Investigation of the Inhibition of the Corrosion of carbon steel in Solution of HCl by Glimepiride

Abstract

The corrosion inhibition effect of glimepiride (GMP) on the corrosion of X70 carbon steel in 1 M HCl solution was investigated using weight loss, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) techniques. The inhibition efficiency was found to increase with increase in inhibitor concentration but decreased with temperature rise. The inhibition efficiency of glimepiride ranged from 54.2 to 95.8% for weight loss measurement, 52.0 to 90.5% for PDP and 53.3 to 90.3% for EIS method at 303 K. Polarization studies give evidence that GMP behaves as a mixed type inhibitor but predominantly anodic. Electrochemical impedance spectroscopy (EIS) spectra exhibit one capacitive loop indicating that, the corrosion reaction is controlled by charge transfer process. It was found that the investigated drug acts via adsorption on the carbon steel surface and obeys Langmuir and Temkin adsorption isotherms. Surface studies ascertain that a protective film was formed on the X70 carbon steel surface. The results have clearly shown that glimepiride has the inhibiting capacity for reducing the corrosion of X70 carbon steel in HCl solution.