Abstract
Bismuth telluride (Bi2Te3) compound has been used as thermoelectric cooling and heating materials, since it has a high figure of merit at room temperature and can be fabricated easily and chiefly. The p-type Bi0.5Sb1.5Te3 compound doped with 4.0 wt% Te was fabricated by the hot extrusion at the temperature range of 300-510 °C under an extrusion ratio of 201 and a ram speed of 5 cm/min. The microstructure of the compound was investigated by scanning electron microscopy and X-ray diffraction. The microstructure was highly dense and fine-grained (∼1.0 Âμm). The hot extrusion gave rise to a preferred orientation of grains. With increasing the extrusion temperature, the bending strength and figure of merit were increased due to the porosity decrease. The highest bending strength (92 MPa) and figure of merit were obtained at 440 °C. It is proposed that the hot extrusion reduced a grain size and increased a density, resulting in an improvement in bending strength and figure of merit.
Published Version
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