Phases and Thermoelectric Properties of Bulk NiSb2 and Composite of NiSb2 and CoSb3 Prepared by Sintering

2012 ◽  
Vol 503-504 ◽  
pp. 507-510 ◽  
Author(s):  
Ke Gao Liu ◽  
Nian Jing Ji ◽  
Zhong Quan Ma
Keyword(s):  
Thermoelectric Properties ◽  
Single Phase ◽  
Semiconductor Materials ◽  
Thermal Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Maximum Value ◽  
Type Semiconductor ◽  
Composite Samples

For researching the thermoelectric properties, bulk NiSb2 and the composite of CoSb3 and NiSb2 were prepared by sintering. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, Bulk NiSb2 and the composite of NiSb2:CoSb3=2:8 and 4:6 were prepared by sintering at 600°C for 10min and they are N-type semiconductor materials with high densities of 6.998~7.142g/cm3. The bulk NiSb2 sample sintered is nearly single phase NiSb2, while the major phases of the composite of NiSb2:CoSb3=2:8 are major phase CoSb3 with impurity phase NiSb2. The electric resistivity of bulk NiSb2 sample increases with temperature rising while those of the composites (NiSb2:CoSb3=2:8 and 4:6) increase at 400~500 °C. The absolute values of Seebeck coefficients of the composite samples (NiSb2:CoSb3=2:8 and 4:6) increase with temperature rising and are evidently higher than those of bulk NiSb2. The power factors of the composites (NiSb2:CoSb3=2:8 and 4:6) are evidently higher than those of bulk NiSb2 while the power factor of NiSb2 sample varies not obviously with temperature rising, but those of the composites (NiSb2:CoSb3=2:8 and 4:6) increase with temperature rising and reaches the maximum value of 21.3 10-4Wk-2m-1 at 500 °C.

Study on Phases and Thermoelectric Properties of Bulk Fe4Sb12 and Fe3CoSb12 Prepared by Milling and Sintering

2011 ◽  
Vol 121-126 ◽  
pp. 1526-1529
Author(s):  
Ke Gao Liu ◽  
Jing Li
Keyword(s):  
Thermoelectric Properties ◽  
Impurity Phase ◽  
Semiconductor Materials ◽  
Thermal Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Maximum Value ◽  
Type Semiconductor ◽  
P Type

Bulk Fe4Sb12 and Fe3CoSb12 were prepared by sintering at 600 °C. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of bulk samples are skutterudite with impurity phase FeSb2. The electric resistivities of the samples increase with temperature rising at 100~500 °C. The bulk samples are P-type semiconductor materials. The Seebeck coefficients of the bulk Fe4Sb12 are higher than those of bulk Fe3CoSb12 samples at 100~200 °C but lower at 300~500 °C. The power factor of the bulk Fe4Sb12 samples decreases with temperature rising while that of bulk Fe3CoSb12 samples increases with temperature rising at 100~500 °C. The thermal conductivities of the bulk Fe4Sb12 samples are relatively higher than those of and Fe3CoSb12, which maximum value is up to 0.0974 Wm-1K-1. The ZT value of bulk Fe3CoSb12 increases with temperature rising at 100~500 °C, the maximum value is up to 0.031.The ZT values of the bulk Fe4Sb12 samples are higher than those of bulk Fe3CoSb12 at 100~300 °C while lower at 400~500 °C.

Thermoelectric Properties of Bulk FeSb2 and the Composite of FeSb2 and CoSb3 Prepared by Sintering

2011 ◽  
Vol 71-78 ◽  
pp. 3741-3744
Author(s):  
Ke Gao Liu ◽  
Jing Li
Keyword(s):  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Electric Resistivity ◽  
Semiconductor Materials ◽  
Thermal Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value ◽  
Type Semiconductor ◽  
P Type

For investigating the thermoelectric properties, bulk FeSb2and the composite of CoSb3:FeSb2=7:3 was prepared via sintering. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, bulk FeSb2and the composite of CoSb3:FeSb2=7:3 are P-type semiconductor materials. The electric resistivity of bulk FeSb2sample increases with temperature rising while that of the composite (CoSb3:FeSb2=7:3) decreases with temperature rising. The Seebeck coefficient of the composite (CoSb3:FeSb2=7:3) is evidently higher than that of bulk FeSb2. The thermal conductivities of the composite (CoSb3:FeSb2=7:3) are relatively lower than those of bulk FeSb2. TheZTvalues of bulk FeSb2sample are lower than those of the composite (CoSb3:FeSb2=7:3), that of the later increases with temperature rising at 100~500°C, the maximum value is up to 0.1647.

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.

Phases and Thermoelectric Properties of Bulk CoSb3 Prepared by Wet Milling and Sintering

2011 ◽  
Vol 480-481 ◽  
pp. 402-405
Author(s):  
Ke Gao Liu ◽  
Wei Ping Zhang ◽  
Lei Shi
Keyword(s):  
Thermoelectric Properties ◽  
Milling Time ◽  
Experimental Results ◽  
Thermal Constant ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Seebeck Coefficients ◽  
P Type

For investigating the effect of wet milling time on thermoelectric properties, bulk CoSb3 was prepared via wet milling and sintering. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of the samples sintered from the powders wet-milled 2 and 6 hours are CoSb3 while the samples sintered from powders wet-milled 12 and 20 hours have more impurity phases under the experimental conditions in this work. The electric resistivities of the samples sintered from the powders wet-milled 2 and 6 hours increase with rising temperature, which show the characteristic of typical semiconductor electricity and P-type conducting due to the positive Seebeck coefficients. However, the samples sintered from powders wet-milled 12 and 20 hours show N-type conducting due to their negative Seebeck coefficients. The ZT values of the samples sintered from the powders wet-milled 2 and 6 hours are relatively higher than other samples, which increases with the temperature rising at 100~400 °C, the highest value is 0.078.

STUDY OF STRUCTURAL, ELECTRICAL TRANSPORT AND MAGNETIC PROPERTIES IN La1-xAgxMnO3 COMPOUNDS

2004 ◽  
Vol 18 (05n06) ◽  
pp. 221-231 ◽  
Author(s):  
MANORANJAN KAR ◽  
S. RAVI
Keyword(s):  
Magnetic Field ◽  
Electrical Transport ◽  
Single Phase ◽  
Ac Susceptibility ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Phase Form ◽  
X Ray ◽  
Maximum Value

X-ray diffraction, electrical resistivity and ac susceptibility measurements have been carried out on La 1-x Ag x MnO 3 compounds for x=0.05 to 0.30. These samples are found to be in single phase form with [Formula: see text] space group and with typical lattice parameters a=b=5.524Å and c=13.349Å for x=0.05 sample. The Mn–O–Mn bond angles and variance, σ2 are found to increase with doping. Metal-insulator transitions in the temperature range 254 to 259 K have been observed. These materials exhibit paramagnetic to ferromagnetic transitions in the vicinity of metal-insulator transition temperatures. The paramagnetic susceptibility could be analyzed using Curie–Weiss law. All the above samples exhibit colossal magneto-resistivity and its maximum value is found to be 73% for x=0.15 sample at 50 kOe magnetic field.

Thermoelectric properties and microstructure of large-grain Mg2Sn doped with Ag

2009 ◽  
Vol 1166 ◽  
Author(s):  
Haiyan Chen ◽  
Nick Savvides
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Single Phase ◽  
Silver Content ◽  
X Ray Diffraction ◽  
Thermoelectric Power Factor ◽  
X Ray ◽  
Maximum Value ◽  
Vertical Bridgman ◽  
Scanning Electron

AbstractMg2Sn ingots, doped p-type by the addition of 0–1.0 at. % Ag, were prepared by the vertical Bridgman method at growth rates ∼0.1 mm/min. The crystalline quality and microstructure of ingots were analyzed by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The single-phase Mg2Sn ingots consist of highly oriented large grains. Measurements of the Hall coefficient, Seebeck coefficient α, and electrical conductivity σ in the temperature range 80–700 K were conducted to study the dependence on the silver content, and to determine the thermoelectric power factor α2σ which reached a maximum value 2.4×10-3 W m-1 K-2 at 410 K for 1.0 at.% Ag content.

scholarly journals Fabrication of PEDOT: PSS-PVP Nanofiber-Embedded Sb2Te3 Thermoelectric Films by Multi-Step Coating and Their Improved Thermoelectric Properties

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2835
Author(s):  
Sang-il Kim ◽  
Kang Yeol Lee ◽  
Jae-Hong Lim
Keyword(s):  
Thermoelectric Properties ◽  
Power Factor ◽  
Photoelectron Spectroscopy ◽  
Hybrid Composites ◽  
Composite Films ◽  
X Ray Diffraction ◽  
Thermoelectric Efficiency ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Electrical Conductivities

Antimony telluride thin films display intrinsic thermoelectric properties at room temperature, although their Seebeck coefficients and electrical conductivities may be unsatisfactory. To address these issues, we designed composite films containing upper and lower Sb2Te3 layers encasing conductive poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS)- polyvinylpyrrolidone(PVP) nanowires. Thermoelectric Sb2Te3/PEDOT:PSS-PVP/Sb2Te3(ED) (STPPST) hybrid composite films were prepared by a multi-step coating process involving sputtering, electrospinning, and electrodeposition stages. The STPPST hybrid composites were characterized by field-emission scanning electron microscopy, X-ray diffraction, ultraviolet photoelectron spectroscopy, and infrared spectroscopy. The thermoelectric performance of the prepared STPPST hybrid composites, evaluated in terms of the power factor, electrical conductivity and Seebeck coefficient, demonstrated enhanced thermoelectric efficiency over a reference Sb2Te3 film. The performance of the composite Sb2Te3/PEDOT:PSS-PVP/Sb2Te3 film was greatly enhanced, with σ = 365 S/cm, S = 124 μV/K, and a power factor 563 μW/mK.

Synthesis and Characterization of Delafossite CuLaO2 for Thermoelectric Application

2007 ◽  
Vol 534-536 ◽  
pp. 1081-1084 ◽  
Author(s):  
Yuhsuke Takahashi ◽  
Hiroaki Matsushita ◽  
Akinori Katsui
Keyword(s):  
Seebeck Coefficient ◽  
Single Phase ◽  
Metallic Copper ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Mixed Powder ◽  
X Ray ◽  
Type Semiconductor ◽  
P Type

The preparation of single-phase CuLaO2 with delafossite-type structure by means of the solid-state reaction method was investigated using X-ray diffraction. The results showed that notwhistanding the fact that there was a trace of metallic copper, nearly single-phase CuLaO2 was obtained by using La(OH)3 as a lanthanum source and by firing the mixed powder with nonstoichiometric composition ratio of La(OH)3:Cu2O =1:1.425 in a vacuum at 1273 K for 10 h. The measurement of electrical conductivity and Seebeck coefficient showed that CuLaO2 thus obtained was a p-type semiconductor and had a Seebeck coefficient of approximately 70 /V/K.

scholarly journals Preparation of ZnO film on p-Si Substrate by Silar and Heterojunction Characteristics of p-Si/n-Zno

2011 ◽  
Vol 8 (1) ◽  
pp. 197-200 ◽  
Author(s):  
P. Mitra
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Reverse Current ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Si Substrate ◽  
Current Ratio ◽  
Axis Orientation ◽  
X Ray ◽  
Maximum Value

Zinc oxide (ZnO) thin films was deposited on p-silicon (Si) substrate from ammonium zincate bath following a chemical dipping technique called SILAR. Structural characterization by X-ray diffraction (XRD) indicates the formation of polycrystalline single phase ZnO with strong c-axis orientation. I-V characteristic of the p-Si/n-ZnO heterojunction was studied and rectification was observed. The maximum value of forward to reverse current ratio at room temperature was ~15 at 3.0 V. It increases to ~30 at 100oC.

Study of residual stresses, microstructure, and hardness in FeB and Fe2B ultra-hard layers

2015 ◽  
Vol 30 (S1) ◽  
pp. S83-S89 ◽  
Author(s):  
Zdenek Pala ◽  
Jaroslava Fojtikova ◽  
Tomas Koubsky ◽  
Radek Musalek ◽  
Josef Strasky ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Density Functional ◽  
Single Phase ◽  
Spatial Distributions ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Maximum Value ◽  
Boron Ions ◽  
Materials Studio

Boriding is a thermochemical diffusion-based process of achieving ultra-hard surface on metals. Two distinct crystalline phases, i.e. tetragonal Fe2B and orthorhombic FeB can exist in the surface layer penetrated by boron ions. In our contribution, we have studied the microstructure, the hardness, and the spatial distributions of both phase composition and residual stresses (RS) in samples exhibiting either single-phase Fe2B or duplex Fe2B-cum-FeB character. The indispensable knowledge of the elastic constants used in the stresses calculations from the measured strains by X-ray diffraction were gained from the refined lattice parameters of both iron borides employing density functional theory implemented in CASTEP software by Materials Studio. In the studied case, there is only minor occurrence of preferred orientation in the Fe2B phase and the evaluated RS have compressive character gradually decreasing from its maximum value on the very surface.

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