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Details

Autor(en) / Beteiligte
Titel
Thermoelectric Half-Heusler compounds TaFeSb and Ta1-xTixFeSb (0 ≤ x ≤ 0.11): Formation and physical properties
Ist Teil von
  • Intermetallics, 2019-08, Vol.111, p.106468, Article 106468
Ort / Verlag
Barking: Elsevier Ltd
Erscheinungsjahr
2019
Link zum Volltext
Quelle
Elsevier ScienceDirect Journals Complete
Beschreibungen/Notizen
  • We report on the formation, physical-chemical, as well as elastic and mechanical properties of the novel Half-Heusler (HH) compound TaFeSb that forms during a solid-state reaction from TaSb2 and TaFe2 in the temperature range between 800 and 850 °C. TaFeSb behaves as a semiconductor, and changes the conductivity type either on temperature or composition. Transport properties of TaFeSb and Ta1-xTixFeSb (0 ≤ x ≤ 0.11) were measured in the temperature range from 4.2 to 823 K, and the effect of titanium on thermoelectric and mechanical properties of Ta1-xTixFeSb was investigated. The Ta/Ti substitution results in a significant increase of the thermoelectric power factor to exciting values of above 6 mW/m⋅K2. In combination with a suppressed phonon thermal conductivity, due to a unique role of Ti, an enhanced figure of merit, ZT900K =1.0 (for Ta0.94Ti0.06FeSb) is obtained, close to the highest values reported for Hf-free p-type HH-systems. In addition, experimental results obtained in this study are discussed and analyzed in the context of ab-initio Density Functional Theory (DFT) calculations. •Physical, chemical and mechanical properties of TaFeSb and Ta1-xTixFeSb are reported.•Maximal thermoelectric performance was observed at x = 0.06•Semiconductor TaFeSb changes the conductivity type on temperature or/and composition.•Ta/Ti substitution results in a significant decrease of lattice thermal conductivity.•Experimental observations agreeing well with DFT calculations.

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