Actonel, Fosamax, Etidron as Save Corrosion Inhibitors for Carbon Steel in Hydrochloric Acid Solutions

The inhibiting effect of some pharmaceutical drugs on the corrosion of carbon steel in 0.5M HCl was studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), electrical frequency modulation (EFM) and surface examination using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. The results of weight loss showed that the inhibition efficiency increases with increasing the inhibitor concentration, while it decreases with increasing the temperature. Potentiodynamic polarization studies have shown that these compounds suppress both the cathodic and anodic processes and thus acted as mixed-type inhibitors. The adsorption of these compounds on carbon steel surface was found to follow the Langmuir isotherm. The effect of temperature on corrosion inhibition has been studied and thermodynamic activation and adsorption parameters were calculated and discussed.