METHOD OF CHEMICAL TREATMENT OF SURFACE OF PART FROM ALUMINUM AND ALUMINUM-BASE ALLOYS Russian patent published in 2003 - IPC

FIELD: chemical treatment of surfaces of parts from aluminum and its alloys; applicable in aircraft and other industries for protection from corrosion. SUBSTANCE: method includes preparation of part surface by degreasing in solution containing, g/l: ES-naftol 5-10; the balance, water; at temperature of 18-28 C; chemical etching in solution containing, g/l: sulfuric acid 90-110; chromic anhydride 46-52; hydrofluoric acid 1.3-1.4; the balance, water; at temperature of 15-30 C for 3-5 min and subsequent oxidation in aqueous solution containing chromic anhydride and sodium fluosilicate. Etching is carried out in acid solution. Additionally introduced into oxidizing aqueous solution are chromium phosphate and barium phosphate with the following amounts of components, g/l: chromic anhydride 3-3.5; sodium fluosilicate 3-3.5; chromium phosphate 0.04-0.5; barium phosphate 0.01-0.1; the balance, water. EFFECT: produced coating offering high protective properties and higher longevity of treated parts. 3 cl, 4 tbl, 1 ex