Enhancement of the Anticorrosion Properties of Epoxy Resin Composites through Incorporating Hydroxylated and Silanised Hexagonal Boron Nitride (h-BN)
Jiansan Li, Xiangqi Huang, Jinye Bi
Abstract
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. h-BN 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 2.67×10-7 A • cm-2 to 5.28×10-8 A • cm-2 compared with that of the pure epoxy resin. The impedance of the composite coating with modified h-BN is 5.27×107 Ω·cm2, approximately 20 times higher than that of the coating with the original h-BN (1.95×106 Ω·cm2) and the EP coating (4.26×105 Ω·cm2), indicating that BN-KH can protect the coating from damaging corrosive ions and that BN-KH/EP can maintain an excellent anticorrosion property.