Exploring the resistance of C38 steel by a new bisimidazole derivative as corrosion inhibitor: Experimental and theoretical studies

The protective efficiency of a new bisimidazole compound, namely 1,2-bis(2-(1Hbenzo(bisimidazol-2-yl)thio)ethoxy)ethane (BBT2E), was studied for C38 steel submerged in 1 M hydrochloric acid.The synthesized molecule was characterized using proton nuclear magnetic resonance ( 1 H NMR), carbon-13 nuclear magnetic resonance ( 13 C NMR) and infrared spectroscopy (IR).The corrosion resistance was evaluated by two electrochemical methods: potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS).The results reveal that the studied molecule provided 97.8% protection efficiency at 10 -4 M. Scanning electron microscopy coupled with energy-dispersive X-ray analysis reveals the presence of the inhibitor on the metal surface.Moreover, an isothermal study shows that the Langmuir model is the most suitable for this molecule.The studied molecule creates a protective layer that forms an obstacle and prevents aggressive agents from penetrating to the substrate surface.A theoretical study by DFT quantum physical chemistry calculations and molecular dynamics simulations was utilised to confirm the experimental results.