METHOD OF APPLYING ELECTROCONDUCTIVE PROTECTIVE COATING ON ALUMINIUM ALLOYS Russian patent published in 2024 - IPC C25D5/14 

FIELD: machine building.

SUBSTANCE: invention relates to machine building, particularly, to production of multilayer electroplated coating of nickel-copper-nickel system on parts made of aluminium alloys. Method includes degreasing, etching and single preliminary anodizing of part, application of first layer of nickel in electrolyte, then second layer of copper in electrolyte of copper plating and final third layer of nickel in electrolyte, with further drying of part. Anodizing is carried out in an electrolyte, g/l: sulfuric acid 100–170, orthophosphoric acid 200–300, acid ammonium fluoride 10–15, at electrolyte temperature from 18 to 25 °C, current density from 2 to 4 A/dm² for 1 to 10 minutes. Prior to application of the first nickel layer, the part is held in electrolyte without current. First and third layers of nickel are applied in electrolyte, g/l: nickel sulphate 100–300, sodium sulphate 30–150, boric acid 10–40, sodium chloride 5–20, magnesium sulphate 5–50, at electrolyte temperature from 18 to 30 °C, current density from 0.1 to 3.0 A/dm². Second layer of copper is applied in copper plating electrolyte, g/l: copper sulphate 100–300, sulfuric acid 40–80, at electrolyte temperature from 18 to 30 °C, current density from 1 to 5 A/dm², at the same time during application of copper layer air mixing is carried out.

EFFECT: providing corrosion resistance, increasing weight efficiency, operability and reliability of operation of promising aviation equipment in all climatic conditions.

1 cl, 3 dwg, 2 tbl, 4 ex