Synergistic Effect of Imidazoline Derivative and Benzimidazole as Corrosion Inhibitors for Q235 Steel: An Electrochemical, XPS, FT-IR and MD Study

The corrosion inhibition effect and synergistic mechanism of novel imidazoline derivative (SMIF) and benzimidazole (BMZ) in 3.5 wt% simulated concrete solution were studied experimentally and theoretically. The complex inhibitors have the most outstanding inhibition efficiency when SMIF concentration is 0.1 g/L and BMZ is 0.9 g/L, the corrosion inhibition efficiencies of weight loss, Electrochemical Impedance Spectroscopy and Potentiodynamic polarization curve (Tafel) were 88.81%, 86.27% and 90.22%, respectively. Electrochemistry analysis results proved that the corrosion inhibition mechanism of the inhibitors in the corrosion solution was mainly the formation of a protective film on the surface of carbon steel. FT-IR, Energy Dispersive Spectroscopy and X-ray Photoelectron Spectroscopy all proved the existence of the protective film. Molecular dynamics proved that the composite inhibitor molecules could be stable on the surface of carbon steel and when consist of complex inhibitor was 0.1 g/L SMIF and 0.9 g/L BMZ the stable adsorption morphology were the highest. This work confirmed that SMIF and BMZ inhibitors have a good synergistic effect, greatly improving the inhibition efficiency and reducing the cost of corrosion inhibition, and has a certain guiding significance for synergistic inhibition.