The Inhibition Of Carbon Steel Corrosion In Hydrochloric Acid Media Using 2-[(5-Methyl-Isoxazol-3-Yl)-Methyl]-Benzimidazole

Carbon steel corrosion inhibition in a hydrochloric acid solution by 2-[(5-methy-lisoxazol-3-yl)-methyl]-benzimidazole (MMB) has been studied by electrochemical techniques (PDP and EIS). Results showed that the inhibition efficiency increases with higher MMB concentration, and the maximum value of 86.6% was obtained at 10(-3) M concentration. The prepared benzimidazole inhibitor showed higher inhibition efficiency upon raising the solution temperature from 303 to 333 K. Corrosion current density decreased from 660.9 mu A cm(-2) (blank) to 97.8 mu A cm(-2) (MMB) and charge transfer resistance increased from 20.2 Omega cm(2) (blank) to 150.8 Omega cm(2) (MMB). PDP studies showed that MMB is a mixed type inhibitor. The adsorption of this compound onto the carbon steel surface in a 1 M HCl solution followed the Langmuir adsorption isotherm, and the value of the standard free energy of adsorption (Delta G(ads)degrees) is associated to physisorption and chemisorption.