Analysis of Electrochemical Noise with Wavelet Transform
X. F. Liu, H. G. Wang, S.J. Huang, Hanwen Gu · CORROSION · 2001
Wavelet transform is a new technique to analyze signals and images, and it can reveal the local and global features of signal and image from different aspects. In this study, the electrochemical potential noises measured on Al 7075-T76 (UNS A97075) in 3.5% sodium chloride (NaCl) solution containing different inhibiting pigments were analyzed with a wavelet transform from time-frequency analysis and detection of abrupt transition. Wavelet transform decomposed the electrochemical noise signal into a series of components in time-frequency domain to reveal the characteristics of the potential noise in detail. It was convenient to distinguish the inhibiting effects of these pigments and corrosion processes on the surface. The finding agreed with the results of electrochemical polarization and immersion studies. The accurate onset time of localized corrosion was detected by examining the module maximums of wavelet transform coefficients, which represented the signal characteristic.