WANG Yixuan ¹, LIU Liangguang ¹, YU Hui ², CHEN Meng ², HU Xianjie ²
(1. School of Materials Science and Engineering, Hainan University, Haikou 570228, Hainan, China; 2. School of Biological and Environmental Engineering, Jingdezhen University, Jingdezhen 333400, Jiangxi, China)

Abstract: Thermal stability and density are two important factors that affect the practical application of intermediate temperature solid oxide fuel cell (SOFC) sealing glass. 32.96BaO-14.45CaO-4.87Al₂O₃-14.62B₂O₃-33.10SiO₂ (BCS1) basic glass was prepared by using the traditional solid-phase melting and annealing method, whose sealing failure was studied according to the results of X-ray diffraction (XRD), scanning electron microscopy (SEM), high temperature microscope and so on. Possible reasons and improving methods to obtain a dense and relatively stable sealing material were proposed. The hexagonal BaAl₂SiO₈ in the BCS1 basic glass was transferred to monoclinic phase with lower thermal expansion coefficient after the heat treatment, which would be mismatched with the Ni-YSZ anode. Also, the BCS1 glass was easy to overfire, resulting in a large number of pores, which would trigger gas leakage. By increasing the content of Al₂O₃, thermal stability, thermal matching and compactness of the sealing glass could be improved, while the sealing glass had a good interface combination with the Ni-YSZ anode. This study provided an effective way to improve the performance of the sealing glass of medium temperature SOFC, which would be helpful to promote the development and application of this technology.
Key words: intermediate temperature solid oxide fuel cell; sealing glass; failure; thermal stability; density