Abstract: The invention relates to a method for producing a sandwich structure on the basis of at least one layer on the basis of metallic material and on the basis of at least one layer of organic polymer, wherein for coating of at least one metallic surface with at least one metallic layer to be combined with the layer on the basis of organic polymer, an aqueous conversion composition on the basis of zinc, additional cations, poly(acrylic acid), and optionally silane, is brought into contact, wherein the liquid film thereby produced is dried on and wherein the metallic layer coated in such manner is brought into contact with at least one layer on the basis of organic polymer and is combined into a sandwich structure by means of compaction under pressure and/or temperature. The invention also relates to such sandwich structures.

Abstract: Metallic surfaces are coated with an aqueous, acidic phosphate solution containing 10 to 60 g/l zinc, 0.5 to 40 g/l manganese, 50 to 300 g/l phosphate ions calculated as P2O5, and optionally other components.

Abstract: The invention relates to a method for coating metallic surfaces by a manganese-zinc phosphatizing process, using an aqueous phosphatizing solution, in which nickel is deliberately not added. Said method is characterized in that the zinc:manganese weight ratio of the phosphatizing solution is maintained in the region of between 0.05:1 and 0.99:1 and that the phosphatizing solution has the following contents: between 0.05 and 5 g/l zinc, between 0.075 and 5.2 g/l manganese and between 0.008 and 0.050 g/l copper and/or hexafluoride complexes of titanium, hafnium and/or zirconium totalling between 0.002 and 0.5 g/l, calculated as F6. The invention also relates to the use of the metal parts coated in this manner.