Researching the fabrication of anticorrosion superhydrophobic surface on magnesium alloy and its mechanical stability and durability

Abstract The poor mechanical stability of most reported superhydrophobic surfaces severely hindered their practical applications. In this paper, a robust and stable superhydrophobic surface fabricated on AZ91D magnesium alloy through a process combining both electrodeposition and chemical modification was presented. The as-prepared surface with pinecone-like hierarchical structure exhibited excellent superhydrophobicity with a water contact angle of 163.3 ± 0.7° and a sliding angle of about 1.2 ± 0.9°. The superhydrophobic surface possessed good mechanical stability due to the fact that the surface could maintain superhydrophobicity after mechanical abrasion for 700 mm. The as-prepared surface possessed robust superhydrophobicity for the liquids with corrosive effect and high salinity, showing good chemical stability. Besides, after exposed to atmosphere for more than 240 days, the resulting surface still maintained a contact angle as high as 158.5 ± 0.9° and a sliding angle of 6.0 ± 1.0°, showing good long-term stability. The superhydrophobic surface exhibited excellent anticorrosion protection for magnesium alloy in neutral 3.5 wt.% NaCl solution. The potentiodynamic polarization test results indicated that the corrosion rate of superhydrophobic surface was only 0.003% of that of bare magnesium alloy. We believed that the presented method could provide a straightforward and effective route to fabricate large-area, mechanically robust, anticorrosion and self-cleaning superhydrophobic surface on various substrate materials for a great number of potential applications.