A multifunctional anticorrosive coating of hydroxyapatite platform based on metal-organic framework decoration with pH-responsive behavior

This study aimed to design a composite epoxy coating HZB/EP with pH-responsive behavior by grafting different material functions. In this approach, ZIF-8 particles were self-assembled on the surface of hydroxyapatite (HAp) through in situ growth, followed by encapsulation of the corrosion inhibitor BTA. Scanning electron microscopy (SEM) analysis of the coating section revealed a significant improvement in the dispersion of HZB in the resin compared to hydroxyapatite (HAp), resulting in a notable reduction in coating defects upon the addition of HZB. Electrochemical impedance spectroscopy (EIS) tests demonstrated that HZB/EP maintained a high low-frequency impedance value even after immersion in a 3.5% NaCl solution for 40 days, exhibiting an impedance magnitude 4–5 orders of magnitude higher than Pure EP. Additionally, scratch and salt spray tests validated the release and action process of the corrosion inhibitor BTA. This study presents a novel strategy for the development of multifunctional anticorrosive coatings.