Electrochemical Potential Noise Analysis of 304 Stainless Steel Weld Zone Exposed to Alkaline Solutions by Different Parameters

摘要

The electrochemical potential noise (EPN) of 304 stainless steel (SS) weld zone in boiling 50%NaOH solution were studied, in order to monitor stress corrosion cracking (SCC). Several EPN parameters were extracted from time domain, frequency domain and statistical analysis. The results showed its corrosion potential appears a downward trend during the experiment. When localized corrosion cracks initiation, amplitude was large and termination appeared. A high frequency plateau appeared using the Fast Fourier Transform (FFT) method in the power spectrum densities (PSD)s, and its standard deviation was larger, indicating the variation of corrosion state. Moreover, Visual records and frequency of events (fn) were discussed. Its fn can distinguish the different state of specimens. EPN shows considerable promise for detecting localized corrosion. Further development work is expected to lead to a useful, for real time detection of localized corrosion.