Benfotiamine as eco-friendly corrosion inhibitor for mild steel in molar hydrochloric acid media, experimental and theoretical approach

The effect of eco-friendly S-benzoylthiamine O-monophosphate (BFT) on Mild steel substrates in 1M HCl medium has been studied by integrating electrochemical methods, SEM/EDX characterization, together with theoretical modeling. Results showed that BFT provides effecient corrosion protection toward mild steel exposed to 1M HCl, exceeding an inhibition efficiency level above 90% at 500 ppm, the electrochemical response suggests that the inhibitor influences the anodic as well as the cathodic reactions, which is characteristic of a mixed-type inhibition mechanism. Electrochemical impedance spectroscopy (EIS) revealed that the diagrams had single loop, whose sizes increased with BFT content, suggesting that it forms an adsorbed surface layer. In addition, the inhibitor exhibited limited sensitivity to temperature variations, while the polarization resistance showed a progressive increase during immersion. SEM/EDX analysis supported the electrochemical measurements results by showing the formation of an adsorbed layer. DFT calculations and MD simulation were employed to clarify the adsorption properties of BFT and the η% obtained for MS corrosion was in line.