Design of superhydrophobic coupling cerium conversion coating for corrosion protection of magnesium alloy: Experimental and theoretical studies.

Superhydrophobic conversion coatings have attracted increasing attention in corrosion protection field due to their exceptional water-repellent properties. However, the retention of protective properties with surface wettability dynamics remains a significant challenge. Herein, a superhydrophobic coupling cerium coating with hierarchical structure is fabricated via cerium-doped deep eutectic solvent pretreatment and modification to extend corrosion resistance duration. The synergistic enhancement between hydrophobicity and active protection can significantly improve the anti-corrosion characteristics of magnesium alloys, resulting in a decrease in corrosion current density by an order of magnitude. The superhydrophobic surface can prevent the metal from corrosive media by reducing the contact area and thus slow down the corrosion rate. The cerium compound within the coating can form a cerium protective layer during the corrosion reaction of magnesium alloy, inhibiting the further corrosion process. Furthermore, the density functional theory (DFT) calculation revealed the corrosion protection mechanism of superhydrophobic coatings. Combining experimental investigations with theoretical calculations, this work provides a new strategy for enhanced anti-corrosion protection of superhydrophobic coatings. • A novel superhydrophobic coupling cerium conversion coating was designed by combining the cerium hierarchical structure with the superhydrophobic surface. • The cerium hierarchical structure was prepared cerium-doped deep eutectic solvent pretreatment. • The coating consists of an active protective primer and a superhydrophobic topcoat. • The corrosion mechanisms are explained through experimental studies, analytical insights, and DFT calculations. [ABSTRACT FROM AUTHOR]