CHEMICAL CONVERSION TREATMENT LIQUID AND CHEMICAL CONVERSION TREATMENT METHOD USING THE LIQUID Russian patent published in 2023 - IPC C23C22/34 C23C22/53 

FIELD: electroplating.

SUBSTANCE: invention can be used in various industries for applying protective and decorative coatings on metals and alloys. A liquid for chemical conversion treatment of a surface coated with zinc or a zinc alloy and a method for chemical conversion treatment are proposed. The chemical conversion treatment liquid contains trivalent chromium ions, nitrate ions, cobalt ions, fluoride ions, one or more water-soluble carboxylic acids or their salts, 0.8-70 mmol/l of an organic ligand selected from aromatic and aliphatic heterocyclic compounds, containing at least one nitrogen atom, and water free of hexavalent chromium. The molar ratio of trivalent chromium ions to organic ligand in the chemical conversion treatment liquid is 2.5-40.

EFFECT: implementation of liquid for chemical conversion treatment of surfaces, increase in corrosion resistance of the formed conversion coating, as well as improvement of utilization of washing water and waste solutions of liquid for chemical conversion treatment not containing hexavalent chromium.

3 cl, 3 ex