Evaluation of an Expired Non-Toxic Amlodipine Besylate Drug as Corrosion Inhibitor for Low Carbon Steel in Hydrochloric Acid Solutions

A.S. Fouda*¹, M. S. Motawee², H. S. Megahid², H. A. Abdul Mageed¹
Chemistry Department, Faculty of Science, Mansoura University, Mansoura-35516, Egypt.

A B S T R A C T
Inhibition of low carbon steel corrosion by Amlodipine Besylate in 1M HCl was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) & electrochemical frequency modulation (EFM) measurements. The inhibition efficiency (%IE) increased with increase in inhibitor concentration but deceased with rise in temperature. The thermodynamic parameters of corrosion and adsorption processes were determined and discussed. The adsorption of these inhibitors was found to obey Langmuir adsorption isotherm. The results obtained from the three different techniques were in good agreement. Quantum structure-activity relationships have been used to study the effect of molecular structure on inhibition efficiency of the inhibitors. The surface morphology of carbon steel sample was investigated by scanning electron microscopy (SEM).
Keywords: Corrosion inhibition, low carbon steel, HCl, Amlodipine Besylate