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:
Dec. 25, 1990
Filed:
Sep. 06, 1989
Shigeo Tanaka, Kanagawa, JP;
Tomoyuki Aoki, Kanagawa, JP;
Yasuo Iino, Kanagawa, JP;
Yoji Ono, Tokyo, JP;
Nihon Parkerizing Co., Ltd., Tokyo, JP;
Abstract
Problems with previously known aqueous acidic rinsing solutions for aluminum after shaping while using surface lubricants are avoided by use of a solution which contains water and (A) orthophosphoric acid in an amount to give a stoichiometric equivalent of 3.0 to 50 g/L as PO.sub.4.sup.-3, (B) an aluminum ion sequestrant component in an amount of 0.01 to 10.0 g/L; and (C) 20 to 170 ppm of ferric ion. The ferric ions act to inhibit corrosion of the stainless steel process equipment. Preferably the solution also contains 0.1 to 1.0 g/L of H.sub.2 O.sub.2, NO.sub.2.sup.-1 ions, or a mixture thereof to reoxidize ferrous ions formed by reduction of ferric ions during use of the solution and thus maintain the concentration of ferric ions above 20 ppm at all times. The solution may also contain surfactant and up to 10 g/L of dissolved aluminum ions.