Oxidation of porous stainless steel supports for metal-supported solid oxide fuel cells

Oxidation behavior of porous P434L ferritic stainless steel, used for the fabrication of metal-supported solid oxide fuel cells (MS-SOFC), is studied under anodic and cathodic atmospheres. Temperature- and atmosphere-dependence is determined for as-sintered and pre-oxidized stainless steel. Pre-oxidation reduced the long-term oxidation rate. For preoxidized samples, the oxidation rate in air exceeds that in humid hydrogen for temperatures above 700 degrees C. The influence of PrOx, LSCF-SDC, and Ni-SDC coatings is also examined. The coatings do not dramatically impact oxide scale growth. Oxidation in C-free and C-containing anodic atmospheres is similar. Addition of CO2, CH4, and CO to humidified hydrogen to simulate ethanol reformate does not significantly impact oxidation behavior. Cr transpiration in humid air is greatly reduced by the PrOx coating, and a PrCrO3 reaction product is observed throughout the porous structure. A dense and protective chromiabased scale forms on steel samples during oxidation in all conditions. A thin silica enriched oxide layer also forms at the metal-scale interface. In general, the oxidation behavior at 700 degrees C is found to be acceptable. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.