Study on the preparation and properties of superhydrophobic Mg-Li alloy surface via composite etching method

Magnesium-lithium (Mg-Li) alloys have significant potential for applications in aerospace, automotive, electronics, and biomedical fields. Despite their attractive properties, the commercialization of Mg-Li alloys remains limited due to their inherently poor corrosion resistance. Superhydrophobic surfaces have attracted significant attention due to their excellent corrosion resistance. In this study, a superhydrophobic surface was successfully fabricated on the LAZ933 Mg-Li alloy via combined etching and surface modification. The microstructure and thickness of the superhydrophobic coating were characterized by cross-sectional FESEM, which revealed a uniform morphology with an average thickness of approximately 93.4 μm. The superhydrophobic surface exhibited a contact angle of 159.5° and a sliding angle of 4.4°. Electrochemical tests, combined with post-corrosion morphology analysis, demonstrated a significantly improvement in corrosion resistance. Specifically, the corrosion potential of the superhydrophobic Mg-Li alloy shifted positively by 0.29 V compared with the untreated sample, while the corrosion current density decreased by two orders of magnitude, resulting in a corrosion inhibition efficiency of 98.8 %. In addition, the fabricated surface demonstrated efficient self-cleaning ability, mechanical durability and excellent resistance to surface contamination. Long-term durability testing also showed that the superhydrophobic surface remained stable after being stored under ambient atmospheric conditions for 60 days. • Analyzed the morphology, characterization results, and performance tests of Mg–Li alloys at various stages. • Investigated the formation mechanism of superhydrophobic Mg–Li alloy surfaces through morphology and characterization analyses. • Demonstrated that the prepared Mg–Li superhydrophobic surfaces show strong corrosion resistance, stability, and self-cleaning.