Sintering and thermal expansion behaviors of glass and glass–YSZ composites as self‐repairable seals for SOFC

Abstract Glass and glass–ceramics are used as sealants in solid oxide fuel cell (SOFC) because their thermophysical properties can be tailored to meet the stringent requirements of the SOFC stack. The processing, sintering, and thermal expansion behaviors of self‐healing and non‐crystallizing glass and glass containing 10%–30 wt.% non‐reacting yttria‐stabilized zirconia (YSZ) are studied. The addition of inert YSZ to glass significantly retarded the sintering behavior. Thermal expansion behaviors of glass and glass–YSZ are also measured to study the role of YSZ addition on the glass transition, softening point, and coefficient of thermal expansion (CTE). It is shown that the densification is controlled by the viscous sintering mechanism, in which the addition of YSZ increased the effective viscosity of the glass–YSZ as evident from higher glass transition and softening temperatures and decreased CTE. These results demonstrated that the addition of YSZ to glass is promising for achieving optimum thermophysical properties useful as seals for SOFC.