CHROME-FREE PROCESS FOR PRE-TREATING ALUMINUM OR ALUMINUM ALLOY SURFACES BEFORE COATING WITH ORGANIC MATERIALS.

摘要

The invention relates to a process for the pretreatment of metallic surfaces before the coating with organic materials. The surfaces are initially cleaned and pickled and then contacted with aqueous solutions and/or dispersions of aluminium/zirconium complexes which can be obtained as reaction product of a chelated aluminium unit, of an organofunctional ligand and of a zirconyl halide, where the organofunctional ligand is chemically bonded to the chelated aluminium unit and to the zirconium unit. According to the invention the surfaces are subjected, before the coating with organic materials, to a subsequent treatment with aqueous solutions or emulsions and/or dispersions of one or more inorganic and/or organic film-formers.