Abstract:In order to overcome the poor processing performance and high orientation of the single crystal products, bismuth telluride based P-type thermoelectric materials were prepared by melting-quenching-crushing-hot pressing process with high-purity elemental Te, Bi and Sb as raw materials. The oxygen content and particle size of the powder before sintering were determined by using the oxygen and nitrogen analyzer, particle size analyzer. The phase structure and microstructure along the two different directions of the sintered body were analyzed by X-ray diffraction and scanning electron microscope. The thermoelectric performances in different directions show that both the electrical and thermal conductivities show anisotropy to a certain extent, while the Seebeck coefficient and the[ZT]value are almost isotropic. Compared with the current commercially available single crystal products, the orientation degree of samples decreases obviously, and the relative density of the final sample reaches up to 99% with a peak[ZT]value of 1.02. The hot pressing process has a lot of advantages, such as simple equipment, low cost and high efficiency, making it suitable for promotion to industrial scale production.
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