Bi2Te3 and Bi2Te3/Nano-SiC Prepared by Mechanical Alloying and Spark Plasma Sintering

2007 ◽  
Vol 280-283 ◽  
pp. 397-400 ◽  
Author(s):  
Jing Liu ◽  
Jing Feng Li
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Mechanical Alloying ◽  
Seebeck Coefficient ◽  
Spark Plasma Sintering ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Mechanically Alloyed ◽  
Plasma Sintering ◽  
Spark Plasma

Bi2Te3-based alloys are currently best-known, technological thermoelectric materials near room temperature. In this paper, Bi2Te3 and nano-SiC dispersed Bi2Te3 were prepared by mechanical alloying followed by spark plasma sintering (SPS). Raw powders of Bi, Te and SiC were mixed and mechanically alloyed in an argon atmosphere using a planetary ball mill. The SPS temperature was 623K, and the holding time was 5 minutes. The samples were characterized by X-ray Diffraction (XRD) and Scanning electron Microscope (SEM). The thermoelectric properties: i.e. Seebeck coefficient, electrical resistivity and thermal conductivity were measured at temperatures from room temperature to 573K, followed by the evaluation of figure of merit. The results revealed that the SiC dispersion in the Bi2Te3 matrix increased Seebeck coefficient. Although the electrical resistivity was increased somewhat, the thermal conductivity was reduced by the SiC dispersion, indicating that promising thermoelectric materials with enhanced mechanical properties may be obtained in the nano-SiC dispersed Bi2Te3 composites with optimal compositions.

Microstructure and Thermoelectric Properties of P-Type Bi0.5Sb1.5Te3 Compounds Prepared by Spark Plasma Sintering

2006 ◽  
Vol 510-511 ◽  
pp. 1122-1125
Author(s):  
Won Seung Cho ◽  
Dong Choul Cho ◽  
Cheol Ho Lim ◽  
C.H. Lee ◽  
Woon Suk Hwang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Spark Plasma Sintering ◽  
Hydrogen Reduction ◽  
Sintering Temperature ◽  
Reduction Process ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
P Type

The microstructure and thermoelectrical properties of the 4wt% Te doped p-type Bi0.5Sb1.5Te3 compounds, fabricated by using spark plasma sintering in the temperature ranging from 250°C to 350°C, were characterized. The density of the sintered compounds was increased to 99.2% of theoretical density by carrying out the consolidation at 350oC for 2 min. The Seebeck coefficient, thermal conductivity and electrical resistivity were dependent on hydrogen reduction process and sintering temperature. The Seebeck coefficient increased with reduction process while the electrical resisitivity significantly decreased. Also, the electrical resistivity decreased and thermal conductivity increased with sintering temperature. The results suggest that the carrier density and mobility vary with reduction process and sintering temperature. The highest figure of merit of 3.5×10-3/K was obtained for the compounds spark plasma sintered at 350°C for 2 min by using the hydrogen-reduced powders.

Thermoelectric Properties of Ag1-xPbmSbTe2+m Compounds

2007 ◽  
Vol 336-338 ◽  
pp. 854-856
Author(s):  
Yong Gao Yan ◽  
Xin Feng Tang ◽  
Hai Jun Liu ◽  
Ling Ling Yin ◽  
Qing Jie Zhang
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
M 10 ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Type Conduction

Ag1-xPbmSbTe2+m (m = 6, 10, 18; x = 0, 0.5, 0.75) compounds were prepared by melting-spark plasma sintering (SPS) process. The effects of m and x on the thermoelectric properties of the compounds were investigated. The results indicate that all samples are n-type conduction. For Ag1-xPb18SbTe20 (x = 0, 0.5, 0.75), the electrical conductivity decreases, whereas Seebeck coefficient increases, with increasing Ag concentration. For AgPbmSbTe2+m (m = 6, 10, 18), as m increases, the Seebeck coefficient slightly decreases and the electrical conductivity increases first, with a maximum at m =10, and then decreases. The thermal conductivity increases with increasing m.

Thermoelectric performance enhancement of Cu2S by Se doping leading to a simultaneous power factor increase and thermal conductivity reduction

2017 ◽  
Vol 5 (31) ◽  
pp. 7845-7852 ◽  
Author(s):  
Yao Yao ◽  
Bo-Ping Zhang ◽  
Jun Pei ◽  
Yao-Chun Liu ◽  
Jing-Feng Li
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Power Factor ◽  
Performance Enhancement ◽  
Thermoelectric Performance ◽  
Plasma Sintering ◽  
Se Doping ◽  
Spark Plasma

A series of single-phased Cu2S1−xSex bulks were prepared by using mechanical alloying (MA) combined with spark plasma sintering (SPS). Our results suggest that the TE properties of Cu2S can be greatly enhanced by simultaneously increasing PF and decreasing κ via doping a sole Se element.

Synthesis of Fullerene by Spark Plasma Sintering and Thermomechanical Transformation of Fullerene Into Diamond on Fe-C Composites

2009 ◽  
Vol 1243 ◽  
Author(s):  
Francisco C. Robles-Hernández ◽  
H. A. Calderon
Keyword(s):  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Thermomechanical Processing ◽  
Control Agent ◽  
Mechanically Alloyed ◽  
Characterization Methods ◽  
Nanostructured Composite ◽  
Heating And Cooling ◽  
Plasma Sintering ◽  
Spark Plasma

ABSTRACTIn this work, results are presented regarding the characterization of nanostructured Fe matrix composites reinforced with fullerene. The fullerene is a mix of 15 wt.%C60, 5 wt.%C70 and 80 wt.% soot that is the product of the primary synthesis of C60. The composite has been produced by means of mechanical alloying and sintered by Spark Plasma Sintering (SPS). The characterization methods include XRD, SEM and TEM. The C60 and C70 withstand mechanical alloying, SPS, and thermomechanical processing and act as a control agent during mechanical alloying. The results show that the mechanically alloyed and SPS product is a nanostructured composite. A larger amount of C60 is found in the sintered composite than in the original fullerene mix, which is attributed to an in-situ synthesis of C60 during the SPS process. The synthesis of C60 is presumably assisted by the catalytic nature of Fe and the electric field generated during the SPS process. In order to study the effect of high temperature, high strain, high heating and cooling rates on C60, the composite is subjected to a thermomechanical processing; demonstrating that some of the C60 resists the above described environment and some of it partially transforms into diamond.

Thermoelectric Properties of Bi2Te3-Sb2Te3 Compounds Prepared by Ma-Pulse Discharge Sintering Process

1999 ◽  
Vol 581 ◽  
Author(s):  
R.E. Park ◽  
Y.H. Park ◽  
T. Abe
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Mechanical Alloying ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Pulse Discharge ◽  
Sintering Process ◽  
Mechanically Alloyed ◽  
Fine Grain ◽  
Process Effects

ABSTRACTThe Bi2Te3-Sb2Te3 compounds with the composition of useful thermoelectric cooling materials were prepared by mechanical alloying-pulse discharge sintering process. Effects of the process on the Seebeck coefficient, electrical resistivity and thermal conductivity were investigated. Temperature dependence of the Hall coefficient was also observed in the temperature range 80 - 325 K.The figure of merit, Z, was found to be about 4.0 × 10−1K−1 at room temperature in the 25%Bi2Te3-75%Sb2Te3 composition sintered at 618K using grain refined mechanically alloyed powders which had the size of under 32 μm. The value of Z was remarkably improved with a decrease of the thermal conductivity shown in the fine grain compacts fabricated by mechanical alloying-pulse discharge sintering process.

Effect of Oxygen Content on Thermoelectric Properties of Sintered Bi-Te Based Compounds

2004 ◽  
Vol 449-452 ◽  
pp. 905-908 ◽  
Author(s):  
Dong Choul Cho ◽  
Cheol Ho Lim ◽  
D.M. Lee ◽  
Seung Y. Shin ◽  
Chung Hyo Lee
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Oxygen Content ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Air Atmosphere ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Effect Of Oxygen

The n-type thermoelectric materials of Bi2Te2.7Se0.3 doped with SbI3 were prepared by spark plasma sintering technique. The powders were ball-milled in an argon and air atmosphere. Then, powders were reduced in H2 atmosphere. Effects of oxygen content on the thermoelectric properties of Bi2Te2.7Se0.3 compounds have been investigated. Seebeck coefficient, electrical resistivity and thermal conductivity of the sintered compound were measured at room temperature. It was found that the effect of atmosphere during the powder production was remarkable and thermoelectric properties of sintered compound were remarkably improved by H2 reduction of starting powder. The obtained maximum figure of merit was 2.4 x 10-3/K.

Fabrication of Mg2Si Thermoelectric Materials by Mechanical Alloying and Spark-Plasma Sintering Process

2006 ◽  
Vol 6 (11) ◽  
pp. 3429-3432
Author(s):  
Chung-Hyo Lee ◽  
Seong-Hee Lee ◽  
Sung-Yong Chun ◽  
Sang-Jin Lee
Keyword(s):  
Grain Size ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Atomic Ratio ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma

A mixture of pure Mg and Si powders with an atomic ratio 2:1 has been subjected to mechanical alloying (MA) at room temperature to prepare the Mg2Si thermoelectric material. Mg2Si intermetallic compound with a grain size of 50 nm can be obtained by MA of Mg66.7Si33.3 powders for 60 hours and subsequently annealed at 620 °C. Consolidation of the MA powders was performed in a spark plasma sintering (SPS) machine using graphite dies up to 800–900 °C under 50 MPa. The shrinkage of consolidated samples during SPS was significant at about 250 °C and 620 °C. X-ray diffraction data shows that the SPS compact from 60 h MA powders consolidated up to 800 °C consists of only nanocrystalline Mg2Si compound with a grain size of 100 nm.

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