The nanostructures of electrodeposited ZnO/ZIF-8 composite coatings on magnesium alloys synergistically enhance superhydrophobic and corrosion resistance

Superhydrophobic coatings have emerged as a primary strategy for protecting magnesium alloys. However, their application is often hindered by reliance on harmful fluorinated materials. In this study, a fluorine-free ZnO/ZIF-8 composite coating was fabricated on magnesium alloy surfaces via electrodeposition. By leveraging synergistic effects between ZnO nanostructure roughness and ZIF-8's intrinsic hydrophobicity, superhydrophobicity was achieved without fluorinated surface modifications. Results demonstrate excellent hydrophobic stability, with superhydrophobicity maintained under low-temperature conditions. The water contact angle remained unchanged in sodium chloride solutions of varying concentrations, indicating exceptional salt-induced corrosion resistance. Furthermore, the coating exhibited hydrophilic-hydrophobic transition properties. Electrochemical tests confirmed superior corrosion resistance, showing a corrosion current density of 3.964 × 10 −9 A∙cm −2 and a four-order-of-magnitude increase in charge transfer resistance versus the AZ91D substrate. Molecular dynamics (MD) simulations and density functional theory (DFT) calculations elucidated the corrosion protection mechanism, providing theoretical support for experimental findings. This study integrates experimental and theoretical approaches, offering new insights and technical references for fluorine-free superhydrophobic coatings in magnesium alloy corrosion protection.