Effects of current output modes on the growth kinetics and corrosion resistance of micro-arc oxidation coatings on magnesium alloy

Abstract

Micro-arc oxidation (MAO) coatings were prepared on the AZ31Mgalloy under the constant/gradient current control modes. The effects of current output modes on the growth rate, energy consumption, microstructure, and corrosion resistance ofMAOcoatings were studied. The results shows that the current step-down mode (G852) exhibited a lower unit energy consumption than the constant current mode (C5) and the current step-up mode (G258), even though the same average current density current was used duringMAOprocess. Meanwhile, the G852 is conducive to a thick and dense coating, resulting in a better corrosion resistance. The method of energy saving preparation of corrosion resistantMAOcoating by adjusting the current mode is of great significance for practical production.