Influencing Factors of AZ91D Magnesium Alloy MAO Film Properties

Micro-arc oxidation (MAO) process was carried out on AZ91D alloy using an alternative double-pulse power source with different parameters. The effects of voltage, duty cycle and current density on the coatings were studied. The results show that the thickness of coatings increased with the increase of voltage , duty cycle and current density. The structure and morphology of the coatings also depended on voltage and duty cycle. The coatings became more porous and cracked with increasing the voltage and duty cycle. The salt-spray testing results indicated that the corrosion resistance of the films was weakened as the duty cycle, current density and voltage increased.