【摘要】 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。更多还原

【Abstract】 Ca₃Co₄O₉ ceramics were prepared by combining a chemical coprecipitation and spark plasma sintering（SPS） technique. The formation process of Ca₃Co₄O₉ and the influence of different process on the phase,microstructure and properties of the ceramics were investigated by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The results show that the single phase Ca₃Co₄O₉ bulk ceramics can be obtained from the precursors pre-calcined at 800 ℃ for （6 h） or 8 h and then sintered by spark plasma at 30 MPa, 850 ℃ for 5 min. The densities of the samples calcined at 800 ℃ for 8 h or 6 h are 4.78 g/cm³ and 4.53 g/cm³ respectively. The bulk ceramics sample sintered by SPS process and using the powders calcined at 800 ℃ for 8 h exhibits better electric properties. After calcined at 700 ℃,the electrical resistivity of the sample is 8.30×10^-5 Ω·m, and the Seebeck coefficient is 182 μV/K. The values of the electrical conductivity and Seebeck coefficient are at the high level in the CaCoO ceramic materials.更多还原