Abstract
The corrosion behavior of pure iron in naturally aerated stagnant solutions of 3.5% NaCl and its inhibition by 1,1’-thiocarbonyldiimidazole have been reported. The study was carried out using open-circuit potential, cyclic potentiodynamic polarization, potentiostatic current-time, and electrochemical impedance spectroscopy measurements. The corroded and inhibited iron surfaces were characterized by in-situ Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray investigations. Results obtained revealed that the addition of the inhibitor decreased the pitting and uniform corrosion reactions of iron in aerated 3.5% NaCl solutions. This effect was found to increase by increasing the concentration of the inhibitor from 0.5 mM to 2.0 mM due to the adsorption of its molecules onto iron preventing the formation of ferrous and ferric chlorides and blocking flawed areas on the electrode surface. The adsorption of the inhibitor molecules onto the iron surface was confirmed by scanning electron microscope, energy dispersive X-ray and in-situ Raman spectroscopy investigations.