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.
|ジャーナル||Journal of Metastable and Nanocrystalline Materials|
|出版ステータス||Published - 2005|
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