Potential - Modulated Reflectance Study of the Iron in Alkaline Solution

K. S. Khairou and I. Zaafarany

Chemistry Department, Faculty of Applied Sciences, Umm Al-Qura University, Makkah Al Mukarammah P. O. Box: 118 (Saudi Arabia).

Cyclic voltammetry and potential modulated reflectance techniques have been used to study the growth of surface films on iron electrodes in alkaline solution. There are still uncertainties about the structure of the passive film or iron. In this article, it is possible to clearly see the relationship between electrode potential and the change of the surface layer structure - particularly when using modulation spectroscopy. It has been suggested, from the results obtained, that in sweeping from hydrogen evolution to oxygen evolution a of processes take place, altering the composition of the surface film; the composition of the surface film being a combination of Fe(II), Fe(III) and Fe(VI) in the transpassive region.

Iron; passivity; potential-modulated reflectance