Facile Fabrication of High-White and Robust Superhydrophobic Ni/Al2O3 Composite Coating on Al Alloy

This work presents a facile method to fabricate high-white and robust superhydrophobic film on Al alloy surface. Ni/Al2O3 film with appropriate roughness and high-white surface is constructed on the Al alloy by a simple chemical bath method via placing the Al alloy into the Ni2+ aqueous solution. Then the surface energy is reduced by spin-coating the stearic acid (STA) to achieve excellent superhydrophobicity. As expected, the reflectivity, self-cleaning, corrosion resistivity, and mechanical durability of Al alloy after modification have all displayed dramatic enhancements. The reflectance of the modified Al alloy is far above the pristine Al alloy at all wavelengths (200-2,000 nm). This high-white film with remarkable reflectivity can effectively reduce its surface temperature and improve visibility in practical applications. Finally, a champion water contact angle of 161 & DEG; and corrosion resistivity of 97.6% are attained by coating Ni/Al2O3-STA composite film on Al alloy. The Leeb hardness of superhydrophobic film-coated Al alloy is enhanced from 325 to 461 after coating superhydrophobic film on Al alloy. This work provides a framework for the development of superhydrophobic Al alloy with high-whiteness and robustness.