Enhancement of the Anticorrosion Properties of Epoxy Resin Composites through Incorporating Hydroxylated and Silanised Hexagonal Boron Nitride (h-BN)

Hexagonal boron nitride (h-BN) has the outstanding properties of high-temperature stability, electrical insulation and impermeability against water, oxygen and corrosive ions. However, BN easily agglomerated in the coating, resulting in coating microporous defects and reducing the anticorrosive properties. Thus, h-BN was modified through a two-step treatment, hydroxylation and silanisation. hBN modified by silane coupling agent 3-glycidoxypropyltrimethoxysilane (KH560) was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Then, the corrosion resistance of the BN-KH/epoxy resin coatings was measured by electrochemical testing. The results demonstrated that the corrosion current density of the coating with modified h-BN nanosheets was decreased from 2.67x10(-7) A center dot cm(-2) to 5.28x10(-8) A center dot cm(-2) compared with that of the pure epoxy resin. The impedance of the composite coating with modified hBN is 5.27x10(7) Omega center dot cm(2), approximately 20 times higher than that of the coating with the original h-BN (1.95x10(6) Omega center dot cm(2)) and the EP coating (4.26x105 Omega center dot cm(2)), indicating that BN-KH can protect the coating from damaging corrosive ions and that BN-KH/EP can maintain an excellent anticorrosion property.