In-situ growth of corrosion-resistant LDH/ZIF-8 hybrid film on the surface of MAO film based on LA93 alloy by the one-step method

An in-situ grown LDH/ZIF-8 hybrid film on the surface of MAO film based on the LA93 alloy was successfully fabricated by the one-step method. The composite film, called as MLZ, demonstrates exceptional corrosion resistance. The corrosion current density is reduced by two orders of magnitude compared to the MAO film. Furthermore, it possesses significant long-term protective capabilities. Experimental measurement and density functional theory (DFT) calculations were conducted to investigate the formation mechanism of MLZ composite film. During the hydrothermal, Zn ions from the in-situ generated LDH on the MAO surface serves as active nucleation sites, facilitating the nucleation and growth of ZIF-8 crystals. The formation of ZIF-8 effectively compensates for the intergranular defects in LDH, enhancing the integrity of the film. LDH/ZIF-8 film effectively seals defects in the MAO film and constructs a robust physical barrier, significantly enhancing the protective capacity of the film.