Electrodeposition of Ni–GNS–TiO2 nanocomposite coatings as anticorrosion film for mild steel in neutral environment

In this article nanocomposites of graphene nanosheets–anatase titanium dioxide (GNS–TiO2) were prepared via hydrothermal method. In this method graphene oxide (GO) was reduced to graphene nanosheets (GNS) simultaneously with anatase (TiO2) growth in situ on the graphene nanosheet (GNS) surface. The resulting GNS–TiO2 nanocomposite was characterized using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR). The percentage of TiO2 in the prepared GNS–TiO2 was determined by thermo gravimetric analysis technique (TGA). The fabricated GNS–TiO2 nanocomposite was codeposited with Ni by electrodeposition technique and used as a protective film for mild steel used in construction of steel silos. Different operating conditions for the deposition process were adopted to obtain Ni–GNS–TiO2 nanocomposite coatings with good morphological properties. The Ni–GNS–TiO2 nanocomposite coatings were characterized using a field emission scanning electron microscope (FE-SEM) and energy dispersive X-ray analysis (EDX). Moreover, Ni–GNS–TiO2 nanocomposite coatings were subjected to different electrochemical and mechanical tests to evaluate their corrosion behavior and hardness in comparison with that of pure Ni coating. It was found that the corrosion rate of the Ni–GNS–TiO2/mild steel electrodes decreases and the microhardness increases with increasing the wt.% of GNS–TiO2 nanocomposite in the prepared electrodes. The best corrosion resistance value of 33.1kΩcm2 and relatively high hardness value of 478HV were recorded for the composite coating electrode that contains 20.4wt.% GNS–TiO2 compared with the other composite coating electrodes or pure Ni coatings. [Display omitted] •GO was successfully prepared by Hummers method.•GO was reduced to GNS in situ with the formation of TiO2 nanoparticles.•GNS–TiO2 composite was co-deposited with Ni matrix by electrodeposition technique.•Presence of GNS–TiO2 in the Ni matrix improves the corrosion resistance.•GNS–TiO2 composite improves the microhardness of Ni matrix.