In situ growth of hierarchical boehmite on 2024 aluminum alloy surface as superhydrophobic materials

A super-hydrophobic 2024 aluminum alloy surface with multi-scale hierarchical flower-like boehmite (gamma-AlOOH) structure has been fabricated via a facile hydrothermal approach. The different morphologies of the g-AlOOH films were totally controlled by the preparation conditions for crystal growth, such as reaction solution and time. The morphology and structure of the films were characterized using scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The super-hydrophobicity can be attributed to both the rough multi-scale structural boehmite coating and surface enrichment of low surface energy with the chemical vapor deposition of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (POTS). The resulting super-hydrophobic surface exhibits a water contact angle of 155 degrees and a sliding angle of about 5 degrees. The corrosion behavior was investigated with potentiodynamic polarization measurements and it was found that the super-hydrophobic coating considerably improved the corrosion resistant performance of aluminum alloy.