The sealants for planar SOFCs must have low reactivity with the other cell components (electrolyte, interconnect and cathode), must be thermo-mechanically and chemically stable in both oxidizing and wet-reducing environments at 800°C and, moreover, be able to withstand thermal cycling between room and operating temperatures. The designed and produced glass-ceramic sealant is a barium-free silica-based glass, which crystallizes by means of heat-treatment after being deposited by the slurry technique. The crystallization behaviour and thermomechanical stability of the glass- ceramic sealant were studied by X-ray diffraction, thermomechanical analysis and by DTA analyses. The interfacial adhesion between the interconnect (Crofer22APU) and the glass-ceramic sealant has been evaluated by SEM observations and by uni-axial tensile tests at room temperature. Crofer22APU/glass-ceramic sealant/ASE (Anode-Supported-Electrolyte) and Crofer22 APU/glass-ceramic sealant/ASC (Anode Supported Cell) joined samples were submitted both to air and to H2-3%H2O atmospheric exposure at 800°C up to 500 hours. Thermal cycles in air between room temperature and 800°C were conducted (up to 500 hours) on joined samples in order to evaluate the thermomechanical and chemical stability of the sealant.
展开▼
