The effect of chemical etching, anodizing and creating a super-hydrophobic state on the corrosion behavior of aluminum

In this research, super-hydrophobic surfaces were made on pure aluminum (92%) using two methods of chemical etching, and onestep anodizing and modification with materials with low surface energy. After creating a uniform roughness on the surfaces, surface modification was done with perfluoroactyltrichlorosilane (PFTS). The wettability was investigated by measuring the drop contact angle (WCA) and the morphology of the coating with a field emission scanning electron microscope (FESEM). The chemical composition of the surface was detected by Fourier transform infrared spectroscopy (ATR-FTIR). The self-cleaning property with coal powder was investigated. Corrosion behavior was evaluated using Tafel polarization test and salt fog. The results of the water contact angle showed that the surface roughness due to anodizing and chemical etching reduced the contact angle to 15ᵒ and 24ᵒ, and after modifying the surfaces, the contact angle increased to 157ᵒ and 153ᵒ. After modifying the surface of the anodized sample, it has higher corrosion resistance than the etched sample. The final coating is self-cleaning.