Effects of additives in electrolyte on characteristics of ceramic coatings formed by microarc oxidation

The effects of adding Na₂ WO₄. 2H₂O and SiC powder to the electrolyte on the characteristics of ceramic coatings on Al based alloys formed by microarc oxidation were studied. The ceramic coating quality was improved by the two additives, but the addition of Na₂ WO₄. 2H₂O was more effective, as it improved the formation of Al₂O₃ phase in the ceramic coating, increased the ratio of the internal dense region to the whole ceramic coating, optimised the ceramic coating phase structure, and improved its wear resistance. The SiC powder was able to enter into the ceramic coating and improve its wear resistance, at the same time increasing the friction coefficient of the coating.