Thermoelectric Properties of Mg2Si1-x-yGexSbyPrepared by Spark Plasma Sintering

ABSTRACTThe magnesium compound Mg2Si and its solid solutions are expected asn-type thermoelectric (TE) material because they are non-toxic, have a large Clarke number, and are light weight. In this study, we improved TE performance by doping Ge into Sb-doped Mg2Si to cause phonon scattering and increase carrier concentration. A bulk of Sb-doped Si-Ge alloy as the raw material was fabricated using an arc-melting method. A high-purity Mg2Si was synthesized from metal Mg and Sb-doped Si-Ge alloy using spark plasma sintering equipment. For the samples with the same Sb concentration, the electrical conductivity was equivalent. On the other hand, the Seebeck coefficient was dependent on Ge concentration. Due to phonon scattering, thermal conductivity decreased by a small amount of Ge doping andκphdominated for thermal conduction. The minimum thermal conductivity of Mg2Si0.90Ge0.10was 2.25 W/mK (κph: 2.06 W/mK,κel: 0.19 W/mK). The dimensionless figure of merit (ZT) for the Mg2Si0.945Ge0.05Sb0.005sample was higher than that of the others due to reducing thermal conductivity and increasing carrier concentration. The maximumZTwas 0.47 at 713 K.

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Thermoelectric properties of synthesized Mg2Si0.95-xGe0.05Sbx by spark plasma sintering

MRS Proceedings ◽

10.1557/opl.2015.240 ◽

2015 ◽

Vol 1735 ◽

Cited By ~ 1

Author(s):

Asumi Sasaki ◽

Koya Arai ◽

Yuto Kimori ◽

Tomoyuki Nakamura ◽

Kenjiro Fujimoto ◽

...

Keyword(s):

Thermal Conductivity ◽

Electrical Conductivity ◽

Carrier Concentration ◽

Spark Plasma Sintering ◽

Phonon Scattering ◽

Laser Flash ◽

Magnesium Silicide ◽

X Ray ◽

Plasma Sintering ◽

Spark Plasma

AbstractMagnesium silicide (Mg2Si) has attracted much interest as an n-type thermoelectric material because it is eco-friendly, non-toxic, light, and relatively abundant compared with other thermoelectric materials. In this study, we tried to improve the thermoelectric performance by doping Sb and Ge in the Mg2Si, as well as further optimizing x in the carrier concentration to cause phonon scattering. A high purity Mg2Si was synthesized from metal Mg and Sb doped Si-Ge alloy by using spark plasma sintering (SPS) equipment. The sintered samples were cut and polished. They were evaluated by using X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses. The carrier concentration of the samples was measured by using Hall measurement equipment. The electrical conductivity and Seebeck coefficient were measured by using a standard four-probe method in a He atmosphere. The thermal conductivity was measured by using a laser-flash system. We succeeded in obtaining a Sb doped Mg2Si0.95Ge0.05 sintered body easily without any impurities with the SPS equipment. The electrical conductivity of the sample was increased, and thermal conductivity was decreased by increasing the amount of doped Sb. The dimensionless figure of merit ZT became 0.74 at 733 K in the Mg2Si0.95-xGe0.05Sbx sample with x = 0.0022.

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Tunable thermopower and thermal conductivity in Lu doped In2O3

RSC Advances ◽

10.1039/c4ra02358g ◽

2014 ◽

Vol 4 (60) ◽

pp. 31926-31931 ◽

Cited By ~ 8

Author(s):

BeiBei Zhu ◽

Ruoming Tian ◽

Tianshu Zhang ◽

Richard Donelson ◽

Thiam Teck Tan ◽

...

Keyword(s):

Thermal Conductivity ◽

Hall Effect ◽

Carrier Concentration ◽

Spark Plasma Sintering ◽

Valence State ◽

Hall Effect Measurement ◽

Precipitation Method ◽

Plasma Sintering ◽

Spark Plasma ◽

Co Precipitation

Lu doped polycrystalline In2O3 compounds (x = 0, 0.025, 0.05, 0.10, 0.15) were synthesized by a co-precipitation method followed by the spark plasma sintering processing. Hall Effect measurement indicates that the carrier concentration was drastically decreased with doping, although Lu and In have the same valence state.

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Densification and Thermal Conductivity of Y2O3-Doped AlN Ceramics by Spark Plasma Sintering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.352.227 ◽

2007 ◽

Vol 352 ◽

pp. 227-231 ◽

Cited By ~ 2

Author(s):

Qiang Shen ◽

Z.D. Wei ◽

Mei Juan Li ◽

Lian Meng Zhang

Keyword(s):

Thermal Conductivity ◽

Grain Boundaries ◽

Spark Plasma Sintering ◽

Particle Surface ◽

Boundary Phase ◽

Homogeneous Microstructure ◽

Densification Mechanism ◽

Sintering Additive ◽

Plasma Sintering ◽

Spark Plasma

AlN ceramics doped with yttrium oxide (Y2O3) as the sintering additive were prepared via the spark plasma sintering (SPS) technique. The sintering behaviors and densification mechanism were mainly investigated. The results showed that Y2O3 addition could promote the AlN densification. Y2O3-doped AlN samples could be densified at low temperatures of 1600-1700oC in 20-25 minutes. The AlN samples were characterized with homogeneous microstructure. The Y-Al-O compounds were created on the grain boundaries due to the reactions between Y2O3 and Al2O3 on AlN particle surface. With increasing the sintering temperature, AlN grains grew up, and the location of grain boundaries as well as the phase compositions changed. The Y/Al ratio in the aluminates increased, from Y3Al5O12 to YAlO3 and to Y4Al2O9. High-density, the growth of AlN grains and the homogenous dispersion of boundary phase were helpful to improve the thermal conductivity of AlN ceramics. The thermal conductivity of 122Wm-1K-1 for the 4.0 mass%Y2O3-doped AlN sample was reached.

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In-situ synthesis of n-type unfilled skutterudite with reduced thermal conductivity by hybrid flash-spark plasma sintering

Scripta Materialia ◽

10.1016/j.scriptamat.2018.07.028 ◽

2018 ◽

Vol 157 ◽

pp. 58-61 ◽

Cited By ~ 8

Author(s):

Francesco Gucci ◽

Theo Graves Saunders ◽

Michael John Reece

Keyword(s):

Thermal Conductivity ◽

Spark Plasma Sintering ◽

In Situ Synthesis ◽

Plasma Sintering ◽

Spark Plasma

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Thermoelectric properties of Cu3SbSe3 with intrinsically ultralow lattice thermal conductivity

Journal of Materials Chemistry A ◽

10.1039/c4ta02590c ◽

2014 ◽

Vol 2 (38) ◽

pp. 15829-15835 ◽

Cited By ~ 34

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.

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