Microstructural Development of SiC Ceramics by Liquid-Phase Sintering with Spark Plasma Sintering Technique

2006 ◽  
Vol 510-511 ◽  
pp. 1022-1025 ◽  
Author(s):  
Mikinori Hotta ◽  
Junichi Hojo
Keyword(s):  
Grain Size ◽  
Spark Plasma Sintering ◽  
Liquid Phase Sintering ◽  
Molar Ratio ◽  
Microstructural Development ◽  
Sic Ceramics ◽  
Plasma Sintering ◽  
N2 Atmosphere ◽  
Average Grain Size ◽  
Spark Plasma

Sub-micron and nano-sized β-SiC powders were sintered with AlN and Y2O3 as sintering additives by spark plasma sintering (SPS). The sintered densities reached >95% of theoretical with a different molar ratio of AlN to Y2O3 at total amount of 10vol% and temperature of 1900oC for 10min in N2 atmosphere under a pressure of 30MPa. With increasing amount of the AlN additive, the size of SiC grains decreased and the shape changed from globular to columnar. The fully densified SiC at AlN:Y2O3=95:5mol% had an average grain size of 0.5-1µm and 50-100nm in diameter by using sub-micron and nano-sized SiC starting powders, respectively. Flexural strength of the specimen having grain size of 0.5-1µm was approximately 1200MPa at room temperature.

Preparation of Fine-grained BaTiO3 Ceramics by Spark Plasma Sintering

2002 ◽  
Vol 17 (3) ◽  
pp. 575-581 ◽  
Author(s):  
Tomonari Takeuchi ◽  
Claudio Capiglia ◽  
Nalini Balakrishnan ◽  
Yasuo Takeda ◽  
Hiroyuki Kageyama
Keyword(s):  
Grain Size ◽  
Spark Plasma Sintering ◽  
Fine Powder ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Ferroelectric Domains ◽  
Spark Plasma ◽  
Ray Density ◽  
Permittivity Measurements

Dense BaTiO3 ceramics consisting of fine grains were prepared using fine powder (average grain size of 0.06 μm; BT006) as a starting material and the spark plasma sintering (SPS) method. The powder was densified to >95% of theoretical x-ray density by the SPS process, and the average grain size of the resulting ceramics was <0.5 μm; the particle size of the initial powder significantly affects the grain size of the resulting SPS pellets. Fixed-frequency (100 kHz), room-temperature permittivity measurements of the BT006-SPS ceramics showed relatively low values (3000–3500) compared with those (typically 5000) for SPS ceramics consisting of larger grains (approximately 1 μm). Lower permittivity was attributed to poor development of ferroelectric domains in the ceramics, which originated from incomplete development of the tetragonal structure as well as the presence of a local orthorhombic structure.

scholarly journals The Effect of SiC Content on Microstructure and Microwave Heating Rate of h-BN/SiC Ceramics Fabricated by Spark Plasma Sintering

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1909 ◽  
Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Lei Zhao ◽  
Dongling Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Relative Density ◽  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Hexagonal Boron Nitride ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Sic Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma

Hexagonal boron nitride/silicon carbide (h-BN/SiC) ceramics were fabricated by a spark plasma sintering (SPS) method. Phase and microstructure of ceramics were characterized and observed, respectively, using the X-ray diffraction, scanning electron microscope and electron probe microanalysis. The effect of molar ratios of SiC to h-BN on the microstructure, relative density, hardness, thermal conductivity, and the heating rate by microwaves on the ceramics were investigated. The results showed that the orientation of flake-like h-BN was significantly influenced by SiC content in h-BN/SiC ceramics. With the increasing of SiC content, the h-BN flakes gradually became an isotropic distribution from the preferred orientation aligning in a SPS pressure direction. The relative density of h-BN/SiC ceramics was 97.6 ± 0.9% at a molar ratio of SiC to h-BN of 40/60 mol%. The preferential orientation of h-BN flakes contributed to a relatively high thermal conductivity along the SPS pressure direction, which was beneficial to increasing the heating rate of h-BN/SiC ceramics in microwave fields.

Manufacturing of Cu-15.0Zn-8.1Al Shape Memory Alloy Using Spark Plasma Sintering

2004 ◽  
Vol 449-452 ◽  
pp. 1109-1112 ◽  
Author(s):  
No Jin Park ◽  
Suck Jong Lee ◽  
In Sung Lee ◽  
Kyeong Sik Cho ◽  
Sung Jin Kim
Keyword(s):  
Grain Size ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Spark Plasma Sintering ◽  
Powder Size ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Fine Microstructure ◽  
Spark Plasma ◽  
Ar Gas

In order to control the grain size of Cu-15.0Zn-8.1Al shape memory alloy, the spark plasma sintering (SPS) technique was applied. The sintering processes were carried out under different atmospheres with a different powder size. The sintered bodies were denser under the Ar+4%H2 gas atmosphere than under the 100% Ar gas. By using the small-sized powders, the fine microstructure with average grain size of 2~3􀀀 was obtained. With the large-sized powders, the single martensitic phase was observed with the average grain size of 70~72􀀀 . When the starting powders with different sizes were mixed, it is confirmed that the average grain size of the manufactured alloys was 15􀀀 , but the distribution of grain size was not uniform.

Fabrication of Y2Ti2O7 Transparent Ceramic by Spark Plasma Sintering

2021 ◽  
Vol 1035 ◽  
pp. 663-667
Author(s):  
Li Qiong An ◽  
Rong Wei Shi ◽  
Run Hua Fan ◽  
Takashi Goto
Keyword(s):  
Grain Size ◽  
Spark Plasma Sintering ◽  
Pyrochlore Structure ◽  
Transparent Ceramic ◽  
Sintered Body ◽  
Reactive Sintering ◽  
Uniform Microstructure ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma

Y2Ti2O7 transparent ceramic was fabricated by reactive sintering using spark plasma sintering at 1673 K for 2.7 ks. The sintered body exhibited a cubic pyrochlore structure and uniform microstructure with an average grain size of 2.9 μm. The transmittance reached 73% at a wavelength of 2000 nm after annealing at 1023 K for 21.6 ks.

Transparent nanocrystalline MgO by rapid and low-temperature spark plasma sintering

2004 ◽  
Vol 19 (9) ◽  
pp. 2527-2531 ◽  
Author(s):  
Rachman Chaim ◽  
Zhijian Shen ◽  
Mats Nygren
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
Oxygen Vacancy ◽  
Spark Plasma Sintering ◽  
Color Centers ◽  
Reducing Atmosphere ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma ◽  
Nanocrystalline Mgo

We investigated superfast densification of nanocrystalline MgO powders by spark plasma sintering (SPS) between 700 °C and 825 °C under applied pressures of 100and 150 MPa. Fully-dense transparent nanocrystalline MgO with a 52-nm average grain size was fabricated at 800 °C and 150 MPa for 5 min. In-line transmissionsof 40% and 60% were measured compared to MgO single crystal, for the yellowand red wavelengths, respectively. Densification occurs by particles sliding over each other; the nanometric grain size and pores lead to the optical transparency. The light brownish color of the nanocrystalline MgO is due to the oxygen vacancy color centers, originating from the reducing atmosphere of the SPS process.

Controlled Atmosphere Thermal Treatment for Pyrochlore Phase Elimination of PMN-PT/CFO Prepared by Spark Plasma Sintering

2014 ◽  
Vol 975 ◽  
pp. 274-279 ◽  
Author(s):  
Diego Seiti Fukano Viana ◽  
José Antônio Eiras ◽  
William Junior Nascimento ◽  
Fabio Luiz Zabotto ◽  
Ducinei Garcia
Keyword(s):  
Grain Size ◽  
Spark Plasma Sintering ◽  
Single Phase ◽  
Magnetoelectric Effect ◽  
Pyrochlore Phase ◽  
Practical Applications ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma ◽  
Phase Elimination

Multiferroics are interesting materials which present more than one ferroic property and have a great potential for practical applications [,,]. In addition, the coupling of magnetic and electric properties, the magnetoelectric effect (ME), offers news possibilities to applications [2,]. The magnetoelectric effect can be observed in single-phase materials like LuFe2O4, BiFeO3, etc. [1,] or in composites like PMN-PT/CFO, BaTiO3/CoFe2O4, etc. The ME composites have advantages over single-phase materials. They are easier to fabricate, less expensive, and have a wider range of working temperatures than single-phase materials []. However, some parameters that enhance the ME response need to be optimized. These parameters are the composition, the microstructure (grain size, grain orientation) and sintering parameters [6]. Thus, this work attempts to create a synthesis protocol to prepare the ME composite PMN-PT/CFO by Spark Plasma Sintering (SPS) keeping the average grain size as small as possible.

Optical and Microwave Dielectric Properties of Transparent MgAl2O4 Ceramics

2013 ◽  
Vol 647 ◽  
pp. 758-761
Author(s):  
Ping Fu ◽  
Wen Zhong Lu ◽  
Wen Lei ◽  
Yong Xu ◽  
Xian Long Lu
Keyword(s):  
Grain Size ◽  
Dielectric Properties ◽  
Spark Plasma Sintering ◽  
Microwave Dielectric Properties ◽  
Temperature Range ◽  
Microwave Dielectric ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma ◽  
Sintering Processes

Transparent polycrystalline MgAl2O4ceramics were fabricated by using spark plasma sintering (SPS) technique at a temperature range from 1275 °C to 1400 °C. The average grain size of the samples fabricated at optimal sintering processes was 345 nm. The in-line transmittance of the sintered ceramics can be as high as 70% at 550 nm and 82% at 2000 nm, respectively. The optimal microwave dielectric properties (εr = 8.38, Q×f = 54000 GHz and τf = -74 ppm/°C) were achieved at 1325°C for 20 min.

Spark Plasma Sintering of Two Commercial Al2O3 Powders

2011 ◽  
Vol 412 ◽  
pp. 336-339 ◽  
Author(s):  
Zhen Hua Liu ◽  
Qin Ma ◽  
Jin Jun Lu
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma

Al2O3 ceramic is prepared by spark plasma sintering (SPS) using two commercial α-Al2O3 powders at elevated sintering temperature. The relative density and average grain size of the prepared Al2O3 ceramics are measured and compared. One α-Al2O3 powder has good sintering property because the relative density of the prepared α-Al2O3 ceramic is higher than 97% while another α-Al2O3 powder has poor sintering property.

scholarly journals A Comparative Study of Spark Plasma and Conventional Sintering of Undoped SnO2 Sputtering Targets

2021 ◽  
Author(s):  
Levent Koroglu ◽  
Cem Aciksari ◽  
Erhan Ayas ◽  
Emel Ozel ◽  
Ender Suvaci
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Dwell Time ◽  
Sintering Temperature ◽  
Phase Evolution ◽  
Microstructural Development ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Spark Plasma

Abstract SnO2 ceramics were fabricated by spark plasma sintering (SPS) and conventional (pressureless) sintering techniques by using undoped submicron SnO2 powders. The effect of sintering temperature and dwell time on the densification behavior, phase evolution and microstructural development of sintered ceramics were investigated. The relative density of SPSed ceramics increased when dwell time was raised from 1 to 10 min at 950ºC. However, full densification was prevented by the decomposition of SnO2 to Sn and O2(g). The decomposition starts after ~ 10 min at 950ºC. In parallel to this observations, as sintering temperature increases, amount of the elemental Sn in agglomerated form increases. On the other hand, the relative densities of conventionally sintered ceramics (at 1200ºC-1400ºC) were relatively low (i.e., 63 % relative density), and abnormal grain growth was observed due to the shift in sintering mechanisms to evaporation-condensation as a dominant mechanism. Since the undoped SnO2 ceramics, SPSed at 950°C for 5 min under 30 MPa exhibit 93 % relative density, high chemical purity, homogeneous grain size distribution and smaller average grain size, they demonstrate great potential as sputtering targets for production of high-quality thin film gas sensors.

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