Abstract The inhibition effect of 1-methyl-1H-imidazole-2-thiol (MTI) on the corrosion of mild steel in 1 M HCl, 3M HCl, 0.5 M H2SO4 and 1.5 M H2SO4 solution was investigated electrochemical methods (potentiodynamic polarization curves, resistance polarization and electrochemical impedance spectroscopy). The results show that MTI is a very good inhibitor, and is more efficiency in 1 M HCl than the other medium. The ordere is 1 M HCl> 0.5 M H2SO4 >3M HCl > 1.5 M H2SO4. The adsorption of MTI on mild steel surface obeys Langmuir adsorption isotherm for 1 M HCl, 3M HCl and 0.5 M H2SO4, and El Awady kenetic-thermodynamic isotherm for 1.5 M H2SO4. Polarization curves reveal that MTI acts as a mixed-type inhibitor in both acids. The adsorption mechanism is discussed.
Keywords acid medium, mild steel, corrosion, inhibition.