LI Linlin ¹, CHENG Liang ², FENG Bixiao ³

(1. Wuxi Vocational Institute of Arts & Technology, Yixing 214206, Jiangsu, China; 2. Key Laboratory of Fuel Cell Materials and Devices, Jingdezhen Ceramic Institute, Jingdezhen 333001, Jiangxi, China; 3. Jiangxi Bocent Advanced Ceramic Co., Ltd., Pingxiang 337200, Jiangxi, China) 

Abstract: The intermediate temperature solid oxide fuel cell occupies an important position in the development of new energies, whereas the performance of the sealing glass has a significant impact on its commercialization. The effect of Y₂O₃ on crystallization behavior of Na₂O-BaO-CaO-B₂O₃-SiO₂ sealing glass was studied with thermal mechanical analysis, phase analysis (XRD), scanning electron microscopy (SEM) and other testing methods. It is found that the introduction of Y₂O₃ has only a very slight effect on thermal expansion coefficient of the Na₂O-BaO-CaO-B₂O₃-SiO₂ sealing glass, with values in the range of 11.0-11.6×10^-6 ℃^-1. However, according to the relationship between the content and the temperature transition point, Y₂O₃ has a positive effect on stability of the glass. XRD results reveal that the introduction of Y₂O₃ is beneficial to the crystallization of Ba_1.55Ca_0.45SiO₄, while inhibiting the formation of Ba_0.9Ca_0.1SiO₃. SEM results indicate that the introduction of Y₂O₃ is beneficial to the refinement of the crystalline grains and the precipitation of single crystals. The Ba_1.55Ca_0.45SiO₄ grains have a sheet morphology, while the Ba_0.9Ca_0.1SiO₃ crystals possess a columnar shape. According to the thermal stability and the cross-section between the glass and the half-cell, the optimal content of Y₂O₃ is 1mol%.
Key words: intermediate temperature solid oxide fuel cell; sealing glass; Y₂O₃; crystallization behavior