高温质子导体Ba_3Ca_(1.18)Nb_(1.82)O_(9-δ)的制备和表征

PREPARATION AND CHARACTERISTICS OF HIGH TEMPERATURE PROTON CONDUCTOR Ba_3Ca_(1.18)Nb_(1.82)O_(9-δ)

对经6与10h球磨的BaCO_3,CaCO_3和Nb_2O_5的混合粉体进行冷压成型,1400℃/10h高温烧结后,获得了不同致密度的Ba_3Ca_(1.18)Nb_(1.82)O_(9-δ)样品,激光粒度、DSC-TG和SEM分析表明,适度延长球磨时间,可降低合成温度,细化粉体粒度,提高样品的致密度.电化学阻抗谱测试表明,在300—800℃温度范围内,6和10h球磨粉体制备的烧结样品总电导率与温度的关系符合Arrhenius方程,电导激活能分别为O.84和0.68eV.提高样品的致密度是降低电导激活能、提高中低温(300—600℃)导电性能的有效途径.

Ba3Ca1.18Nb1.82O9-δ powders with different particle sizes were synthesized by high temperature sintering （1400 ℃/10 h） of the mixed powders of BaCO3, CaCO3 and Nb2O5 milled for different times. Laser paticle size analysis, DSC-TG and SEM results show that the proper milling time can make particle refine, decrease the synthesis temperature, and increase the density of sample. EIS result shows that the temperature dependences of total conductivities of the sintered samples prepared by 6 and 10 h milling conform to the Arrhenius equation in the measured temperature range of 300-800 ℃, and the activation energies are 0.84 and 0.68 eV, respectively. Raising the density of Ba3Ca1.18Nb1.82O9-δ sample is an effective way to decrease the activity energy and increase the total conductivity at low and intermediate temperatures （300-600 ℃）.