B2O3-free SiO2–Al2O3–SrO–La2O3–ZnO–TiO2 glass sealants for intermediate temperature solid oxide fuel cell applications

In this study, the chemical and thermal stabilities of eleven B2O3-free SiO2–Al2O3–SrO–La2O3–ZnO–TiO2 glasses were investigated, and the adhesion and sealing properties of the glasses with respect to Gd0.2Ce0.8O2−δ (GDC) electrolyte and SUS 430 stainless steel (SUS430) were evaluated for use in intermediate temperature solid oxide fuel cells (ITSOFCs). It was found that the major crystallites formed in the glasses were initiated during the joining process at 950 °C, and only slight changes were observed in the intensity of crystallite peaks for the glasses subsequently soaked at 700 °C for 200 h. Experiments on the glass sandwiched with GDC electrolyte and SUS430 indicated that the SALSTi11 and SALSZT10 glasses provided good adhesion along the interfaces after heat treatment. According to the results of leakage test, the seals with the SALSTi11 and SALSZT10 glasses at 700 °C for a duration of 500 h showed good thermal stability with low leak rates of 0.007 and 0.003 sccm/cm at 0.5 psi, respectively. This property indicates a highly promising long-term thermal stability qualifying the sealing materials for ITSOFC applications.

► Sealing properties of SiO2–Al2O3–SrO–La2O3–ZnO–TiO2 glasses were evaluated.
► SALSTi11 and SALSZT10 glasses provided good adhesion to SDC and SUS430.
► They showed good thermal stability with low leak rates for a duration of 500 h.