PROCESS FOR A PASSIVATING POSTRINSING OF PHOSPHATE LAYERS

摘要

In a process for a passivating postrinsing of phosphate layers on metals before the application of a paint or adhesive, aqueous solutions are employed which have been adjusted to a pH value of 3 to 5 and which contain an aluminum fluorozirconate in which the Al:Zr:F mole ratio is (0.15 to 0.65):1:(5 to 7), and in which solutions the total concentration of Al + Zr + F is 0.1 to 2.0 g/l, preferably 0.2 to 0.8 g/l. the postrinsing solutions may additionally contain at least one of the anions benzoate, caprylate, ethyl hexoate, salicylate in a total concentration of 0.05 to 0.5 g/l and may preferably be adjusted to the required pH value with cations of volatile bases, such as ammonium, ethanolammonium and di- and triethanolammonium. The paint is subsequently applied suitably by cathodic electrocoating or powder coating or from a low-solvent high-solids paint.