Abstract: An aqueous alkaline cleaner for aluminum has a pH in the range from 10.0-12.0 and contains:(A) from 0.5 to 10.0 g/L of an alkali builder component;(B) from 0.5 to 10.0 g/L of aminoalkyl- and/or hydroxyalkyldi-phosphonic acids and/or their water soluble salts;(C) from 0.1 to 3.0 g/L of an aluminum ion sequestering agent component; and(D) from 0.5 to 5.0 g/L of a surfactant component.Cleaning aluminum and aluminum alloy with such a cleaner generates an excellent surface condition with respect to de-smutting performance, water wettability, avoidance of black smut production, blackening, and paint adherence at least as good as that achieved with conventional acid cleaners, without requiring any acid wash.

Abstract: The stability of an acidic liquid cleaner for aluminum comprising mineral acid, oxidant, polyvalent metal ions, and surfactant is substantially improved by the presence in the cleaner of from 0.05 to 5 g/L of a component selected from the group of glycols containing from 2 to 10 carbon atoms per molecule and mixtures of such glycols. The effectiveness of the cleaner for primary cleaning and de-smutting of aluminum and its alloys is not impaired and may even be improved by the addition of the glycol component.

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.