Hydrotalcite-modified diatomite with encapsulation of 8-hydroxyquinoline for early corrosion detection of long-term anti-corrosion coating

Anti-corrosion coating with corrosion detection ability will provide more efficient protection for metal equipment. In this work, the microencapsulated filler (Ni-Co/8-HQ@DE) with both anti-corrosion and corrosion detection ability was prepared by in-situ growth and vacuum impregnation assembly technology. The load of 8-HQ was determined to be 23.68 % by thermal decomposition test. The combination of test and simulation is used to quantify the ability of Ni-Co/8-HQ@DE to capture Cl − and verify the persistence of 8-HQ release. VASP simulated the reaction mechanism between 8-HQ and iron ions, and electrochemical data calculated that the thickness of the passivation film produced by 8-HQ was 3.1 nm. In addition, the impedance modulus of the prepared EP/Ni-Co/8-HQ@DE coating is three orders of magnitude higher than that of the EP coating, and the water absorption is reduced by 98.27 %. The 14 day salt spray test and 90 day salt water immersion test showed obvious corrosion detection effect.