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International Journal of Electrochemistry
Volume 2011 (2011), Article ID 152143, 8 pages
http://dx.doi.org/10.4061/2011/152143
Research Article

An Electrochemical Impedance Spectroscopic Study of the Passive State on AISI 304 Stainless Steel

Faculty of Engineering, Bu-Ali Sina University, Hamedan 65178-38695, Iran

Received 15 December 2010; Accepted 7 January 2011

Academic Editor: Sheng S. Zhang

Copyright © 2011 A. Fattah-alhosseini et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The passivity and protective nature of the passive films are essentially related to ionic and electronic transport processes, which are controlled by the optical and electronic properties of passive films. In this study, the electrochemical behavior of passive films anodically formed on AISI 304 stainless steel in sulfuric acid solution has been examined using electrochemical impedance spectroscopy. AISI 304 in sulphuric acid solution is characterized by high interfacial impedance, thereby illustrating its high corrosion resistance. Results showed that the interfacial impedance and the polarization resistance ( 𝑅 p o l ) initially increase with applied potential, within the low potential passive. However, at a sufficiently high potential passive ( 𝐸 > 0 . 4  V), the interfacial impedance and the polarization resistance decrease with increasing potential. An electrical equivalent circuit based on the impedance analysis, which describes the behavior of the passive film on stainless steel more satisfactorily than the proposed models, is presented.