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US 7,989,078 B2Granted
Halogen-free trivalent chromium conversion coating
AssigneeUnited Technologies Corporation
InventorsMark R. Jaworowski, Sarah Arsenault, James T. Beals
Life of this patent
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Abstract
Trivalent chromium conversion coatings are provided on a metal substrate wherein the trivalent chromium conversion coating has a halogen content of 1 atom % maximum.
Claims18
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.
2 more elements
A process for preparing a substantially halogen free trivalent chromium conductive conversion coating on a metal substrate comprising the steps of
- (a) preparing a coating solution consisting essentially of from greater than zero to 5 wt % of a metal compound selected from the group consisting of zirconium, titanium, hafnium, and mixtures thereof, greater than zero to 3 wt % of a trivalent chromium compound, and up to 1 wt % of a halogen and balance essentially water;
- (b) adjusting the pH of the conversion coating solution to a range of between 1 to 6;
- and
- (c) 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 substantially halogen free trivalent conductive conversion coating wherein a halogen is present in an amount of up to 1 atom %.
1 more element
Dependencies are inferred from the claim text.