Thermal expansion and melting temperature of the half-Heusler compounds: MNiSn (M = Ti, Zr, Hf)

Jung, Doyoung; Kurosaki, Ken; Kim, Chang-Eun; Muta, Hiroaki; Yamanaka, Shinşuke

doi:10.1016/j.jallcom.2009.09.139

Cited by 89 publications

(59 citation statements)

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“…Hence, the solidus trace for hH must extend into the Ni-rich side of TiNiSn at the higher temperatures. The implication is that the hH phase may not melt incongruently at a single temperature, 1453K, as reported earlier [23], but is likely to involve multiple stages as suggested by Fig. 13…”

Section: Submitted To Acta Materialia (October 2015)supporting

confidence: 54%

Microstructure Evolution of Biphasic TiNi1+x Sn Thermoelectric Materials

Verma

Douglas

Krämer

et al. 2016

Metall Mater Trans A

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The effects of thermal treatment on the microstructure of bi-phasic materials comprising halfHeusler (hH) and full-Heusler (fH) phases, as well as on their associated thermal conductivity, are discussed. The focus is on a biphasic hH/fH alloy of nominal stoichiometry TiNi 1.2 Sn, synthesized by containerless (magnetic levitation) induction melting. The alloy samples were exposed to various heat treatments to generate microstructures containing second phase precipitates ranging from ~10 nm to a few micrometers. The materials were characterized with regard to morphology, size, shape and orientation relationship of the fH and hH phases, both of which are present as precipitates within larger regions of the counterpart phase. The solidification path of the alloy and its implications for the subsequent microstructure evolution during heat treatment were elucidated, and relationships with the ensuing thermal conductivity were characterized.

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Section: Submitted To Acta Materialia (October 2015)supporting

confidence: 54%

Microstructure Evolution of Biphasic TiNi1+x Sn Thermoelectric Materials

Verma

Douglas

Krämer

et al. 2016

Metall Mater Trans A

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“…The temperature used for densification was set close to the melting point of ZrNiSn (1708 K, Ref. 17). As a result, disk-shaped pellets of about 2 mm thickness and 20 mm diameter were formed with densities higher than 99% of the theoretical value (measured both by the Archimedes method and by direct volumetric-gravimetric assessment).…”

Section: Methodsmentioning

confidence: 99%

Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution

Gałązka

Populoh

Xie

et al. 2014

Journal of Applied Physics

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Articles you may be interested inThe thermoelectric performance of Ta substituted (ZrHf)NiSn-based half-Heusler compounds is studied. Here, Ta is used on the Hf site for controlling the charge carrier concentration in contrast to the widely used Sb substitution on the Sn site. The influence of the Ta content on the thermoelectric and transport properties of (Zr 0.3 Hf 0.7-x Ta x )NiSn (x ¼ 0, 0.01, 0.05) is investigated by means of Seebeck coefficient, electrical resistivity, thermal conductivity, and Hall coefficient measurements. The results are analyzed in context of the single parabolic band model. Ta substitution increases the charge carrier concentration and suppresses the influence of impurity band, which is present in the pristine (Zr 0.3 Hf 0.7 )NiSn. Moreover, Ta substitution decouples and simultaneously increases the density-of-states effective mass (m*) and the charge carrier mobility (l), leading to a larger weighted mobility lÁ(m*) 3/2 . The lattice thermal conductivity is slightly suppressed due to increased point defect scattering. As a result, a Figure

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“…[1][2][3][4] These alloys have composition XYZ, where X and Y denote transition or rare earth elements and Z denotes a main group element. In particular, the RNiSn-type half-Heusler (HH) alloys, where R=Hf, Zr, Ti, are the most investigated to date due to their thermally stable 5 and mass producibility. 6 However, their thermoelectric (TE) figure of merit ZT was limited by the rather high thermal conductivity.…”

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confidence: 99%

“…(i) An ingot was annealed at 700 o C for 8 days and another ingot at 1000 o C for 2 days, significantly below the melting temperature, T melt ~1460 o C, 5 to obtain single phase samples. [1][2][3][4]30 X-ray diffraction pattern for the annealed samples is shown in Figure 1.…”

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confidence: 99%

Uncovering high thermoelectric figure of merit in (Hf,Zr)NiSn half-Heusler alloys

Chen

Gao

Zeng

et al. 2015

Applied Physics Letters

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Half-Heusler alloys (MgAgSb structure) are promising thermoelectric materials. RNiSn halfHeusler phases (R=Hf, Zr, Ti) are the most studied in view of thermal stability. The highest dimensionless figure of merit (ZT) obtained is ~1 in the temperature range ~450-900 o C, primarily achieved in nanostructured alloys. Through proper annealing, ZT~1.2 has been obtained in a previous ZT~1 n-type (Hf,Zr)NiSn phase without the nanostructure. There is an appreciable increase in power factor, decrease in charge carrier density, and increase in carrier mobility. The findings are attributed to improved structural order. Present approach may be applied to optimize the functional properties of Heusler-type alloys. a)

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Thermal expansion and melting temperature of the half-Heusler compounds: MNiSn (M = Ti, Zr, Hf)

Cited by 89 publications

References 12 publications

Microstructure Evolution of Biphasic TiNi1+x Sn Thermoelectric Materials

Microstructure Evolution of Biphasic TiNi1+x Sn Thermoelectric Materials

Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution

Uncovering high thermoelectric figure of merit in (Hf,Zr)NiSn half-Heusler alloys

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Thermal expansion and melting temperature of the half-Heusler compounds: MNiSn (M = Ti, Zr, Hf)

Cited by 89 publications

References 12 publications

Microstructure Evolution of Biphasic TiNi1+x Sn Thermoelectric Materials

Microstructure Evolution of Biphasic TiNi1+x Sn Thermoelectric Materials

Improved thermoelectric performance of (Zr0.3Hf0.7)NiSn half-Heusler compounds by Ta substitution

Uncovering high thermoelectric figure of merit in (Hf,Zr)NiSn half-Heusler alloys

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Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution