无机材料学报 ›› 2017, Vol. 32 ›› Issue (10): 1089-1094.DOI: 10.15541/jim20160693 CSTR: 32189.14.10.15541/jim20160693

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共压共烧法制备La0.8Sr0.2(Ga0.8Mg0.2)0.1Fe0.9O3-δ致密扩散障碍层极限电流型氧传感器

张小芳, 刘 涛, 金宏斌, 于景坤, 高 翔, 王 成, 王相南   

  1. (东北大学 冶金学院, 沈阳 110819)
  • 收稿日期:2016-12-22 修回日期:2017-02-23 出版日期:2017-10-20 网络出版日期:2017-09-21
  • 作者简介:张小芳(1983–), 女, 博士研究生. E-mail: xfzhang2009@163.com
  • 基金资助:
    国家自然科学基金(51374055;52174059)

La0.8Sr0.2(Ga0.8Mg0.2)0.1Fe0.9O3-δ Dense Diffusion Barrier Limiting Current Oxygen Sensor Prepared by Co-pressing and Co-sintering Method

ZHANG Xiao-Fang, LIU Tao, JIN Hong-Bin, YU Jing-Kun, GAO Xiang, WANG Cheng, WANG Xiang-Nan   

  1. (School of Metallurgy, Northeastern University, Shenyang 110819, China)
  • Received:2016-12-22 Revised:2017-02-23 Published:2017-10-20 Online:2017-09-21
  • About author:ZHANG Xiao-Fang. E-mail: xfzhang2009@163.com
  • Supported by:
    National Natural Science Foundation of China (51374055;52174059)

摘要:

采用固相合成法制备了La0.8Sr0.2(Ga0.8Mg0.2)0.1Fe0.9O3-δ(LSGMF)混合导体和La0.8Sr0.2Ga0.8Mg0.2O3-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, lgIL(极限电流IL)与1000/T呈线性关系, LSGMF中氧离子的扩散激活能为0.4008 eV。800℃、0.3mol%<x(O2)<21.0mol%时, 极限电流IL与氧含量x(O2)间的关系为: IL(mA)=10.285x(O2)(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。

 

关键词: 氧传感器, 共压共烧结, 致密扩散障碍层, 极限电流

Abstract:

The La0.8Sr0.2(Ga0.8Mg0.2)0.1Fe0.9O3-δ (LSGMF) mixed conductor and La0.8Sr0.2Ga0.8Mg0.2O3-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-3c 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. lgIL (limiting current) depends linearly on 1000/T, and the activation energy for oxide-ion diffusion in LSGMF is 0.4008 eV. The limiting current responses depend linearly on the oxygen concentration at 800℃ and 0.3mol% < x (O2) < 21.0mol%, i.e., IL (mA) = 10.285x (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.

Key words: oxygen sensor, co-pressing and co-sintering, dense diffusion barrier layer, limiting current

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