A facile route of making silica nanoparticles-covered graphene oxide nanohybrids (SiO2-GO); fabrication of SiO2-GO/epoxy composite coating with superior barrier and corrosion protection performance

This study reports two facile routes for the synthesis and characterization of silica nanoparticles-decorated graphene oxide (SiO2-GO) nanohybrids by a two-step in-situ sol-gel process using a mixture of 3-Aminopropyl triethoxysilane and Tetraethylorthosilicate in water-alcohol solution. Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) were employed for the SiO2-GO nanohybrids characterization. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were employed to characterize the SiO2 nanoparticles precipitation on the surface of GO sheets. FT-IR, XPS, AFM, FE-SEM and TGA analyses revealed that fine nanometric SiO2 particles (<20 nm) covered the surface of GO sheets. X-ray diffraction and FE-SEM analyses showed better dispersion of SiO2-GO nanohybrids in the epoxy coating than pure GO. The effect of SiO2-GO nanohybrids on the corrosion protection and barrier performance of the epoxy coating was investigated by electrochemical impedance spectroscopy (EIS). Results revealed that SiO2-GO nanohybrids significantly enhanced the barrier and corrosion protection properties of the epoxy coating. It was also shown that SiO2-GO nanohybrids significantly reduced the cathodic delamination rate of epoxy coating. (C) 2016 Elsevier B.V. All rights reserved.