Microstructural Evolution in Spinodal Half-Heusler Thermoelectrics
- Spinodal Zr0.4Hf0.6Ni1.15Sn half-Heusler thermoelectrics are synthesized and aged. The complex microstructure due to the spinodal decomposition is investigated by powder X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). By Rietveld refinements, it is confirmed that excess Ni atoms in the arc-melted and spark-plasma-sintered half-Heusler matrix prefer to form nanoscale/ submicron Heusler precipitates via spinodal decomposition and growth during the aging at 1173 K. Such phase separation changes the band gap of semiconductors, reduces the thermal conductivity drastically and improves the performance of thermoelectrics. As a result, a more than 50 % improvement of the ZT value on the unaged specimens was achieved.
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| Author: | Jian Feng |
|---|---|
| URN: | urn:nbn:de:bsz:840-opus4-1376 |
| Referee: | A. Weidenkaff, G. Schmitz, H. Näfe |
| Document Type: | Diploma Thesis |
| Language: | English |
| Year of Completion: | 2014 |
| Publishing Institution: | Hochschule Heilbronn |
| Granting Institution: | Universität Stuttgart |
| Date of final exam: | 2014/12/30 |
| Release Date: | 2017/05/31 |
| Tag: | Thermoelektrik |
| GND Keyword: | Thermoelektrik |
| Pagenumber: | 58 Seiten |
| DDC classes: | 600 Technik, Medizin, angewandte Wissenschaften |
| Access Right: | Frei zugänglich |
| Licence (German): |  Creative Commons - Namensnennung-Nicht kommerziell-Keine Bearbeitung |
