Fabrication of Bi-Te Based Thermoelectric Semiconductors by Using Hybrid Powders

2005 ◽  
Vol 297-300 ◽  
pp. 875-880
Author(s):  
Cheol Ho Lim ◽  
Ki Tae Kim ◽  
Yong Hwan Kim ◽  
Dong Choul Cho ◽  
Young Sup Lee ◽  
...  

P-type Bi0.5Sb1.5Te3 compounds doped with 3wt% Te were fabricated by spark plasma sintering and their mechanical and thermoelectric properties were investigated. The sintered compounds with the bending strength of more than 50MPa and the figure-of-merit 2.9×10-3/K were obtained by controlling the mixing ratio of large powders (PL) and small powders (PS). Compared with the conventionally prepared single crystal thermoelectric materials, the bending strength was increased up to more than three times and the figure-of-merit Z was similar those of single crystals. It is expected that the mechanical properties could be improved by using hybrid powders without degradation of thermoelectric properties.

2020 ◽  
Vol 21 (4) ◽  
pp. 628-634
Author(s):  
O. Kostyuk ◽  
B. Dzundza ◽  
M. Maksymuk ◽  
V. Bublik ◽  
L. Chernyak ◽  
...  

Bismuth antimony telluride is the most commonly used commercial thermoelectric material for power generation and refrigeration over the temperature range of 200–400 K. Improving the performance of these materials is a complected balance of optimizing thermoelectric properties. Decreasing the grain size of Bi0.5Sb1.5Te3 significantly reduces the thermal conductivity due to the scattering phonons on the grain boundaries. In this work, it is shown the advances of spark plasma sintering (SPS) for the preparation of nanocrystalline p-type thermoelectrics based on Bi0.5Sb1.5Te3 at different temperatures (240, 350, 400oC). The complex study of structural and thermoelectric properties of Bi0.5Sb1.5Te3 were presented. The high dimensionless thermoelectric figure of merit ZT ~ 1 or some more over 300–400 K temperature range for nanocrystalline p-type Bi0.5Sb1.5Te3 was obtained.


2015 ◽  
Vol 3 (20) ◽  
pp. 10777-10786 ◽  
Author(s):  
A. Bhardwaj ◽  
N. S. Chauhan ◽  
D. K. Misra

Several nanostructuring methods have been demonstrated to produce a variety of nanostructured materials, and these methods are well recognized as effective paradigms for improving the performance of thermoelectric materials.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Beibei Liang ◽  
Zijun Song ◽  
Minghui Wang ◽  
Lianjun Wang ◽  
Wan Jiang

Graphene/Bi2Te3thermoelectric materials were prepared by spark plasma sintering (SPS) using hydrothermal synthesis of the powders as starting materials. The X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM) were used to investigate the phase composition and microstructure of the as-prepared materials. Electrical resistivity, Seebeck coefficient, and thermal conductivity measurement were applied to analyze the thermoelectric properties. The effect of graphene on the performance of the thermoelectric materials was studied. The results showed that the maximum dimensionless figure of merit of the graphene/Bi2Te3composite with 0.2 vol.% graphene was obtained at testing temperature 475 K, 31% higher than the pure Bi2Te3.


2005 ◽  
Vol 486-487 ◽  
pp. 253-256 ◽  
Author(s):  
D.M. Lee ◽  
Cheol Ho Lim ◽  
Dong Choul Cho ◽  
Seung Y. Shin ◽  
Won Seung Cho

N-type Bi2Te3 based thermoelectric compound was prepared by spark plasma sintering with a temperature range of 340~460°C and powder size of ~75㎛, 76~150㎛, 151~250㎛. Thermoelectric properties of the compound were measured as a function of the sintering temperature and powder size. With increasing sintering temperature, the electrical resistivity and thermal conductivity of the compound greatly changed because of the increase in relative density. The Seebeck coefficient and electrical resistivity were varied largely with increasing powder size. Therefore, the compound sintered at 460°C, with the powder of ~75㎛, showed a figure of merit of 2.44 x 10-3/K. Also, the bending strength was 75MPa.


2007 ◽  
Vol 1044 ◽  
Author(s):  
Masayasu Akasaka ◽  
Tsutomu Iida ◽  
Youhiko Mito ◽  
Takeru Omori ◽  
Yohei Oguni ◽  
...  

AbstractPolycrystalline Mg2Si was fabricated from a reused-Silicon source, based on Si sludge, using Spark Plasma Sintering technique. The n-type and p-type dopants, bismuth (Bi) and silver (Ag), respectively, were incorporated into the Mg2Si. The thermoelectric properties were estimated from 300 to 873K. The power factors of undoped and Bi-doped samples from the reused-Si source were comparable to those from a solar grade Si source (99.99999%). The power factor was estimated to be 2.5 × 10-5 W/cmK2 for the Bi-doped sample from the reused-Si source. However, the power factor of the Ag-doped, p-type sample from the reused-Si source was lower than that from solar grade Si source. The dimensionless figures of merit of samples from the resused-Si source were slightly lower than those from a solar grade Si source. The dimensionless figure of merit was estimated to be 0.53 at 812 K for Bi-doped sample from the reused-Si source.


2007 ◽  
Vol 336-338 ◽  
pp. 864-867
Author(s):  
Wei Ren ◽  
Xue Quan Liu ◽  
Xiao Lin Wang ◽  
Hong Yi Jiang

Polycrystalline samples of Bi2Te3 based alloys were prepared by powder metallurgy processing including a melting-grinding and a sintering procedure of compacted pellets. Two sintering procedures as hot-pressing and spark plasma sintering (SPS) were employed. The thermoelectric properties and mechanical strength were measured in all case. Thermoelectric properties for p-type (Bi0.25Sb0.75)2Te3 and n-type Bi2(Te0.2Se0.8)3 changed with sintering temperature in both sintering methods. Mechanical strength and relative density increase with sintering temperature in two sintering procedures. The results firmly suggest that both sintering procedures are promising to obtain high performance thermoelectric materials.


1997 ◽  
Vol 478 ◽  
Author(s):  
K. Park ◽  
J. Seo ◽  
C. Lee

AbstractThe p-type Bi0.5Sb1.5Te3 compounds with Te dopant (4.0 and 6.0 wt%) and without dopant were fabricated by hot extrusion in the temperature range of 300 to 510 °C under an extrusion ratio of 20:1. The undoped and Te doped compounds were highly dense and showed high crystalline quality. The grains contained many dislocations and were fine equiaxed (˜ 1.0 μm) owing to the dynamic recrystallization during the extrusion. The hot extrusion gave rise to the preferred orientation of grains. The bending strength and the figure of merit of the undoped and Te doped compounds were increased with increasing the extrusion temperature. The Te dopant significantly increased the figure of merit. The values of the figure of merit of the undoped and 4.0 wt% Te-doped compounds hot extruded at 440 °C were 2.11×10−3/K and 2.94×10−3/K, respectively.


2006 ◽  
Vol 415 (1-2) ◽  
pp. 251-256 ◽  
Author(s):  
Satoru Furuyama ◽  
Tsutomu Iida ◽  
Shinsuke Matsui ◽  
Masayasu Akasaka ◽  
Keishi Nishio ◽  
...  

2021 ◽  
Vol 878 ◽  
pp. 83-88
Author(s):  
Hideaki Tsukamoto ◽  
Chang Sun

This study aims to fabricate SiC whisker (w)/ particle (p)-reinforced magnesium (Mg) composites with enhanced mechanical properties using spark plasma sintering (SPS) methods. It has been confirmed that dispersing state of SiCw can be improved by addition of SiCp. However, due to presence of voids and cracks between the oxide layers, surrounding SiCw/p, and Mg matrix in the composites, SiCw with SiCp cannot contribute to enhance the bending strength of Mg matrix. This issue can be tackled by adding low melting point metals such as Sn into the composites to fill the defects in the composites.


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