PROCEDURE FOR APPLICATION OF COMPLEX PROTECTIVE COATING ON STEEL PARTS Russian patent published in 2011 - IPC C25D5/10 C25D5/50 

FIELD: machine building.

SUBSTANCE: procedure for application of complex protective coating on steel parts consists in successive application of zinc coating from electrolyte containing sulphuric zinc and sodium salt, in application of tin coating from solution containing tin salt and in successive thermal treatment. Also, into zinc electrolyte there is additionally introduced salt ammonia, while as sodium salt there is introduced sodium acetic and liquid disperser NF at pH of electrolyte 3.5-5. Into tinning solution there is additionally introduced pyro-phosphate-acetic potassium, sulphuric ammonium and as tin salt there is used tin dichloride at pH of solution 9.2-9.8. Thermal treatment is carried out at temperature below temperature of tin melting.

EFFECT: fabrication of complex coating possessing higher corrosion resistance and protective properties on steel parts of various configuration and strength including high strength parts.

4 cl, 2 tbl, 3 ex