Electrodeposition and corrosion behavior of Sn and Sn-reduced graphene oxide coatings on mild steel from the non-cyanide acid chloride bath solution

Abstract

Reduced graphene oxide (rGO) derived from graphite has received attention among researchers because of its special unique characteristic properties. Based on the studies, rGO-based coatings on stainless steel (SS) act as an anti-corrosive protective coating on stainless steel. Herein, we prepared a few layered rGO via graphite oxide by a simple thermal exfoliation of graphite oxide. Tin and Sn-rGO coatings have been electrodeposited on SS using an optimized acid chloride bath composition in the absence and presence of rGO respectively. The prepared specimens were subjected to an aggressive corrosive environment (aqueous 5% NaCl). The corrosion behavior of Sn and Sn-rGO composite coating has been examined by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) techniques. The potential shifted towards the negative region after polarization for Sn-rGO composite coating compared to pure Sn coating. Also, Sn-rGO composite coating exhibits more resistance when subjected to EIS measurements in 5% NaCl. The change in the surface morphology of coatings before and after exposure to corrosive environments has been observed by Scanning electron microscopy. After exposure to aqueous 5% NaCl, Sn coated specimen exhibited pores on the SS surface whereas fewer pore structures were observed on the SS surface for Sn-rGO coating. The results reveal a significant increase in anti-corrosion properties of Sn-rGO on SS compared to that of pure Sn coating.