Fabrication of corrosion resistant superhydrophobic surface with self-cleaning property on magnesium alloy and its mechanical stability

A stable superhydrophobic surface with self-cleaning property was obtained on AZ31 magnesium alloy via a process combining both electrodeposition and post-modification with stearic acid. The surface morphologies, chemical composition and wettability were characterized using scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transformed infrared (FT-IR) spectroscopy and water contact angle measurement. The as-prepared superhydrophobic surface with leaf-like clusters had a static water contact angle of 156.2 ± 0.6° and a sliding angle as low as 1.0°. Potentiodynamic polarization measurements demonstrated that the superhydrophobic surface greatly improved the corrosion resistance of magnesium alloy in 3.5 wt.% NaCl solution. Moreover, the chemical stability and mechanical stability of the superhydrophobic surface were investigated. The superhydrophobic surface showed good chemical stability for the liquids with high salinity and corrosive effect. The as-prepared surface could maintain superhydrophobicity after mechanical abrasion for 900 mm, showing high mechanical stability. The superhydrophobic surface could maintain good corrosion resistance even after abrasion for 1100 mm. The presented method is of significant value for the industrial fabrication of mechanically robust, corrosion resistant and self-cleaning superhydrophobic surfaces. It could be easily extended to other metallic materials.