METHOD OF PREPARING COATINGS SUITABLE FOR PROTECTION OF STEEL PARTS AGAINST CORROSION Russian patent published in 2001 - IPC

FIELD: mechanical engineering and corrosion protection. SUBSTANCE: to form composite coating of steel part, the latter is degreased, activated by acid solution, subjected to deposition of zinc coating in alkaline zincate electrolyte containing tin complex compound with polybasic organic acids, phosphatation in solution containing nitrates, zinc, barium, zinc monophosphate, and a surfactant (mixture of sodium salts of sulfate esters of secondary alcohols containing 6-16 carbon atoms), and treatment with chromate solution. EFFECT: improved protection properties and increased corrosion resistance compared to zinc coating. 3 cl, 2 tbl