Thermoelectric Properties of Nickel and Boron Co-Substituted NaCo2O4 Prepared by Electrospinning Technique

2018 ◽  
Vol 19 ◽  
pp. 34-45 ◽  
Author(s):  
Mehmet Okan Erdal ◽  
Mustafa Koyuncu ◽  
Mehmet Levent Aksu ◽  
Ibrahim Uslu ◽  
Serhat Koçyiğit
Keyword(s):  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Calcination Process ◽  
Boron Doped ◽  
Bet Analysis ◽  
Sodium Cobalt Oxide ◽  
Before And After ◽  
Different Temperatures

In this study nickel and boron doped sodium cobalt oxide NaCo2-xNixByO4 (0≤x≤0.3, 0≤y≤0.1) nanocrystalline thermoelectric ceramic powders were synthesized using electrospinning techniques and then consolidated into bulk ceramics. The differences in the microstructure and thermoelectric properties of the samples as a result of doping effect have been investigated. The crystalline structures of the powders and nanofibers were characterized using X-ray diffraction and scanning electron microscopy and BET Analysis before and after the calcination process at different temperatures. Nanofibers prepared by the use of electrospinning technique, have a diameter of approximately 300 nm, and the diameter of the grains of calcined powders was observed to range between 150 to 500 nanometers. Thermoelectric properties of the bulk ceramics were measured by physical properties measurement system (Lot-Oriel PPMS) in a temperature range of 15–300 K. The calculated values of dimensionless figure of merit at 300 K are 4.25×10-5, 5.3×10-6, 8.6×10-5 and 9×10-6 for sintered powders from undoped, Ni and B doped powders, respectively.

Microstructure and Thermoelectric Properties of B4C+TiB2 Composite by Hot Pressed Sintering

2014 ◽  
Vol 602-603 ◽  
pp. 910-915
Author(s):  
Zhen Ye Zhu ◽  
Xing Hong Zhang ◽  
Jie Cai Han
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Thermoelectric Figure ◽  
Conductivity Increase ◽  
Thermal Conductivity Increase ◽  
Pressing Technology

TiB2 doped B4C composite whichTiB2 contents were 12.4% and 25.4% have been fabricated by the combination of the ball milling process and hot pressing technology. The phase analysis and microstructure of the composite materials are investigated through X-ray diffraction and scan electron microscope, respectively. In addition, thermoelectric properties of the composite materials are studied. The results show that the microcracks are easy to form in the interface between B4C and TiB2. It is also found that, the electrical and thermal conductivity increase wi2. Edit Paperth the increase of TiB2 doping, while the Seebeck coefficient decreases with the increase of TiB2 doping. The thermoelectric figure of merit of the B4C+25.4%TiB2 composite material is 50% higher than that of B4C at 573K, while the ZT of B4C+25.4% TiB2 composite material is lower than that of B4C at 873K.

Thermoelectric Properties of YbBiPt and YBiPt Thin Films

2008 ◽  
Vol 1100 ◽  
Author(s):  
Sadik Guner ◽  
Satilmis Budak ◽  
Claudiu I Muntele ◽  
Daryush Ila
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Rutherford Backscattering Spectrometry ◽  
Conductivity Measurement ◽  
Electronic Energy ◽  
Before And After

AbstractMonolayer thin films of YbBiPt and YBiPt have been produced with 560 nm and 394 nm thick respectively in house and their thermoelectric properties were measured before and after MeV ion bombardment. The energy of the ions were selected such that the bombarding Si ions stop in the silicon substrate and deposit only electronic energy by ionization in the deposited thin film. The bombardment by 5.0 MeV Si ions at various fluences changed the homogeneity as well as reducing the internal stress in the films thus affecting the thermal, electrical and Seebeck coefficient of thin films. The stoichiometry of the thin films was determined using Rutherford Backscattering Spectrometry, the thickness has been measured using interferometry and the electrical conductivity was measured using Van der Pauw method. Thermal conductivity of the thin films was measured using an in-house built 3ω thermal conductivity measurement system. Using the measured Seebeck coefficient, thermal conductivity and electrical conductivity we calculated the figure of merit (ZT). We will report our findings of change in the measured figure of merit as a function of bombardment fluence.

Effect of Post-Deposition Annealing on some Optical Properties of Thermally-Evaporated V2O5 Thin Film

2012 ◽  
Vol 329 ◽  
pp. 139-145
Author(s):  
S.A. Aly
Keyword(s):  
Optical Properties ◽  
Amorphous State ◽  
X Ray Diffraction ◽  
Post Deposition Annealing ◽  
X Ray ◽  
Spectral Behaviour ◽  
Before And After ◽  
Different Temperatures ◽  
Reflectance Measurements ◽  
Post Deposition

A Vanadium Pentoxide Sample with a Film Thickness of 75 Nm Has Been Thermally Evaporated on Unheated Glass Substrate Using V2O5High Purity Powder. the Sample Was Subjected to a Subsequent Post-Deposition Annealing in Air at Different Temperatures for a Period of One Hour. the Optical Properties Were Studied by Transmittance and Reflectance Measurements. the Integrated Visible ,TVis, and Solar, TSol, Transmittance Were Calculated. the Spectral Behaviour of the Refractive Index as Well as the Absorption Coefficient before and after Post-Deposition Heat-Treatment Was Also Reported. X-Ray Diffraction Confirmed that the Film in the as-Deposited as Well as after Annealing up to 400 °C Is in the Amorphous State.

The Fabrication and Thermoelectric Properties of Amorphous Si-Ge-Au Bulk Samples

2001 ◽  
Vol 691 ◽  
Author(s):  
Sang Min Lee ◽  
Yoichi Okamoto ◽  
Oshio Kawahara ◽  
Jun Morimoto
Keyword(s):  
Thermoelectric Properties ◽  
Power Supply ◽  
Figure Of Merit ◽  
Melt Spinning ◽  
Bulk Sample ◽  
X Ray Diffraction ◽  
Amorphous Thin Film ◽  
X Ray ◽  
Cooling Devices ◽  
Amorphous Si

ABSTRACTThe amorphous Si-Ge-Au bulk samples were fabricated with using the melt spinning method for the practical power supply or cooling devices. X-ray diffraction results showed that our samples were amorphous and the thermoelectric properties were measured by DC method. Although the electrical resistivity of the bulk sample was higher than that of the amorphous thin film, the thermoelectric power of the bulk sample was larger. The thermal conductivity of the amorphous Si-Ge-Au bulk sample was almost the same to the conventional crystalline Si-Ge bulk value. Consequently, non-dimensional figure of merit ZT is around 2 (at 600 K, • •=6.5 10λ-1V/K, • =1.9 10 ohm-m, • •= 6 W/mK) that is about ten times higher than the conventional crystalline Si-Ge bulk value.

Oxidation Behavior of NiAl Produced by Gel Combustion Synthesis

2016 ◽  
Vol 701 ◽  
pp. 122-126
Author(s):  
Tammy Anne Gonsalvez ◽  
Abreeza Manap ◽  
Nurfanizan Afandi ◽  
Halina Misran
Keyword(s):  
Combustion Synthesis ◽  
Oxidation Behavior ◽  
Mixed Oxides ◽  
Synthesis Method ◽  
Mass Gain ◽  
Isothermal Oxidation ◽  
X Ray Diffraction ◽  
Gel Combustion ◽  
Before And After ◽  
Different Temperatures

This paper presents the results of a study of the oxidation behavior of NiAl produced by gel combustion synthesis calcined at two different temperatures. The objective is to compare the oxide growth rates, oxide scale composition, morphology and elemental composition of the sample powder subjected to isothermal oxidation and calcined at 1050 °C and 1300 °C for 1, 2, 4 and 10 hours by means of mass gain measurements, X-ray diffraction (XRD), field emission scanning electron microsocopy (FESEM) and energy-dispersive spectrometry (EDX) in order to investigate the reliability of the gel combustion synthesis method and evaluate the effect of calcination temperature on the oxidation behaviour of the powder. It was found that for the sample calcined at 1300°C the sample was made up mainly of metastable and stable alumina before oxidation and stable alpha alumina after oxidation whereas for the powder calcined at 1050°C the sample was mainly composed of detrimental mixed oxides before and after oxidation. Overall findings indicate that the oxidation behavior of the powder calcined at 1300°C is more protective compared to the powder calcined at 1050°C.

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 Structural optical and electrical properties of a transparent conductive ITO/Al–Ag/ITO multilayer contact

2020 ◽  
Vol 11 ◽  
pp. 695-702 ◽  
Author(s):  
Aliyu Kabiru Isiyaku ◽  
Ahmad Hadi Ali ◽  
Nafarizal Nayan
Keyword(s):  
Electrical Properties ◽  
Indium Tin Oxide ◽  
Figure Of Merit ◽  
Transparent Conductive Oxide ◽  
Optical Transmittance ◽  
Multilayer Films ◽  
Optical And Electrical Properties ◽  
X Ray Diffraction ◽  
Before And After ◽  
Ito Films

Indium tin oxide (ITO) is a widely used material for transparent conductive oxide (TCO) films due to its good optical and electrical properties. Improving the optoelectronic properties of ITO films with reduced thickness is crucial and quite challenging. ITO-based multilayer films with an aluminium–silver (Al–Ag) interlayer (ITO/Al–Ag/ITO) and a pure ITO layer (as reference) were prepared by RF and DC sputtering. The microstructural, optical and electrical properties of the ITO/Al–Ag/ITO (IAAI) films were investigated before and after annealing at 400 °C. X-ray diffraction measurements show that the insertion of the Al–Ag intermediate bilayer led to the crystallization of an Ag interlayer even at the as-deposited stage. Peaks attributed to ITO(222), Ag(111) and Al(200) were observed after annealing, indicating an enhancement in crystallinity of the multilayer films. The annealed IAAI film exhibited a remarkable improvement in optical transmittance (86.1%) with a very low sheet resistance of 2.93 Ω/sq. The carrier concentration increased more than twice when the Al–Ag layer was inserted between the ITO layers. The figure of merit of the IAAI multilayer contact has been found to be high at 76.4 × 10−3 Ω−1 compared to a pure ITO contact (69.4 × 10−3 Ω−1). These highly conductive and transparent ITO films with Al–Ag interlayer can be a promising contact for low-resistance optoelectronics devices.

scholarly journals Influence of Heat Treatment on the Mechanical Properties of Ni Films on 430 Stainless Steel Substrate

2017 ◽  
Vol 36 (8) ◽  
pp. 855-861
Author(s):  
Yong Pan ◽  
Junwei Cui ◽  
Weixin Lei ◽  
Jie Zhou ◽  
Zengsheng Ma
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
X Ray Diffraction ◽  
Before And After ◽  
430 Stainless Steel ◽  
Different Temperatures ◽  
Texture Orientation

AbstractEffects of heat treatment on the mechanical properties of Ni films on 430 stainless steel substrate were investigated. The Ni films were annealed at heat treatment temperatures ranging from 0 °C to 800 °C for 2 h. The surface morphology, composition, and texture orientation of Ni films were studied by scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction. The load–indentation depth curves of Ni films before and after heat treatment were measured by using nanoindentation method. In conjunction with finite element modeling and dimensional analysis, the stress–strain relationships of Ni films on 430 stainless steel substrate at different temperatures are successfully obtained by using a power-law hardening model.

Effect of Thermal Treatment on the Physical Properties of Electrospun PVDF Membrane

2012 ◽  
Vol 591-593 ◽  
pp. 1113-1116
Author(s):  
Si Chen Cheng ◽  
Yin Zheng Liang ◽  
Yi Ping Qiu
Keyword(s):  
Thermal Treatment ◽  
Tensile Property ◽  
Tensile Testing ◽  
Vinylidene Fluoride ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Pvdf Membrane ◽  
X Ray ◽  
Before And After ◽  
Poly Vinylidene Fluoride

The electrospinning technique was used to produce poly (vinylidene fluoride) (PVDF) membrane. Thermal treatment was introduced to improve the mechanical property and dimensional stability. In this paper, the PVDF membranes before and after thermal treatment were characterized by Scanning electron microscope (SEM), differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD), tensile testing. The crystallinity, tensile property, as well as melting temperature changed with the treated temperature. The results hows that thermal treatment could notably increase the tensile property of electrospun PVDF membrane and 160°C is a proper temperature for thermal treating

scholarly journals Hydrothermal synthesis and thermoelectric properties of PbS

2016 ◽  
Vol 34 (4) ◽  
pp. 754-759 ◽  
Author(s):  
He Zhang ◽  
Haiyan Wang ◽  
Hongyu Zhu ◽  
Hongtao Li ◽  
Taichao Su ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrothermal Method ◽  
Thermoelectric Properties ◽  
Electrical Transport ◽  
Figure Of Merit ◽  
X Ray Diffraction ◽  
High Pressure Sintering ◽  
Coarse Grains ◽  
Hydrothermal Approach ◽  
Sintering Method

AbstractIn this paper, hydrothermal approach combined with high pressure sintering method was employed to synthesize PbS. The X-ray diffraction results show that single phase PbS can be obtained by a simple hydrothermal method. The scanning electron microscope results show that the PbS sample has nearly cubic shape and preserves well crystallized and coarse grains after high pressure sintering. The thermoelectric performance of PbS obtained in this study is comparable to that of a PbS sample prepared by conventional method. The carrier type and concentration of PbS can be tuned effectively by doping with Bi. The maximum figure of merit for PbS doped with 1 mol% Bi reaches 0.44 at 550 K, which is about 30 % higher than that of undoped PbS. These results indicate that hydrothermal method provides a viable and controllable way of tuning the electrical transport and thermoelectric properties for PbS.

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