Enhanced corrosion resistance of Mg alloy embedded in Cl--containing Portland cement with the formation of CaCO3-coated Mg(Al)O passive film via one-step pulse electrodeposition

In this study, a novel CaCO3/Mg(Al)O coating system was successfully synthesized via one-step pulse electro-deposition. The thickness of inner passivation layer and outer CaCO3 layer was tailored by modulating the pulse voltage. Anticorrosion performance of the coated Mg alloy was assessed by both electrochemical methods and embedment tests. The coated Mg alloy demonstrated improved corrosion resistance, attributed to the synergistic impact of a compact outer CaCO3 layer and an Al-assisted inner passivation layer. Both layers' quality primarily governed the alloy's anticorrosion performance. Remarkably, embedment tests revealed a re-passivation phe-nomenon instead of corrosion, with its mechanism discussed comprehensively.