Publication Date:
2011-06-22
Description:
The thermoelectric properties of the fluorite-related oxide, In 4 Sn 3 O 12 , have been investigated by studying the system In 4− x Ga x Sn 3 O 12 , with 0 ≤ x ≤ 0.15. It has been shown that Ga does not enter the In 4 Sn 3 O 12 matrix, and two secondary phases form via the Ga introduction: SnO 2 and Ga 2 In 6 Sn 2 O 16 . By reactive sintering between In 2 O 3 , SnO 2 , and Ga 2 O 3 precursors, the density of the samples is considerably increased from 66% (actual density/theoretical density) for x = 0 up to 90% for x = 0.15, which significantly decreases the electrical resistivity. This is attributed to the large number of grain boundaries localized among the secondary phases, which inhibit the grain growth and hence favor the densification. The phase In 4 Sn 3 O 12 is for the first time reported to exhibit a semi-metallic behavior. The Seebeck coefficient does not change significantly with respect to the pristine matrix in accordance with the fact that Ga does not play any role as a doping agent. The thermal conductivity increases with the Ga content. The maximum figure of merit, ZT = 0.23, at 1000 K obtained at a very low Ga content ( x = 0.05), is comparable to the value obtained for Ge doped In 2 O 3 ( ZT ~ 0.3). This study suggests that In 4 Sn 3 O 12 can be a potential material for thermoelectric applications.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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