Long-Term Oxidation Studies on Porous Stainless Steel 430L Substrate Relevant to Its Application in Metal-Supported SOFC

Abstract

Metal-supported solid oxide fuel cells (MS-SOFCs) can be used in portable mobile power generators due to their excellent thermal cycling performance, low cost, and strong mechanical strength. The selection and lifetime of the support material are crucial factors that affect the cell’s performance and long-term stability. The oxidizability of porous 430L stainless steel in a dry air atmosphere at 800 °C was systematically studied and reported for up to 1500 h. The aim was to investigate the lifetime of porous stainless steel as a support skeleton in a symmetric MS-SOFC. The substrates were characterized and analyzed using scanning electron microscopy, energy spectroscopy, and X-ray diffractometry after different periods of oxidation. The analysis indicated that the porous substrate’s surface oxides, under dry air conditions, consisted primarily of Fe2O3 and Cr2O3, with small amounts of Fe3O4 and MnCr2O4 spinel. The long-term oxidation process can be divided into two stages with distinct characteristics. However, the oxide flaking phenomenon occurred after 1500 h of exposure. The estimated service life of the stainless steel was consistent with the experimental results, which were around 1500 h. This estimation was based on the measured weight gain and thickness data.