Henkel Corporation

Nihon Parkerizing Co., Ltd.

Yoji Ono

Tomoyuki Aoki

Yasuo Iino

Shigeo Tanaka

Shinichiro Asai

Method for cleaning aluminum and aluminum alloys

Acidic aluminum cleaner containing an oxidant and a nonionic surfactant

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.

Fluoride and chromium free acid etchant rinse for aluminum

Growing community of inventors

Tokyo, Japan

Yoji Ono