Thermoelectric Properties of Half-Heusler TiCoSb1-xSnx Synthesized by Mechanical Alloying Process

2013 ◽  
Vol 660 ◽  
pp. 61-65
Author(s):  
Il Ho Kim ◽  
Young Geun Lee ◽  
Moon Kwan Choi ◽  
Soon Chul Ur
Keyword(s):  
Electrical Conductivity ◽  
Mechanical Alloying ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Subsequent Annealing ◽  
Absolute Value ◽  
Vacuum Hot Pressing ◽  
Seebeck Coefficients ◽  
Sb Doping ◽  
The Absolute

Half-heusler TiCoSb1-xSnx (0.00≤x≤0.05) alloys were prepared by mechanical alloying of elemental powders, and consolidated by vacuum hot pressing. Sn doped half-Heusler phases of TiCoSb was successfully produced in all doping ranges by vacuum hot pressing using as-milled powders without subsequent annealing. However, a little fraction of CoSb phase appeared after hot pressing. Thermoelectric properties as functions of temperature were evaluated for hot pressed specimens. Seebeck coefficients showed to change in conductivity by doping and the absolute value revealed relatively low. It is shown that electrical conductivity is relatively high and thermal conductivities are compatibly low. Sb doping up to x=0.02 in TiCoSb1-xSnx was shown to be effective on thermoelectric properties in this study.

Mechanical Alloying and Thermoelectric Properties of CoSb3 Skutterudite

2005 ◽  
Vol 486-487 ◽  
pp. 642-645 ◽  
Author(s):  
Moon Kwan Choi ◽  
Soon Chul Ur ◽  
Joon Chul Kwon ◽  
K.W. Cho ◽  
Il Ho Kim ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Mechanical Alloying ◽  
Phase Transformations ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Single Phase ◽  
Stoichiometric Composition ◽  
Subsequent Annealing ◽  
Vacuum Hot Pressing ◽  
Temperature Dependences

In an effort to synthesize homogenized single phase d-CoSb3, this study considers the mechanical alloying (MA) of elemental Co and Sb powders using a nominal stoichiometric composition followed by hot pressing. Single phase, undoped CoSb3 skutterudites were successfully produced by vacuum hot pressing using MA powders without subsequent annealing. Phase transformations during mechanical alloying, powder annealing, and hot pressing were systematically investigated using XRD and SEM. Thermoelectric properties were measured and compared with the results of similar studies. Temperature dependences were also evaluated, and their correlations to phase transformation were examined.

Synthesis and Thermoelectric Properties of Undoped Half-Heusler Zr-Co-Sb Alloy Processed by Mechanically Alloying and Hot Pressing

2011 ◽  
Vol 695 ◽  
pp. 69-72
Author(s):  
Il Ho Kim ◽  
Joon Chul Kwon ◽  
Young Geun Lee ◽  
Sung Lim Ryu ◽  
Man Soon Yoon ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Hot Pressing ◽  
Heusler Alloys ◽  
Processing Route ◽  
Mechanically Alloyed ◽  
Fundamental Study ◽  
Vacuum Hot Pressing ◽  
Fine Grain

Half-Heusler alloys are one of the potential thermoelectric materials for medium to high temperature range application. As a part of fundamental study to establish processing route and to observe thermoelectric properties in undoped state, ZrCoSb was selected, processed and evaluated. In an attempt to produce a half-Heusler thermoelectric materials having ultra fine grain structures, ZrCoSb was synthesized by mechanical alloying of stoichiometric elemental powder compositions, and consolidated by vacuum hot pressing. Phase transformations during mechanical alloying and hot consolidation were investigated using XRD, SEM and EDS. Single-phase, half-Heusler was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. Thermoelectric properties as functions of temperature were evaluated in terms of Seebeek coefficient, electrical conductivity, thermal conductivity and the figure of merit for the hot pressed specimens. Mechanically alloyed half-Heusler phase, ZrCoSb, appeared to have a great potential as a thermoelectric materials in this study.

scholarly journals Thermoelectric Properties of Nano/microstructured p-Type Bi0.4Sb1.6Te3 Powders Fabricated by Mechanical Alloying and Vacuum Hot Pressing

2013 ◽  
Vol 43 (6) ◽  
pp. 1718-1725 ◽  
Author(s):  
Pee-Yew Lee ◽  
Joey Hao ◽  
Tz-Yuan Chao ◽  
Jing-Yi Huang ◽  
Huey-Lin Hsieh ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Vacuum Hot Pressing ◽  
P Type

Thermoelectric Properties of Nanostructured CoSb3 Synthesized by Mechanical Alloying

2007 ◽  
Vol 534-536 ◽  
pp. 1425-1428
Author(s):  
Soon Chul Ur ◽  
Joon Chul Kwon ◽  
Moon Kwan Choi ◽  
Soon Young Kweon ◽  
Tae Whan Hong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Alloying ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Figure Of Merit ◽  
Single Phase ◽  
Phonon Scattering ◽  
Stoichiometric Composition ◽  
Processing Route ◽  
Vacuum Hot Pressing

Undoped CoSb3 powders were synthesized by mechanical alloying of elemental powders using a nominal stoichiometric composition. Nanostructured, single-phase skutterudite CoSb3 was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. Phase transformations during synthesis were investigated using XRD, and microstructure was observed using SEM and TEM. Thermoelectric properties in terms of Seebeck coefficient, electrical conductivity, thermal conductivity and figure of merit were systematically measured and compared with the results of analogous studies. Lattice thermal conductivity was reduced owing to increasing phonon scattering in nanostructured CoSb3, leading to enhancement in the thermoelectric figure of merit. Mechanical Alloying associated with vacuum hot pressing technique offers an alternative potential processing route for the production of skutterudites.

scholarly journals Blend Structure and n-Type Thermoelectric Performance of PA6/SAN and PA6/PMMA Blends Filled with Singlewalled Carbon Nanotubes

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1146
Author(s):  
Beate Krause ◽  
Alice Liguoro ◽  
Petra Pötschke
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Immiscible Blends ◽  
Seebeck Coefficients ◽  
Selective Localization ◽  
The Absolute ◽  
Pmma Blends ◽  
Absolute Seebeck Coefficient

The present study investigates how the formation of melt-mixed immiscible blends based on PA6/SAN and PA6/PMMA filled with single walled nanotubes (SWCNTs) affects the thermoelectric (TE) properties. In addition to the detailed investigation of the blend morphology with compositions between 100/0 wt.% and 50/50 wt.%, the thermoelectric properties are investigated on blends with different SWCNT concentrations (0.25–3.0 wt.%). Both PA6 and the blend composites with the used type of SWCNTs showed negative Seebeck coefficients. It was shown that the PA6 matrix polymer, in which the SWCNTs are localized, mainly influenced the thermoelectric properties of blends with high SWCNT contents. By varying the blend composition, an increase in the absolute Seebeck coefficient, power factor (PF), and figure of merit (ZT) was achieved compared to the PA6 composite which is mainly related to the selective localization and enrichment of SWCNTs in the PA6 matrix at constant SWCNT loading. The maximum PFs achieved were 0.22 µW/m·K2 for PA6/SAN/SWCNT 70/30/3 wt.% and 0.13 µW/m·K2 for PA6/PMMA/SWCNT 60/40/3 wt.% compared to 0.09 µW/m·K2 for PA6/3 wt.% SWCNT which represent increases to 244% and 144%, respectively. At higher PMMA or SAN concentration, the change from matrix-droplet to a co-continuous morphology started, which, despite higher SWCNT enrichment in the PA6 matrix, disturbed the electrical conductivity, resulting in reduced PFs with still increasing Seebeck coefficients. At SWCNT contents between 0.5 and 3 wt.% the increase in the absolute Seebeck coefficient was compensated by lower electrical conductivity resulting in lower PF and ZT as compared to the PA6 composites.

Microstructure and Properties of Dilute Cu-Nb Alloy Prepared by Mechanical Alloying

2017 ◽  
Vol 729 ◽  
pp. 3-7 ◽  
Author(s):  
Ruo Shan Lei ◽  
Ming Pu Wang ◽  
Guang Run Chen ◽  
Yin Yan Li
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Hot Pressing ◽  
Microstructure And Properties ◽  
Vacuum Hot Pressing ◽  
Hot Pressing Sintering

This paper presents the synthesis of a Cu-0.5wt%Nb alloy via mechanical alloying (MA) and subsequent hot pressing. The evolutions of the density, microstructure, microhardness and electrical conductivity of the alloy as a function of the sintering temperatures were investigated. The results show that the microhardness of the alloy decreases with increasing consolidation temperatures, while the density and the conductivity improve. The alloy, subjected to vacuum hot-pressing sintering under 25 MPa pressure and 800 °C for 2h, has a microhardness of 102 HV and an electrical conductivity of 98% IACS. The as processed alloy is characterized by Nb nanoparticles distributed in the submicron sized Cu grains. The microhardness and electrical conductivity of the alloy are closely related with the microstructure, i.e. Cu grain size, as well as the presence and distribution of Nb nanoparticles.

scholarly journals Thermoelectric Properties of Alumina-Doped Bi0.4Sb1.6Te3 Nanocomposites Prepared through Mechanical Alloying and Vacuum Hot Pressing

Energies ◽  
2015 ◽  
Vol 8 (11) ◽  
pp. 12573-12583 ◽  
Author(s):  
Chung-Kwei Lin ◽  
May-Show Chen ◽  
Rong-Tan Huang ◽  
Yu-Chun Cheng ◽  
Pee-Yew Lee
Keyword(s):  
Mechanical Alloying ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Vacuum Hot Pressing

Effect of Fe Doping on Thermoelectric Properties of Mechanically Alloyed CoSb3

2007 ◽  
Vol 534-536 ◽  
pp. 177-180
Author(s):  
Soon Chul Ur ◽  
Joon Chul Kwon ◽  
Il Ho Kim
Keyword(s):  
Mechanical Alloying ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Figure Of Merit ◽  
Solubility Limit ◽  
Nominal Composition ◽  
Second Phase ◽  
Fe Doping ◽  
Mechanically Alloyed ◽  
Vacuum Hot Pressing

Fe doped skutterudite CoSb3 with a nominal composition of FexCo1-xSb12 (0≤x≤2.5) have been synthesized by mechanical alloying (MA) of elemental powders, followed by vacuum hot pressing. Phase transformations during mechanical alloying and vacuum hot pressing were systematically investigated using XRD. Single phase skutterudite was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. However, second phase in the form of marcasite structure FeSb2 was found to exist in case of x≥2, suggesting the solubility limit of Fe with Co in this system. Thermoelectric properties as functions of temperature and Fe contents were evaluated for the hot pressed specimens. Fe doping up to x=1.5 with Co in FexCo4-xSb12 appeared to increase thermoelectric figure of merit (ZT) and the maximum ZT was found to be 0.78 at 525K in this study.

Sign in / Sign up

Export Citation Format

Share Document