SiO_2-CaO-Al_2O_3-B_2O_3微晶釉在平板式中温固体氧化物燃料电池密封中的应用

SiO_2-CaO-Al_2O_3-B_2O_3 MICROCRYSTALLINE GLAZE AS SEALANT FOR PLANAR INTERMEDIATE TEMPERATURE SOLID OXIDE FUEL CELL

平板式中温固体氧化物燃料电池 (intermediatetemperaturesolidoxidefuelcells,ITSOFC)在 60 0～ 85 0℃温度下运行 ,电解质两侧的燃料气体 (H2 )和氧化气体 (O2 )必须加以分离 ,这要求金属双极板和陶瓷电解质高温气密封接。两者之间的密封材料应该与双极板和电解质很好的浸润粘附 ,达到气密要求 ;还会产生高温蠕变或粘滞流动以消除使用中因热膨胀系数差异引起的热应力。为了保证电池长期安全稳定的运行 ,还要求密封材料保持尺寸稳定性 ,与双极板和电解质材料有良好的化学稳定性。采用SiO2 CaOAl2 O3B2 O3系统微晶釉制备出一种适用于 85 0℃工作的ITSOFC密封材料。该系列微晶釉在 85 0～ 90 0℃与ZrO2 电解质和不锈钢双极板材料充分浸润粘附 ,在 85 0℃保证高温尺寸稳定性和化学稳定性的前提下 ,能够提供一种“软”密封 ,通过粘滞流动很好的满足了应力释放的要求。经过近 10 0h ,10次循环密封实验(4 0 0～ 85 0℃ )证明 ,该材料适用于 85 0℃工作的ITSOFC的密封。

The sealant materials for planar intermediate temperature solid oxide fuel cells (ITSOFC) are required for the sealing of the different components to prevent from leakage. Besides the gas tightness, the sealants should show good wetting and adhering behavior, chemical stability, and dimension stability. Microcrystalline glaze based on the SiO_2CaOAl_2O_3 B_2O_3system as sealant material applied for ITSOFC operated at 850 ℃ was investigated. After heat treatment at 850-900 ℃ the ceramic glaze was completely bonded with zirconia electrolyte and stainless steel bipolar plate, resulted in producing a good gas-tight seal on the basis of ensuring dimension stability and chemical stability at 850 ℃. During 10 thermal cycles, a suitable viscous flow could well relax thermal stress and no decrease in electromotive force caused by N_2 leaking was observed. Its micrograph shows a perfect connection with clear interface and good chemical stability. So, the microcrystalline glaze is a suitable sealant for ITSOFC operated at 850 ℃.