engleski

Corrosion Inhibition of Armco Iron in Hydrochloric Acid Solution by New Imidazole Derivatives

The study of 1-penthyl-3-methyl imidazolium hexafluorophosphate, [C5-MIm]^+[PF6]^-, as inhibitors for iron corrosion in 1 M HCl solution at 25 ◦C was carried out. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were applied to study the metal corrosion behaviour in the absence and presence of different concentrations of this inhibitor under the influence of various experimental conditions. Measurements of open circuit potential (OCP) as a function of time till reaching the steady-state potentials (Est) were also established. The studies have shown that [C5-MIm]^+[PF6]^- was the efficient inhibitor reaching values of inhibition efficiency (IE%) up to 71.5 % at a concentration of 5 x (10)^−3 M. The process of inhibition was attributed to the formation of adsorbed film on the metal surface that protects the metal against corrosive agents. The results of EIS and polarization curves demonstrated that films of the [C5-MIm]^+[PF6]^- were able to protect iron from corrosion effectively. The protection efficiency increased with increase in inhibitor concentration. The potential of zero charge (PZC) of iron in HCl solution as function of pH was determined, and a mechanism of adsorption process was proposed. The effect of chemical structure of the inhibitor was discussed.

Armco iron; Hydrochloric acid; Corrosion inhibition; Imidazole; Electrochemical techniques

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