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Effect of rotary-die equal channel angular pressing on the thermoelectric properties of a (Bi,Sb)2Te3 alloy

Published online by Cambridge University Press:  01 April 2005

Z.M. Sun ,
H. Hashimoto ,
N. Keawprak ,
A.B. Ma ,
L.F. Li  and
M.W. Barsoum
Z.M. Sun*
Affiliation:
National Institute of Advanced Industrial Science and Technology, Nagoya 463-8560, Japan; and Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104
H. Hashimoto
Affiliation:
National Institute of Advanced Industrial Science and Technology, Nagoya 463-8560, Japan
N. Keawprak
Affiliation:
National Institute of Advanced Industrial Science and Technology, Nagoya 463-8560, Japan
A.B. Ma
Affiliation:
National Institute of Advanced Industrial Science and Technology, Nagoya 463-8560, Japan
L.F. Li
Affiliation:
Technical Institute of Physics and Chemistry, Chinese Academy of Sciences,Beijing, People's Republic of China
M.W. Barsoum
Affiliation:
Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104
*
a) Address all correspondence to this author.e-mail: z.m.sun@aist.go.jp
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Abstract

A (Bi,Sb)2Te3 alloy powder was sintered via a pulse discharge sintering process followed by a rotary-die equal channel angular pressing (ECAP) process. It was found by x-ray diffraction analysis that the as-sintered material shows preferentially orientated microstructure, which were considerably eliminated by following ECAP processes. Generally, the Seebeck coefficient of the material was reduced by ECAP processing, which was attributed to the increased carrier concentration after the severe plastic deformation. Electrical conductivity increases after ECAP, which was also originated from the increased carrier concentration. The figure of merit of the material in different conditions shows higher value in the transverse direction. In the transverse samples, those after ECAP processing showed increased figures of merit, which reached 3.85 × 10−3/K in the material after 4 passes of ECAP.

Keywords

Powder processingThermoelectricity
Type
Research Article
Information
Journal of Materials Research , Volume 20 , Issue 4 , April 2005 , pp. 895 - 903
Copyright
Copyright © Materials Research Society 2005

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