Corrosion and Self-healing Properties of Microcapsule Modified Plasma Electrolytic Oxidation Epoxy Composite Coatings with 8-hydroxyquinoline Inhibitor

Abstract

A novel type of microcapsule-encapsulated corrosion inhibitor was prepared in a water-based solution with a pH range of 7–8, and it was applied to the composite organic coating of magnesium alloy plasma electrolytic oxidation to enhance its corrosion resistance and self-healing properties. The morphology, chemical composition, structure, and functional properties of the composite coating were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), polarization curve, alternating current impedance, and salt immersion test. The experimental results showed that, after immersion in a 3.5 wt% NaCl solution for 12 h, the coating could effectively protect AZ91D from corrosion. When the coating was damaged, the exposed alloy surface would release metal ions in the corrosive environment and react with the corrosion inhibitor 8-hydroxyquinoline to form a Mg(8-HQ)₂ chelate, exhibiting significant self-healing behavior. The study results demonstrate the broad application prospects of microcapsule technology in the coating field, providing new ideas for the development of efficient anti-corrosion coatings.

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Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature