Improving sealing properties of CaO-SrO-Al2O3-SiO2 glass and glass-ceramics for solid oxide fuel cells: Effect of La2O3 addition
Improving sealing properties of CaO-SrO-Al2O3-SiO2 glass and glass-ceramics for solid oxide fuel cells: Effect of La2O3 addition
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DOI：
10.1016/j.ceramint.2020.04.074
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发表时间：
2020-08
影响因子：
5.2
通讯作者：
Zhiwei Luo;Weicheng Lei;Haozhang Liang;Wenjing Xu;Xinyu Liu;Chunchun Qin;A. Lu
中科院分区：
文献类型：
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作者：
Zhiwei Luo;Weicheng Lei;Haozhang Liang;Wenjing Xu;Xinyu Liu;Chunchun Qin;A. Lu
采用熔融法制备了La 2 O3掺杂的CaO-SrO-Al 2 O3-SiO2玻璃。引入La 2 O3后，玻璃的红外吸收主峰向低波数方向移动，表明玻璃中非桥氧的含量增加，玻璃网络发生退极化。随着La 2 O3含量的增加，材料的显微硬度、玻璃化转变温度和晶化温度均呈上升趋势。耐酸碱性的质量损失小于0.5wt%，不影响燃料电池的密封效果。玻璃在850 °C下成核2小时，并在1050 °C下结晶1小时。微晶玻璃的析出晶相主要由SrAl 2Si 2 O 8、Ca 2Al 2SiO 7和CaSrAl 2SiO 7组成。当La_2O_3含量达到2.5mol%时，微晶玻璃中出现了新的晶相Ca_3La_6（SiO_4）_6。Ca 3La 6（SiO 4）6晶体释放出更多的SiO2（与其他晶体相比），在边界上留下Al 2 O3，这可能导致CTE增加，因为Al 2 O3与SiO2相比具有显著更高的CTE。玻璃陶瓷的CTE在9.3-11.3 ± 0.1 × 10-6°C-1范围内变化。通常，La 2 O3掺杂的25 CaO-20 SrO-10Al 2 O3 - 45 SiO2密封玻璃具有与其他SOFC组件相似的热膨胀系数。
The La2O3-doped CaO-SrO-Al2O3-SiO2glasses were prepared by the melting method. The main IR absorption peaks shift to the low wavenumber direction after the introduction of La2O3, which indicates that the amount of non-bridged oxygen in the glasses increases and the glass network depolarizes. With the increase of La2O3content, the micro-hardness, glass transition temperature, and crystallization temperature show an increasing trend. The mass loss of acid and alkali resistance is less than 0.5 wt%, which does not affect the sealing effect of the fuel cells. The glasses were nucleated at 850 °C for 2 h and crystallized at 1050 °C for 1 h. The precipitated crystal phases of the glass-ceramics were mainly composed of SrAl2Si2O8, Ca2Al2SiO7,and CaSrAl2SiO7. As the amount of La2O3reaches 2.5 mol%, the new crystal phase Ca3La6(SiO4)6appears in the glass-ceramic. Ca3La6(SiO4)6crystals liberate much more SiO2(in comparison to other crystals) leaving Al2O3on the border that can results in CTE increase since Al2O3has a significantly higher CTE in compare to SiO2. The CTE of the glass-ceramics varies within the range of 9.3–11.3 ± 0.1 × 10-6°C-1. Generally, the La2O3-doped 25CaO-20SrO-10Al2O3-45SiO2sealing glasses have the thermal expansion coefficients similar to that of other SOFCs components.