A multi-strategy coating for Al alloy based on orientationally arranged nanosheets doped SiO2 coating and corrosion inhibitor loaded porous anodic alumina film

Although aluminum alloys are widely used in various industries, their wear and corrosion resistance are still needed to be enhanced. In this study, a robust anti-corrosion composite coating was prepared on the surface of Al alloy based on multiple reinforcement strategies. The composite coating is consisted of horizontally arranged and functionally modified h-BN nanosheets doped SiO2 coating (SiO2-hBN(NH3+) coating) and corrosion inhibitor MBT loaded porous anodic alumina (PAA-MBT) film. Results show that the composite coating prepared in this work has excellent corrosion resistance due to the effect of the extended penetration path of corrosive medium by h-BN(NH3+) nanosheets, the full-thickness hydrophobicity of the SiO2 coating, the corrosion inhibition of the MBT released from the PAA film and the physical barrier of the entire coating system. In addition, the composite coating also exhibits good mechanical properties including high hardness, high bonding strength and superior wear resistance. This work provides a novel design of protective coating with excellent anti-corrosion resistance and mechanical properties, which has a promising prospect in the development of superior long-term anti-corrosion coatings for aluminum alloy.