Cerium nitrate and stearic acid modified corrosion-resistant micro-arc oxidation coating on magnesium alloy

This paper aims to overcome the adverse influence of intrinsic micropores and microcracks in the micro-arc oxidation (MAO) layer by creating a hydrophobic cerium-based conversion top layer through a vacuum-assisted post-treatment. The electrochemical results reveal that the corrosion current density (jc) and impedance modulus at the low-frequency region of the duplex protective coating system are significantly lower and higher than that of the bare magnesium alloy and MAO coating without modification. The unprecedentedly low jc and high impedance of the as-prepared coating are attributed to the notable improvement in hydrophobicity, sealing effect to micropores, and self-healing function of the outer cerium-based film.