Self-healing plasma electrolytic oxidation (PEO) coating developed by an assembly of corrosion inhibitive layer and sol-gel sealing on AA2024

The inherent porous structure of PEO coatings is regarded as a drawback for long-term protection. In this investigation, the presence of pores and defects in the PEO coating was exploited as reservoirs for corrosion inhibitors to generate self-healing properties on AA2024. Smart coating systems were fabricated on the PEO layer in which 8-hydroxyquinoline (8-HQ) and benzotriazole (BTA) were employed as corrosion inhibitive layers followed by a sol-gel sealing. The protective performance relies on the mechanical interlocking between the sol-gel coating and the sublayer plus the sealing ability of the sol-gel in the presence of the intermediate layer.