scholarly journals Nanostructured kesterite (Cu2ZnSnS4) for applications in thermoelectric devices

2019 ◽  
Vol 34 (S1) ◽  
pp. S42-S47 ◽  
Author(s):  
E. Isotta ◽  
N. M. Pugno ◽  
P. Scardi
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Thermal Diffusivity ◽  
Thermal Treatment ◽  
Large Fraction ◽  
Milled Powder ◽  
High Energy ◽  
Tetragonal Form ◽  
Cubic Structure ◽  
Positive Effect

Kesterite (Cu2ZnSnS4, CZTS) powders were produced by reactive high-energy milling, starting from stoichiometric mixtures of the elemental components. CZTS forms fine crystals with a cubic structure, which evolves to the stable tetragonal form after thermal treatment. Tablets were produced by cold pressing of the ball milled powder, and sintered up to 660 °C. Seebeck coefficient, electrical resistivity, and thermal diffusivity were measured on the sintered tablets, pointing out the positive effect of CZTS nanostructure and of the rather large fraction of porosity: thermal conductivity is rather low (from ~0.8 W/(m K) at 20 °C to ~0.42 W/(m K) at 500 °C), while electrical conduction is not seriously hindered (electrical resistivity from ~8500 µΩ m at 40 °C to ~2000 µΩ m at 400 °C). Preliminary results of thermoelectric behavior are promising.

Thermal Properties of Tungsten SRM’S 730 and 799

1978 ◽  
Vol 100 (2) ◽  
pp. 330-333 ◽  
Author(s):  
R. E. Taylor
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Thermal Properties ◽  
High Temperature ◽  
Thermal Diffusivity ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Standard Material ◽  
International Program ◽  
Sintered Tungsten

Samples of sintered and arc-cast tungsten are available from NBS as thermal conductivity (SRM 730) and electrical resistivity (SRM 799) standards for the temperature range from 4 to 3000K. NBS recommended values for these properties above room temperature are based on results of various researchers during a previous international program which included arc-cast and sintered tungsten. The sintered tungsten used in this program was found to be unsuited for use as a standard material due to inhomogeneity and high temperature instability. The present paper gives results at high temperatures for thermal conductivity, electrical resistivity, specific heat, thermal diffusivity and Wiedemann-Franz-Lorenz ratio for a sample of the NBS sintered tungsten using the Properties Research Laboratory’s multiproperty apparatus. These results are compared to values recommended by the Thermophysical Properties Research Center, NBS, and an international program.

4K-GM Cryocooler Performance and Thermal Conductivity of HoxEr1-xN

2013 ◽  
Vol 1492 ◽  
pp. 53-58
Author(s):  
Takanori Nakano ◽  
Yusuke Hirayama ◽  
Takushi Izawa ◽  
Takashi Nakagawa ◽  
Yasushi Fujimoto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Stainless Steel ◽  
Electrical Resistivity ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Three Samples ◽  
Regenerator Material

ABSTRACTHoxEr1-xN (x=0.25, 0.5, 0.75) samples were synthesized by nitriding of HoxEr1-x alloy bars and their thermal conductivity κ were measured. The measured κ values were comparable to those of stainless steel and Er3Ni. Ho0.5Er0.5N showed the highest κ of the present three samples. The thermal diffusivity calculated from the κ and the specific heat indicates that Ho0.5Er0.5N is a very promising regenerator material for the cryocoolers. The electrical resistivity ρ was also measured as a function of temperature.

Spinodal Decomposition in Off-stoichiometric Zr0.5Hf0.5Co1-yIrySb1-zSnz half-Heusler Phases

2010 ◽  
Vol 1267 ◽  
Author(s):  
Nathan J. Takas ◽  
Dinesh Misra ◽  
Heike Gabrisch ◽  
Pierre F. P. Poudeu
Keyword(s):  
Thermal Conductivity ◽  
Spinodal Decomposition ◽  
Lattice Thermal Conductivity ◽  
Large Fraction ◽  
High Energy ◽  
Metallic Phase ◽  
Inclusion Phase ◽  
The Matrix ◽  
Energy Ball

AbstractThe formation of nanostructures within the matrix of half-Heusler thermoelectric materials can be produced by spinodal decomposition of off-stoichiometric compositions. CoSb is insoluble at high temperatures in Zr0.5Hf0.5Co1-yIrySb1-zSnz half-Heusler phases. This phase can be solubilized into the half-Heusler matrix by the use of high energy ball milling at room temperature as the synthetic method of choice. The metastable half-Heusler material decomposes in-situ while hot-pressing the powder sample into a compact pellet. Despite the fact that the thermal conductivity of the inclusion material, CoSb, is very large, (>35W/m•K), we observed reduction in the lattice thermal conductivity of the composite material. Furthermore, the electrical resistivity of the specimen was also reduced due to the metallic nature of the CoSb inclusion phase. Addition of a large fraction of the metallic inclusion leads to a percolation network of the metallic phase, thus reducing the Seebeck coefficient of the composites. Electron microscopy is carried out in order to examine boundaries between the two. Changes in the thermoelectric properties of Zr0.5Hf0.5Co1-yIrySb1-zSnz half-Heusler matrix with increasing mass percent of CoSb inclusion will be discussed.

The Iceland Research Drilling Project Crustal Section: Physical properties of some basalts from the Reydarfjordur borehole, Iceland

1985 ◽  
Vol 22 (11) ◽  
pp. 1588-1593 ◽  
Author(s):  
Malcolm J. Drury
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Thermal Diffusivity ◽  
Measurement Techniques ◽  
Physical Property ◽  
Property Data ◽  
Conductivity Increase ◽  
Derived Properties ◽  
History Of ◽  
Physical Property Data

Thermal, electrical, and other physical property data are reported for a suite of basalts from the core of a 1.9 km hole at Reydarfjordur, eastern Iceland. The principal aim is to add to the literature thermal diffusivity data on basalts. Both lava-flow and dyke-intrusion samples have been measured, in roughly the proportion of their abundances in the drilled section. Density and porosity measurements are in good agreement with values published previously by others. Thermal conductivity values are approximately 10% higher than those published by others, probably because of differences in measurement techniques. Porosity of the samples generally decreases with depth because of increasing infilling of voids and cracks with alteration products. Density, thermal conductivity, thermal diffusivity, and the derived properties grain density and grain conductivity increase with depth, whereas electrical resistivity decreases. Bulk properties of the section have been estimated. They are thermal diffusivity, 0.70 mm2/s (0.70 × 10−6 m2/s); thermal conductivity, 1.97 W/m∙K; bulk density, 2.82 Mg/m3; and porosity, 0.039 (3.9%). Curves modelling in situ electrical resistivity indicate values in the range 50–3000 ?∙m. The electrical structure of the crust in the Reydarfjordur area is apparently different from that in southwest Iceland, probably reflecting a different history of hydrothermal circulation and alteration.

Thermoelectric Properties of PbTe

2013 ◽  
Vol 802 ◽  
pp. 223-226 ◽  
Author(s):  
Sunti Phewphong ◽  
Tosawat Seetawan
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Room Temperature ◽  
Single Phase ◽  
Argon Atmosphere ◽  
Steady State Method ◽  
State Method ◽  
Cubic Structure ◽  
Annealing Method

The PbTe has been prepared by pressing and annealing method in argon atmosphere. The PbTe sample was obtained single phase and cubic structure. The Seebeck coefficient, the electrical resistivity, thermal conductivity measured by steady state method and evaluated dimensionless figure merit at room temperature. The values of Seebeck coefficient, the electrical resistivity, thermal conductivity and dimensionless figure merit are about -260 µV/K, 3 mΩcm, 0.5 W/m K and ~ 0.35 respectively at 420 K.

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