A facile approach to fabricate robust superhydrophobic Cu/TiO₂ composite coating on stainless steel

A superhydrophobic Cu/TiO₂ composite coating was prepared through the electrodeposition and fluorinated modification of a 304 stainless steel surface. The Cu plating coated with the hierarchical concave-convex structure was initially fabricated by tuning current density and electrodeposition time. A codeposition technique was used in obtaining a composite coating comprising Cu matrix and TiO₂ nanoparticles on the basis of the optimal electrodeposition parameters, then fluorination modification was immediately conducted for the production of a superhydrophobic Cu/TiO₂ composite coating. The surface structure and chemical composition for the prepared coatings were studied. The wettability property shows that the modified Cu/TiO₂ composite coating possesses excellent superhydrophobicity, with a water contact angle (CA) of 156.4° and a sliding angle (SA) of 4.6°. The superior mechanical stability of the superhydrophobic Cu/TiO₂ composite coating has been confirmed using scratching, tape peeling and sandpaper abrasion tests, respectively. In addition, compared to the stainless steel with a certain protection capability, the corrosion current density of the as-prepared composite coating is decreased by nearly two orders of magnitude, and the corrosion resistance significantly improves. This composite coating exhibits the outstanding long-term stability and self-cleaning property, and may thus be a valuable tool for enlarging the application of the superhydrophobic coatings.