Electrochemical noise studies on the effect of nitrogen on the pitting corrosion of stainless steel using wavelet analysis. (18th August 2022) - Upadhyay, Namrata
ABSTRACT: The effect of nitrogen on the pitting process is investigated using the electrochemical noise (EN) approach in 0.01 M FeCl3 for 24 h at a sampling frequency of 1 Hz. The EN signals were investigated using wavelet analysis on four alloys of 316L SS containing varying quantities of nitrogen (0.07, 0.12, 0.14 and 0.22 wt-% nitrogen). Using an energy distribution (ED) and standard deviation of partial signal (SDPS) plot, the primary corrosion process in various nitrogen-containing 316L SS was found. The ED plot showed that as the nitrogen percentage in the alloy increased, the energy of the low-frequency signal decreased, indicating that long-time transients were suppressed. The SDPS figure revealed a drop in pit density as nitrogen levels increased. For specimens containing 0.07, 0.11, 0.14 and 0.22 wt-% nitrogen, the pit density was determined to be 439 ± 8, 383 ± 6, 212 ± 6 and 108 ± 4 pits mm −2, respectively.