H-BN base triple-functional filler enhances the anti-corrosion performance of epoxy coating

Abstract

The dispersion of hexagonal boron nitride (h-BN) in resin to prepare anti-corrosion coating has only a single physical shielding function, and does not inhibit the electrochemical reaction process, which significantly reduces the durability of anti-corrosion coating. In this paper, polyaniline with anodic passivating function was synthesized on the surface of h-BN by in-situ polymerization, and Ce3+ cation with corrosion inhibition was loaded into polyaniline/h-BN. Thus, a triple functional anti-corrosion filler Ce3+&PANI/h-BN with physical shielding - anode passivation - cathode corrosion inhibition was prepared. The microstructure, crystal form, element distribution, thermal stability and corrosion inhibition ability of the composite filler were characterized. The anti-corrosion, anti-friction and adhesion properties of EP/Ce3+&PANI/h-BN composite coating was investigated. EIS and Tafel test results show that the corrosion inhibition efficiency of Ce3+&PANI/h-BN is 55.5% and 89.67%, respectively. The low-frequency impedance modulus of the composite coating after 40 days of exposure is 13 times that of the pure EP coating, up to 9.79 × 109 ·cm2. The results of salt spray test also show that the barrier ability and anti-corrosion effect of the composite coating are significantly improved compared with the pure EP coating. The wear mass loss of the composite coating is reduced by 43.69% compared with the pure EP coating. This research provides a way to prepare multi-functional, high shielding, wear resistance anti-corrosion fillers to achieve long-term protection of coatings.