Effect of regularly arranged reduced graphene oxide on the anti-corrosion performance of waterborne silicate zinc-rich coatings

ABSTRACT The effect of a barrier layer composed of reduced graphene oxide (rGO) with edge adsorption of K+ (rGOK+) on anticorrosive performance was investigated. Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), DC polarisation technique and electrochemical impedance spectroscopy (EIS) were used to investigate the morphology, corrosion product, corrosion mechanism and process. XPS results show that the corrosion products are ZnCl2, Zn(OH)2, ZnCO3 and Zn5(OH)8Cl2. SEM, energy-dispersive spectrometer (EDS), polarisation curve and EIS show that the coating with the most rGOK+ not only builds a barrier layer but also improves the utilisation of zinc powder, thereby providing better corrosion protection for the substrate despite the 30% reduction in zinc powder usage.