Effects of Positive Pulse Voltage on the Morphology and Corrosion Resistance of Micro-arc Oxidation Film of Rare Magnesium Alloy

The effects of positive pulse voltage on the morphology and corrosion resistance of micro-arc oxidation film of Mg-4Gd-3Y-0.5Zr alloy treated by double pulse micro-arc technique was investgated by SEM, coating thickness gauge and electrochemical workstation etc.The results show that fwer pores with larger diameters, more strength sintering and larger crack were found on the film when the positive pules voltage increased; Corrosion resistance of the film, which significantly better than the alloy substrate, increases first and thereafter decreases as positive pulse raise gradually; The optimal positive pulse voltage was 450 V, corrosive voltage and current were-1.495 V and 10^-8.62 A/cm².