Formation and rupture of carbonate film: an electrochemical noise approach

Abstract

Purpose

The purpose of this paper is to evaluate advanced mathematical electrochemical noise analysis (ENA) as a way of corrosion monitoring for carbon steel.

Design/methodology/approach

The electrochemical potential/current noise was recorded simultaneously with a working‐reference‐working electrode set up and the processing of data was performed through fast Fourier transformation (FFT) and wavelet transformation (WT) routes. The formation and rupture of carbonate films on St37 steel electrodes in a 0.5 M sodium bicarbonate electrolyte was studied for 20 h utilizing an electrochemical noise approach.

Findings

Although the slope of mid‐range of noise impedance exhibited a mechanistic style, and increased with film formation and decreased with film rupture, FFT of potential noise was more sensitive to film formation and rupture. WT of potential noise depicted that ν=1.41 × 10⁻² Hz was the boundary frequency in the film formation. At frequencies higher than the mentioned limit, the fraction of distributed potential decreased with time. However, the opposite behavior was observed during the rupture of the film.

Originality/value

The preliminary results show that the proposed novel electrochemical method, wavelet and FFT ENA, is very able to monitor the corrosion behavior of carbon steel corrosion in carbonate media.

Citation

Attarchi, M., Mazloumi, M., Sadrnezhaad, S.K., Jafari, A. and Asadi, M. (2009), "Formation and rupture of carbonate film: an electrochemical noise approach", Anti-Corrosion Methods and Materials, Vol. 56 No. 2, pp. 103-109. https://doi.org/10.1108/00035590910940096