Molten Salt Corrosion Evaluation of Alloy T22 Applying Electrochemical Techniques and the Conventional Weight Loss Method

摘要

High temperature corrosion tests were made to study the alloy T22 exposed to 80 V_2O_5-20Na_2SO_4 (wt. %) at 550 and 650°C, applying the electrochemical noise technique (EN) during 5 days, potentiodynamic polarization curves (PC), and the conventional weight loss method (WL). From the current and potential time series, it was stated that the type of corrosion suffered by the alloy T22 was mixed corrosion (uniform-localized). Through EN results, a statistical analysis was made to determine the localization index LI, and the resistance noise Rn, which was used to calculated the corrosion kinetics. A comparison of the corrosion rates obtained from EN and WL is presented. This comparison showed the same qualitative results with a difference of one order of magnitude. Visual characterization of alloy T22 was in agreement with the noise pattern and the localization index (LI). Polarization curves demonstrated that the corrosion potential was more active with the temperature.