摘要
采用固相合成法制备了La_(0.8)Sr_(0.2)(Ga_(0.8)Mg_(0.2))_(0.1)Fe_(0.9)O_(3-δ)(LSGMF)混合导体和La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3-δ)(LSGM)固体电解质,利用XRD、TGA、范德堡直流四探针法和热膨胀仪等对试样进行了分析。以LSGMF为致密扩散障碍层,以LSGM为氧泵层,采用共压共烧结法制备了极限电流型氧传感器,利用SEM和EDS对LSGMF/LSGM陶瓷体横截面的微观形貌和成分进行了分析。结果表明:LSGMF具有菱方钙钛矿结构(R-3c空间群),它在650℃失重速率最快,其电导率随温度的升高而增大;300~1000℃范围,LSGM与LSGMF的热膨胀系数分别为12.51×10^(–6)/℃和12.80×10^(–6)/℃。650~850℃范围,氧传感器具有良好的极限电流平台,lg I_L(极限电流I_L)与1000/T呈线性关系,LSGMF中氧离子的扩散激活能为0.4008 e V。800℃、0.3mol%<x(O_2)<21.0mol%时,极限电流IL与氧含量x(O_2)间的关系为:I_L(m A)=10.285x(O_2)(mol%),R=0.9982。LSGMF和LSGM结合牢固,未产生裂纹,EDS分析基本符合各化合物的化学计量比。
The La（0.8）Sr（0.2）（Ga（0.8）Mg（0.2））（0.1）Fe（0.9）O（3-δ）（LSGMF） mixed conductor and La（0.8）Sr（0.2）Ga（0.8）Mg（0.2）O（3-δ）（LSGM） solid electrolyte were prepared by solid-state reaction and characterized by XRD, TGA, Van Der Pauw dc four-probe method, and thermal expansion measurement. A limiting current oxygen sensor with LSGMF as a dense diffusion barrier and LSGM as a solid electrolyte was prepared by a co-pressing and co-sintering method. The microstructure and composition of LSGMF/LSGM cross-section were analyzed by SEM and EDS. The results show that crystal structure of LSGMF is rhombohedral perovskite which belongs to R-3 c space group. Its weight loss rate is the fastest at about 650℃. The electrical conductivity increases with the temperature increasing. The thermal expansion coefficients（TECs） of LSGM and LSGMF are 12.51×10^（–6）/℃ and 12.80×10^（–6）/℃ in the range of 300–1000℃, respectively. In the range of 650-850℃, the sensor exhibits an excellent limiting current plateau. lg IL（limiting current） depends linearly on 1000/T, and the activation energy for oxide-ion diffusion in LSGMF is 0.4008 e V. The limiting current responses depend linearly on the oxygen concentration at 800 and 0.3 mol℃ % x（O2） 21.0 mol%, i.e., IL（m A） = 10.285 x（O2）（mol%）, R=0.9982. LSGMF and LSGM combines firmly without crack, and the mole ratio of their elements is basically in agreement with the stoichiometric of LSGMF and LSGM.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2017年第10期1089-1094,共6页
Journal of Inorganic Materials
基金
国家自然科学基金(51374055
52174059)~~
关键词
氧传感器
共压共烧结
致密扩散障碍层
极限电流
oxygen sensor
co-pressing and co-sintering
dense diffusion barrier layer
limiting current
