Thermal cycling of Crofer22APU-sealant-anode supported electrolyte joined structures for planar SOFCs up to 3000 h

Abstract

Thermal cyclic tests in air were performed for Crofer22APU/glass-ceramic/ Anode-Supported-Electrolyte (ASE) joined samples for a total period of 3000 h. Different cooling rates from the SOFC operating temperature of 800 C to room temperature were carried out. Large and elongated voids were observed to develop just below the CrO/Cr-Mn spinel layer of the Crofer22APU. Diffusion of Al to the areas just below the protective oxide layer led to formation of AlO on the surface of the voids. The emergence of CaAlSiO as a new phase in the glass-ceramic was attributed to the diffusion of Ca away from the interfacial areas thus decreasing the proportion of Ca to Al and Si. The glass-ceramic sealant maintained good adherence with the Crofer22APU and the ASE without presence of any crack even after 3000 h of exposure.