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 ( j c ) 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 j c 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.