高温质子导体BaCe_(0.90)Y_(0.10)O_(3-α)的制备与性质

Preparation and characteristics of high temperature proton conductor BaCe_(0.90)Y_(0.10)O_(3-α)

对不同球磨时间的BaCO3，CeO2和Y2O3原料粉体进行固相反应，合成了不同粒度的BaCe0.90V0.10O3-α粉体．将其冷压成型、高温烧结后，获得了不同致密度的BaCe0.90V0.10O3-α样品．利用激光粒度分析、差式扫描量热-热重、X射线衍射和扫描电镜技术研究了球磨时间对粉体粒度、合成过程、晶体结构及样品微观形貌的影响．结果表明：适度延长球磨时间，原料颗粒细化，BaCe0.90V0.10O3-α。的合成温度降低，合成粉体的粒度变小、分布变窄、比表面积增大，从而提高了烧结样品的致密度．利用电化学阻抗谱技术测量了原料球磨6h和10h的BaCe0.90V0.10O3-α。烧结样品在空气中573～1073K内的阻抗谱，并计算出其电导率分别为3．25×10^-3～6．98×10^-2S·cm^-1和5．46×10^-3-7．20×10^-2S·cm^-1．在测试温度范围内，两种样品的电导率与温度的关系符合Arrhenius方程，电导激活能分别为0．39eV和0．34eV．提高烧结样品的致密度是降低电导激活能，提高导电性能的有效途径．BaCe0.90V0.10O3-α，BaCe0.90V0.10O3-α和BaCe0.85V0.15O3-α的电导激活能依次降低，符合理论预测．

BaCe0.90V0.10O3-α powder with different particle size was synthesized by solid state reaction of mixed original powder of BaCO3, CeO2 and Y2O3 milled for different time. BaCe0.90V0.10O3-α, samples with different density were prepared by the synthesized powder through cold isostatic pressing and sintering. The effects of milling time on the particle size of powder, synthesis process, crystal structure and micro - morphology of samples were studied by laser paticle size analysis, differential scanning calorimetry -thermogravimetry, X -ray diffraction and scanning electron microscopy. The results show that the original powder was refined with reasonably prolonging milling time, which decreased the synthesis temperature of BaCe0.90V0.10O3-α and synthesized the powder with small particle size, narrow particle size distribution and large specific surface area. As a result, the density of sintered sample was increased. The impedance spectra of sintered samples prepared from original powder milled for 6 h and 10 h were measured by means of electrochemical impedance spectroscopy in the temperature range of 573 ~ 1073 K in air, and then their conductivity was calculated to be 3.25×10^-3～6.98×10^-2S·cm^-1 and 5.46×10^-3-7.20×10^-2S·cm^-1 , respectivelY. The temperature dependence of the conductivity conforms to the Arrhenius equadon in the measured temperature range, and the conductance activation energy is obtained to be 0. 39 eV and 0. 34 eV, respectively. Raising the density of sintered sample is an effeetive way to decrease the conductance activation energy and increase the conductivity. The conductance activation energies of BaCe0.90V0.10O3-α,BaCe0.90V0.10O3-α and BaCe0.85V0.15O3-α decreased in turn, which is in agreement with theoretical prediction.