PHOSPHATE COATING PRODUCTION METHOD Russian patent published in 2019 - IPC C23C22/07 C23C22/13 C23C22/36 

FIELD: technological processes.

SUBSTANCE: invention relates to protection of metals from corrosion and can be used in machine building, instrument making and other industries. Method involves treatment of metal surface with aqueous solution of phosphating at temperature from plus 35 to plus 50 °C for period of 2 to 10 minutes. An aqueous phosphating solution is used, having stability at temperature of up to 50 °C and containing the following components, g/l: Zn²⁺ 1.53–3.27; P₂O₅ 4.35–8.64; NO₃^- 1.41–4.30; Na⁺ 0.15–0.28; Ni²⁺ 0.02–0.11; F^- 0.75–0.85; SiF₆ 0.20–0.25; water – balance. Before use, the aqueous phosphating solution is corrected with 20 % aqueous solution of sodium hydroxide to a ratio of relative total acidity to free acidity of 5.2 to 5.4.

EFFECT: obtaining a fine-crystalline phosphate coating having high adhesion and high corrosion resistance, as well as low consumption rate of the aqueous phosphating solution used at application temperature of plus 35 to 50 °C and possibility of its application by means of spraying and immersion.

1 cl, 4 ex