Evaluation on Properties of CaO–BaO–B2O3–Al2O3–SiO2 Glass–Ceramic Sealants for Intermediate Temperature Solid Oxide Fuel Cells

To develop suitable sealants for intermediate temperature solid oxide fuel cells (IT-SOFC), glass–ceramics based on the CaO–BaO–B2O3–Al2O3–SiO2 system were studied. Coefficient of thermal expansion (CTE), glass transition temperature (Tg) and dilatometric softening point temperature (Td) of specimens were determined by means of dilatometer analysis and crystallization temperature was measured by differential thermal analysis (DTA). Also, crystallization behavior during prolonged heat-treatment and microstructure properties were studied by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Electrical properties were measured at different temperatures, and the results showed a high resistance (>104 Ω) at the SOFC operation temperature (600–800 °C). Moreover, mechanical properties of heat-treated specimens (1, 10, 30, 50 h) were measured. Microstructure investigation revealed a well-adhered bonding between the sealant glass–ceramic electrolyte and glass.