The anodized oxide film of magnesium alloy has many defects (poor bond strength, low wear and corrosion resistance, easy fading, uneven color, etc) in traditional surface coloring technology. These defects have largely limited the applications of magnesium alloy. In this paper, black ceramic film with uniform color, smooth surface, compact structure and excellent corrosion resistance on AZ91D alloy was successfully obtained by micro-arc oxidation(MAO).Three electrolytic solution systems (silicate, organic a...