B_2O_3-free SiO_2-Al_2O_3-SrO-La_2O_3-ZnO-TiO_2 glass sealants for intermediate temperature solid oxide fuel cell applications

摘要

In this study, the chemical and thermal stabilities of eleven B_2O_3-free SiO_2. -Al_2O_3-SrO-La_2O_3-ZnO-TiO_2 glasses were investigated, and the adhesion and sealing properties of the glasses with respect to Gd_(0.2)Ce_(0.8)O_(2-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 ℃, and only slight changes were observed in the intensity of crystallite peaks for the glasses subsequently soaked at 700 ℃ for 200 h. Experiments on the glass sandwiched with GDC electrolyte and SUS430 indicated that the SALSTill and SALSZT10 glasses provided good adhesion along the interfaces after heat treatment. According to the results of leakage test, the seals with the SALSTill and SALSZT10 glasses at 700 ℃ 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.