scholarly journals Fabrication and Enhanced Thermoelectric Properties of Alumina Nanoparticle-Dispersed Bi0.5Sb1.5Te3Matrix Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Kyung Tae Kim ◽  
Gook Hyun Ha
Keyword(s):  
Milling Process ◽  
Alumina Nanoparticles ◽  
Sintering Process ◽  
Composite Powders ◽  
Alumina Nanoparticle ◽  
Plasma Sintering ◽  
The Matrix ◽  
High Resolution Tem ◽  
Spark Plasma ◽  
P Type

Alumina nanoparticle-dispersed bismuth-antimony-tellurium matrix (Al2O3/BST) composite powders were fabricated by using ball milling process of alumina nanoparticle about 10 nm and p-type bismuth telluride nanopowders prepared from the mechanochemical process (MCP). The fabricated Al2O3/BST composite powders were a few hundreds of nanometer in size, with a clear Bi0.5Sb1.5Te3phase. The composite powders were consolidated into p-type bulk composite by spark plasma sintering process. High-resolution TEM images reveal that alumina nanoparticles were dispersed among the grain boundary or in the matrix grain. The sintered 0.3 vol.% Al2O3/BST composite exhibited significantly improved power factor and reduced thermal conductivity in the temperature ranging from 293 to 473 K compared to those of pure BST. From these results, the highly increased ZT value of 1.5 was obtained from 0.3 vol.% Al2O3/BST composite at 323 K.

scholarly journals Fabrication Process and Thermoelectric Properties of CNT/Bi2(Se,Te)3Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Kyung Tae Kim ◽  
Yeong Seong Eom ◽  
Injoon Son
Keyword(s):  
Figure Of Merit ◽  
Reduction Process ◽  
Sintering Process ◽  
Composite Powders ◽  
Synergistic Enhancement ◽  
Dimensionless Figure Of Merit ◽  
Plasma Sintering ◽  
The Matrix ◽  
Spark Plasma ◽  
Matrix Modifications

Carbon nanotube/bismuth-selenium-tellurium composites were fabricated by consolidating CNT/Bi2(Se,Te)3composite powders prepared from a polyol-reduction process. The synthesized composite powders exhibit CNTs homogeneously dispersed among Bi2(Se,Te)3matrix nanopowders of 300 nm in size. The powders were densified into a CNT/Bi2(Se,Te)3composite in which CNTs were randomly dispersed in the matrix through spark plasma sintering process. The effect of an addition of Se on the dimensionless figure-of-merit (ZT) of the composite was clearly shown in 3 vol.% CNT/Bi2(Se,Te)3composite as compared to CNT/Bi2Te3composite throughout the temperature range of 298 to 473 K. These results imply that matrix modifications such as an addition of Se as well as the incorporation of CNTs into bismuth telluride thermoelectric materials is a promising means of achieving synergistic enhancement of the thermoelectric performance levels of these materials.

The Influence of RuO2 Addition on the Thermoelectric Properties of BiSbTe Alloys

2012 ◽  
Vol 512-515 ◽  
pp. 1651-1654 ◽  
Author(s):  
Yu Kun Xiao ◽  
Zhi Xiang Li ◽  
Jun Jiang ◽  
Sheng Hui Yang ◽  
Ting Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Lattice Thermal Conductivity ◽  
Combined Process ◽  
Plasma Sintering ◽  
The Matrix ◽  
Spark Plasma ◽  
Xrd Patterns ◽  
Factor Α ◽  
P Type

P-type BiSbTe/RuO2 composite was fabricated using a combined process of melting and spark plasma sintering. The XRD patterns showed that RuO2 reacted with the matrix for the RuO2 content of 1.0 wt% and 4.0 wt% samples. The measured thermoelectric properties showed that the highest electrical conductivity was obtained for the sample with 2.0 wt% RuO2. The power factor (α2σ/κ) decreased with the increase of RuO2 below 450 K. The lattice thermal conductivity was lower than that of BiSbTe over the whole temperature range for BiSbTe/2.0 wt% RuO2.

scholarly journals Influence of molybdenum content on the microstructure of spark plasma sintered titanium alloys

2021 ◽  
Vol 1 (1) ◽  
pp. 41-47
Author(s):  
M. Saravana Kumar ◽  
S. Rashia Begum ◽  
M. Vasumathi ◽  
Chinh Chien Nguyen ◽  
Quyet Van Le
Keyword(s):  
Relative Density ◽  
Phase Evolution ◽  
Microstructural Development ◽  
Sintered Titanium ◽  
Sintering Process ◽  
Plasma Sintering ◽  
The Matrix ◽  
Molybdenum Addition ◽  
Spark Plasma ◽  
Mo Content

Five titanium-based alloys containing 4, 8, 12, 16, and 20 wt% molybdenum additive were fabricated by spark plasma sintering process at 1200 ˚C. The samples were scrutinized in terms of relative density, phase evolution, and microstructural development. The relative density reached 99.9% with the molybdenum addition up to 16 wt% but slightly dropped in the sample with 20 wt% additive. In the specimens with 4 wt% Mo, molybdenum solved completely in the matrix and three different phase morphologies were observed, namely continuous α-Ti, laminar α-Ti, and very thin laminar β-Ti. With increasing Mo content to 20 wt%, widespread single β-Ti appeared alongside remained Mo and α-Ti. Ductile fracture mode was dominant in the samples with low Mo contents whilst it changed to brittle in the specimens with higher content of molybdenum.

scholarly journals Characteristics of Nanophase WC and WC-3 wt% (Ni, Co, and Fe) Alloys Using a Rapid Sintering Process for the Application of Friction Stir Processing Tools

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Daeup Kim ◽  
Young Choi ◽  
Yongil Kim ◽  
Seungboo Jung
Keyword(s):  
Friction Stir Processing ◽  
Average Particle Size ◽  
Milling Process ◽  
Phase Changes ◽  
Average Particle ◽  
Sintering Process ◽  
Friction Stir ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Rapid Sintering

Microstructures and mechanical characteristics of tungsten carbide- (WC-) based alloys, that is, WC, WC-3 wt% Ni, WC-3 wt% Co, and WC-3 wt% Fe, fabricated using a spark plasma sintering (SPS) method for the application of friction stir processing tools were evaluated. The sintered bodies with a diameter of 66 mm showed relative densities of up to 99% with an average particle size of 0.26~0.41 μm under a pressure condition of 60 MPa with an electric current for 35 min without noticeable grain growth during sintering. Even though no phase changes were observed after the ball milling process the phases of W2C andWC1-xappeared in all sintered samples after sintering. The Vickers hardness and fracture toughness of the WC, WC-3 wt% Ni, WC-3 wt% Co, and WC-3 wt% Fe samples ranged from 2,240 kg mm2to 2,730 kg mm2and from 6.3 MPa·m1/2to 9.1 MPa·m1/2, respectively.

scholarly journals Sintering Behavior of CNT Reinforced Al6061 and Al2124 Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Nouari Saheb
Keyword(s):  
Ball Milling ◽  
Sintering Behavior ◽  
Automotive Electronics ◽  
Composite Powders ◽  
Plasma Sintering ◽  
The Matrix ◽  
Potential Applications ◽  
Spark Plasma ◽  
Nanocomposite Powders ◽  
Very High

Ball milling and spark plasma sintering were successfully used to produce carbon nanotube reinforced Al6061 and Al2124 nanocomposites which have potential applications in the fields of aerospace, automotive, electronics, and high precision instrumentation. Al2124 and Al6061 nanocomposite powders containing 0.5 to 2 wt.% CNTs prepared through sonication and wet ball milling were spark plasma sintered at 400, 450, and 500°C for 20 minutes under a pressure of 35 MPa. CNTs were better dispersed, and less agglomerated and had good adhesion to the matrix in composites containing 1 wt.% CNTs. The increase of CNT content to 2 wt.% led to the formation of CNT clusters which resulted in less uniform and homogenous composite powders. Almost full densification of Al6061 reinforced with CNTs was achieved at 500°C. Also, CNTs reinforced Al2124 nanocomposites reached very high densities at 500°C. Composites reinforced with 1 wt.% CNTs displayed better densification compared to composites containing 2 wt.% CNTs. The increase of CNTs content from 0.5 to 1 wt.% increased the hardness of the Al6061 and Al2124 alloys to maximum values. Further increase of CNTs content to 2 wt.% decreased the hardness to values lower than that of the monolithic alloys.

Microstructure and Tribological Properties of Aluminum Matrix Composite

2015 ◽  
Vol 641 ◽  
pp. 30-38 ◽  
Author(s):  
Magdalena Suśniak ◽  
Joanna Karwan-Baczewska ◽  
Iwona Sulima
Keyword(s):  
Matrix Composite ◽  
Tribological Properties ◽  
Volume Fraction ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composite ◽  
Sintering Process ◽  
Alloy Matrix ◽  
Plasma Sintering ◽  
The Matrix ◽  
Spark Plasma

AlSi5Cu2 alloy matrix composite have been studied by microscopic examination and basic tribological properties was evaluated. Composite material was produced by the mechanical milling and spark plasma sintering technique. After sintering process SiC particles were uniformly distributed in the matrix. The wear and the friction coefficients were determinate as a function of the SiC volume fraction. The addition of SiC wt. % had significant effect on tribological properties of that composites. The increase in reinforcement content improves the wear resistance of obtained materials.

scholarly journals Effect of Intermetallic Compounds on the Thermal and Mechanical Properties of Al–Cu Composite Materials Fabricated by Spark Plasma Sintering

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1546 ◽  
Author(s):  
Kyungju Kim ◽  
Dasom Kim ◽  
Kwangjae Park ◽  
Myunghoon Cho ◽  
Seungchan Cho ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Intermetallic Compounds ◽  
Spark Plasma Sintering ◽  
Sintering Process ◽  
Composite Powders ◽  
Cu Content ◽  
Plasma Sintering ◽  
Spark Plasma

Aluminium–copper composite materials were successfully fabricated using spark plasma sintering with Al and Cu powders as the raw materials. Al–Cu composite powders were fabricated through a ball milling process, and the effect of the Cu content was investigated. Composite materials composed of Al–20Cu, Al–50Cu, and Al–80Cu (vol.%) were sintered by a spark plasma sintering process, which was carried out at 520 °C and 50 MPa for 5 min. The phase analysis of the composite materials by X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) indicated that intermetallic compounds (IC) such as CuAl2 and Cu9Al4 were formed through reactions between Cu and Al during the spark plasma sintering process. The mechanical properties of the composites were analysed using a Vickers hardness tester. The Al–50Cu composite had a hardness of approximately 151 HV, which is higher than that of the other composites. The thermal conductivity of the composite materials was measured by laser flash analysis, and the highest value was obtained for the Al–80Cu composite material. This suggests that the Cu content affects physical properties of the Al–Cu composite material as well as the amount of intermetallic compounds formed in the composite material.

Preparation of Lithium Sulfide-Carbon Composites Using Spark-Plasma-Sintering Process and their Electrochemical Properties

2010 ◽  
Vol 638-642 ◽  
pp. 2184-2188 ◽  
Author(s):  
Tomonari Takeuchi ◽  
Hikari Sakaebe ◽  
Tetsuo Sakai ◽  
Kuniaki Tatsumi
Keyword(s):  
Spark Plasma Sintering ◽  
Carbon Composite ◽  
Milling Process ◽  
Sintering Process ◽  
Rechargeable Lithium Batteries ◽  
Positive Electrodes ◽  
Electrochemical Tests ◽  
Plasma Sintering ◽  
Lithium Sulfide ◽  
Spark Plasma

Lithium sulfide (Li2S)-carbon composite positive electrodes were prepared by the spark-plasma-sintering (SPS) process for use in rechargeable lithium batteries. By the SPS treatment of Li2S and acetylene black (AB) blended powder, the strong binding between the active materials and the carbon powders were formed. Such contact effect improved the electrochemical performance of the cells with liquid electrolytes (1M LiFP6/(EC+DMC)), probably due to the increase in conductivity of the positive electrodes, though the samples prepared by the ball-milling process showed no significant capacity in the electrochemical tests.

Febrication of MWNTs Composites with In Situ Precipitation Method

2007 ◽  
Vol 121-123 ◽  
pp. 135-138 ◽  
Author(s):  
Jing Wang ◽  
Hua Min Kou ◽  
Yu Bai Pan ◽  
Jing Kun Guo
Keyword(s):  
Aqueous Suspension ◽  
Precipitation Method ◽  
Composite Powders ◽  
Plasma Sintering ◽  
The Matrix ◽  
Ceramics Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Walled Carbon Nanotubes

In this article stable multi-walled carbon nanotubes (MWNTs) aqueous suspension with a 1.0 wt.% concentration was obtained with a very small quantity of dispersant. Precursor of ceramics were synthesized in the suspension and densely deposited on the surface of MWNTs successfully by a simple and effective in-situ precipitation method. The most important advantage for the in-situ composite method is to make MWNTs homogeneously distributed in the matrix. The fully dense compacts were obtained by spark-plasma-sintering (SPS) the in-situ precipitated composite powders at temperature 200 oC lower than that of composite powders made from the traditional mixing method. Furthermore, the microstructure and the mechanical property of the composites are much better than that of traditional method. The in-situ precipitation could be a promising method to fabricate CNTs composites of ceramics matrix especially those hard to sinter.

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