Fabrication of self-healing superhydrophobic film via inhibitor loaded LDH for improving the anti-corrosion performance of aluminum alloy

Abstract

The critical factor in developing an environmentally friendly conversion film to replace chromium passivated films is endowing the conversion film with self-healing capabilities and enhancing its anti-corrosion properties. In this study, layered double hydroxides (LDH) films with self-healing characteristics were fabricated in situ on aluminum alloy surfaces by intercalating tungstate ions. Simultaneously, the unique microstructure of the LDH film was leveraged to fabricate superhydrophobic films via surface modification with fluorosilane. Scanning electron microscopy (SEM) results reveal that the prepared LDH films exhibit a uniform and dense lamellar structure. The intercalation of tungstate ions and the surface modification with fluorosilane do not compromise the structural integrity of the films. The water contact angle of the prepared films reaches up to 171°. Electrochemical impedance spectroscopy (EIS) results demonstrate that the protective efficiency of the films is 99.9 %. Even after prolonged immersion in NaCl solution for 80 days, the protective efficiency remains at 99.6 %. Furthermore, EIS results of artificially scratched samples show significant self-healing capabilities. The self-healing mechanism involves the release of tungstate ions to the scratched areas, which subsequently form a dense oxide layer on the aluminum alloy surface, thereby repairing the damaged film.