [Cr(C.sub.2 O.sub.4).sub.x (H.sub.2 O).sub.6-2x].sub.m.sup.+(3-2x).K.sub.3-2x.sup.+m
• wherein 1.5>x=>3.0, K is a cation selected from the group consisting of H.sup.+, Li.sup.+, Na.sup.+, K.sup.+ and NH.sub.4.sup.+ and m is the value of the cation K.