Effect of particle size distribution on crystallization behavior of glass‐based seals in reversible solid oxide cells

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AbstractReversible solid oxide cell (RSOC), integrating solid oxide fuel cell and solid oxide electrolysis cell, usually utilizes a glass material as seals. The particle size distribution of glass has a significant influence on crystallization and sintering behavior in the sealing process during RSOC operation. In this work, the effects of particle size on the non‐isothermal crystallization kinetics of BaO–ZnO–MgO–B2O3–SiO2 glass in RSOC are conducted. The crystallization behavior of glass is experimentally investigated and theoretically analyzed using Kissinger, Augis–Bennett, and Ozawa models. The values of crystallization activation energies are 164.4, 188.4, and 223.2 kJ/mol for 50, 150, and 300 μm (average particle sizes of S1, S2, and S3 glasses, respectively). The Avrami parameter (n) and dimensionality (m) of S1 glass are 0.6 and 0.7, similarly those of S2 glass were 0.9 and 0.7, corresponding to surface crystallization. However, the n and m values of S3 glass are both 1.8, suggesting that crystal growth between 1 (rod like) and 2 (plate like). Coarse glass exhibits better thermal stability and higher sluggishness to crystallize than that of fine glass. The main crystallization phases are characterized as thermally stable structure BaZn2Si2O7. Combined crystallization behavior with sintering behavior of glass, it is indicated that fine glass owns fast crystallization kinetics compared with sintering kinetics, generating a porous structure, whereas glass with larger particles crystallizes more slowly, exhibiting a relatively dense structure in RSOC operation.