High temperature oxidation of porous alloys for solid oxide fuel cell applications

Metal-supported solid oxide fuel cells are regarded as a new generation of SOFC devices. The use of porous metal substrate provides a high mechanical strength of a SOFCsʹ support and lowers the cost of fuel cells. In this study, powders of PI600, 317L and 430L steel grades were used to prepare porous metallic supports. After sintering at different temperatures, their porosity and high temperature corrosion resistance were evaluated. Cyclic thermogravimetric analysis, X-ray diffractometry and SEM imaging were used to describe properties of these porous alloys. Electrical properties were studied for selected samples. The influence of porosity on resulting properties was elucidated. The porosity changes measured between oxidation cycles were presented. Results showed that the properties of porous alloys differ significantly from those of dense ones. The high temperature corrosion rate is high and is strongly influenced by the porosity level. Open porosity decreases rapidly upon oxidation at 800 °C. As an outcome of this study, the PI600 alloy performs best among those investigated; however, better corrosion resistant materials are needed for SOFCsʹ supports operating at 800 °C.