Magnetic Properties and High Thermal Conductivity of Al2O3 Ceramics Prepared by Spark Plasma Sintering

2013 ◽  
Vol 750-752 ◽  
pp. 512-516 ◽  
Author(s):  
Zhen Hua Jia ◽  
Xin Gui Tang ◽  
Donge Chen ◽  
Jun Bo Wu ◽  
Qiu Xiang Liu
Keyword(s):  
Thermal Conductivity ◽  
Magnetic Properties ◽  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
High Thermal Conductivity ◽  
X Ray ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma

The Al2O3 ceramics with high thermal conductivity prepared the spark plasma sintering (SPS) technology. The structure, image and magnetic properties of the SPS Al2O3 ceramics was characterized by X-ray, field emission scanning electron microscope (FE-SEM) and the vibrating sample magnetometer (VSM) at room temperature. The results shown that the average grain size of the Al2O3 ceramics is about 5~15μm, the thermal conductivity of Al2O3 ceramics up to 24.928 W/(m·K), and the remanent magnetization as higher as 0.00546emu/g and the saturation magnetization as higher as 0.0321 emu/g, respectively. The room-temperature ferromagnetism, which is different from the traditional, possibly originates from the oxygen vacancies.

Spark Plasma Sintering of Ti-4.5Al-3V-2Fe-2Mo (SP-700)

2010 ◽  
Vol 654-656 ◽  
pp. 819-822
Author(s):  
Genki Kikuchi ◽  
Hiroshi Izui ◽  
Yuya Takahashi ◽  
Shota Fujino
Keyword(s):  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Volume Fraction ◽  
Titanium Boride ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Tib2 Particles

In this study, we focused on the sintering performance of Ti-4.5Al-3V-2Mo-2Fe (SP-700) and mechanical properties of SP-700 reinforced with titanium boride (TiB/SP-700) fabricated by spark plasma sintering (SPS). TiB whiskers formed in titanium by a solid-state reaction of titanium and TiB2 particles were analyzed with scanning electron microscopy and X-ray diffraction. The TiB/SP-700 was sintered at temperatures of 1073, 1173, and 1273 K and a pressure of 70 MPa for 10, 30, and 50 min. The volume fraction of TiB ranged from 1.7 vol.% to 19.9 vol.%. Tensile tests of TiB/SP-700 were conducted at room temperature, and the effect of TiB volume fraction on the tensile properties was investigated.

Fabrication of Mg2Si Thermoelectric Materials by Mechanical Alloying and Spark-Plasma Sintering Process

2006 ◽  
Vol 6 (11) ◽  
pp. 3429-3432
Author(s):  
Chung-Hyo Lee ◽  
Seong-Hee Lee ◽  
Sung-Yong Chun ◽  
Sang-Jin Lee
Keyword(s):  
Grain Size ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Atomic Ratio ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma

A mixture of pure Mg and Si powders with an atomic ratio 2:1 has been subjected to mechanical alloying (MA) at room temperature to prepare the Mg2Si thermoelectric material. Mg2Si intermetallic compound with a grain size of 50 nm can be obtained by MA of Mg66.7Si33.3 powders for 60 hours and subsequently annealed at 620 °C. Consolidation of the MA powders was performed in a spark plasma sintering (SPS) machine using graphite dies up to 800–900 °C under 50 MPa. The shrinkage of consolidated samples during SPS was significant at about 250 °C and 620 °C. X-ray diffraction data shows that the SPS compact from 60 h MA powders consolidated up to 800 °C consists of only nanocrystalline Mg2Si compound with a grain size of 100 nm.

Thermoelectric properties of synthesized Mg2Si0.95-xGe0.05Sbx by spark plasma sintering

2015 ◽  
Vol 1735 ◽  
Author(s):  
Asumi Sasaki ◽  
Koya Arai ◽  
Yuto Kimori ◽  
Tomoyuki Nakamura ◽  
Kenjiro Fujimoto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Carrier Concentration ◽  
Spark Plasma Sintering ◽  
Phonon Scattering ◽  
Laser Flash ◽  
Magnesium Silicide ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma

AbstractMagnesium silicide (Mg2Si) has attracted much interest as an n-type thermoelectric material because it is eco-friendly, non-toxic, light, and relatively abundant compared with other thermoelectric materials. In this study, we tried to improve the thermoelectric performance by doping Sb and Ge in the Mg2Si, as well as further optimizing x in the carrier concentration to cause phonon scattering. A high purity Mg2Si was synthesized from metal Mg and Sb doped Si-Ge alloy by using spark plasma sintering (SPS) equipment. The sintered samples were cut and polished. They were evaluated by using X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses. The carrier concentration of the samples was measured by using Hall measurement equipment. The electrical conductivity and Seebeck coefficient were measured by using a standard four-probe method in a He atmosphere. The thermal conductivity was measured by using a laser-flash system. We succeeded in obtaining a Sb doped Mg2Si0.95Ge0.05 sintered body easily without any impurities with the SPS equipment. The electrical conductivity of the sample was increased, and thermal conductivity was decreased by increasing the amount of doped Sb. The dimensionless figure of merit ZT became 0.74 at 733 K in the Mg2Si0.95-xGe0.05Sbx sample with x = 0.0022.

Bi2Te3 and Bi2Te3/Nano-SiC Prepared by Mechanical Alloying and Spark Plasma Sintering

2007 ◽  
Vol 280-283 ◽  
pp. 397-400 ◽  
Author(s):  
Jing Liu ◽  
Jing Feng Li
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Mechanical Alloying ◽  
Seebeck Coefficient ◽  
Spark Plasma Sintering ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Mechanically Alloyed ◽  
Plasma Sintering ◽  
Spark Plasma

Bi2Te3-based alloys are currently best-known, technological thermoelectric materials near room temperature. In this paper, Bi2Te3 and nano-SiC dispersed Bi2Te3 were prepared by mechanical alloying followed by spark plasma sintering (SPS). Raw powders of Bi, Te and SiC were mixed and mechanically alloyed in an argon atmosphere using a planetary ball mill. The SPS temperature was 623K, and the holding time was 5 minutes. The samples were characterized by X-ray Diffraction (XRD) and Scanning electron Microscope (SEM). The thermoelectric properties: i.e. Seebeck coefficient, electrical resistivity and thermal conductivity were measured at temperatures from room temperature to 573K, followed by the evaluation of figure of merit. The results revealed that the SiC dispersion in the Bi2Te3 matrix increased Seebeck coefficient. Although the electrical resistivity was increased somewhat, the thermal conductivity was reduced by the SiC dispersion, indicating that promising thermoelectric materials with enhanced mechanical properties may be obtained in the nano-SiC dispersed Bi2Te3 composites with optimal compositions.

Greatly Enhanced Thermal Conductivity of Fully Inert Matrix Dispersion Pellet (IMDP) Produced by Spark Plasma Sintering (SPS) Technique

2018 ◽  
Author(s):  
Zhaodandan Ma ◽  
Tong Liu ◽  
Rui Li ◽  
Maozhou Sun ◽  
Zhiwei Lu
Keyword(s):  
Thermal Conductivity ◽  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Inert Matrix ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
New Type ◽  
Normal Method ◽  
Enhanced Thermal Conductivity ◽  
Better Than

In order to improve nuclear reactor’s performance and safety, a new-type fuel, Inert Matrix Dispersion Pellet (IMDP) with greatly enhanced thermal conductivity was studied. In this paper, the pellet was developed by Spark Plasma Sintering Technique (SPS), which brings an improved thermal conductivity compared with normal method and exhibits fully dense SiC matrix with a higher TRISO volume in kernel of pellet. Thermal-physical properties of the IMDP from room temperature to 1400 °C were investigated. The thermal conductivity improved 1100% at room temperature and 974% under 1000°C when TRISO volume is 40%, which behave much better than traditional UO2 fuel. The thermal diffusivity reduced and heat capacity increased at different TRISO volumes, linearly implied stable geometry at high temperature. From CT test we can see an intact structure of uniform TRISO granules. For comparison, modeling thermal conductivity is analyzed by FEM, which shows lower than measured data, indicating an optimized technology of this new method. Advantages of SPS will be discussed as well.

Synthesis and Thermal Properties of Nanoscale Skutterudite via Cross-Coprecipitation

2007 ◽  
Vol 336-338 ◽  
pp. 831-833
Author(s):  
Ying Chu ◽  
Xin Feng Tang ◽  
Ling Wan ◽  
Qing Jie Zhang
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Grain Size ◽  
Room Temperature ◽  
Single Phase ◽  
Antimony Oxide ◽  
Hydrogen Atmosphere ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma

CoSb3 with nanoscale was synthesized by Cross-coprecipitation. A precursor consisting of antimony oxide and cobalt hydrate was prepared by the reaction of CoCl2, SbCl3 and both precipitators at room temperature. The precursor was reduced in thermal treatment under hydrogen atmosphere whereby the CoSb3 was thus obtained. The parameters especially reducing temperature and atmosphere (content of H2) influence the constituent phases and particle size of product significantly. The single phase CoSb3 with the average grain size of 60~70 nm was obtained after reduced at 723 K for 2 h with pure H2. Nanoscale CoSb3 powder was used as starting materials, and bulk CoSb3 compound was prepared by spark plasma sintering (SPS). The effect of grains size on thermal conductivity was investigated.

Microstructure and thermoelectric properties of CuInSe2/In2Se3 compound

2018 ◽  
Vol 32 (03) ◽  
pp. 1850018 ◽  
Author(s):  
Kang Wang ◽  
Jing Feng ◽  
Zhen-Hua Ge ◽  
Peng Qin ◽  
Jie Yu
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Room Temperature ◽  
Solvothermal Method ◽  
Chalcopyrite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

CuInSe2 powders were synthesized by solvothermal method, and then the CuInSe2/In2Se3 bulk samples were fabricated by spark plasma sintering (SPS) technique. To investigate the phase composition, the powders were determined by X-ray diffraction (XRD). The microstructures of the powders and bulk samples were observed by scanning electron microscopy (SEM). The transportation of the electronic properties and thermal conductivity were measured at room temperature to 700 K. According to the results, the CuInSe2 powders appeared in flower-like patterns which ranged from 3 [Formula: see text]m to 6 [Formula: see text]m. CuInSe2 powders were synthesized at 180[Formula: see text]C with a chalcopyrite structure. The Seebeck coefficient increased significantly in composite thermoelectric materials up to [Formula: see text] at 623 K. The thermal conductivity of the sample significantly decreases from the room temperature to 700 K. The CuInSe2 bulk composite by solvothermal method achieves the highest ZT value of 0.187 at 700 K.

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