Using of asymmetric cell to monitor corrosion performance of 304 austenitic stainless steel by electrochemical noise method

Abstract

In this study, corrosion of 304 Austenitic stainless steel (ASS) with varies oxide layers, developed at two temperatures, is investigated by an asymmetric (Asy) cells in 0.05 M FeCl3 solution with time. Therefore, the Asy electrodes system is introduced to perform valuable data. Electrochemical current noise (ECN) signals resulting from the Asy cells are elucidated using the standard deviation of partial signals (SDPS) plot, the recurrence plot (RP), and the statistical procedure which derived from wavelet transform (WT) along with electrochemical impedance spectroscopy (EIS). The Asy electrodes indicated a high advantage and improved the detection of intergranular corrosion (IGC) on the 304 ASS alloy compared with the symmetric (Sym) ones. The trend of signals is eliminated, and then the disintegration of every signal is also performed into 10 crystals. Afterward, the standard deviation of every crystal is shown with the SDPS plots. Besides, ECN signals related to dissimilar crystal numbers are distinguished by the RP, based on the signals population. According to EIS measurements, the thickness of passive oxide layer of sample heated at 0–700 °C is decreased from 57 to 33 nm with immersion time, while it is increased from 9 to 27 nm for sample heated at 1100-700 °C.