A Critical Appraisal of the Interpretation of Electrochemical Noise for Corrosion Studies

Abstract

In this paper, procedures and parameters that enable identification of, or discrimination between, general and localized corrosion processes through electrochemical noise are critically discussed. Their relevant similarities, differences, and interdependences are indicated. In addition, the relation between different procedures and parameters with the underlying physico-chemical processes is indicated. Consistent and reliable information can be obtained from electrochemical noise data when a data analysis procedure is selected, which on the one hand has a high discrimination ability and on the other hand yields a descriptive parameter that is directly associated to the underlying physico-chemical process. Procedures that meet these two requirements appear to be the Hilbert-Huang transform (Hilbert spectrum), wavelet transform (energy distribution plot), and the analysis of charge and frequency of corrosion events. In addition to the procedures that meet these two requirements, some of the descriptive parameters can be determined by different analysis procedures, which increase their reliability.

A Novel Approach for the Evaluation of Under Deposit Corrosion in Marine Environments Using Combined Analysis by Electrochemical Impedance Spectroscopy and Electrochemical Noise

“…metastable pitting) and a relatively slow process corresponds to larger timescales in the lower frequency domain (e.g. general corrosion) [66][67][68][69][70]. Therefore, in the present case, the translation of the discussed stages in the timefrequency domain will be as follows: (1) (Fig.…”

“…The Hilbert Huang Transformations (HHT) also operates in the timefrequency domain (although it has an empirical basis instead of an analytical one), however here a time resolution is added to this principle. By this way, it provides the ability to visualize the development of the energy distribution over time [70]. Distinct types of events in an EN signal can be classified according to their time constants in the EPN signal, indicating diffusion, activation or mixed controlled phenomena [66,67].…”

Quantification of the Atmospheric Corrosion of 304 and 2205 Stainless Steels Using Electrochemical Probes Based on Thevenin Electrochemical Equivalent Circuit Model

“…The application of EN technique requires proper data analysis [4][5][6], and the establishment of a reliable electrode system in the atmospheric environment [7,8]. The data analysis of EN can represent the characteristic parameters of the corrosion type and corrosion degree of metal materials through time domain analysis, frequency domain analysis, and time-frequency analysis [9,10].…”

Wavelet Transform Modulus Maxima and Holder Exponents Combined with Transient Detection for the Differentiation of Pitting Corrosion Using Electrochemical Noise

“…Although the measurement technique has remained largely unchanged, many different data analysis procedures have been proposed to extract the desired information [15]. Classical spectral analysis of EN can be done using the well-known Fourier transform, which can be regarded as the most direct way to estimate a power spectrum [1].…”