Preparation and corrosion resistance of nano SiO₂-graphene oxide/epoxy composite coating

Graphene oxide (GO) was prepared by modified Hummers method, and nano SiO₂-GO was prepared by combining GO with nano SiO₂, which modified by silane coupling agent γ-aminopropyltriethoxysilane(KH550). The nano SiO₂-GO was characterized by FTIR, XRD, SEM and TEM. The nano SiO₂-GO was added to the epoxy resin(EP) coating by mechanical mixing and ultrasonic dispersion.The physical properties and electrochemical properties of the coatings with different mass fraction of nano SiO₂, GO and nano SiO₂-GO composites were tested. The results show that compared with the pure EP coating, the hardness, adhesion and corrosion resistance of nano SiO₂/EP, GO/EP and nano SiO₂-GO/EP are obviously enhanced. The hardness of the coating with 2wt% nano SiO₂-GO is 5 H, the adhesion grade reaches 1, and the protection efficiency is 99.33% after immersion 24 h. The results of 15 days immersion test show that the coating hardness of 1.5wt% nano SiO₂-GO/EP reaches 5 H, the adhesion grade is 1, and the protection efficiency still remain at 97.12%.