FIELD: protective metal treatment.
SUBSTANCE: invention relates to nickel-free phosphating of a metal surface. In the method, a metal surface that can be cleaned and /or activated is first treated with an acidic aqueous phosphating composition containing zinc ions, manganese ions, and phosphate ions. Further, after optional rinsing and /or drying, the surface is treated with an aqueous composition for post-rinsing treatment containing from 10 to 500 mg/l, calculated as metal, of molybdenum ions in the form of molybdate, and having a pH within the range of 3 to 5. In this case, a phosphating composition and a composition for processing after rinsing are used, in which the content of nickel ions is less than 0.3 g/l.
EFFECT: nickel-free phosphating method makes it possible to obtain a phosphated metal surface having an electrolytic conductivity corresponding to the electrolytic conductivity of the metal surface obtained by nickel-containing phosphating, as well as preventing corrosion and providing adhesion of subsequent coating layers.
15 cl, 6 tbl, 16 ex
