In this study, the inhibition effect of 3-phenyl-1H-pyrazole-4-carboxaldehyde (PP4C) on mild steel corrosion in 1.0 M HCl solution was studied. For this aim, electrochemical techniques such as potentiodynamic polarization (PDP) curves, electrochemical impedance spectroscopy (EIS) and weight loss (WL) were used. It was shown that, the PP4C has remarkable inhibition efficiency on the corrosion of mild steel in 1.0 M HCl solution. Polarization measurements indicated that the studied inhibitor acts as mixed type corrosion inhibitor. The inhibition efficiency depends on the concentration of inhibitor and reaches 96.33% at 5 mM PP4C. The remarkable inhibition efficiency of PP4C was discussed in terms of blocking of electrode surface by adsorption of inhibitor molecules through active centers. The adsorption of PP4C molecules on the mild steel surface obeys Langmuir adsorption isotherm. The adsorption characteristics of PP4C were theoretically evaluated by DMol3 method and confirm distinct adsorption of the inhibitor matter on the mild steel surface.
Keywords: Corrosion inhibition; Mild steel; EIS, 3-phenyl-1H-pyrazole-4-carboxaldehyde; DMol3