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:
Jul. 16, 1991
Filed:
Aug. 23, 1989
Larry F Wieserman, Apollo, PA (US);
Karl Wefers, Apollo, PA (US);
Gary A Nitowski, Natrona, PA (US);
Edward S Martin, New Kensington, PA (US);
Aluminum Company of America, Pittsburgh, PA (US);
Abstract
A process is disclosed for treating the surface of a valve metal such as aluminum to form a two layer protective coating thereon using an anodizing bath consisting essentially of an aqueous solution having a concentration ranging from about 0.001 molar to a saturated solution of a monomeric phosphorus-containing compound selected from the class consisting of a 1-30 carbon water soluble phosphonic acid, a 1-30 carbon water soluble phosphinic acid, and mixtures thereof. The valve metal surface is anodized in the anodizing bath while maintaining a voltage selected from a range of from about 1 to about 400 volts until the current density falls to a level indicative of the fact that a nonporous valve oxide layer has been formed on the valve metal surface and a reaction product from the monomeric phosphonic/phosphinic acid compound is chemically bonded to the oxide layer.