PROCESS FOR A PASSIVATING POSTRINSING OF PHOSPHATE LAYERS

摘要

In a process for the passivating rinsing of phosphate layers on metals on which a coating or an adhesive is subsequently to be applied, aqueous solutions which contain aluminium fluorozirconate possessing a molar ratio of Al : Zr : F of (0.15 to 0.67) : 1 : (5 to 7) and have a total concentration of Al + Zr + F of 0.1 to 2.0 g/l, preferably 0.2 to 0.8, g/l and a pH of 3 to 5 are used. The rinsing solutions may additionally contain at least one of the anions benzoate, caprylate, ethylhexanoate and salicylate in a total concentration of 0.05 to 0.5 g/l and may preferably be adjusted to the required pH with cations of volatile bases, such as ammonium, ethanolammonium and di- and triethanolammonium. Subsequent coating is advantageously carried out using a cathodic electrocoating finish, a powder coating or a high-solid coating having a low solvent content.