Title :

Simultaneous increase in thermopower and electrical conductivity through Ta-doping and nanostructuring in half-Heusler TiNiSn alloys

Author(s) :

Karati, Anirudha [Auteur]
Indian Institute of Technology Madras [IIT Madras]
Mukherjee, Shriparna [Auteur]
Indian Institute of Science [Bangalore] [IISc Bangalore]
Mallik, Ramesh Chandra [Auteur]
Indian Institute of Science [Bangalore] [IISc Bangalore]
Shabadi, Rajashekhara [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Murty, B.S. [Auteur]
Indian Institute of Technology Madras [IIT Madras]
Varadaraju, U.V. [Auteur]
Indian Institute of Technology Madras [IIT Madras]

Journal title :

Materialia

Abbreviated title :

Materialia

Volume number :

7

Pages :

100410

Publisher :

Elsevier BV

Publication date :

2019-09

ISSN :

2589-1529

HAL domain(s) :

Chimie/Matériaux
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]

English abstract : [en]

A new series of Ta-doped Ti1−xTaxNiSn (x = 0–0.05) were synthesized through mechanical alloying (MA) followed by spark plasma sintering (SPS) for the first time. MA for 5 h gave rise to Ti/Ti+Ta and Ni3Sn4 phases. With ...
Show more >A new series of Ta-doped Ti1−xTaxNiSn (x = 0–0.05) were synthesized through mechanical alloying (MA) followed by spark plasma sintering (SPS) for the first time. MA for 5 h gave rise to Ti/Ti+Ta and Ni3Sn4 phases. With increasing milling time and subsequent SPS, half-Heusler phase formed along with Ni3Sn4 and TiC as secondary phases. To see the effect of temperature on the density of TiNiSn pellets, SPS was carried out at 1073, 1173 and 1273 K. Sintering of TiNiSn at 1073 K produced full-Heusler (TiNi2Sn) and Ni3Sn4as secondary phases and the pellets had long continuous pores. In contrast, SPS at 1273 K gave rise to increased volume fraction of TiNi2Sn impurity phase with almost no porosity. Thus, SPS conditions were set with respect to optimized densification (95 %) and volume fraction of secondary phases (19 %) at 1173 K for 5 h MA of TiNiSn. Ta-doping is expected to decrease the thermal conductivity and improve the ZT of the alloys. The Ta-doped TiNiSn samples were subsequently milled for 5 h and SPS were carried out for them at 1173 K. Increase in Thermopower and electrical conductivity were observed with increasing temperature for all the samples. Due to the simultaneous improvement in electrical conductivity and Thermopower, a maximum power factor of 1.12 and 2.57 mWm−1K−2 at 830 K were observed for TiNiSn and Ti0.95Ta0.05NiSn sintered at 1173 K, respectively. Due to reduced lattice thermal conductivity of 1.8 and 3 Wm−1K−1 for TiNiSn and Ti0.95Ta0.05NiSn sintered at 1173 K, respectively, maximum ZT of 0.17 and 0.31 were obtained at 823 K.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Métallurgie Physique et Génie des Matériaux

Submission date :

2024-01-15T14:40:29Z
2024-01-24T09:11:59Z