The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 25, 1992
Filed:
Sep. 27, 1990
Kenshi Saeki, Okayama, JP;
Noriaki Yoshitake, Kanagawa, JP;
Henkel Corporation, Ambler, PA (US);
Abstract
The resistance of chromated zinc surfaced steel objects, particularly plates and sheets, to extraction of hexavalent chromium by alkaline degreasing solutions used on the chromated objects, can be substantially increased by utilizing an aqueous acidic liquid chromating composition containing (A) about 9.6 to about 96 g/L, expressed as its stoichiometric equivalent as chromic acid, of total chromium; (B) about 2 to about 35 g/L of trivalent chromium ions; (C) about 1 to about 128 g/L of phosphate ions; and (D) about 0.3 to about 4 g/L of fluorozirconate ions, with the chromium ratio in the aqueous acidic liquid composition being about 0.41 to about 0.70, the chromic acid/fluorozirconate weight ratio being about 10 to about 40, and the PO.sub.4 /Cr.sup.+3 ratio being greater than about 0.03, greater than or equal to about {(9.2) (the chromium ratio)-4.0}, and less than or equal to about {(9.2) (the chromium ratio)-1.2}. . . The corrosion resistance of the coatings formed can be further improved if the chromating composition also contains about 0.1 to about 200 g/L of dispersed silica.