Thermal Stability and Phase Purity in Polycrystalline Ba_8Ga_xGe_(46−x)
Abstract
Polycrystalline Ba_8Ga_xGe_(46−x) exhibits promising thermoelectric performance with the figure of merit ZT close to that of single crystals. Polycrystalline Ba_8Ga_xGe_(46−x) is promising for applications, but reproducibility and thermal stability of thermoelectric properties need to be demonstrated. Polycrystalline samples of Ba_(8+d)Ga_xGe_(46−x)-type clathrates (15.0 ≤ x ≤ 16.8 with varied nominal Ga content and d = 0 or 0.2) were prepared by direct reaction of the elements, followed by ball milling and hot pressing. Trace Ge impurity was observed (<1.0 wt.%) depending on the synthesis method. The electrical resistivity was stable in measurements up to 1000 K, regardless of Ge impurity. However, measurements to 1050 K resulted in irreversible increase in carrier concentration while the carrier mobility remained unchanged.
Additional Information
© 2009 TMS. Received: 15 August 2008. Accepted: 17 December 2008. Published online: 19 January 2009. The Beckman Institute at Caltech, the Swedish Bengt Lundqvist Minne Foundation, and JPL-NASA are greatly acknowledged for financial support.Additional details
- Eprint ID
- 15666
- Resolver ID
- CaltechAUTHORS:20090908-092930675
- Caltech Beckman Institute
- Bengt Lundqvist Minne Foundation
- NASA/JPL
- Created
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2009-09-24Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field