Superhydrophobic coatings by electrodeposition on Mg–Li alloys: Attempt of armor-like Ni patterns to improve the robustness

Due to the fragility of the layered structure, the mechanical properties of superhydrophobic surfaces, particularly wear resistance, are still too poor, limiting the industrial application of protecting magnesium-lithium (LZ91) alloys from corrosion. As a result, we're testing screen-printed masks to electroplate armor-like Ni columns. Then, using electrodeposition, compact micro/nanometer-sized papillary structured superhydrophobic surfaces are created on Mg–Li alloys, which exhibit good low viscosity, self-cleaning, chemical stability, and excellent corrosion resistance with a 2 order of magnitude decrease in corrosion current density in both corrosive media. Surprisingly, increasing the deposition time causes the dissolution of Cu anode electrodes and the subsequent formation of Cu compounds on the superhydrophobic coating, resulting in the formation of dense needle-like structures on these papillae. Even after the superhydrophobic structures are worn away, the armor-like Ni columns reduce the contact angle's tendency to decrease. This proposed deposition method provides a simple and fast process for protecting the surface of Mg–Li alloys, and the concept of armored Ni patterns may pave the way for future advances in the robustness and application of superhydrophobic coatings.