scholarly journals Thermal Stability and Thermoelectric Properties of NaZnSb

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 48 ◽  
Author(s):  
Volodymyr Gvozdetskyi ◽  
Bryan Owens-Baird ◽  
Sangki Hong ◽  
Julia Zaikina
Keyword(s):  
High Temperature ◽  
Thermoelectric Properties ◽  
Structural Changes ◽  
Theoretical Calculations ◽  
Sodium Hydride ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Plasma Sintering ◽  
Semiconductor Behavior ◽  
Spark Plasma

A layered Zintl antimonide NaZnSb (PbClF or Cu2Sb structure type; P4/nmm) was synthesized using the reactive sodium hydride NaH precursor. This method provides comprehensive compositional control and facilitates the fast preparation of high-purity samples in large quantities. NaZnSb is highly reactive to humidity/air and hydrolyzes to NaOH, ZnO, and Sb in aerobic conditions. On the other hand, NaZnSb is thermally stable up to 873 K in vacuum, as no structural changes were observed from high-temperature synchrotron powder X-ray diffraction data in the 300–873 K temperature range. The unit cell expansion upon heating is isotropic; however, interatomic distance elongation is not isotropic, consistent with the layered structure. Low- and high-temperature thermoelectric properties were measured on pellets densified by spark plasma sintering. The resistivity of NaZnSb ranges from 11 mΩ∙cm to 31 mΩ∙cm within the 2–676 K range, consistent with heavily doped semiconductor behavior, with a narrow band gap of 0.23 eV. NaZnSb has a large positive Seebeck coefficient (244 μV∙K−1 at 476 K), leading to the maximum of zT of 0.23 at 675 K. The measured thermoelectric properties are in good agreement with those predicted by theoretical calculations.

Study on Phases and Thermoelectric Properties of Bulk FexCo4-xSb12 Sintered by MM-SPS

2011 ◽  
Vol 179-180 ◽  
pp. 294-297
Author(s):  
Ke Gao Liu ◽  
Shi Lei
Keyword(s):  
Thermoelectric Properties ◽  
Thermal Constant ◽  
X Ray Diffraction ◽  
Semiconducting Materials ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Plasma Sintering ◽  
Electrical Resistivities ◽  
Spark Plasma ◽  
P Type

Bulk FexCo4-xSb12 with x varies from 0.1 to 2.0 were prepared by mechanical milling (MM) and spark plasma sintering (SPS). The phases of the products were characterized by X-ray diffraction (XRD) and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of bulk FexCo4-xSb12 are skutterudite. The electrical resistivities of the products increase first and then decrease. The Seebeck coefficients ( ) are negative when x=0.1 at 100 °C and 200 °C while positive at 300~500 °C. The products with x=0.5~2.0 at 100~500 °C are P type semiconducting materials due to their positive values. The thermal conductivities of most samples increase first and then decrease with x increasing and the maximum is up to 0.39 Wm-1K-1 when x=1.0. The ZT values at 200~500 °C increase first and then decrease with x increasing when x=0.1~1.0 and x=1.0~2.0 respectively and the maximum ZT value is 0.196 when x=1.5 at 400 °C.

High Temperature Thermoelectric Properties of Oxide Ca2Co2O5

2009 ◽  
Vol 79-82 ◽  
pp. 2143-2146 ◽  
Author(s):  
Guo Jing Li ◽  
Shu Jin Zhao ◽  
Ao Mei ◽  
Jin Le Lan ◽  
Yuan Hua Lin
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
The Body ◽  
Ceramic Powders ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Maximum Power Factor ◽  
Better Than

Ca2Co2O5 ceramic powders were synthesized by the coprecipitation method and consolidated by spark plasma sintering (SPS) technique.The observation by the SEM indicated that the ceramics body showed fine and layer microstructure.The density of the body increased with an increase of the fritting temperature.XRD patterns showed that the ceramics sample exhibits inpure phase with increasing the sintering temperayure to 850°C and that the grain was preferentially oriented.The electrical conductivity was reduce and the Seebeck coefficient slightly increased with an increase of the sintering temperature.As a result,the thermoelectric properties of the sample prepared by SPS at 800 °C for 5 min was better than the sample prepared by SPS at 750 °C for 5 min at high temperature.The sample treated by the SPS process under the condition of 800 °C,40 MPa and 5 min showed the maximum power factor (PF) of 3.85×10-4W∙m-1∙K-2 at 923 K.

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 Properties of Scandium Sesquitelluride

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 734 ◽  
Author(s):  
Dean Cheikh ◽  
Kathleen Lee ◽  
Wanyue Peng ◽  
Alexandra Zevalkink ◽  
Jean-Pierre Fleurial ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Lattice Thermal Conductivity ◽  
Structure Type ◽  
Chemical Similarity ◽  
Temperature Dependent ◽  
Figures Of Merit ◽  
Lanthanide Series ◽  
Plasma Sintering ◽  
Spark Plasma

Rare-earth (RE) tellurides have been studied extensively for use in high-temperature thermoelectric applications. Specifically, lanthanum and praseodymium-based compounds with the Th3P4 structure type have demonstrated dimensionless thermoelectric figures of merit (zT) up to 1.7 at 1200 K. Scandium, while not part of the lanthanide series, is considered a RE element due to its chemical similarity. However, little is known about the thermoelectric properties of the tellurides of scandium. Here, we synthesized scandium sesquitelluride (Sc2Te3) using a mechanochemical approach and formed sintered compacts through spark plasma sintering (SPS). Temperature-dependent thermoelectric properties were measured from 300–1100 K. Sc2Te3 exhibited a peak zT = 0.3 over the broad range of 500–750 K due to an appreciable power factor and low-lattice thermal conductivity in the mid-temperature range.

scholarly journals Microstructure And Thermoelectric Properties Of Tags-90 Compounds Fabricated By Mechanical Milling Process

2015 ◽  
Vol 60 (2) ◽  
pp. 1231-1234 ◽  
Author(s):  
H.-S Kim ◽  
M. Babu ◽  
S.-J. Hong
Keyword(s):  
Thermoelectric Properties ◽  
Milling Time ◽  
Fine Particles ◽  
High Energy ◽  
Dispersion Analysis ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Fine Grain ◽  
Plasma Sintering ◽  
Spark Plasma

Abstract TAGS-90 compound powder was directly prepared from the elements by high-energy ball milling (HEBM) and subsequently consolidated by a spark plasma sintering (SPS). Effect of milling time on the microstructure and thermoelectric properties of the samples were investigated. The particle size of fabricated powders were decreased with increasing milling time, finally fine particles with ~1μm size was obtained at 90 min. The SPS samples exhibited higher relative densities (>99%) with fine grain size. X-ray diffraction analysis (XRD) and energy dispersion analysis (EDS) results revealed that all the samples were single phase of GeTe with exact composition. The electrical conductivity of samples were decreased with milling time, whereas Seebeck coefficient increased over the temperature range of RT~450°C. The highest power factor was 1.12×10−3W/mK2 obtained for the sample with 90 min milling at 450°C.

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.

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