Influence of TiO2 addition on the sealing performance of Bi2O3–BaO–SiO2–RxOy (RK, Ca, etc.) glass

A series of Bi2O3–BaO–SiO2–RxOy (designated BiBaSi glass) glass sealants doped with different contents of TiO2 were prepared by conventional melting and annealing technique. The onset of crystallization temperature was determined by differential thermal analysis. The CTEs along with transition temperature (Tg) and softening temperature (Tf) were determined from dilatometric measurement. X-ray diffraction was used to determine the crystal phases. Scanning electron microscopy was used to study the microstructure and an associated energy dispersive X-ray spectroscopy was used to study element distribution. The good matching of thermal properties and the strong adherence to the electrolyte and connector indicate that the composite glass with 7.3 mol% TiO2 (BAS3) appeared to be a good candidate for SOFC sealing.

► The sealing temperature increases and liquidity deteriorates with increasing TiO2 content.
► The formation of titanate crystals indicates that TiO2 entered the network and replaced Si4 +.
► The composite glass with 7.3 mol % TiO2 appeared to be a good candidate for SOFC sealing.