Title: Hot pressing effect on (Bi_0.25Sb_0.75)2Te₃ thermal conductivity

Authors: Ghassem Kavei, Kameran Ahmadi

Addresses: Material and Energy Research Centre, P.O. Box 14155-4777, Tehran, Iran. ' Material and Energy Research Centre, P.O. Box 14155-4777, Tehran, Iran

Abstract: (Bi_0.25Sb_0.75)2Te₃ thermoelectric material is a well known p type of compound that has higher figure of merit than other stoichiometries. The crystal of this compound was prepared then, pulverised in a particle size ratio of 64% with mesh 80 (200 μm²)/36% with a mesh of 60 (250 μm²). The powder was sintered in a heat up to 350°C-500°C under pressure of 500 MPa (hot pressing). To find out the temperatures effects on thermal conductivity of the sample, it was systematically investigated in nano-scale intrinsic structures by systems of X-ray diffraction, scanning electron microscopy and, for only one successful attempt, atomic force microscopy. The acquired images ensured to show homogeneous structures for hot pressed samples. In term of thermal conductivity and with regard to the figure of merit (Z), optimum sintering temperature hovers 500°C, which leads to a maximum Z value of around 1.53 K⁻¹.

Keywords: sintering temperature; longitudinal; transverse; hot pressing; thermal conductivity; scanning probe microscopy; SPM; nanostructures; nanotechnology; thermoelectric materials.

DOI: 10.1504/IJMMP.2010.038156

International Journal of Microstructure and Materials Properties, 2010 Vol.5 No.6, pp.575 - 586

Published online: 19 Jan 2011 *

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