IMPROVED METHOD FOR ANTICORROSIVE PRETREATMENT OF METAL SURFACES INCLUDING STEEL, GALVANIZED STEEL, ALUMINUM, MAGNESIUM, AND / OR ZINC-MAGNESIUM ALLOY Russian patent published in 2021 - IPC C23C22/34 C23C22/36 C23C22/73 C23C22/78 C23C22/83 

FIELD: anticorrosive metal surface pretreatment.

SUBSTANCE: invention relates to the anticorrosive pretreatment of metal surface including steel, galvanized steel, aluminum, magnesium and/or a zinc-magnesium alloy. In the method, the metal surface is brought into contact with aqueous composition A, including a) from 0.01 to 0.5 g/l expressed in terms of solids, at least one copolymer, including one in an alternating arrangement, i) monomer units that include at least one carboxylic acid group, a phosphonic acid group and/or a sulfonic acid group, and ii) monomer units that do not include any acidic groups and the metal surface is contacted with acidic aqueous composition B comprising b1) at least one compound selected from the group consisting of titanium, zirconium and hafnium compounds. And the metal surface is brought into contact i) first with composition A, and then with composition B, or ii) first with composition B, and then with composition A.

EFFECT: improved corrosion protection while ensuring good adhesion.

13 cl, 2 tbl