scholarly journals Thermoelectric Transport Properties of n-Type Sb-doped (Hf,Zr,Ti)NiSn Half-Heusler Alloys Prepared by Temperature-Regulated Melt Spinning and Spark Plasma Sintering

2020 ◽  
Vol 10 (14) ◽  
pp. 4963 ◽  
Author(s):  
Ki Wook Bae ◽  
Jeong Yun Hwang ◽  
Sang-il Kim ◽  
Hyung Mo Jeong ◽  
Sunuk Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Spark Plasma Sintering ◽  
Figure Of Merit ◽  
Melt Spinning ◽  
Lattice Thermal Conductivity ◽  
Heusler Alloys ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Thermoelectric Transport Properties ◽  
Spark Plasma

Herein we report a significantly reduced lattice thermal conductivity of Sb-doped Hf0.35Zr0.35Ti0.3NiSn half-Heusler alloys with sub-micron grains (grain size of ~300 nm). Polycrystalline bulks of Hf0.35Zr0.35Ti0.3NiSn1−xSbx (x = 0.01, 0.02, 0.03) with a complete single half-Heusler phase are prepared using temperature-regulated melt spinning and subsequent spark plasma sintering without a long annealing process. In these submicron-grained bulks, a very low lattice thermal conductivity value of ~2.4 W m−1 K−1 is obtained at 300 K due to the intensified phonon scatterings by highly dense grain boundaries and point-defects (Zr and Ti substituted at Hf-sites). A maximum thermoelectric figure of merit, zT, of 0.5 at 800 K is obtained in Hf0.35Zr0.35Ti0.3NiSn0.99Sb0.01.

MICROSTRUCTURE AND THERMOELECTRIC PROPERTIES OF (Zr,Hf)NiSn-BASED HALF-HEUSLER ALLOYS BY MELT SPINNING AND SPARK PLASMA SINTERING

2010 ◽  
Vol 03 (04) ◽  
pp. 227-231 ◽  
Author(s):  
CUI YU ◽  
TIEJUN ZHU ◽  
KAI XIAO ◽  
JUNJIE SHEN ◽  
XINBING ZHAO
Keyword(s):  
Thermal Conductivity ◽  
Spark Plasma Sintering ◽  
Melt Spinning ◽  
Lattice Thermal Conductivity ◽  
Heusler Alloys ◽  
Grain Sizes ◽  
Plasma Sintering ◽  
Melt Spun ◽  
The Matrix ◽  
Spark Plasma

(Zr,Hf)NiSn -based half-Heusler thermoelectric materials have been prepared by melt spinning and spark plasma sintering to refine the grain size. The grain sizes of the melt-spun thin ribbons varied from ~500 nm to ~3 μm and no significant grain growth were found for the bulk samples compacted by spark plasma sintering. Nanoscale precipitates dispersed in the matrix were observed, which should be more metallic due to the increase of the electrical conductivity. The reduction of lattice thermal conductivity was observed due to the refined grain sizes.

scholarly journals Is LiI a Potential Dopant Candidate to Enhance the Thermoelectric Performance in Sb-Free GeTe Systems? A Prelusive Study

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 643 ◽  
Author(s):  
Bhuvanesh Srinivasan ◽  
David Berthebaud ◽  
Takao Mori
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Short Communication ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Spark Plasma

As a workable substitute for toxic PbTe-based thermoelectrics, GeTe-based materials are emanating as reliable alternatives. To assess the suitability of LiI as a dopant in thermoelectric GeTe, a prelusive study of thermoelectric properties of GeTe1−xLiIx (x = 0–0.02) alloys processed by Spark Plasma Sintering (SPS) are presented in this short communication. A maximum thermoelectric figure of merit, zT ~ 1.2, was attained at 773 K for 2 mol% LiI-doped GeTe composition, thanks to the combined benefits of a noted reduction in the thermal conductivity and a marginally improved power factor. The scattering of heat carrying phonons due to the presumable formation of Li-induced “pseudo-vacancies” and nano-precipitates contributed to the conspicuous suppression of lattice thermal conductivity, and consequently boosted the zT of the Sb-free (GeTe)0.98(LiI)0.02 sample when compared to that of pristine GeTe and Sb-rich (GeTe)x(LiSbTe2)2 compounds that were reported earlier.

scholarly journals Thermoelectric Properties of Cu2SnSe3-Based Composites Containing Melt-Spun Cu–Te

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 971
Author(s):  
Degang Zhao ◽  
Lin Wang ◽  
Di Wu ◽  
Lin Bo
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Melt Spinning ◽  
Lattice Thermal Conductivity ◽  
Milling Process ◽  
Plasma Sintering ◽  
Nanocrystalline Structures ◽  
Spark Plasma

In this study, the Cu–Te alloy ribbons containing nanocrystalline structures were prepared by melt spinning (MS), and were composed of Cu2−xTe, Cu2Te, Cu3−xTe, and CuTe phases. Crystal grains on both sides of the ribbons were uniformly distributed and the grain size of the contact surface was about 400 nm. The Cu–Te powder was incorporated into the Cu2SnSe3 powder by the ball milling process and the Cu–Te/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). With the amount of Cu–Te powder increasing, the carrier concentration of the Cu–Te/Cu2SnSe3 composite increased, while the carrier mobility and electrical conductivity initially increased and then decreased. Compared to the Seebeck coefficient of the Cu2SnSe3 matrix, the Seebeck coefficient of the Cu–Te/Cu2SnSe3 samples increased slightly. Moreover, the Cu–Te/Cu2SnSe3 composites had lower thermal conductivity and lattice thermal conductivity over the whole temperature range. The lattice thermal conductivity of the 0.8 vol.% Cu–Te/Cu2SnSe3 composite achieved the lowest value of 0.22 W/m·K, which was 78% lower than that of the Cu2SnSe3 matrix. The maximum figure of merit of the 0.8 vol.% Cu–Te/Cu2SnSe3 composite was 0.45 at 700 K.

scholarly journals Thermoelectric properties of Cu3SbSe3 with intrinsically ultralow lattice thermal conductivity

2014 ◽  
Vol 2 (38) ◽  
pp. 15829-15835 ◽  
Author(s):  
Kriti Tyagi ◽  
Bhasker Gahtori ◽  
Sivaiah Bathula ◽  
A. K. Srivastava ◽  
A. K. Shukla ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Electrical Transport ◽  
Single Phase ◽  
Lattice Thermal Conductivity ◽  
Plasma Sintering ◽  
Spark Plasma

Intrinsically ultra-low thermal conductivity and electrical transport in single-phase Cu2SbSe3 synthesized employing a solid state reaction and spark plasma sintering.

Thermoelectrical properties of α phase and γ phase NaxCo2O4 ceramics prepared by spark plasma sintering method

2013 ◽  
Vol 1490 ◽  
pp. 57-62 ◽  
Author(s):  
Natsuko Mikami ◽  
Keishi Nishio ◽  
Koya Arai ◽  
Tatsuya Sakamoto ◽  
Masahiro Minowa ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Spark Plasma Sintering ◽  
Figure Of Merit ◽  
Dimensionless Figure Of Merit ◽  
Α Phase ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Method ◽  
Acid Compound

ABSTRACTThe thermoelectrical properties of α and γ phases of NaxCo2O4 having different amounts of Na were evaluated. The γ NaxCo2O4 samples were synthesized by thermal decomposition in a metal-citric acid compound, and the α NaxCo2O4 samples were synthesized by self-flux processing. Dense bulk ceramics were fabricated using spark plasma sintering (SPS), and the sintered samples were of high density and highly oriented. The thermoelectrical properties showed that γ NaxCo2O4 had higher electrical conductivity and lower thermal conductivity compared with α NaxCo2O4 and that α NaxCo2O4 had a larger Seebeck coefficient. These results show that γ NaxCo2O4 has a larger power factor and dimensionless figure of merit, ZT, than α NaxCo2O4.

Synthesis and Thermoelectric Properties of WO3/Cu2SnSe3 Composites

2018 ◽  
Vol 913 ◽  
pp. 811-817 ◽  
Author(s):  
Di Wu ◽  
Ji Ai Ning ◽  
De Gang Zhao ◽  
Xue Zhen Wang ◽  
Na Liu
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Figure Of Merit ◽  
Milling Process ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Spark Plasma

In this study, nanometer WO3 powder was uniformly dispersed into the Cu2SnSe3 powder by ball milling process, and the WO3/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). The results showed that the nano-WO3 particles were mainly distributed in the grain boundary of Cu2SnSe3 matrix, and the grain growth of Cu2SnSe3 was inhibited. The addition of nano-WO3 could enhance the electrical conductivity of Cu2SnSe3, and while the Seebeck coefficient increased slightly for the 0.4% WO3/Cu2SnSe3 composite. The thermal conductivity was not decreased until the content of WO3 exceeded 1.6%. The highest thermoelectric figure of merit ZT of 0.177 was achieved at 700 K for 0.4% WO3/Cu2SnSe3 composite. The enhancement of ZT value of WO3/Cu2SnSe3 thermoelectric material was mainly attributed to the improvement of the electrical properties.

Thermoelectric Properties of Silicon Germanium Alloy Nanocomposite Fabricated by Mechanical Alloying and Spark Plasma Sintering

2016 ◽  
Vol 703 ◽  
pp. 70-75 ◽  
Author(s):  
Zhen Ye Zhu ◽  
Shi Lei Guo
Keyword(s):  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Silicon Germanium ◽  
Figure Of Merit ◽  
Thermoelectric Figure ◽  
Long Wavelength ◽  
Plasma Sintering ◽  
Germanium Alloy ◽  
Spark Plasma ◽  
P Type

High dense p-type Si95Ge5 doped with nanoSi70Ge30B5particles thermoelectric materials were firstly fabricated by mechanical alloying (MA) and spark plasma sintering (SPS) method. The effects of different nanoSi70Ge30B5 doping content on the thermoelectric and phase properties were studied. A dimensionless thermoelectric figure-of-merit (ZT) of 0.47 at 710K in p-type nanocomposite bulk silicon germanium (SiGe) alloys is achieved. The enhancement of ZT is due to a large reduction of thermal conductivity caused by the increased grain boundaries of the numerous nanograins that effectively scatter long wavelength phonons.

THERMOELECTRIC PROPERTIES OF p-TYPE SKUTTERUDITES (Pr0.25Nd0.75)xFe3CoSb12 BY LEVITATION MELTING AND SPARK PLASMA SINTERING

2013 ◽  
Vol 06 (05) ◽  
pp. 1340006 ◽  
Author(s):  
JINGSHU XU ◽  
CHENGUANG FU ◽  
JIAN XIE ◽  
XINBING ZHAO ◽  
TIEJUN ZHU
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Lattice Thermal Conductivity ◽  
Levitation Melting ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
P Type

The p-type skutterudite compounds of ( Pr 0.25 Nd 0.75)x Fe 3 CoSb 12 (x = 0.67–0.78) have been successfully synthesized by levitation melting followed by annealing and spark plasma sintering. The thermoelectric properties have been characterized by the measurements of Seebeck coefficient, electrical conductivity and thermal conductivity in the temperature range from 300 K to 850 K. The improvement in the thermoelectric properties was realized due to the reduction in the lattice thermal conductivity when the voids were partially filled by Pr 0.25 Nd 0.75. The maximum ZT value of ~ 0.83 for ( Pr 0.25 Nd 0.75)0.76 Fe 3 CoSb 12 was obtained at 700 K.

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