In、Ta共掺对BaCeO3烧结性能及稳定性的影响

采用改进的柠檬酸盐法制备了不同In、Ta掺杂量的BaCeO₃基质子导体粉体, 干压成型后分别在1150℃、1250℃和1350℃下进行烧结。采用X射线衍射仪、扫描电镜分别对质子导体的物相结构和微观形貌进行了表征, 并采用电化学工作站测定了样品不同温度下的电导率。结果表明, 1350℃烧结样品气孔率均小于10%, 并且In掺杂量越高越容易烧结。样品在CO₂和H₂O中的化学稳定性测试结果表明, 只掺杂In可以提高样品在水中的化学稳定性, 但是对粉末样品高浓度CO₂气氛下的稳定性影响不大。In、Ta共掺杂可以大幅度提高样品在CO₂中的稳定性, 且稳定性随着Ta掺杂量的增加而提高。但是样品在10%湿润氢气气氛下的电导率随着Ta含量的增加而降低, 其中, BaCe_0.7In_0.25Ta_0.05O_3-δ在800℃时湿氢气下的电导率为1.16×10^-3 S/cm。

Effects of In,Ta Co-doped on the Sinterability and Stability of BaCeO3

BaCe_0.7In_0.3-xTa_xO_3-δ powders were synthesized by a modified citrate method. The powders were pressed into pellets, and then sintered at 1150℃, 1250℃ and 1350℃. The phase composition and the microstructure were investigated by using X-ray diffraction patterns and scanning electron microscope, respectively. The conductivity was measured by AC impedance method. The results indicate that porosities of the samples sintered at 1350℃ are less than 10% and the sample’s sinterability becomes better with the increasing doping amount of In. The doping of In can improve stability of the BaCeO₃ based powders against water, but not improve its stability against high concentration CO₂. However, Co-doping with In and Ta definitely improves the samples’ resistance against CO₂ and the higher Ta-doping level, the much more stability is, while the conductivities in wet H₂ decrease. Conductivity of the BaCe_0.7ln_0.25Ta_0.05O_3-δ sample at 800℃ in wet 10% H₂ atmosphere reaches 1.16×10^-3 S/cm.