Abstract：In order to improve the properties of micro arc oxidation (MAO) coating on AZ91D magnesium alloy,
the MAO coating with different ZrO2 powder content in electrolyte was prepared on AZ91D magnesium alloy.
The surface morphology, roughness, thickness and corrosion resistance of the coating samples were characterized.
The results show that with increasing of the content of ZrO2 powder from 0.5 g/L to 2.5 g/L in the electrolyte, the
roughness of coated surface increases from 2.0 μm to 3.3 μm, the thickness of surface layer decreases from
115 μm to 85 μm. SEM-EDS mapping results show that the films are mainly consist of O, Mg, Al, Si and Zr ele‐
ments. The microcracks on the surface of the MAO coating decrease significantly when ZrO2 content in electro‐
lyte are more than or equal to 1.5 g/L. When the addition amount of ZrO2 is 2.0 g/L, the corrosion current density
of the coating is the smallest and the corrosion resistance is the best, which is only 0.93 μA/cm2.
2022, Vol. 32 
