The stationarity characteristics of electrochemical current noise

Abstract

The results of the electrochemical noise observations in 0H18N9 steel are presented. Current noise was obtained by potentiostatic measurements in aqueous solution of 0.1M H₂SO₄ and 0.06M Cl⁻. The recorded noise had an evident trend and peaks that are typically observed during pitting corrosion. The trend was removed by means of the third order polynomial approximation. The statistical hypothesis, i.e. the difference between the approximation and the observed noise, was tested. The results confirmed that current noise caused by pitting corrosion has nonstationary or weakly stationary character. The recorded noise was analysed using the Joint Time‐Frequency Analysis method, which is appropriate for nonstationary signals. The derived results confirmed the presence of pitting corrosion. It was usual for a few pits to form on the surface of the electrodes in distinct phases, and these were observed as peaks in current fluctuations.

Citation

Zielinski, A., Smulko, J., Krakowiak, A. and Darowicki, K. (2002), "The stationarity characteristics of electrochemical current noise", Anti-Corrosion Methods and Materials, Vol. 49 No. 1, pp. 27-32. https://doi.org/10.1108/00035590210413575