Chauhan, Nagendra S. and Bathula, Sivaiah and Vishwakarma, Avinash and Bhardwaj, Ruchi and Johari, Kishor Kumar and Gahtori, Bhasker and Saravanan, Muthiah and Dhar, Ajay (2018) Compositional tuning of ZrNiSn half-Heusler alloys: Thermoelectric characteristics and performance analysis. Journal of Physics and Chemistry of Solids, 123. pp. 105-112. ISSN 0022-3697

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Nanostructuring has rejuvenated great interest in thermoelectric (TE) based power generation by enabling enhanced performance in nano-grained TE materials over their bulk counterparts. In ZrNiSn based half-Heusler (HH), a promising n-type TE materials, we examine the prospects of nanostructuring by synthesizing nano crystalline iso-electronically substituted n-type Zr1-xHfxNiSn HH alloys to achieve a state-of-the-art TE figure-of-merit ZT similar to 1.2 at 873 K, which is similar to 20% higher than its bulk counterparts and corresponds to high conversion efficiency of similar to 9% with output power density similar to 7 Wcm(-2), estimated using cumulative temperature dependence model. Enhanced phonon scattering at nano-scale grain boundaries and crystal defects, arising from nanostructuring and mass defect fluctuation in Hf substituted ZrNiSn alloys resulted in significantly reduced thermal conductivity. It was found that the partial substitution at Zr site with its heavier homologue Hf causes variation in the carrier effective mass and carrier concentration, which at lower Hf concentration results in an enhancement in the power factor.

Item Type: Article
Additional Information: Copyright for this article belongs to M/s Elsevier.
Subjects: Chemistry
Depositing User: Mr. Yogesh Joshi
Date Deposited: 04 Dec 2019 07:37
Last Modified: 04 Dec 2019 07:37

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