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采用化学共沉淀与放电等离子烧结相结合的方法制备了Ca3Co4O9陶瓷。通过X射线衍射,红外光谱仪,扫描电镜等表征手段,探讨 了Ca3Co4O9的形成过程,研究了不同制备工艺对陶瓷的物相,显微结构和性能的影响。实验结果表明:共沉淀前驱物800℃预烧6h或8h 后,再经放电等离子850℃,压力30MPa下烧结5min,可以获得纯相Ca3Co4O9陶瓷;800℃预烧6h的烧结体密度为4.53g/cm3,800℃预烧 8h的烧结体密度为4.78g/cm3;前驱物预烧8h后再经放电等离子烧结的块体具有较好的电学性能。700℃时,电阻率为8.30×10-5Ω· m,Seebeck系数为182μV/K。电导率和Seebeck系数在目前CaCoO材料中是较高的。
Ca3Co4O9 ceramics were prepared by a combination of chemical coprecipitation and spark plasma sintering. The formation process of Ca3Co4O9 was investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. The effects of different preparation processes on the phase, microstructure and properties of the ceramics were also studied. The experimental results show that the precipitated precursors calcined at 800 ℃ for 6h or 8h and then sintered at 850 ℃ for 5min under the pressure of 30MPa, the pure phase Ca3Co4O9 ceramics can be obtained. The density of sintered compact at 800 ℃ for 6h is 4.53g / cm3 calcined at 800 ℃ for 8h, the density of the sintered body is 4.78g / cm3. The blocks sintered by spark plasma sintering after precursor calcined for 8h have good electrical properties. At 700 ℃, the resistivity is 8.30 × 10-5Ω · m and the Seebeck coefficient is 182μV / K. Conductivity and Seebeck coefficients are higher in current CaCoO materials.