Transient analysis through Hilbert spectra of electrochemical noise signals for the identification of localized corrosion of stainless steel

• Published in: Electrochimica acta 2013-08, Vol.104, p.84-93
• Main Authors: Homborg, A.M., Tinga, T., Zhang, X., van Westing, E.P.M., Oonincx, P.J., Ferrari, G.M., de Wit, J.H.W., Mol, J.M.C.
• Format: Article
• Language: English
• Subjects: Austenitic stainless steels; Corrosion identification; Corrosion mechanisms; Data processing; Electrochemical noise; Hilbert spectra; Localized corrosion; Spectra; Stainless steels; Transient analysis
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2013.04.085

•Hilbert spectra allow selection of instantaneous frequencies of corrosion phenomena.•Advanced data analysis distinguishes valuable frequency information from artefacts.•Advanced data analysis prevents domination of the analysis by the largest transient.•Improved definition of frequency characteristics of localized corrosion mechanisms. Hilbert spectra allow identification of instantaneous frequencies that are attributed to specific corrosion mechanisms in electrochemical noise data. The present work proposes to identify and analyze areas of interest in Hilbert spectra, which enables to obtain valuable frequency information from electrochemical noise signals. Experiments were performed on AISI304 exposed to aqueous HCl solutions at different pH values resulting in either distinct general or localized attack. Results indicate that application of the proposed transient analysis to Hilbert spectra provides a significantly improved determination of the frequency characteristics of the electrochemical noise signals compared to time–frequency data analysis without transient analysis.