Corrosion resistance of superhydrophobic film on aluminum alloy surface fabricated by chemical etching and anodization

A superhydrophobic surface was fabricated by chemical etching and anodization on AA2024 aluminum alloy. A static water contact angle of more than 150° was achieved at a wide pH value range when the surface chemical etching time was more than 3 min. The SEM and AFM images showed that the surface morphology and roughness were dependent on chemical etching time. The FTIR results indicated that the FAS (fluorinated agent silane) molecules reacted with alundum on the aluminum alloy surface and the surface exhibited excellent adhesion performance on the anodization specimen. The corrosion resistance of the superhydrophobic surfaces was estimated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements in 3.5wt% NaCl aqueous solution. The electrochemical measurements and appropriate equivalent circuit models revealed that the anticorrosion performance was greatly improved by the superhydrophobic surface.