Self-sealing, self-healing, and corrosion-resistant microarc oxidation coatings via in situ Ce doping for Mg alloys

A two-step microarc oxidation (MAO) fabricates in situ Ce-doped coatings with self-sealing and self-healing capabilities on the magnesium (Mg) alloy. The CePO 4 /MgO composite melt effectively seals discharge pores, while its nanocrystalline-amorphous structure enhances coating densification and corrosion resistance. Electrochemical and salt solution demonstrate that Ce-doped coatings exhibit excellent corrosion resistance. During corrosion, released Ce 3+ promotes formation of Ce(OH) 3 /Mg(OH) 2 products. Density functional theory (DFT) calculations reveal these products exhibit increased work function and weakened Cl − adsorption, synergistically forming a robust electronic barrier that suppresses corrosive attack and enables persistent self-healing protection.