MEASURING CORROSION RATE OF TYPE 304 STAINLESS STEEL IN SUBCRITICAL AND SUPERCRITICAL AQUEOUS SOLUTIONS VIA ELECTROCHEMICAL NOISE ANALYSIS

摘要

Electrochemical noise (EN) sensors have been developed to measure the corrosion rate of Type 304 steel (SS) in subcritical and supercritical environments. The potential and coupling current noise were recorded simultaneously and the noise resistance (R_n) was calculated from the standard deviations in the potential and current records. We found that the inverse noise resistance correlated very well with the corrosion rate evaluated from separate mass loss experiments, and that both the inverse noise resistance and the average corrosion rate were functions of temperature and flow rate. In the temperature range from 200 to 390°C, the corrosion rate was found to be proportional to the inverse noise resistance and hence the Stern-Geary relationship can be used to evaluate the corrosion rate.