QIN Ying 1, LUO Linghong 2, 3, WANG Leying 2, 3, LI Wenfeng 1, WANG Zhibin 1
(1. Henan Building Material Research & Design Institute Co., Ltd, Zhengzhou 450002, Henan, China ; 2. Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China; 3. Key Laboratory of Fuel Cell Material and Devices, Jiangxiprovince, Jingdezhen 333000, Jiangxi, China)
Abstract: In this paper, the BaO-CaO-Al2O3-B2O3-SiO2 (BCABS) and SrO-CaO-Al2O3-B2O3-SiO2 (SCABS) based sealing glasses for intermediate-temperature solid oxide fuel cells (IT-SOFCs) were prepared by using the high-temperature melting method. The crystallization behaviors of the two groups of glass under working conditions were studied by using coefficient of thermal expansion testing (CTE), Raman spectral analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and other methods. It was found that the CTE of BCABS and SCABS were 9.86×10-6 K-1 and 9.69×10-6 K-1, while the Tg, Ts and viscosity met the requirements of sealing glasses for IT-SOFCs. As reflected by the deconvolution results of the Raman and FTIR spectra, the network modified ions in the SCABS glass had a more uniform distribution, and the crystallization tendency was smaller. After the sealing procedure at 1073 K for 10 min and the following operating condition at 973 K for 0 h or 160 h, the barium feldspar precipitated in the BCABS glass were changed from hexagonal to monoclinic phase, while the CTE was reduced to 8.50×10-6 K-1. However, the SCABS glass remained to be amorphous state after the sealing and heat-treatment procedures, so that the CTE was remained basically unchanged. Therefore, the SCABS glass has higher thermal stability, which would be more suitable than the BCABS glass for IT-SOFCs sealing.
Key words: sealing glass; Raman spectra; FTIR spectra; crystallization; coefficient of thermal expansion