Abstract
The effect of extract of cannabis plant on the corrosion of nickel in aqueous 0.5M sulphuric acid was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. EIS measurements showed that the dissolution process of nickel occurs under activation control. Potentiodynamic polarization curves indicated that the plant extract behaves as mixed-type inhibitor. The corrosion rates of nickel and the inhibition efficiencies of the extracts were calculated. The results obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of nickel in sulphuric acid media. Inhibition was found to increase with increasing concentration of the plant extract Theoretical fitting of different adsorption isotherms, Langmuir, Flory-Huggins, and the kinetic-thermodynamic model, were tested to clarify the nature of adsorption. Effect of temperature on the inhibitive action of cannabis extract for the corrosion of nickel in 0.5M sulphuric acid was investigated and the activation parameters of the corrosion process in absence and presence of cannabis extract were calculated.