Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_3-δ晶格缺陷、电性能与氧渗透研究  

Defect Structure, Electrical Property and Oxyge n Permeation of Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_3-δ

作　　者：江国顺[1] 宋春林[1] 李栋才[1] 冯绍杰[1] 刘卫[1] 陈初升[1] 

机构地区：[1]中国科学技术大学材料科学与工程系,合肥230026

出　　处：《Chinese Journal of Chemical Physics》2004年第1期75-78,共4页化学物理学报（英文）

摘　　要：对新型氧渗透材料Ba0 .5 Sr0 .5 Co0 .8Fe0 .2 O3 -δ(BSCF)进行了O2 TPD表征、非化学计量 (δ)测定、电导率 (σ)测量和氧渗透性能测试的研究 .结果表明 ,经纯氧气氛处理后的BSCF ,其O2 TPD谱存在三个失氧峰 :低温峰对应于晶格中V O 位置上的吸附氧 ,高温区两个峰对应于晶格中两种不同位置的晶格氧 ;σ对温度的实验表明 ,不论在升温还是降温过程中 ,σ在 470℃左右均出现极大值 ,可能与BSCF体系的δ值随温度变化相关 ;氧渗透实验表明 ,850℃以上 ,BSCF的氧渗透率JO2 较大 ,达到 1μmol/cm2 s ,活化能较低 ,Ea =63 .1kJ/mol ,而低于 850℃时 。A study of oxygen permeation material Ba 0.5 S r 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) is presented. The O 2-TPD , nonstoichiometry(δ), electrical conductivity(σ) and oxygen permeatio n were investigated. In the experiment of O 2-TPD, three oxygen-releasing pea ks are observed: one peak at low temperature is attributed to the absorbed oxyge n at the position of V  O, the other two peaks are relate d with the release of oxygen ions at two different positions in the BSCF crystal lattice. At 470℃, δ reaches minimum and σ achieves maximum: with increa sing temperature, absorbed oxygen at the position of V  O is released, resulting in the first peak of O 2-TPD; the rest of absorbed oxy gen entered BSCF lattice, causing the decrease of δ; the temperature depend ence of the conductivity demonstrates increasing conductivity with temperatures up to a maximum at about 470℃, indicating thermally activated p-type semicondu ctivity, which changed to metallic conduction behavior above 470℃. Furthermore, the experiment shows that the σ maximum at the heating step is higher than that obtained at cooling step, which can be explained: when heating, some absor bed oxygen at the position of V  O enters the lattice, δ decreases and concentration of Co 4+ & Fe 4+ increases, leading t o an enhanced p-type conductivity of BSCF; on the other hand, when cooling from high temperature, absorbed oxygen at the position of V  O does not exist. In the experiment of oxygen permeation, BSCF proves to be a su itable material for oxygen-separating at above 850℃, its oxygen permeability J O 2 is higher than 1 μmol/cm 2s with air as feed gas and He as sweep gas, the activation energy Ea is 63.1 kJ/mol .

关 键 词：电性能 氧渗透 缺陷 

分 类 号：O77[理学—晶体学]