Surface and corrosion study on electroreduced graphene oxide nanosheets-coated carbon steel in NaCl 3.5 %

Electrochemical reduction of graphene oxide on a carbon steel electrode leads to the formation of reduced graphene oxide nanosheets (RGON). The samples were characterized using FT-IR, Raman, XRD, EDXA, SEM and TEM techniques. The anticorrosion properties were proven by electrochemical methods such as open circuit potential (OCP), potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS) in NaCl 3.5 %. Moreover, parameters affecting film formation and consequently anti-corrosion performance, such as deposition time and applied voltage, were optimized. Results showed that covering the surface with RGON led to hinder the corrosion reaction (negative shift in the corrosion potential, a decrease in the slope of the cathodic and anodic reactions, a decrease in current density and corrosion rate, and an increase in charge transfer resistance). After applying 12 V during 180 s, the formed layer showed the best corrosion protection (the lowest corrosion current density and corrosion rate, and the highest charge transfer resistance). The morphology of the uncoated and coated surface after 72 h immersion in NaCl 3.5 %, was studied using SEM and EDXA techniques. (author)