Enhanced Corrosion Protection of Mild Steel Using a Sn-Graphene Oxide Composite Coating

Sn-graphene oxide (Sn-GO) composite coatings were electrodeposited on mild steel to improve the corrosion resistance of tin-based protective layers. Graphene oxide was synthesized and characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), confirming its characteristic structural features and oxygen-containing functional groups. The electrodeposition parameters, including current density, graphene oxide concentration, and deposition time, were investigated using an experimental design methodology. The corrosion behavior of the coatings was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements in a 3.5% NaCl solution. The Sn-GO coating obtained under the best-performing conditions (0.125 g L^-1 GO, current density of 10.0 mA cm^-2, and deposition time of 30 min) exhibited improved morphology and enhanced anticorrosive performance compared with pure tin deposits. Electrochemical results showed a significant increase in charge transfer resistance, from 3834 Ω cm² for metallic tin to 13149 Ω cm² for the Sn-GO composite coating. These results demonstrate that the incorporation of graphene oxide, combined with appropriate electrodeposition parameters, leads to composite coatings with improved barrier properties and corrosion resistance, highlighting the potential of Sn-GO coatings as promising protective materials for industrial applications.