In-Situ Study of Single and Double Loop Reactivation Methods During the Characterisation of the Degree of Sensitisation of a Duplex Stainless Steel (UNS 1.4462) Using a Minicell and a Confocal Microscope

Abstract

[EN] The aim of this work is to study the evolution of the electrode surface during the single and double reactivation methods at microscopic scale. The tested material has been a duplex stainless steel (UNS 1.4462) in its as-received state and heated at 825 degrees C for 1 hour in an inert atmosphere. Tests have been carried out in an electrochemical minicell that can be put in the stage of a confocal microscope. These devices allow the in-situ observation of the electrode surface at microscopic scale during the tests. Differences in the evolution of the electrode surface have been observed between the single and the double loop methods. Furthermore, the sensitised sample shows different evolution during the electrochemical tests than the as-received sample. These differences are due to the formation of new phases during the heat treatment. Therefore, the minicell permits obtaining additional information during the electrochemical characterisation of the degree of sensitisation in duplex stainless steels.