scholarly journals Simultaneous spark plasma synthesis and consolidation of WC/Co composites

2005 ◽  
Vol 20 (3) ◽  
pp. 734-741 ◽  
Author(s):  
Antonio Mario Locci ◽  
Roberto Orrù ◽  
Giacomo Cao
Keyword(s):  
Intermediate Phase ◽  
Single Step ◽  
Operating Conditions ◽  
Plasma Synthesis ◽  
Mechanical Pressure ◽  
Sintering Time ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Time Required ◽  
Spark Plasma Synthesis

The single-step synthesis and densification of the WC–6Co cemented carbide starting from elemental powders was obtained by the spark plasma sintering (SPS) technique. The operating conditions that guarantee the complete conversion of the reactants to the desired full dense material have been identified. Specifically, under the application of 800 A and a mechanical pressure of 40 MPa for about 200 s, a product with relative density higher than 99%, hardness of 14.97 ± 0.35 GPa, and 12.5 ± 1.0 MPa m0.5 fracture toughness was obtained. A kinetic investigation of the SPS process was also performed. It revealed that an intermediate phase, i.e., W2C, is the first carbide formed during the carburization process. It was observed that the synthesis and sintering stages take place simultaneously. It was also found that as the applied pulsed current intensity was augmented, the synthesis/sintering time required decreased significantly.

Spark Plasma Synthesis/Sintering of Dense Ceramic, Intermetallic and Composite Materials

2006 ◽  
Vol 45 ◽  
pp. 1411-1416
Author(s):  
Antonio Mario Locci ◽  
Roberta Licheri ◽  
Roberto Orrù ◽  
A. Cincotti ◽  
Giacomo Cao
Keyword(s):  
Mechanical Load ◽  
Plasma Synthesis ◽  
Simultaneous Application ◽  
Plasma Sintering ◽  
Pulsed Dc ◽  
Spark Plasma ◽  
One Step ◽  
Powder Particles ◽  
Dc Current ◽  
Spark Plasma Synthesis

Spark Plasma Sintering (SPS) represents a very attractive technique for the obtainment of dense materials including nanostructured ones. SPS basically consists in the simultaneous application of a pulsed DC current and an uniaxial mechanical load through a powder compact. Other than providing rapid Joule heating and likely enhancing mass transport through electromigration, the imposed pulsed high current is also reported to generate a plasma within the voids surrounding the powder particles, thus facilitating the removal of oxides surface layers that may hinder the sintering process. Selected results obtained through SPS in our laboratory for the preparation of a wide variety of materials, i.e. TiC-TiB2, MgB2, and NbAl3, will be presented in this work. Specifically, all the chosen examples are related to the use of the SPS technique for obtaining the desired material by simultaneously performing synthesis and consolidation stages in one-step.

Preparation of Dense Ultrafine TiAl Alloys by Spark Plasma Synthesis from Mechanically Activated Powders

2011 ◽  
Vol 217-218 ◽  
pp. 1747-1752
Author(s):  
Zhi Wei Wang ◽  
Dong Dong Zhang ◽  
Xiu Hong Zhang
Keyword(s):  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Al Alloy ◽  
Plasma Synthesis ◽  
Tial Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Short Period ◽  
Spark Plasma ◽  
Spark Plasma Synthesis

Powder of Ti-46at%Al alloy was synthesized through mechanical activation (MA) and then sintered and concurrently consolidated in a short sintering time of 900 s by using spark plasma sintering (SPS) process. The XRD and SEM profiles show that the microstructures of TiAl alloys contained γ TiAl and small amount α-2 Ti3Al phase, whose amount can be controlled by the sintering temperature. The compacts retained the original fine-grained fully densified bodies by avoiding an excessively high sintering temperature. The alloys sintered at higher temperature with this process showed a coarser microstructure. So it is possible to produce dense nanostructured TiAl alloys by mechanically activated spark plasma sintering (MASPS) within a very short period of time.

Reactive Spark Plasma Synthesis of Porous Bioceramic Wollastonite

2020 ◽  
Vol 65 (2) ◽  
pp. 263-270 ◽  
Author(s):  
E. K. Papynov ◽  
O. O. Shichalin ◽  
I. Yu. Buravlev ◽  
A. S. Portnyagin ◽  
A. A. Belov ◽  
...  
Keyword(s):  
Plasma Synthesis ◽  
Porous Bioceramic ◽  
Spark Plasma ◽  
Spark Plasma Synthesis

Kinetics Model for the Initial Stage of Spark Plasma Sintering

2007 ◽  
Vol 336-338 ◽  
pp. 2366-2368 ◽  
Author(s):  
Ming Hao Fang ◽  
Wei Pan ◽  
Sui Lin Shi ◽  
Zhen Yi Fang
Keyword(s):  
Spark Plasma Sintering ◽  
Kinetics Model ◽  
Shrinkage Ratio ◽  
Sintering Kinetics ◽  
Sintering Time ◽  
Plasma Sintering ◽  
Initial Stage ◽  
Spark Plasma ◽  
Powder Particles ◽  
The Relationship

The sintering kinetics model of initial stage by spark plasma sintering (SPS) is discussed in this paper. During SPS, there are discharges among the powder particles. And the particles surface will be melted and form viscose flow. These phenomena accelerate the particles rearrangement and reduce the sintering time. The relationship between the shrinkage ratio of particles and the sintering time during the initial stages of sintering by SPS has been obtained. The results show that L/L0 is linear to the time.

Preparation of BaTiO3/SrTiO3 composite dielectric ceramics with a flat temperature dependence of permittivity

2003 ◽  
Vol 18 (8) ◽  
pp. 1809-1815 ◽  
Author(s):  
Tomonari Takeuchi ◽  
Hiroyuki Kageyama
Keyword(s):  
Temperature Dependence ◽  
X Ray ◽  
Sintering Time ◽  
Plasma Sintering ◽  
Complete Solid Solution ◽  
Phase Transition Temperatures ◽  
Spark Plasma ◽  
Ray Density ◽  
Dielectric Ceramics ◽  
Permittivity Measurements

Composite dielectric ceramics of BaTiO3/SrTiO3 were prepared using the spark plasma sintering (SPS) method. Relatively dense (>92% of the theoretical x-ray density) composite ceramics were obtained for a relatively short sintering time (∼3 min). Such a short sintering time was advantageous in suppressing the formation of a complete solid solution (Ba, Sr)TiO3. Fixed-frequency (100 kHz), room-temperature permittivity measurements of the BaTiO3/SrTiO3 = 9/1 composites showed a flat temperature dependence within the range 30–110 °C. X-ray diffractometry measurements showed that the current SPS-BaTiO3/SrTiO3 composites consisted of BaTiO3 and small amounts of (Ba1−xSrx)TiO3 with various x values having different phase transition temperatures. Such multicomponent microstructures would be responsible for the flat temperature dependence of permittivity.

THE GROWTH OF MnSi1.73 PREPARED BY SPARK PLASMA SINTERING

2004 ◽  
Vol 18 (01) ◽  
pp. 87-93 ◽  
Author(s):  
ZHIMIN WANG ◽  
YIDONG WU ◽  
YUANJIN HE
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spark Plasma Sintering ◽  
X Ray Diffraction ◽  
Mechanical Pressure ◽  
Growth Processes ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

Crystals of MnSi 1.73 were prepared by Spark Plasma Sintering (SPS) technique, analyzed by X-ray diffraction (XRD), and invested by metalogragh and scanning electron microscopy (SEM). The growth processes of the samples were studied. It was found that the Mn–Si powders partly formed MnSi 1.73 crystals at 912–937 K under the mechanical pressure of 20 MPa in low vacuum (about 5.0 Pa), and fully formed MnSi 1.73 crystals after sintered at 1173 K for 15 minutes under 40 MPa.

scholarly journals Modification of Densification Mechanisms By The Timing of Mechanical Pressure During Spark Plasma Sintering

2021 ◽  
Author(s):  
David Salamon ◽  
Hua Tan ◽  
Haibo Zhang
Keyword(s):  
Grain Size ◽  
Alumina Powder ◽  
Sintering Process ◽  
Mechanical Pressure ◽  
Vapor Transfer ◽  
Plasma Sintering ◽  
Nano Alumina ◽  
Diffusion Enhancement ◽  
Spark Plasma ◽  
Rapid Sintering

Abstract The application of mechanical pressure during a sintering process is connected with grains sliding and diffusion enhancement. However, the timing of mechanical pressure during the rapid sintering process was not addressed. In the present study, four different timings of mechanical pressure with final pressure 50 MPa starting from the beginning, 600 ℃, 900 ℃ and at sintering temperature, furthermore one pressure-less SPS have been studied during SPS of Nano-Alumina powder (Taimei, Japan) at 1100 ℃, 1150 ℃, 1200 ℃, and 1300 ℃, respectively. The density, hardness, microstructure, and grain size of each sample were measured and calculated carefully. The results show that applying the pressure at 900 ℃ brings high density and small grain size, leading to the best Vickers hardness. The interaction between pressure and vapor, leading to the different vapor transfer rate of the first sintering stage, is considered as a reason for the differences in the microstructure.

scholarly journals Dense nanostructured materials obtained by spark plasma sintering and field activated pressure assisted synthesis starting from mechanically activated powder mixtures

2004 ◽  
Vol 36 (3) ◽  
pp. 155-164 ◽  
Author(s):  
F. Bernard ◽  
Gallet le ◽  
N. Spinassou ◽  
S. Paris ◽  
E. Gaffet ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Nanostructured Materials ◽  
Bulk Materials ◽  
Mechanical Pressure ◽  
Powder Mixtures ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
One Step ◽  
Nanostructured Ceramics ◽  
Simultaneous Influence

The preparation of highly dense bulk materials with a grain size in the range of a few to a few hundreds nanometers is currently the objective of numerous studies. In our research we have achieved a measure of success in this regard by using the methods of mechanically-activated, field-activated, pressure-assisted synthesis, MAFAPAS, which has been patented, and mechanically-activated spark plasma sintering, MASPS. Both methods, which consist of the combination of a mechanical activation step followed by a consolidation step under the simultaneous influence of an electric field and mechanical pressure, have led to the formation of dense nanostructured ceramics, intermetallics, and composites, such as, MoSi2 FeAl, NbAl3, and TiN-TiB2. In this report, both one-step synthesis-consolidation and sintering of different nanostructured materials by SPS and FAPAS were investigated. .

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