中文摘要：

氧化钇稳定氧化锆（yttria-stabilized zirconia,YSZ）是目前使用最多的电解质材料,YSZ结构和性能的长期稳定对固体氧化物燃料电池（solid oxide full cell,SOFC）系统的可靠性至关重要。重点研究了具有亚微米结构的YSZ在850℃环境中的长期老化性能,结果发现：在850℃空气气氛中老化处理300h后,YSZ中小于1μm的部分晶粒出现了继续生长的现象,使得小于1μm晶粒比例下降10%～20%;当这部分晶粒长大到1～2μm,呈现稳定状态,即没有出现晶粒的过分长大;老化600h和1000h后,小晶粒（小于1μm）所占比例几乎不变。伴随着晶粒尺寸分布变化,YSZ电解质的电导率也比老化处理初期（300h）有所降低;当老化处理600h后,电导率下降趋势变缓;老化处理1000h后,电导率基本稳定,且1000℃电导率仍然保持在0.15S/cm以上。电导率下降主要是由YSZ晶粒部分长大引起的。具有上述性能的YSZ用作SOFC电解质可以满足长期使用的要求。

英文摘要：

As a high efficient and clean energy recourse,solid oxide fuel cell （SOFC） has been concerned.Since yttria stabilized zirconia （YSZ） is the most popular electrolyte in the SOFC,the stability of microstructure and properties of the YSZ is important for the reliability of the SOFC system.The long term aging properties of the YSZ with sub-micro crystalline grains at 850℃ were investigated.The results show that after aging in air at 850 ℃ for 300 h,some of the YSZ gains less than 1μm become coarser at the decreased ratio of 10%-20%,and the final grain sizes are 1-2 μm.The ratio of the smaller grains （less than 1μm） unchanged after 600 h and 1000 h.The electrical conductivity of YSZ electrolyte decreased a little for the aging time of 300 h,decreased slowly for 600 h,and finally stabled for 1000h.The decrease of electrical conductivity was induced by the increase of the coarser YSZ grains.The electrical conductivity of YSZ at 1000 ℃ after aged for 1000 h was still higher than 0.15S/cm,which could be used for a long term operation of the SOFC system.