AQUEOUS CONVERSION TREATMENT SOLUTION FOR FORMING CHROMIUM-FREE CHEMICAL CONVERSION COATING ON PLATED FILM OF ZINC OR ZINC ALLOY, AND CHROMIUM-FREE CHEMICAL CONVERSION COATING OBTAINED FROM THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a film formed on a plated film of zinc or a zinc alloy, which does not contain chromium but has corrosion resistance equivalent to or more excellent than a conventional chemical conversion coating of hexavalent chromate or trivalent chromium.;SOLUTION: An aqueous conversion treatment solution for forming chromium-free chemical conversion coating on the plated film of zinc or the zinc alloy includes: (A) a salt of metal Ti; (B) an oxidizing substance; (C) an oxyate of phosphorus; and (D) a complex compound. The chromium-free chemical conversion coating is formed by bringing the film of zinc or the zinc alloy plated on a substrate into contact with the above aqueous conversion treatment solution. Furthermore, a surface treatment method for the plated film of zinc or the zinc alloy includes forming an overcoat on the above chromium-free chemical conversion coating.;COPYRIGHT: (C)2010,JPO&INPIT