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以La2O3、SrCO3和Co3O4为原料,采用高温固相反应法制备了La0.8Sr0.2CoO3(LSC)粉体。采用丝网印刷涂膜法在Y2O3稳定的ZrO2(YSZ)固体电解质表面制备LSC膜层,经1400℃煅烧,制成厚膜型NO2传感器。采用扫描电子显微镜(SEM)观察其断面形貌。采用交流阻抗技术对NO2敏感性能进行测试。研究了氧气浓度和LSC厚度对传感器阻抗值的影响。结果表明:LSC膜层均匀致密,且与YSZ结合良好。传感器的阻抗值随NO2浓度的增加而迅速减小,敏感性能良好。氧气体积分数越大,LSC膜层厚度越小,传感器低频区阻抗值越大。
La0.8Sr0.2CoO3 (LSC) powder was prepared by high temperature solid-state reaction using La2O3, SrCO3 and Co3O4 as raw materials. The LSC film was prepared on the surface of ZrO2 (YSZ) solid electrolyte stabilized by Y2O3 by screen printing method and calcined at 1400 ℃ to produce thick film NO2 sensor. The cross-sectional morphology was observed by scanning electron microscopy (SEM). The use of AC impedance technology to test the sensitivity of NO2. The effects of oxygen concentration and LSC thickness on the impedance of the sensor were investigated. The results show that the LSC film is uniform and compact, and has a good combination with YSZ. The sensor impedance value decreases rapidly with the increase of NO2 concentration, and the sensitivity is good. The larger the oxygen volume fraction, the smaller the thickness of the LSC film, the greater the impedance value of the sensor in the low frequency region.