Superhydrophobicity of thermally annealed aluminum surfaces and its effect on corrosion resistance

Surface functionalization with chemical modification, i.e., low surface energy coating, is the most commonly used method to obtain hydrophobic/superhydrophobic surfaces. However, the fabrication procedures are complex or harmful to environment, and the factors affecting corrosion resistance of chemically modified surfaces are difficult to determine owing to the complicated anticorrosive mechanism. In this study, a simple and environment-friendly method was employed to prepare hydrophobic/superhydrophobic surfaces without chemical modification. The electrochemical impedance method was applied to measure the corrosion resistances, and the effective wetting area was used to elucidate the anticorrosive mechanism of hydrophobic surfaces. We found that the corrosion resistances of the fabricated Al samples were closely correlated with the surface wettability and further related to the effective wetting area at the solid–liquid interface. Consequently, a smaller effective wetting area results in a larger corrosion resistance and thus enhances the corrosion protection performance.