Research on preparation of Ca3−x La xCo4O9 thermoelectric material by microwave heating

Ca_3-xLa_xCo₄O₉ powders were prepared by sol-gel process and microwave heating. The Ca-Co-O thermoelectric material ceramics were prepared. The Ca_3-xLaxCo₄O₉ powders and ceramic materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microstructure and thermoelectric properties of ceramics were researched. The results indicated that the crystal of Ca_3-xLaxCo₄O₉ grew ideally, crystallite were fine. The Ca_3-xLaxCo₄O₉ ceramics contained directional array plate-shaped grains with layered structure. The thermoelectric properties of Ca_3-xLaxCo₄O₉ ceramics were excellent. There were high electrical conductivity of Ca_3-xLaxCo₄O₉ ceramics. Microwave sintering method had the advantages of high efficiency.