Effects of Annealing Treatment on Microstructure and Thermoelectric Properties of Ba8Al16Si30

2006 ◽  
Vol 118 ◽  
pp. 561-564 ◽  
Author(s):  
Jung Il Lee ◽  
Jong Bum Park ◽  
Sin Wook You ◽  
Joo Ho Lee ◽  
Il Ho Kim ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Isothermal Annealing ◽  
Annealing Treatment ◽  
Hardness Test ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Annealing Effects ◽  
Type Conduction

Clathrate Ba8Al16Si30 was produced by arc melting and annealing effects on the microstructure and thermoelectric properties were investigated. The phase transformation behavior of arc-melted Ba8Al16Si30 was examined by thermogravimetric analysis, differential scanning calorimetry, hardness test, X-ray diffraction and scanning electron microscope analyses. Isothermal annealing was carried out to induce the transformation to a thermoelectric phase at 500°C to 700°C for 5 hrs. Thermoelectric properties in the temperature range between 300K and 600K were measured and evaluated. Electrical conductivity was decreased and Seebeck coefficient was increased with increasing isothermal annealing temperature. The arc-melted and the isothermal annealed specimens represented n-type conduction at temperatures examined, and they showed reliable thermoelectric behaviors.

Thermoelectric Properties of Arc-Melted Ba8Al16Si30 Clathrate

2007 ◽  
Vol 539-543 ◽  
pp. 3309-3312 ◽  
Author(s):  
Jung Il Lee ◽  
Jong Bum Park ◽  
Sin Wook You ◽  
Joo Ho Lee ◽  
Young Ho Kim ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Density Measurement ◽  
Hardness Test ◽  
Homogenization Temperature ◽  
Vacuum Furnace ◽  
Type I ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Type Conduction

Ba8Al16Si30 type I clathrate was produced by arc melting and thermoelectric properties were investigated. The phase transformation behavior of arc-melted type I Ba8Al16Si30 was examined by thermogravimetric analysis, differential scanning calorimetry, hardness test, density measurement, X-ray diffraction and scanning electron microscope analyses. Homogenization was carried out to induce the transformation to a thermoelectric phase at 773K to 973K for 5 hours and 24 hours in the vacuum furnace. Thermoelectric properties in the temperature range between 300K and 600K were measured and evaluated. Electrical conductivity was decreased and Seebeck coefficient was increased with increasing homogenization temperature and time. The arc-melted and the homogenized specimens represented n-type conduction at temperatures examined, and they showed reliable thermoelectric behaviors with increasing homogenization temperature and time.

Thermoelectric Properties of Undoped CoSb3

2004 ◽  
Vol 449-452 ◽  
pp. 917-920 ◽  
Author(s):  
Il Ho Kim ◽  
G.S. Choi ◽  
M.G. Han ◽  
Ji Soon Kim ◽  
Jung Il Lee ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Transitions ◽  
Thermoelectric Properties ◽  
Single Phase ◽  
Arc Melting ◽  
Annealing Effects ◽  
P Type ◽  
Type Conduction ◽  
Semiconducting Behavior

CoSb3 compounds were prepared by the arc melting and their thermoelectric properties were investigated at 300K-600K. Annealing effects were examined and they were correlated to phase transformation and homogenization. Undoped CoSb3 showed p-type conduction and intrinsic semiconducting behavior at all temperatures examined. Thermoelectric properties were changed with constituent phases because α-CoSb2, β-CoSb and Sb are metallic or semimetallic phases while δ-CoSb3 is semiconducting phase. Thermoelectric properties were remarkably improved by annealing in vacuum and they were closely related to phase transitions. Single phase δ-CoSb3 was successfully obtained by annealing at 400°C for 24hrs.

Effects of Cooling Rate and Sn Addition on the Microstructure of Ti-Nb-Sn Alloys

2011 ◽  
Vol 172-174 ◽  
pp. 190-195 ◽  
Author(s):  
Giorgia T. Aleixo ◽  
Eder S.N. Lopes ◽  
Rodrigo Contieri ◽  
Alessandra Cremasco ◽  
Conrado Ramos Moreira Afonso ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Melting Furnace ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Β Phase ◽  
Arc Melting ◽  
Ti Alloys ◽  
Ω Phase

Ti-based alloys present unique properties and hence, are employed in several industrial segments. Among Ti alloys, β type alloys form one of the most versatile classes of materials in relation to processing, microstructure and mechanical properties. It is well known that heat treatment of Ti alloys plays an important role in determining their microstructure and mechanical behavior. The aim of this work is to analyze microstructure and phases formed during cooling of β Ti-Nb-Sn alloy through different cooling rates. Initially, samples of Ti-Nb-Sn system were prepared through arc melting furnace. After, they were subjected to continuous cooling experiments to evaluate conditions for obtaining metastable phases. Microstructure analysis, differential scanning calorimetry and X-ray diffraction were performed in order to evaluate phase transformations. Depending on the cooling rate and composition, α” martensite, ω phase and β phase were obtained. Elastic modulus has been found to decrease as the amount of Sn was increased.

Crystallization of Amorphous Cu49.7Ti31.8Zr11.3Ni7.2 Alloy

2016 ◽  
Vol 869 ◽  
pp. 464-469 ◽  
Author(s):  
Carlos Triveño Rios ◽  
R. Contieri
Keyword(s):  
Low Cost ◽  
Centrifugal Casting ◽  
Amorphous State ◽  
Bulk Sample ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Fracture ◽  
Crystalline Materials ◽  
Thermal Crystallization ◽  
Arc Melting

Bulk metallic glasses are attractive materials for structural and functional applications when compared to crystalline materials. The Cu-based glasses exhibit particular interest due primarily to their relatively low cost and high fracture resistance. In this work the Cu49.7Ti31.8Zr11.3Ni7.2 alloy was prepared from the mixture of pure metals by arc melting and following the ingot was re-melted by centrifugal casting in wedge-section copper mould. The structure of wedge bulk sample was evaluated by a combination of X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The results show that the amorphous state is formed in the thinner region and it is maintained up to thickness of 3.5 mm in the wedge bulk-sample. The crystallization temperature was observed above 400 °C coinciding with the studies of thermal crystallization by XRD and DSC. Dynamical heating of the amorphous phase from room temperature up to 750°C showed the formation of CuTi, Cu10Zr7 e Cu2TiZr crystalline phases.

Annealing Effect on the Thermoelectric Properties of Undoped CoSb3

2006 ◽  
Vol 118 ◽  
pp. 565-570 ◽  
Author(s):  
Il Ho Kim ◽  
Jung Il Lee ◽  
Soon Chul Ur ◽  
Kyung Wook Jang ◽  
Good Sun Choi ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Transitions ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Annealing Effect ◽  
Metallic Behavior ◽  
Arc Melting ◽  
P Type ◽  
Type Conduction

Binary skutterudite CoSb3 compounds were prepared by the arc melting and hot pressing processes and their thermoelectric properties were investigated at 300K-600K. Annealing effect was examined and it was correlated to phase transformation and homogenization. Thermoelectric properties of the arc-melted and hot-pressed CoSb3 were discussed and compared. Undoped CoSb3 prepared by the arc melting showed p-type conduction and metallic behavior at all temperatures examined. However, hot pressed specimens showed n-type conduction, possibly due to Sb evaporation. Thermoelectric properties were remarkably improved by annealing in vacuum and they were closely related to phase transitions.

Annealing Effects on Powder Metallurgy Based Pb1-xSnxTe Materials for Thermoelectric Applications

2007 ◽  
Vol 336-338 ◽  
pp. 860-863
Author(s):  
Y. Gelbstein ◽  
Z. Dashevsky ◽  
R. Kreizman ◽  
Y. George ◽  
M. Gelbstein ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Thermoelectric Properties ◽  
Annealing Treatment ◽  
Preparation Technique ◽  
Tin Telluride ◽  
Powder Metallurgy Process ◽  
Lead Tin Telluride ◽  
Annealing Effects ◽  
P Type ◽  
Metallurgy Process

Lead tin telluride based alloys are known p-type materials for thermoelectric applications, in the 50-600oC temperature range. These alloys combine desired features of mechanical and thermoelectric properties. The electronic transport properties of PbTe and Pb1-xSnxTe materials may be strongly dependent on the preparation technique. Powder metallurgy process is known to introduce defects and strains, that may alter carrier concentration. Under such non-equilibrium conditions the thermoelectric properties are instable at the operating temperature. An appropriate annealing treatment can eliminate this effect.. The present communication describes the annealing treatment applied to cold compacted and sintered Pb1-xSnxTe materials.

scholarly journals Structural Phase Transition and Related Thermoelectric Properties in Sn Doped AgBiSe2

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1016
Author(s):  
Xiao-Cun Liu ◽  
Ming-Yan Pan
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Complex Structural

AgBiSe2, which exhibits complex structural phase transition behavior, has recently been considered as a potential thermoelectric material due to its intrinsically low thermal conductivity. In this work, we investigate the crystal structure of Sn-doped AgBiSe2 through powder X-ray diffraction and differential scanning calorimetry measurements. A stable cubic Ag1−x/2Bi1−x/2SnxSe2 phase can be obtained at room temperature when the value of x is larger than 0.2. In addition, the thermoelectric properties of Ag1−x/2Bi1−x/2SnxSe2 (x = 0.2, 0.25, 0.3, 0.35) are investigated, revealing that Ag1−x/2Bi1−x/2SnxSe2 compounds are intrinsic semiconductors with a low lattice thermal conductivity. This work provides new insights into the crystal structure adjustment of AgBiSe2 and shows that Ag1−x/2Bi1−x/2SnxSe2 is a potentially lead-free thermoelectric material candidate.

Effect of Annealing Treatment on the Microstructure and Magnetic Properties of FeSiBAlNi(C, Ce) High Entropy Alloys

2016 ◽  
Vol 849 ◽  
pp. 52-57 ◽  
Author(s):  
Jing Xu ◽  
Zheng Feng Zhao ◽  
Yan Wang
Keyword(s):  
Magnetic Properties ◽  
Amorphous Phase ◽  
Annealing Treatment ◽  
Particle Morphology ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Entropy ◽  
Temperature Range ◽  
Microstructure And Magnetic Properties

In this paper, the effects of annealing treatment on the microstructure, thermal property and magnetic properties of mechanical alloyed FeSiBAlNiC and FeSiBAlNiCe amorphous high entropy alloys has been systematically investigated using X-ray diffraction, differential scanning calorimetry, field emission scanning electron microscopy and alternation gradient magnetometry. The results showed that annealing at different temperature range induced the pronounced microstructural evolution from the amorphous phase to a mixture of amorphous phase and intermetallics but without any formation of solid solutions. In addition, the thermal stability and heat resistance were enhanced with increasing the annealing temperature. Similarly, annealing treatment also had significant effect on the particle morphology, making the particles evolve from near-round shape to plate-like shape. Furthermore, subsequent annealing of W6-Ce amorphous HEAs enhanced the saturation magnetization (Ms) remarkably (from 0.6 emu/g of 140 h as-milled W6-Ce to 20.17 emu/g). But for the Ms values of the 140 h as-milled amorphous W6-C HEAs, annealing in different temperature range all exhibited a slightly decreased effect.

Annealing effects of high sensitive thin strain gauges consisting of nickel carbon nanocomposites

2018 ◽  
Vol 37 (22) ◽  
pp. 1378-1384 ◽  
Author(s):  
Christos Karapepas ◽  
Daisy Nestler ◽  
Daniel Wett ◽  
Guntram Wagner
Keyword(s):  
Annealing Treatment ◽  
Temperature Stability ◽  
Strain Gauges ◽  
Smart Sensor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phase Development ◽  
Different Temperatures ◽  
Annealing Effects ◽  
Hybrid Laminates

Hybrid laminates consisting of fiber-reinforced thermoplastic films and metallic thin sheets are successively replacing thermoset-based systems due to their obvious advantages of higher formability and the aptitude for mass production. In order to monitor the material under operating condition, hybrid laminates need to be equipped with smart sensor units. Therefore, the aim of the present work is to evaluate the temperature stability of the Ni-C thin film strain gauge sensors. The analyses of the deposited Ni-C films manufactured by means of a magnetron sputtering process were carried out by means of Raman spectroscopy and X-ray diffraction to investigate the phase development after a heat treatment at different temperatures and holding times. In addition, the four-terminal sensing was utilized to study the change of temperature coefficients of resistance after a single annealing treatment.

Transformation Behavior of a Ti-Ni-Cu-Fe Alloy

2004 ◽  
Vol 449-452 ◽  
pp. 185-188 ◽  
Author(s):  
Tae Hyun Nam ◽  
Tae Yeon Kim ◽  
Ji Soon Kim ◽  
Seung Baik Kang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Electrical Resistivity ◽  
Resistivity Measurement ◽  
Electrical Resistivity Measurement ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
Scanning Calorimetry ◽  
X Ray

Transformation behavior of a Ti-43.0Ni-5.0Cu-2.0Fe(at%) alloy has been investigated by means of electrical resistivity measurement, differential scanning calorimetry and X-ray diffraction. The alloy transformed in three-stage during each cooling and heating procedure. That is, the B2-R-B19-B19' on cooling and the B19'-B19-R-B2 on heating.

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