关键词:

电化学噪声, 检测, 不锈钢, 焊缝, 碱性腐蚀

Abstract:

Electrochemical noise was used to detect the corrosion process of the weld zone of 304 stainless steel（SS）in 50% NaOH solution at boiling point, its morphology was observed and its characteristic parameters were analyzed.The result showed that the weld’s corrosion potential dropped from -445 mV to below -560 mV during the experiment.When localized corrosion cracking was initiated, the amplitude was large and termination appeared.A high frequency plateau appeared in the power spectrum by use of the fast fourier transform（FFT）and high frequency roll-off slope K >-20 dB·dec^-1 in the power spectral density (PSD) plot.Electrochemical noise of 304SS specimens at room temperature in 50% NaOH solution showed that different specimens had different corrosion potentials and electrochemical potential noise time spectra.The noise was produced by fluctuations in the electrochemical process and larger fluctuations would typically be indicative of a more localized process.Moreover, the use of the roll-off slope K in the PSD plot could detect whether the localized corrosion occurred or not.Further development work is expected to lead to a useful, real time detection of localized corrosion.

Key words:

电化学噪声, 检测, 不锈钢, 焊缝, 碱性腐蚀