The inhibition effect of sulfathiazole (STZ) on the corrosion inhibition of mild steel in 1.0 M HCl solution was studied by polarization, EIS, weight loss measurements and quantum chemical calculation. It was found that the inhibitor was effective and the inhibition efficiency was significantly increased with increasing concentration. Polarization curves revealed that the used inhibitor represent mixed-type inhibitor. Adsorption of the inhibitor led to a reduction in the double layer capacitance and an increase in the charge transfer resistance, and was found also to obey Langmuir isotherm. A good correlation between theoretical data and experimental data has been obtained.
