TY - JOUR
T1 - Texture control of bulk mechanical alloyed Bi-Te thermoelectric materials via shear extrusion
AU - Kim, Sang Seok
AU - Aizawa, Tatsuhiko
N1 - Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2005
Y1 - 2005
N2 - Shear extrusion processing with combination of bulk mechanical alloying (BMA) is employed to yield the p-type (Bi2Te3)0.2(Sb 2Te3)0.8 and n-type (Bi2Se 3)0.05(Bi2Te3)0.95 Bi-Te thermoelectric materials from elemental granules. The shear-extruded p-type, n-type Bi-Te compounds have the preferred orientation factor (F) to anisotropic crystallographic structure : FP(max)= 0.63, Fn(max)= 0.67. For p-type, in case of the single crystal, F = 1.0 and p min = 0.995x10-5 Ωm. On the contrary, hot pressed sample has F = 0.02 and p = p random = 2.110xl0-5 Ω m. In case of the shear extruded sample, 0.5<F<0.63. This high F value assures that the measured resistivity becomes nearly equal to lxlO-5 Ωm, the resistivity for the single crystals with F = 1. Maximum power factors of p-type, n-type materials are achieved to 4.33xl0-3(W/mK2), 3.31xl0-3(W/mK2) even without any dopants. The bending strength of the material produced is also improved to be the range of 120-160MPa, six times larger than that for zone-melted specimen.
AB - Shear extrusion processing with combination of bulk mechanical alloying (BMA) is employed to yield the p-type (Bi2Te3)0.2(Sb 2Te3)0.8 and n-type (Bi2Se 3)0.05(Bi2Te3)0.95 Bi-Te thermoelectric materials from elemental granules. The shear-extruded p-type, n-type Bi-Te compounds have the preferred orientation factor (F) to anisotropic crystallographic structure : FP(max)= 0.63, Fn(max)= 0.67. For p-type, in case of the single crystal, F = 1.0 and p min = 0.995x10-5 Ωm. On the contrary, hot pressed sample has F = 0.02 and p = p random = 2.110xl0-5 Ω m. In case of the shear extruded sample, 0.5<F<0.63. This high F value assures that the measured resistivity becomes nearly equal to lxlO-5 Ωm, the resistivity for the single crystals with F = 1. Maximum power factors of p-type, n-type materials are achieved to 4.33xl0-3(W/mK2), 3.31xl0-3(W/mK2) even without any dopants. The bending strength of the material produced is also improved to be the range of 120-160MPa, six times larger than that for zone-melted specimen.
KW - Anisotropy
KW - Bi-Te
KW - N-type
KW - P-type
KW - Shear extrusion
KW - Thermoelectric materials
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U2 - 10.4028/www.scientific.net/JMNM.24-25.197
DO - 10.4028/www.scientific.net/JMNM.24-25.197
M3 - Article
AN - SCOPUS:63849206853
VL - 24-25
SP - 197
EP - 200
JO - Journal of Metastable and Nanocrystalline Materials
JF - Journal of Metastable and Nanocrystalline Materials
SN - 1422-6375
ER -