Ca3Co4O9热电材料前驱体制备及性能表征

摘要

分别采用固相反应法和空间俘获法制备了Ca3Co4O9前驱体，并经冷等静压后常压烧结工艺制备了块体陶瓷样品。利用TG-DSC、XRD、SEM等方法对前驱体进行了表征，同时测试了陶瓷样品的热电性能。结果表明：空间俘获法可获得纯相、晶粒较小的前驱粉体，同时降低了合成温度，而且合成样品的Seebeck系数和功率因子明显高于固相反应法。在976 K获得最大Seebeck系数和功率因子分别为179μV/K、7.5×10–7W/(cm·K2)，较固相反应优化60%、16倍；电阻率略有升高。%Thermoelectric materials Ca3Co4O9 precursor was prepared by solid state reaction and steric entrapment synthesis, combined with normal pressure sintering process to prepare block ceramic samples after cold isostatic pressing. The precursor were investigated by TG-DSC, XRD and SEM. And thermoelectric properties of ceramic samples were characterized. The results show that steric entrapment synthesis can successfully get pure phase, grain fine powder, and decreases synthesized temperature, and sample’s Seebeck coefficient and power factor are obviously higher than those of samples prepared by solid state reaction, which reaches optimal values at 976 K,Smax=179μV/K,PFmax=7.5×10–7 W/(cm·K2), optimizing 60%, 16 times, respectively. The electrical resistivity is slightly increased.