Abstract: The present invention relates to an aqueous alkaline composition (A) for alkaline passivation of metallic components comprising at least in part surfaces of zinc or zinc alloys, containing iron(III) ions, phosphate ions, and one or more complexing agents, where a free alkalinity ranges from 1 to 6 points, and the pH is at least 11. The aqueous compositions (A) can additionally contain nonionic surfactants, so that such compositions are suitable for use in a method in which both cleaning and alkaline passivation of the metallic component occur in one step. The present invention further relates to a method for alkaline passivation of metallic components by contacting them with composition (A), and further a method for surface treatment in automobile body production, in which the alkaline passivation step using composition (A) is followed by an acid passivation step using a composition (B).

Abstract: The present invention relates to an aqueous alkaline composition (A) for alkaline passivation of metallic components comprising at least in part surfaces of zinc or zinc alloys, containing iron(III) ions, phosphate ions, and one or more complexing agents, where a free alkalinity ranges from 1 to 6 points, and the pH is at least 11. The aqueous compositions (A) can additionally contain nonionic surfactants, so that such compositions are suitable for use in a method in which both cleaning and alkaline passivation of the metallic component occur in one step. The present invention further relates to a method for alkaline passivation of metallic components by contacting them with composition (A), and further a method for surface treatment in automobile body production, in which the alkaline passivation step using composition (A) is followed by an acid passivation step using a composition (B).

Abstract: An acidic aqueous phosphating solution is presented having 0.2 to 3 g/l of zinc ions, 3 to 50 g/l of phosphate ions expressed as PO4−3, and 0.05 to 4 g/l of an organic N-oxide containing a saturated, unsaturated or aromatic 5- or 6-membered ring system, where the N atom of the N-oxide is part of said ring system, and where the ratio by weight of phosphate ions to zinc ions is from 3.7 to 30:1. The solution is free of hydroxylamine and useful in phosphating metal surfaces.

Abstract: Described are a concentrate, a working solution and a process for iron phosphating of metals, in which the solution contains nitrobenzene sulfonic acid and substituted short-chain monocarboxylic acids of the amino acid and/or hydroxycarboxylic acid type as the accelerators.