A hydrophobic organic coating on micro/nano-texture fabricated by galvanic corrosion

This paper is focused on the electrochemical corrosion protection issue of marine equipment during actual service. The two metals (45 # steel and 6061 aluminum alloy) are brought into contact to form the galvanic corrosion. The micro/nano-structure with honeycomb-like protrusions (1.82 μm) and network-like texture (370–460 nm) is fabricated on the steel surface, which becomes superhydrophilic (water contact angle (WCA) ≈ 0°). Perfluorooctanoic acid, a low surface energy modifier, is used to modify the corroded micro/nano-texture surface. Thus, a hydrophobic organic coating (WCA = 158° ± 4°) is fabricated, which effectively inhibits droplet wetting and penetrating into the metal layer. Furthermore, it is found that the coating surface still maintained its hydrophobicity (WCA = 101.5°) after 2 h of the coating immersed in the corrosive solution. Thus, a new surface remanufacture method, utilizing the galvanic corrosive surface to prepare the hydrophobic coating, is proposed. This study hopes to provide new ideas for designing the protective coating applied to engineering maintenance.