scholarly journals Extremely Fast and Cheap Densification of Cu2S by Induction Melting Method

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7311
Author(s):  
Paweł Nieroda ◽  
Krzysztof Ziewiec ◽  
Juliusz Leszczyński ◽  
Paweł Rutkowski ◽  
Andrzej Koleżyński
Keyword(s):  
Chemical Composition ◽  
Figure Of Merit ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Temperature Range ◽  
Plasma Sintering ◽  
Melting Technique ◽  
Thermoelectric Transport Properties ◽  
Spark Plasma ◽  
Phase And Chemical Composition

The aim of this work was to obtain dense Cu2S superionic thermoelectric materials, homogeneous in terms of phase and chemical composition, using a very fast and cheap induction-melting technique. The chemical composition was investigated via scanning electron microscopy (SEM) combined with an energy-dispersive spectroscopy (EDS) method, and the phase composition was established by X-ray diffraction (XRD). The thermoelectric figure of merit ZT was determined on the basis of thermoelectric transport properties, i.e., Seebeck coefficient, electrical and thermal conductivity in the temperature range of 300–923 K. The obtained values of the ZT parameter are comparable with those obtained using the induction hot pressing (IHP) technique and about 30–45% higher in the temperature range of 773–923 K in comparison with Cu2S samples densified with the spark plasma sintering (SPS) technique.

scholarly journals Hf-Doping Effect on the Thermoelectric Transport Properties of n-Type Cu0.01Bi2Te2.7Se0.3

2020 ◽  
Vol 10 (14) ◽  
pp. 4875
Author(s):  
Jeong Yun Hwang ◽  
Sura Choi ◽  
Sang-il Kim ◽  
Jae-Hong Lim ◽  
Soon-Mok Choi ◽  
...  
Keyword(s):  
Carrier Mobility ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
Mass Difference ◽  
Solidification Process ◽  
Transport Parameters ◽  
Plasma Sintering ◽  
Thermoelectric Transport Properties ◽  
Spark Plasma ◽  
Melt Solidification

Polycrystalline bulks of Hf-doped Cu0.01Bi2Te2.7Se0.3 are prepared via a conventional melt-solidification process and subsequent spark plasma sintering technology, and their thermoelectric performances are evaluated. To elucidate the effect of Hf-doping on the thermoelectric properties of n-type Cu0.01Bi2Te2.7Se0.3, electronic and thermal transport parameters are estimated from the measured data. An enlarged density-of-states effective mass (from ~0.92 m0 to ~1.24 m0) is obtained due to the band modification, and the power factor is improved by Hf-doping benefitting from the increase in carrier concentration while retaining carrier mobility. Additionally, lattice thermal conductivity is reduced due to the intensified point defect phonon scattering that originated from the mass difference between Bi and Hf. Resultantly, a peak thermoelectric figure of merit zT of 0.83 is obtained at 320 K for Cu0.01Bi1.925Hf0.075Te2.7Se0.3, which is a ~12% enhancement compared to that of the pristine Cu0.01Bi2Te2.7Se0.3.

High Temperature Thermoelectric Properties of AgPb18+xSbTe20

2007 ◽  
Vol 336-338 ◽  
pp. 857-859
Author(s):  
Wen Bing Zhang ◽  
Li Dong Chen ◽  
Xiao Ya Li
Keyword(s):  
Crystal Structure ◽  
Figure Of Merit ◽  
Lead Telluride ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Pure Lead ◽  
Melting Method ◽  
Temperature Range ◽  
Plasma Sintering ◽  
Spark Plasma

Polycrystalline AgPb18+xSbTe20 compounds with different Pb contents (x=1-4) were prepared by melting method and spark plasma sintering techniques. The crystal structure and chemical composition were determined by XRD and EPMA. The thermal conductivity, electrical conductivity and Seebeck coefficient were measured in the temperature range of 300-800K. The dimensionless thermoelectric figure of merit (ZT) of AgPb18+xSbTe20 (x=1-4) increases in the whole temperature range of 300-750K which is different to the pure lead telluride compound. The maximum ZT value reaches 1.03 at 800K.

scholarly journals Development of Spark Plasma Syntering (SPS) technology for preparation of nanocrystalline p-type thermoelctrics based on (BiSb)2Te3

2020 ◽  
Vol 21 (4) ◽  
pp. 628-634
Author(s):  
O. Kostyuk ◽  
B. Dzundza ◽  
M. Maksymuk ◽  
V. Bublik ◽  
L. Chernyak ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Antimony Telluride ◽  
Bismuth Antimony Telluride ◽  
Thermoelectric Figure ◽  
Temperature Range ◽  
Plasma Sintering ◽  
Different Temperatures ◽  
Spark Plasma ◽  
P Type

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.

scholarly journals Fabrication and Thermoelectric Properties of Graphene/Bi2Te3Composite Materials

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Beibei Liang ◽  
Zijun Song ◽  
Minghui Wang ◽  
Lianjun Wang ◽  
Wan Jiang
Keyword(s):  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Conductivity Measurement ◽  
Testing Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensionless Figure Of Merit ◽  
Plasma Sintering ◽  
Spark Plasma

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.

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.

scholarly journals Synthesis of Nb0.8Hf0.2FeSb0.98Sn0.02 and Hf0.25Zr0.25Ti0.5NiSn0.98Sb0.02 Half-Heusler Materials and Fabrication of Thermoelectric Generators

2021 ◽  
Vol 59 (12) ◽  
pp. 904-910
Author(s):  
Sung-Jae Joo ◽  
Ji-Hee Son ◽  
JeongIn Jang ◽  
Bong-Seo Kim ◽  
Bok-Ki Min
Keyword(s):  
Temperature Gradient ◽  
Maximum Power ◽  
Induction Melting ◽  
Figures Of Merit ◽  
Arc Melting ◽  
Plasma Sintering ◽  
Melting Technique ◽  
Spark Plasma ◽  
P Type ◽  
Metal Layers

In this study, half-Heusler (HH) thermoelectric materials Nb0.8Hf0.2FeSb0.98Sn0.02 (p-type) and Hf0.25Zr0.25Ti0.5NiSn0.98Sb0.02 (n-type) were synthesized using induction melting and spark plasma sintering. For alloying, a conventional induction melting technique was employed rather than arc melting, for mass production compatibility, and the thermoelectric properties of the materials were analyzed. The maximum dimensionless figures of merit (zTmax) were 0.75 and 0.82 for the p- and n-type material at 650 oC and 600 oC, respectively. These materials were then used to fabricate generator modules, wherein two pairs of p- and nlegs without interfacial metal layers were brazed on direct bonded copper (DBC)/Al2O3 substrates using a Zrbased alloy. A maximum power of 0.57 W was obtained from the module by applying a temperature gradient of 476 oC, which corresponds to a maximum power density of 1.58 W cm -2 when normalized by the area of the material. The maximum electrical conversion efficiency of the module was 3.22% at 476 oC temperature gradient. This value was negatively affected by the non-negligible contact resistivity of the brazed interfaces, which ranged from 6.63 × 10 -9 Ωm2 to 7.54 × 10 -9 Ω m2 at hot-side temperatures of 190 oC and 517 oC, respectively. The low electrical resistivity of the HH materials makes it especially important to develop a brazing technique for ultralow resistance contacts.

scholarly journals Thermoelectric Properties of Cu2Se Synthesized by Hydrothermal Method and Densified by SPS Technique

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3650
Author(s):  
Paweł Nieroda ◽  
Anna Kusior ◽  
Juliusz Leszczyński ◽  
Paweł Rutkowski ◽  
Andrzej Koleżyński
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Thermoelectric Properties ◽  
Composition Studies ◽  
X Ray Diffraction ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Thermoelectric Transport Properties ◽  
Spark Plasma ◽  
Very High

The aim of the work was to obtain copper (I) selenide Cu2Se material with excellent thermoelectric properties, synthesized using the hydrothermal method and densified by the spark plasma sintering (SPS) method. Chemical and phase composition studies were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. Measurements of thermoelectric transport properties, i.e., electrical conductivity, the Seebeck coefficient, and thermal conductivity in the temperature range from 300 to 965 K were carried out. Based on these results, the temperature dependence of the thermoelectric figure of merit ZT as a function of temperature was determined. The obtained, very high ZT parameter (ZT~1.75, T = 965 K) is one of the highest obtained so far for undoped Cu2Se.

SEEBECK COEFFICIENTS OF Mn-Si MATERIALS PREPARED BY SPARK PLASMA SINTERING

2004 ◽  
Vol 18 (16) ◽  
pp. 2279-2286 ◽  
Author(s):  
ZHI MIN WANG ◽  
YI DONG WU ◽  
YUAN JIN HE
Keyword(s):  
Seebeck Coefficient ◽  
Spark Plasma Sintering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Seebeck Coefficients ◽  
Plasma Sintering ◽  
Pure Phase ◽  
Spark Plasma ◽  
P Type

MnSi 1.73 and MnSi samples were grown by spark plasma sintering (SPS) from different Si / Mn ratio powders, at different sintering temperatures, and for different sintering times. X-ray diffraction (XRD) measurements showed samples containing MnSi and MnSi 1.73 and Si phases, depending on the initial stoichiometries. Measurements of the Seebeck coefficient revealed p-type conductance for all samples. The Seebeck coefficients of the samples with MnSi pure phase were very low (about 10 μ V/K) and changed little at the temperature range measured. The Seebeck coefficients of the samples with MnSi 1.73, MnSi and Si phases were similar to that of the sample with near-pure MnSi 1.73 phase, which were larger than those of the samples with MnSi 1.73 and MnSi phases, but a little smaller than those of the samples with MnSi 1.73 and Si phases. It seems that, for the samples with the same phases, larger ratio of the strongest intensity peak of MnSi 1.73 to [Formula: see text], MnSi 1.73 to [Formula: see text] or both lead to larger Seebeck coeffiecients.

scholarly journals Experimental Realization of Heavily p-doped Half-Heusler CoVSn Compound

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1459
Author(s):  
Sadeq Hooshmand Zaferani ◽  
Alireza Darebaghi ◽  
Soon-Jik Hong ◽  
Daryoosh Vashaee ◽  
Reza Ghomashchi
Keyword(s):  
Phase Diagram ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Experimental Realization ◽  
X Ray ◽  
Plasma Sintering ◽  
Phase Compound ◽  
Thermoelectric Transport Properties ◽  
Spark Plasma ◽  
Multi Phase

Hypothetical half-Heusler (HH) ternary alloy of CoVSn has already been computationally investigated for possible spintronics and thermoelectric applications. We report the experimental realization of this compound and the characterizations of its thermoelectric properties. The material was synthesized by a solid-state reaction of the stoichiometric amounts of the elements via powder metallurgy (30 h mechanical milling and annealing at 900 °C for 20 h) and spark plasma sintering (SPS). The temperature-dependent ternary thermodynamic phase diagram of Co-V-Sn was further calculated. The phase diagram and detailed analysis of the synthesized material revealed the formation of the non-stoichiometry HH CoVSn, mixed with the binary intermetallic phases of SnV3, Co2Sn, and Co3V. The combination of X-ray diffraction, energy-dispersive X-ray spectroscopy, and thermoelectric transport properties confirmed the formation of a multi-phase compound. The analysis revealed the predicted thermoelectric features (zT = 0.53) of the highly doped CoVSn to be compromised by the formation of intermetallic phases (zT ≈ 0.007) during synthesis. The additional phases changed the properties from p- to overall n-type thermoelectric characteristics.

scholarly journals Synthesis, microstructure, and properties of high purity Mo2TiAlC2 ceramics fabricated by spark plasma sintering

2020 ◽  
Vol 9 (6) ◽  
pp. 759-768
Author(s):  
Yunhui Niu ◽  
Shuai Fu ◽  
Kuibao Zhang ◽  
Bo Dai ◽  
Haibin Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Flexural Strength ◽  
Spark Plasma Sintering ◽  
Layered Structure ◽  
High Purity ◽  
High Fracture Toughness ◽  
Temperature Range ◽  
Microstructure And Properties ◽  
Plasma Sintering ◽  
Spark Plasma

AbstractThe synthesis, microstructure, and properties of high purity dense bulk Mo2TiAlC2 ceramics were studied. High purity Mo2TiAlC2 powder was synthesized at 1873 K starting from Mo, Ti, Al, and graphite powders with a molar ratio of 2:1:1.25:2. The synthesis mechanism of Mo2TiAlC2 was explored by analyzing the compositions of samples sintered at different temperatures. It was found that the Mo2TiAlC2 phase was formed from the reaction among Mo3Al2C, Mo2C, TiC, and C. Dense Mo2TiAlC2 bulk sample was prepared by spark plasma sintering (SPS) at 1673 K under a pressure of 40 MPa. The relative density of the dense sample was 98.3%. The mean grain size was 3.5 μm in length and 1.5 μm in width. The typical layered structure could be clearly observed. The electrical conductivity of Mo2TiAlC2 ceramic measured at the temperature range of 2–300 K decreased from 0.95 × 106 to 0.77 × 106 Ω–1·m–1. Thermal conductivity measured at the temperature range of 300–1273 K decreased from 8.0 to 6.4 W·(m·K)–1. The thermal expansion coefficient (TEC) of Mo2TiAlC2 measured at the temperature of 350–1100 K was calculated as 9.0 × 10–6 K–1. Additionally, the layered structure and fine grain size benefited for excellent mechanical properties of low intrinsic Vickers hardness of 5.2 GPa, high flexural strength of 407.9 MPa, high fracture toughness of 6.5 MPa·m1/2, and high compressive strength of 1079 MPa. Even at the indentation load of 300 N, the residual flexural strength could hold 84% of the value of undamaged one, indicating remarkable damage tolerance. Furthermore, it was confirmed that Mo2TiAlC2 ceramic had a good oxidation resistance below 1200 K in the air.

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