Optimum processing parameters to improve sealing performance in solid oxide fuel cells

Glass–ceramic composites are among the favorable candidates as a sealing material for solid oxide fuel cells (SOFC). In order to obtain a reliable, robust and hermetic sealing, the glass–ceramics must chemically bond to both the metallic interconnector and the ceramic electrolyte. A high-bonding strength and good wetting, which strongly depend on the thermal treatment, are always preferred to ensure gas-tight sealing. The thermal treatment involves three stages: binder burnout (stage-I), sintering (stage-II), and cooling (stage-III). This study investigates effects of various parameters on the sealing quality at the sintering stage. The effects of sintering temperature, clamping pressure and sealant thickness are considered. The glass–ceramic laminates are produced employing a tape casting method. The sealing quality is evaluated by measuring leakage and final macro-structure of the sealing region. It is suggested that a 900–930 °C sintering temperature and 1.5–7.6 N cm−2 clamping pressure ranges are better for successful sealing. The initial thickness of glass–ceramic laminates is also desired to be between 0.25–0.5 mm thickness range for both a cost-effective and reliable sealing.