Influences of Additive on the Formation and Corrosion Resistance of Micro-arc Oxidation Ceramic Coatings on Aluminum Alloy

The influence of Na2WO4 on the forming process and corrosion resistance of ceramic coatings was researched in silicate electrolyte system. The surface morphology and phase composition of ceramic coatings were analyzed by SEM and XRD. The results show that Na2WO4 can promote the formation of high impedance coatings, reduce the arcing-terminal voltages, and increase the thickness of ceramic coatings. When the concentration of Na2WO4 is 5 g/L, the arcing voltage is the lowest, the corrosion resistance of ceramic coatings is improved by 1.6 times compared with the ceramic coatings’ in silicate electrolyte system.