Thermal Conductivity of Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ Affected by Grain Size and Pores

A fine measurement system for measuring thermal conductivity was constructed. An accuracy of 1% was determined for the reference quartz with a value of 1.411 W/m K. Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ samples were prepared by mechanical alloying followed by hot-pressing. Grain sizes were varied in the r...

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Veröffentlicht in:Journal of electronic materials 2009-07, Vol.38 (7), p.1048
Hauptverfasser: Hamachiyo, Takashi, Ashida, Maki, Hasezaki, Kazuhiro
Format: Artikel
Sprache:eng
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Zusammenfassung:A fine measurement system for measuring thermal conductivity was constructed. An accuracy of 1% was determined for the reference quartz with a value of 1.411 W/m K. Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ samples were prepared by mechanical alloying followed by hot-pressing. Grain sizes were varied in the range from 1 µm to 10 µm by controlling the sintering temperature in the temperature range from 623 K to 773 K. The thermal conductivity was 0.89 W/m K for the sample sintered at 623 K, while a grain size of 1.75 µm was measured by optical microscopy and scanning electron microscopy. The thermal conductivity increased on the sample sintered at 673 K because of grain growth and decreased on those sintered at the temperatures from 673 K to 773 K because the increase of pore size caused to decrease thermal conductivity. The increase of thermal conductivity for the samples sintered at temperatures above 773 K was affected by the increase of carrier concentration. [PUBLICATION ABSTRACT]
ISSN:0361-5235
1543-186X