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

• Published in: Corrosion science Vol. 222; p. 111424
• Main Authors: Akbarzadeh, Sajjad, Coelho, Leonardo Bertolucci, Dangreau, Lisa, Lanzutti, Alex, Fedrizzi, Lorenzo, Olivier, Marie-Georges
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2023
• Subjects: AA2024; GDOES; Plasma electrolytic oxidation; Sol-gel sealing; SVET; GDOES; Plasma electrolytic oxidation; SVET; Sol-gel sealing; AA2024
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2023.111424

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. •The synergistic inhibitive behavior in 0.1 M NaCl was found for 8-HQ and BTA with a ratio of 7/3.•The impregnation of the PEO layer by inhibitors reduced its porosity.•The optimal concentration to form the inhibitive layer was 5 g/L.•Mechanical interlocking and self-healing properties in the PEO/intermediate/sol-gel coating system were evidenced.•High corrosion protection performance was obtained for the optimized system till five weeks of immersion in 0.1 M NaCl.