Experimental and theoretical study of corrosion inhibition performance of N-phenylthiourea for mild steel in hydrochloric acid and sodium chloride solution

The corrosion inhibition performance of N-phenylthiourea for mild steel in solutions of 1.0M hydrochloric and 3.5% wt. sodium chloride was investigated using tandem potentiodynamic polarization curves, scanning electron microscope analysis and quantum chemical calculations. The inhibition efficiency values of N-phenylthiourea in acidic solution and in salt solution were 94.95% and 55.70%, respectively. The results show that the corrosion inhibitor ability of N-phenylthiourea was better than that of urotropine under the same conditions. The adsorption of N-phenylthiourea on the mild steel electrode surface obeys the Langmuir adsorption isotherm in acidic solution and modified Langmuir adsorption isotherm in salt solution. The results of quantum chemical calculations and molecular dynamics simulations were found to be in accord with experimental data.