Electrochemical Impedance Spectroscopy of Oxide Layers on the Titanium Surface

The method of electrochemical impedance spectroscopy is used to study oxide layers formed at the titanium surface by a variety of methods. The sample’s polarization permitted the isolation, in an impedance spectrum, of the response caused by the capacitance of the space-charge region, which obeys the Mott-Schottky dependence. It is established that the high-frequency portion of an impedance spectrum is defined by morphological peculiarities of the porous portion of coatings. Assumptions, concerning the nature of a time constant, which reveals itself in the region of low frequencies at polarizing biases, are made. Equivalent circuits, intended for modeling impedance spectra, are proposed. The circuits take into consideration the effect of the space-charge region, as well as the peculiarities of the structure and morphology of the oxide film formed at the titanium surface.__________Translated from Elektrokhimiya, Vol. 41, No. 8, 2005, pp. 963–971.Original Russian Text Copyright © 2005 by Gnedenkov, Sinebryukhov.