Key factor for the corrosion resistance of MAO coating on Mg alloy

MAO coating is a significant research topic to improve the corrosion resistance of Mg alloys, which are currently being received much attention. The majority of current research is centered on optimizing the pore structure of MAO coatings to improve corrosion resistance, but the bonding between the coating and the substrate has been neglected. In this work, MAO coatings with different porosity and adhesion strength were obtained in phosphate and silicate electrolytes at different voltages. The structure, chemical composition, and mechanical properties of MAO coatings were also analyzed by various means, and their corrosion resistance was tested by electrochemical metholds. The influence of porosity and adhesion on the corrosion resistance of the coatings was analyzed and their mechanism has been examined, which is beneficial to obtain longer corrosion resistance MAO coating.