Galliosilicate glasses for viscous sealants in solid oxide fuel cell stacks: Part I: Compositional design

摘要

Galliosilicate glasses were developed for sealing intermediate temperature planar solid oxide fuel cell (SOFC) stacks. Candidate sealing glasses were identified for use at operating temperatures of 750 ℃ and at 850 ℃ after assessing flow behavior, thermal expansion properties, and crystallization behavior. A series of non-alkali glasses was identified for use at 750 ℃ within a strontium boro-galliosilicate compositional region that exhibited glass transition temperatures (T_g) between 658 and 675 ℃ and coefficients of thermal expansion (CTE) between 8 and 9.4 × 10~(-6) K~(-1). Glass frits and powders flowed below 850 ℃ and did not crystallize dramatically after 500 h at 750 ℃. Several glasses containing 5 mol% mixed alkali were identified in a strontium boro-galliosilicate compositional region for use at 850 ℃. The glasses exhibited T_g between 615 and 620 ℃ with CTE from 7.8 to 9.7 × 10~(-6) K~(-1). Glass frits flowed well below 850 ℃ and retained remnant glass phase after partial crystallization at 850 ℃. The galliosilicate glasses developed in this work enable viscous sealing of SOFC stacks.