Healing effects of LDHs nanoplatelets on MAO ceramic layer of aluminum alloy

The ceramic layer prepared by micro-arc oxidation (MAO) on aluminum alloy 2024 surface contained a lot of micro-pores and micro-cracks, providing the passage for corrosive medium to penetrate into the substrate. This work provided an effective strategy to heal the structural defects of MAO ceramic layer, utilizing the inhibitor-loaded LDHs formed on the surface by an in-situ growth method. The structure, morphology, composition and corrosion resistance of the as-prepared films were investigated. The results showed that the LDHs nanoplatelets were preferentially formed in/on the micro-pores/-cracks of MAO ceramic layers, which led to an effective healing of the film defects. The vanadate-loaded LDHs nanoplatelets significantly enhanced the corrosion resistance through the gradual release of inhibitors, rendering a long-term active protection for the MAO covered aluminum alloy substrate.