Patent ID: 7989078

Claim:
A process for forming non-halogen containing trivalent chromium conductive conversion coatings on metal substrates comprising the steps of: (a) preparing a coating solution consisting essentially of from 1 to 3 wt % soluble trivalent chromium compound, and from 1 to 3 wt % of a non-halogenated ligand compound of a metal selected from the group consisting of zirconium, titanium, hafnium, and mixtures thereof and balance essentially water; (b) adjusting the pH of the conversion coating solution to a range of between 1.5 to 4.5; (c) controlling the temperature of the conversion coating solution to a range of between 15 to 95° C.; and (d) contacting a metal substrate with the coating solution to form a single layer conversion coating on the substrate wherein the single layer conversion coating consists of a non-halogen containing trivalent chromium conductive conversion coating.