Abstract: An agent and process for the corrosion protection treatment of a metal surface are provided.

Abstract: An aqueous solution for producing a conversion layer on metal surfaces, which has a pH in the range 1.5 to 6 and which contains the complex fluorides of Ti, Zr, Hf, Si and/or B, in an amount such that the concentration of Ti, Zr, Hf, Si and/or B is 20 to 500 mg/l, and 0.1 to 2 g/l of adhesion-promoting lacquer additives and wherein the composition of the aqueous solution is selected so that no crystalline zinc-containing phosphate layer is produced on the metallic surface.

Abstract: The invention relates to a method for providing a metal surface with an anti-corrosion treatment. Said method is characterized in that the metal surface is brought into contact with a homo- or copolymer of vinylpyrrolidone. The invention also relates to a solution for application, containing a) 0.02 to 20 g/l phosphoric acid and/or at least one fluoro acid of one or more elements of the following group: Zr, Ti, Hf and Si; or their respective anions and b) 0.05 to 20 g/l of a homo or copolymer of vinylpyrrolidone; and to a concentrate for the same.