Corrosion Behavior of Epoxy Coating Containing Poly-dopamine Modified Hexagonal Boron Nitride

In order to improve the dispersion of hexagonal boron nitride (h-BN) in the solvents and organic matrix, and to investigate the effect of h-BN on the corrosion resistance of epoxy coating, polydopamine was modified on the h-BN to achieve the well dispersion stability of h-BN in the solvents and epoxy coating. The corresponding morphology, chemical composition and thermal stability were characterized by SEM, TEM, XPS, Raman spectrum and TG. In addition, the corrosion behavior of the epoxy coating and h-BN@PDA/epoxy coating was investigated in 3.5%NaCl solution by electrochemical measurements. The results indicate that h-BN@PDA/epoxy composite coating exhibites nobler open circuit potential (-0.1 V), higher impedance modulus and coating resistance (~1010 Ω·cm2), lower breakpoint frequency (~0.1 Hz) than those of the epoxy coating during long time immersion in 3.5% NaCl solution. Furthmore, very little corrosion is found at the substrate surface coated with h-BN@PDA/epoxy composite coating, indicating the outstanding corrosion resistance of the composite coating. Addition of h-BN nanosheets can reduce the coating's porosity and inhibit the penetration of corrosive medium, which helps to improve the corrosion resistance of the composite coating. © 2017, Editorial Office of CHINA SURFACE ENGINEERING. All right reserved.