Long-term corrosion protection and self-healing behavior of epoxy coatings incorporating polyacrylamide-coated Co/Ni MOF@BTA nanoparticles

Researchers have developed a novel anticorrosion particle, denoted as CPAM@Co/Ni MOF@BTA (CMB). In this system, benzotriazole (BTA) acts as a corrosion inhibitor and is incorporated into the Co/Ni MOF framework through an in-situ host–guest nano-confinement strategy. Meanwhile, cationic polyacrylamide (CPAM) serves as cladding layer and is electrostatically assembled onto the surface of Co/Ni MOF@BTA. The composite coating was prepared by dispersing these particles into an epoxy resin matrix. In immersion tests, the coating was found to effectively enhance the corrosion resistance of Q235 steel in a sodium chloride medium, with impedance remaining as high as 2.24 × 10 5 Ω·cm 2 after 45 days of exposure. In polarization measurements, a corrosion current density as low as 5.294 × 10 –10 A/cm 2 was observed, indicating a pronounced anodic inhibition effect. In scratch tests, a distinct self-healing capability was also demonstrated. These results confirm that the incorporation of CMB particles significantly improves the passive corrosion resistance of epoxy coatings and imparts self-healing properties.