Hybrid silane coating reinforced with silanized graphene oxide nanosheets with improved corrosion protective performance

Silane coating has been used as a steel surface treatment for the promotion of adhesion between a substrate and an organic coating. However, the corrosion protection properties of this coating are not sufficient. Incorporation of various additives and nano-fillers into the coating is a promising way to improve the coating barrier action. In this paper a new nano-filler based on graphene oxide is recommended for this type of coating. The graphene oxide is silanized in the first step through a sol-gel route by using aminopropyl triethoxysilane (ATPES). Then, it is employed in a hybrid silane coating based on the mixture of aminopropyl triethoxysilane and tetraethyl orthosilicate (TEOS). The graphene oxide functionalization was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The silane coatings filled with silanized and untreated graphene oxide were also characterized by FT-IR, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results obtained from different characterizations showed successful silanization and dispersion of graphene oxide in the silane hybrid coating. The silane coating containing silanized graphene oxide showed superior corrosion protective performance compared to the unfilled silane coating in electrochemical impedance spectroscopy (EIS) and polarization measurements, indicating the considerable corrosion barrier effect of this nano-filler.