FIELD: metallurgy.
SUBSTANCE: group of inventions relates to a method for phosphating of a metal surface, an alkaline aqueous composition for purification of a metal surface, used in the mentioned method, its concentrate, and the use of a metal surface phosphatized by the mentioned method. The method includes processing of the metal surface with following compositions, one after the other: an alkaline aqueous purifying composition, which contains at least one water-soluble silicate, which is present at the total concentration in the range from 0.01 to 15 g/l, and which, at 25°C, has water solubility in completely demineralized water of at least 1 mg/l, while pH of the purifying composition is in the range from 10.7 to 12.0, and then with an acidic aqueous phosphating composition, which contains zinc ions, manganese ions, phosphate ions, and less than 0.01 g/l of nickel ions.
EFFECT: improvement of adhesion of coating and protection from corrosion.
14 cl, 3 tbl
