Thermal performance of glass-based seals for reversible solid oxide cell: Effect of Al₂O₃ ceramic addition on the crystallization behavior

Al(2)O(3 )ceramic addition in glass significantly influenced thermal performance during sealing process in RSOC stack. The effect of Al(2)O(3 )ceramic on crystallization behavior, phase compositions, microstructure, and viscosity of glass were discussed. With increasing Al(2)O(3 )ceramic content, the crystallization activation energy of glass gradually increased. The crystallization behavior of glass was effectively suppressed with Al(2)O(3 )ceramic addition. The glass with 20 wt% Al(2)O(3 )ceramic exhibited that the content of BaAl2Si2O8 crystallization phase remained at around 45 wt% after heat-treated at 750 C for 300 h. The controlled hexagonal BaAl2Si2O8 crystallization content combining with Al(2)O(3 )ceramic in seals effectively adjusted viscosity at about 105.1 Pa s and 107.2 Pa s during 700 degrees C-900 degrees C. During sealing process, the moderate Al(2)O(3 )ceramic and BaAl2Si2O8 were embedded in glass matrix acting as frame to enhance structural stability. Simultaneously, the glass phase owned proper fluidity, which could infiltrate components and ceramic without wide flow and release thermal stress during sealing.