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Thermoelectric Properties of Nearly Single-Phase Half-Heusler NbCoSn Alloys and Importance of Microstructures for Improving Performance

Published online by Cambridge University Press:  01 February 2011

Yoshisato Kimura
Affiliation:
[email protected], Tokyo Institute of Technology, Materials Science and Engineering, 4259-G3-23 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
Yukio Tamura
Affiliation:
[email protected], Tokyo Institute of Technology, Materials Science and Engineering, 4259-G3-23 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
Takuji Kita
Affiliation:
[email protected], Toyota Motor Corporation, 1200 Mishuku,, Susono, Shizuoka, 410-1193, Japan
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Abstract

In order to evaluate the thermoelectric properties of n-type half-Heusler compound NbCoSn, single-phase NbCoSn alloy was prepared using directional solidification based on the phase diagram information of the Nb-Co-Sn ternary system which was investigated in this work. The isotherm at 1273 K and the reaction scheme together with the projection of liquidus surface were determined. Thermoelectric properties of NbCoSn based alloys were evaluated by Seebeck coefficient, electrical resistivity and power factor, which were measured in a temperature range from room temperature to 1073 K. NbCoSn has excellent values of Seebeck coefficient exceeding -250 μV/K at around 900 K and shows the metal-like temperature dependence of electrical resistivity.

Type
Research Article
Copyright
Copyright © Materials Research Society 2008

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