PROCESS AND COMPOSITION FOR TREATING METAL SURFACES

摘要

A composition for forming a protective coating on a metal surface includes water; Cr2(GF6)3 in which G is a Group IV-B element; and optionally at least one polymer having a plurality of carboxylic acid groups and at least one polymer having a plurality of hydroxyl groups, and/or at least one polymer having a plurality of both carboxylic acid and hydroxyl groups; wherein the composition contains less than 500 ppm of alkali metal ions and less than 200 ppm of halide ions relative to chromi-um. A method of forming a protective coating on a metal surface includes contacting the metal surface with the composition.