Comparison of electrochemical current noise signals arising from symmetrical and asymmetrical electrodes made of Al alloys at different pH values using statistical and wavelet analysis. Part II: Alkaline solutions

Evaluation of the localized corrosion on Mg electrode surface by electrochemical noise technique

“…Further studies reveal that in addition to the maximum position of the SDPS diagram, another way of detecting the dominant transients is to compare the original signal with the partial signals. [29,37] The partial signal of the d6 crystal is shown in Figure 3a, which indicates that there is a dominant beat in the time range of about 550 s. The main signal in the time range of 550 s (Figure 3b) comprises the overlapping transients with a smaller time scale. However, consideration of the smaller partial signals determined that d2 and d3 transients were single transients.…”

“…Therefore, the aim of utilizing asymmetric electrodes is to improve the noise detection and prevent signal overlapping. [29,37] The great skewness of the asymmetric electrode current signals is due to the unidirectionality of the signals ( Table 1). The unidirectionality of the signals results from carrying out the anodic and cathodic reactions on the small and the large electrodes, respectively.…”

“…The SDPS diagrams of the ECN signals are shown in Figure 2. As mentioned in the previous works, [29,33,40] the SDPS diagram has the potential of characterizing the dominant transients of each signal according to the situation of the maximum peak in the diagram. Figure 2 illustrates that the maximum peak in the SDPS diagram of the LS signal has appeared at the d6 crystal position.…”

“…[28] EN assessments are commonly performed using two working electrodes (WEs) whose connection is provided through a zero-resistance ammeter (ZRA), which monitors the coupling current of inter-WEs. [29][30][31] Although two similar WEs (equal size and type) setting a symmetrical cell are commonly used to measure the electrochemical current noise (ECN), [32] current research indicates that asymmetric cell configuration using considerably different sizes of two WEs that can be otherwise identical will be preferable in measuring ECN on Al and mild steel alloys. [29,30,33,34] The authors did not find any paper about the efficiency of asymmetrical Mg electrodes (different size, equal type) in the measurement of ECN after exact reviewing of the relevant literature in this subject.…”

A study on synergistic effect of chloride and sulfate ions on copper corrosion by using electrochemical noise in asymmetric cells

“…A cell having two similar working electrodes (WEs) was called symmetrical (Sym) cell, with identical materials, sizes and surface preparation, these WEs connected with a zero-resistance ammeter (ZRA) coupling current between the electrodes 36 . Recent evidences have revealed that asymmetrical (Asy) cells having WEs with quite different sizes improve noise detection because the phenomena on one electrode are recorded 27 , 33 , 34 , 37 . These cells are capable of keeping time width in the SDPS plot, increasing the EN current transient amplitude, and preventing the recording of excess signals produced in Sym cells.…”