In order to improve the corrosion resistance of waterborne epoxy coatings,SiO2/reduced graphene oxide nanosheet(rGOS)was synthesized through a soft template method.Encapsulating the graphene with SiO2 not only inhibited the corrosion-promotion activity of graphene,but also realized self-unfolding of graphene.Waterborne epoxy coatings reinforced with rGOS(rGOSc)were prepared by embedding appropriate amounts of rGOS in waterborne epoxy coatings.The scanning electron microscope(SEM),infrared spectroscopy,and X-ray photoelectron spectroscopy(XPS)were utilized to analyse the structure and morphology of rGOS.The corrosion resistance of rGOSc was studied through the potentiodynamic polarization curve,electrochemical AC impendence spectroscopy and scratching test.Results indicated that,unlike the rGO that with a large number of crumples and folds,the rGOS-10.0 sample(GO:TEOS=0.3 g:10 mL)had a high diameter-to-thickness ratio and a special unfolded flake morphology.When used as an anti-corrosion filler,the rGOS-10.0 could extend the diffusion path of corrosive medium in coating substrate effectively,thus improving the impermeability of the coating.The rGOSc with 0.5%(mass fraction)rGOS-10.0 had a corrosion resistance 93.8%higher than that of blank epoxy coating,and could protect the metal matrix immersed in 3.5%(mass fraction)NaCl solution for 30 days from corrosion, showing an excellant anti-corrosion performance.
