scholarly journals The Effect of Reactive Electric Field-Assisted Sintering of MoS2/Bi2Te3 Heterostructure on the Phase Integrity of Bi2Te3 Matrix and the Thermoelectric Properties

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 53
Author(s):  
Yanan Wang ◽  
Cédric Bourgès ◽  
Ralph Rajamathi ◽  
C. Nethravathi ◽  
Michael Rajamathi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Electric Field ◽  
Hydrothermal Reaction ◽  
X Ray Diffraction ◽  
Nanocomposite Structure ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Field Assisted Sintering

In this work, a series of Bi2Te3/X mol% MoS2 (X = 0, 25, 50, 75) bulk nanocomposites were prepared by hydrothermal reaction followed by reactive spark plasma sintering (SPS). X-ray diffraction analysis (XRD) indicates that the native nanopowders, comprising of Bi2Te3/MoS2 heterostructure, are highly reactive during the electric field-assisted sintering by SPS. The nano-sized MoS2 particles react with the Bi2Te3 plates matrix forming a mixed-anion compound, Bi2Te2S, at the interface between the nanoplates. The transport properties characterizations revealed a significant influence of the nanocomposite structure formation on the native electrical conductivity, Seebeck coefficient, and thermal conductivity of the initial Bi2Te3 matrix. As a result, enhanced ZT values have been obtained in Bi2Te3/25 mol% MoS2 over the temperature range of 300–475 K induced mainly by a significant increase in the electrical conductivity.

Preparation and Properties of Spark Plasma Sintered AlN/BN Nano-Composites

2007 ◽  
Vol 352 ◽  
pp. 197-200
Author(s):  
Mei Juan Li ◽  
Lian Meng Zhang ◽  
Z.D. Wei ◽  
Qiang Shen ◽  
Dong Ming Zhang
Keyword(s):  
Thermal Conductivity ◽  
Chemical Process ◽  
Bending Strength ◽  
Nano Composites ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
X Ray ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma

Nano-sized turbostritic-BN (t-BN) was fabricated through chemical process using boric acid and urea in this work. By the same method, the AlN powders coated with nano-BN were prepared too. The results of X-ray diffraction (XRD) and transmission electron microscope (TEM) revealed that nano-sized t-BN was synthesized at about 600°C in nitrogen gas and it surrounded the surface of AlN particles. High-density AlN/BN nano-composites were fabricated spark plasma sintering (SPS). Microstructure and properties of AlN/BN nano-composites (5~30vol% BN) were investigated. The h-BN flake particles were homogenously dispersed at AlN grain boundaries and within grains in the AlN/BN composites. A little nano-BN additions significantly improved the bending strength of the nano-composites. However, the bending strength was decreased with the BN content increasing. The thermal conductivity of AlN/BN nano-composites was investigated too.

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

2015 ◽  
Vol 1735 ◽  
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.

Thermal Conductivities of β-SiAlONs by Mechanically Activated Combustion Synthesis

2008 ◽  
Vol 403 ◽  
pp. 139-140 ◽  
Author(s):  
R. Sivakumar ◽  
K. Aoyagi ◽  
T. Watanabe ◽  
T. Akiyama
Keyword(s):  
Thermal Conductivity ◽  
Combustion Synthesis ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Diffraction Patterns ◽  
Thermal Conductivities

–sialons (Si6-zAlzOzN8-z, z=3) synthesized by mechanically activated combustion synthesis (MA-CS) at a low N2 pressure of 1 MPa, were sintered by Spark Plasma Sintering (SPS) and thermal conductivity was measured at room temperatures. Specimens were fully densified at 1600oC for 10 mins. and showed only –sialon phases confirmed by x-ray diffraction patterns though un-reacted Si was present as impurities after MA-CS. Thermal conductivities increased with sintering temperature and had a maximum value 5.49 W m-1 K-1 for specimens sintered at 1700oC.

scholarly journals Investigation of the Microstructure and Thermoelectric Properties of P-Type BiSbTe Alloys by Usage of Different Revolutions Per Minute (RPM) During Mechanical Milling

2017 ◽  
Vol 62 (2) ◽  
pp. 1167-1171 ◽  
Author(s):  
S.-M. Yoon ◽  
B. Madavali ◽  
Y.-N. Yoon ◽  
S.-J. Hong
Keyword(s):  
Electrical Conductivity ◽  
Thermoelectric Properties ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Refinement ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball ◽  
P Type

AbstractIn this work, p-type Bi0.5Sb1.5Te3alloys were fabricated by high-energy ball milling (MA) and spark plasma sintering. Different revolutions per minute (RPM)s were used in the MA process, and their effect on microstructure, and thermoelectric properties of p-type Bi0.5Sb1.5Te3were systematically investigated. The crystal structure of milled powders and sintered samples were characterized using X-ray diffraction. All the powders exhibited the same morphology albeit with slight differences find at 1100 RPM conditions. A slight grain size refinement was observed on the fracture surfaces from 500 to 1100 RPM specimens. The temperature dependence of Seebeck coefficient, electrical conductivity, and power factors were measured as a function of temperature with different RPM conditions. The power factor shows almost same (~3.5 W/mK2at RT) for all samples due to unchanged Seebeck and electrical conductivity values. The peak ZT of 1.07 at 375K is obtained for 1100 RPM specimen due to low thermal conductivity.

Microstructure and thermoelectric properties of CuInSe2/In2Se3 compound

2018 ◽  
Vol 32 (03) ◽  
pp. 1850018 ◽  
Author(s):  
Kang Wang ◽  
Jing Feng ◽  
Zhen-Hua Ge ◽  
Peng Qin ◽  
Jie Yu
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Room Temperature ◽  
Solvothermal Method ◽  
Chalcopyrite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

CuInSe2 powders were synthesized by solvothermal method, and then the CuInSe2/In2Se3 bulk samples were fabricated by spark plasma sintering (SPS) technique. To investigate the phase composition, the powders were determined by X-ray diffraction (XRD). The microstructures of the powders and bulk samples were observed by scanning electron microscopy (SEM). The transportation of the electronic properties and thermal conductivity were measured at room temperature to 700 K. According to the results, the CuInSe2 powders appeared in flower-like patterns which ranged from 3 [Formula: see text]m to 6 [Formula: see text]m. CuInSe2 powders were synthesized at 180[Formula: see text]C with a chalcopyrite structure. The Seebeck coefficient increased significantly in composite thermoelectric materials up to [Formula: see text] at 623 K. The thermal conductivity of the sample significantly decreases from the room temperature to 700 K. The CuInSe2 bulk composite by solvothermal method achieves the highest ZT value of 0.187 at 700 K.

Development of WC-Fe3Al Composites by Spark Plasma Sintering Process

2016 ◽  
Vol 881 ◽  
pp. 307-312
Author(s):  
Luis Antonio C. Ybarra ◽  
Afonso Chimanski ◽  
Sergio Gama ◽  
Ricardo A.G. da Silva ◽  
Izabel Fernanda Machado ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Zinc Stearate ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Al Composite ◽  
Spark Plasma ◽  
Short Time ◽  
Vibration Mill

Tungsten carbide (WC) based composites are usually produced with cobalt, but this binder has the inconvenience of shortage, unstable price and potential carcinogenicity. The objective of this study was to develop WC composite with intermetallic Fe3Al matrix. Powders of WC, iron and aluminum, with composition WC-10 wt% Fe3Al, and 0.5 wt% zinc stearate were milled in a vibration mill for 6 h and sintered in a SPS (spark plasma sintering) furnace at 1150 °C for 8 min under pressure of 30 MPa. Measured density and microstructure analysis showed that the composite had significant densification during the (low-temperature, short time) sintering, and X-ray diffraction analysis showed the formation of intermetallic Fe3Al. Analysis by Vickers indentation resulted in hardness of 11.2 GPa and fracture toughness of 24.6 MPa.m1/2, showing the feasibility of producing dense WC-Fe3Al composite with high mechanical properties using the SPS technique.

Spark Plasma Sintering of Ti-4.5Al-3V-2Fe-2Mo (SP-700)

2010 ◽  
Vol 654-656 ◽  
pp. 819-822
Author(s):  
Genki Kikuchi ◽  
Hiroshi Izui ◽  
Yuya Takahashi ◽  
Shota Fujino
Keyword(s):  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Volume Fraction ◽  
Titanium Boride ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Tib2 Particles

In this study, we focused on the sintering performance of Ti-4.5Al-3V-2Mo-2Fe (SP-700) and mechanical properties of SP-700 reinforced with titanium boride (TiB/SP-700) fabricated by spark plasma sintering (SPS). TiB whiskers formed in titanium by a solid-state reaction of titanium and TiB2 particles were analyzed with scanning electron microscopy and X-ray diffraction. The TiB/SP-700 was sintered at temperatures of 1073, 1173, and 1273 K and a pressure of 70 MPa for 10, 30, and 50 min. The volume fraction of TiB ranged from 1.7 vol.% to 19.9 vol.%. Tensile tests of TiB/SP-700 were conducted at room temperature, and the effect of TiB volume fraction on the tensile properties was investigated.

Lateral deformations of a crystal of potassium acid phthalate in an external electric field

2021 ◽  
Vol 54 (5) ◽  
pp. 1317-1326
Author(s):  
Arsen Petrenko ◽  
Nataliya Novikova ◽  
Alexander Blagov ◽  
Anton Kulikov ◽  
Yury Pisarevskii ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Electric Field ◽  
External Electric Field ◽  
Applied Field ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Potassium Acid Phthalate ◽  
Acid Phthalate

The anisotropy of deformations in potassium acid phthalate crystals arising under the action of an external electric field up to 1 kV mm−1 applied along the [001] polar axis was studied using X-ray diffraction methods at room temperature. Electrical conductivity was measured and rocking curves for reflections 400, 070 and 004 were obtained by time-resolved X-ray diffractometry in Laue and Bragg geometries. Two saturation processes were observed from the time dependences of the electrical conductivity. A shift in the diffraction peaks and a change in their intensity were found, which indicated a deformation of the crystal structure. Rapid piezoelectric deformation and reversible relaxation-like deformation, kinetically similar to the electrical conductivity of a crystal, were revealed. The deformation depended on the polarity and strength of the applied field. The deformation was more noticeable in the [100] direction and was practically absent in the [001] direction of the applied field. X-ray diffraction analysis revealed a disordered arrangement of potassium atoms, i.e. additional positions and vacancies. The heights of potential barriers between the positions of K+ ions and the paths of their possible migration in the crystal structure of potassium acid phthalate were determined. The data obtained by time-resolved X-ray diffractometry and X-ray structure analysis, along with additional electrophysical measurements, allow the conclusion that the migration of charge carriers (potassium cations) leads to lateral deformation of the crystal structure of potassium phthalate in an external electric field.

Spark Plasma Sintering of Paper-Derived Ti3AlC2-Based Composites: Influence of Sintering Temperature

2021 ◽  
Vol 1016 ◽  
pp. 1790-1796
Author(s):  
Maxim Syrtanov ◽  
Egor Kashkarov ◽  
Tatyana Murashkina ◽  
Nahum Travitzky
Keyword(s):  
Phase Composition ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Total Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbide Phases ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

This paper describes the influence of sintering temperature on phase composition and microstructure of paper-derived Ti3AlC2 composites fabricated by spark plasma sintering. The composites were sintered at 100 MPa pressure in the temperature range of 1150-1350 °C. Phase composition and microstructure were analyzed by X-ray diffraction and scanning electron microscopy, respectively. The multiphase structure was observed in the sintered composites consisting of Ti3AlC2, Ti2AlC, TiC and Al2O3 phases. The decomposition of the Ti3AlC2 phase into Ti2AlC and TiC carbide phases was observed with temperature rise. The total content of Ti3AlC2 and Ti2AlC phases was reduced from 84.5 vol.% (1150 °C) to 69.5 vol.% (1350 °C). The density of composites affected by both the content of TiC phase and changes in porosity.

Thermoelectric Performance of Glass Microsphere Dispersed Bi-Sb Composites at Low Temperature

2013 ◽  
Vol 743-744 ◽  
pp. 120-125
Author(s):  
Zhen Chen ◽  
Ye Mao Han ◽  
Min Zhou ◽  
Rong Jin Huang ◽  
Yuan Zhou ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Sem Analysis ◽  
Glass Microsphere ◽  
Thermoelectric Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Measurement Results

In the present study, the glass microsphere dispersed Bi-Sb thermoelectric materials have been fabricated through mechanical alloying followed by pressureless sintering. The phase composition and the microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Electrical conductivity, Seebeck coefficient and thermal conductivity were measured in the temperature range of 77~300 K. The ZT values were calculated according to the measurement results. The results showed that the electrical conductivity, Seebeck coefficient and thermal conductivity decreased by adding glass microsphere into Bi-Sb thermoelectric materials. However, the optimum ZT value of 0.24 was obtained at 260 K, which was increased 10% than that of the Bi-Sb matrix. So it is confirmed that the thermoelectric performance of Bi-Sb-based materials can be improved by adding moderate glass microspheres.

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