Wavelet Analysis of Electrochemical Noise Data

Abstract In this study, the electrochemical noise produced by general and localized corrosion (pitting) in the coupling current between identical electrodes of ASTM A516 steel in 5M NaOH with or without added chloride ion was examined using Wavelet analysis (WA) as a means of differentiating between the two forms of attack. It was found that, under pitting corrosion conditions (the presence of 0.1M Cl-), there was no high-frequency energy contribution seen, but there was an energy contribution of the low-frequency crystals. Additionally, visual time domain examination of the crystals produced by WA shows the individual contributions that were made by each frequency range toward events in the original signal. This allows for the identification of the onset and termination of individual corrosion types.