Fabrication of Dense Nanostructured Bulk Ceramics by Means of Spark-Plasma-Sintering (SPS) Processing

2016 ◽  
Vol 838-839 ◽  
pp. 225-230 ◽  
Author(s):  
Koji Morita ◽  
Byung Nam Kim ◽  
Hidehiro Yoshida ◽  
Keijiro Hiraga ◽  
Yoshio Sakka
Keyword(s):  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
High Heating Rate ◽  
Fine Grained ◽  
Fine Grain ◽  
Plasma Sintering ◽  
High Heating ◽  
Spark Plasma ◽  
Primary Advantage

In order to fabricate fine-grained and dense nanoceramic materials, the effect of spark-plasma-sintering (SPS) conditions was examined in MgAl2O4 spinel as a reference material. The SPS conditions, such as heating rate and loading temperature, strongly affected the microstructures. Although the density can be improved with decreasing the heating rate to less than 10 °C/min, it requires a long processing time. In order to fully utilize the high heating rate that is a primary advantage of the SPS technique, load controlling is very effective to achieve high density with maintaining fine grain size. An increase in the loading temperature during SPS processing can reduce the residual porosity in a spinel even at the widely used high heating rate of 100 °C/min. This suggests that for the SPS processing in ceramics, the load controlling is an important factor as well as the heating rate and sintering temperature.

scholarly journals Effect of the Heating Rate on the Spark-Plasma-Sintering (SPS) of Transparent Y2O3 Ceramics: Microstructural Evolution, Mechanical and Optical Properties

Ceramics ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 56-69
Author(s):  
Lihong Liu ◽  
Koji Morita ◽  
Tohru S. Suzuki ◽  
Byung-Nam Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Near Infrared ◽  
Slow Heating ◽  
High Heating Rate ◽  
Plasma Sintering ◽  
High Heating ◽  
Spark Plasma

High strength transparent Y2O3 ceramics were fabricated from commercial powders using spark plasma sintering (SPS) technique by optimizing the heating rate. The heating rate significantly influenced the microstructures and the optical/mechanical properties of the Y2O3 ceramics. Grain growth was limited accordingly with increasing the heating rate. The ball milling process of the commercial Y2O3 powders is likely to further enhance the sinterability during the SPS processing. The dense Y2O3 ceramics, which were sintered by SPS with 100 °C/min, showed good transmittance range from visible to near infrared (IR). For a high heating rate of 100 °C/min, the in-line transmittance at a visible wavelength of 700 nm was 66%, whereas for a slow heating rate of 10 °C/min, it reduced to 46%. The hardness Hv tends to increase with increasing the heating rate and rigorously followed the Hall–Petch relationship; that is, it is enhanced with a reduction of the grain size. The toughness KIC, on the other hand, is less sensitive to both the heating rate and the grain size, and takes a similar value. This research highlighted that the high heating rate SPS processing can fabricate fully dense fine-grained Y2O3 ceramics with the excellent optical and mechanical properties.

scholarly journals Mechanical Milling-Assisted Spark Plasma Sintering of Fine-Grained W-Ni-Mn Alloy

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1323 ◽  
Author(s):  
Yanlin Pan ◽  
Daoping Xiang ◽  
Ning Wang ◽  
Hui Li ◽  
Zhishuai Fan
Keyword(s):  
Spark Plasma Sintering ◽  
Mechanical Milling ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Interface Fracture ◽  
Composite Powders ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Binding Phase ◽  
Spark Plasma

Fine-grained W-6Ni-4Mn alloys were fabricated by spark plasma sintering (SPS) using mechanical milling W, Ni and Mn composite powders. The relative density of W-6Ni-4Mn alloy increases from 71.56% to 99.60% when it is sintered at a low temperature range of 1000–1200 °C for 3 min. The spark plasma sintering process of the alloy can be divided into three stages, which clarify the densification process of powder compacts. As the sintering temperature increases, the average W grain size increases but remains at less than 7 µm and the distribution of the binding phase is uniform. Transmission electron microscopy (TEM) observation reveals that the W-6Ni-4Mn alloy consists of the tungsten phase and the γ-(Ni, Mn, W) binding phase. As the sintering temperature increases, the Rockwell hardness and bending strength of alloys initially increases and then decreases. The optimum comprehensive hardness and bending strength of the alloy are obtained at 1150 °C. The main fracture mode of the alloys is W/W interface fracture.

Microstructure and Mechanical Properties of Spark-Plasma-Sintered SiC-TiC Composites

2005 ◽  
Vol 287 ◽  
pp. 335-339 ◽  
Author(s):  
Kyeong Sik Cho ◽  
Kwang Soon Lee
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Argon Atmosphere ◽  
Full Density ◽  
Plasma Sintering ◽  
Spark Plasma

Rapid densification of the SiC-10, 20, 30, 40wt% TiC powder with Al, B and C additives was carried out by spark plasma sintering (SPS). In the present SPS process, the heating rate and applied pressure were kept at 100°C/min and at 40 MPa, while the sintering temperature varied from 1600-1800°C in an argon atmosphere. The full density of SiC-TiC composites was achieved at a temperature above 1800°C by spark plasma sintering. The 3C phase of SiC in the composites was transformed to 6H and 4H by increasing the process temperature and the TiC content. By tailoring the microstructure of the spark-plasma-sintered SiC-TiC composites, their toughness could be maintained without a notable reduction in strength. The strength of 720 MPa and the fracture toughness of 6.3 MPa·m1/2 were obtained in the SiC-40wt% TiC composite prepared at 1800°C for 20 min.

Spark Plasma Sintering TiAl Alloy from Mechanically Activated Powders

2011 ◽  
Vol 250-253 ◽  
pp. 3309-3312 ◽  
Author(s):  
Zhi Wei Wang ◽  
Hong Cheng ◽  
Hui Ming Cheng
Keyword(s):  
Spark Plasma Sintering ◽  
Tial Alloy ◽  
Sintering Temperature ◽  
Al Alloy ◽  
Tial Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Short Period ◽  
Spark Plasma ◽  
Higher Temperature

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.

TiAl Alloy Spark Plasma Sintered from Mechanically Activated Powders

2011 ◽  
Vol 284-286 ◽  
pp. 2336-2339
Author(s):  
Zhi Wei Wang ◽  
Jun Chen
Keyword(s):  
Spark Plasma Sintering ◽  
Tial Alloy ◽  
Sintering Temperature ◽  
Al Alloy ◽  
Tial Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Short Period ◽  
Spark Plasma ◽  
Higher Temperature

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.

Microstructure and properties of FeSi6,5 soft magnetic materials prepared by spark plasma sintering

2021 ◽  
Vol 96 ◽  
pp. 2-8
Author(s):  
Trung Tran Bao ◽  
◽  
Phuong Doan Dinh ◽  
Linh Nguyen Ngoc ◽  
Toan Nguyen Van ◽  
...  
Keyword(s):  
Magnetic Materials ◽  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Soft Magnetic Materials ◽  
Magnetic Saturation ◽  
Soft Magnetic ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Research Show

In this paper, FeSi6,5 (6.5 wt.% Si) soft magnetic materials have been prepared Via a Spark Plasma Sintering (SPS) technique at difference sintering temperatures in the range of 1150 to 1300 °c for 15 min and a heating rate of 100 °c/min. The results show that the density of sintered samples increased with the rising sintering temperature resulted in the enhancement of Vickers hardness and magnetic properities otsintered samples. Hovvever, the highest magnetic saturation (Ms) of 209.6 emu/g and lowest coercivity (Hc) of 1.85 Oe were obtained for the SPSed sample at 1250 °c. In contrast, the sample sintered in vacuum at 1300 °c for 1h with heating rate of 20 °c/min shows the lower magnetic properties due to the lower density and high amount of pores in the structure. The results of research show that the spark plasma sintering route has a high potential of fast sintering Fe-Si soft magnetic materials and for application.

Fabrication of high-strength transparent MgAl2O4 spinel polycrystals by optimizing spark-plasma-sintering conditions

2009 ◽  
Vol 24 (9) ◽  
pp. 2863-2872 ◽  
Author(s):  
Koji Morita ◽  
Byung-Nam Kim ◽  
Keijiro Hiraga ◽  
Hidehiro Yoshida
Keyword(s):  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
High Strength ◽  
High Heating Rate ◽  
Heating Rates ◽  
Four Point Bending ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Optical And Mechanical Properties

By optimizing the heating rate during spark-plasma-sintering (SPS) processing, a high-strength transparent spinel (MgAl2O4) can be successfully fabricated for only a 20-min soak at 1300 °C. For the heating rates of ≤10 °C/min, the spinel exhibits an excellent combination of in-line transmission (50–70%), four-point-bending strength (>400 MPa), and hardness (>15 GPa). The excellent optical and mechanical properties can be ascribed to the superimposed effects of the sub-micrograin size, fine-pore size, and low porosity, which are related closely to the heating rate during the SPS processing. The present study demonstrates that to attain a high-strength transparent spinel at low temperatures and short sintering times, the low-heating-rate SPS processing is more efficient compared with the high-heating-rate SPS processing.

Spark plasma sintering and characterization of bulk nanostructured fully stabilized zirconia: Part I. Densification studies

2004 ◽  
Vol 19 (11) ◽  
pp. 3255-3262 ◽  
Author(s):  
U. Anselmi-Tamburini ◽  
J.E. Garay ◽  
Z.A. Munir ◽  
A. Tacca ◽  
F. Maglia ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Significant Influence ◽  
Sintering Temperature ◽  
Stabilized Zirconia ◽  
Sintering Time ◽  
Final Density ◽  
Plasma Sintering ◽  
Spark Plasma

The sintering of nanosize powders of fully stabilized zirconia was investigated using the spark plasma sintering (SPS) method. The influence of sintering temperature, heating rate, direct current pulse pattern, sintering time, and sintering pressure on the final density and grain size of the product was investigated. The dependence of densification on temperature showed a maximum at 1200 °C, resulting with nearly fully dense zirconia with a crystallite size of about 100 nm. Heating rate (50∼300 °C min−1) and sintering time (5–16 min) had no significant influence on the final density and the crystallite size. Pulsing patterns ranging from 2:2 to 48:2 (on:off) had no influence on the density or the crystallite size. However, the applied pressure had a significant influence on the final density but no apparent effect on crystallite size for a sintering temperature of 1200 °C and a hold time of 5 min.

scholarly journals Effect of High Pressure Spark Plasma Sintering on the Densification of a Nb-Doped TiO2 Nanopowder

Ceramics ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 507-520
Author(s):  
Alexandre Verchère ◽  
Sandrine Cottrino ◽  
Gilbert Fantozzi ◽  
Shashank Mishra ◽  
Thomas Gaudisson ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Sintering Process ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Lower Temperature

Sintering under pressure by means of the spark plasma sintering (SPS) technique is a common route to reduce the sintering temperature and to achieve ceramics with a fine-grained microstructure. In this work, high-density bulk TiO2 was sintered by high pressure SPS. It is shown that by applying high pressure during the SPS process (76 to 400 MPa), densification and phase transition start at lower temperature and are accelerated. Thus, it is possible to dissociate the two densification steps (anatase then rutile) and the transition phase during the sintering cycle. Regardless of the applied pressure, grain growth occurs during the final stage of the sintering process. However, twinning of the grains induced by the phase transition is enhanced under high pressure resulting in a reduction in the crystallite size.

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