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.

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 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.

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.

Structure and Properties of Ti55Al45 Alloys Prepared by Mechanical Alloying and Spark Plasma Sintering

2011 ◽  
Vol 308-310 ◽  
pp. 2547-2550
Author(s):  
Yao Dong Liu ◽  
Jing Xing ◽  
Di Ai ◽  
Song Zhe Jin
Keyword(s):  
Grain Size ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Compaction Pressure ◽  
Al Alloy ◽  
Structure And Properties ◽  
Plasma Sintering ◽  
Conventional Sintering ◽  
Spark Plasma ◽  
Short Time

Amorphization and crystallization behaviors of Ti55Al45 powders during mechanical alloys (MA) and subsequent Spark Plasma Sintering are studied. It is found that the nanocrystallization process of the Ti-Al alloy proceeds and the sintering temperature can control the microstructure of alloy. The sintering of the compacts is carried out at the temperatures of 1100—1200°C with a compaction pressure of 30MPa and a heating rate of 30°C min-1. Specimens with high densities and approaching the equilibrium state can be obtained in short time of 180s by spark sintering than conventional sintering. Such shorter high temperature is important to prevent grain growth. The microstructures of the alloy contains equiaxed gamma TiAl with sub-micron grain size and small amount alpha Ti3Al phase.

Damping of FeMo Alloys Obtained from SPS Sintering of Nanostructured Powders

2008 ◽  
Vol 604-605 ◽  
pp. 203-211 ◽  
Author(s):  
Marcello Cabibbo ◽  
Paolo Deodati ◽  
S. Libardi ◽  
Alberto Molinari ◽  
Roberto Montanari ◽  
...  
Keyword(s):  
Grain Size ◽  
Dynamic Modulus ◽  
Sintering Temperature ◽  
Internal Stresses ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma ◽  
Small Cracks ◽  
Heating Up ◽  
Sps Sintering

Spark Plasma Sintering (SPS) of nanostructured FeMo powder produces samples with satisfactory density, however the final grain size critically depends on the sintering temperature. Two groups (sets A and B) of samples have been examined by means of internal friction (IF) and dynamic modulus measurements carried out in successive test runs on the same samples to assess their structural stability. Set A and B had been sintered at 1113 and 1128 K and had an average grain size of 100 nm and 1 µm, respectively. TEM and XRD have been performed on the samples in as-prepared condition and after IF measurements cycles. The samples with smaller grains are more stable and substantially are not affected by grain coarsening which, on the contrary, occurs in those with grains of larger size. The heating up to 923 K during the tests diminishes dislocation density in both the groups. An anomalous trend of resonance frequency during the first test run in samples of set A has been ascribed to the formation of small cracks relaxing internal stresses.

Properties of ZnO Varistors Prepared with Nano-Sized Powders

2008 ◽  
Vol 368-372 ◽  
pp. 514-516 ◽  
Author(s):  
Feng Chao Luo ◽  
Jin Liang He ◽  
Yuan Hua Lin ◽  
Jun Hu
Keyword(s):  
Grain Size ◽  
Raw Material ◽  
Voltage Gradient ◽  
Temperature Changes ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Spark Plasma ◽  
Zno Varistors ◽  
Voltage Gradients

ZnO varistors with higher voltage gradients are expected in the power system, and the key to this property is to diminish the grain size. In this paper, nano-sized ZnO particles are used as the raw material in order to obtain small grains. Pellets are fabricated by two sintering methods: the conventional pressureless sintering and the spark plasma sintering (SPS). For the samples fabricated by the conventional sintering, the average grain size varies from 1 μm to more than 10 μm when the sintering temperature changes from 900 oC to 1200 oC. The voltage gradient can reach as high as 2020 V/mm. The grain size of the SPS samples is less than 1 μm, and the voltage gradients can reach 963 V/mm.

scholarly journals Improvement of the mechanical properties of spark plasma sintered hap bioceramics by decreasing the grain size and by adding multi-walled carbon nanotubes

2013 ◽  
Vol 45 (2) ◽  
pp. 233-243 ◽  
Author(s):  
Dj. Veljovic ◽  
G. Vukovic ◽  
I. Steins ◽  
E. Palcevskis ◽  
P.S. Uskokovic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Grain Size ◽  
Sintering Temperature ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Walled Carbon Nanotubes

Composites based on HAP and oxidized multi-walled carbon nanotubes (o-MWCNT) and monophase HAP materials were processed by spark plasma sintering. Starting from stoichiometric nano-sized HAP powder, monophase bioceramics were obtained with a density close to the theoretical one and with an average grain size of several hundred nanometers to micron dimensions. It was shown that decreasing the sintering temperature resulted in a decrease of the grain size, which affected an increase in the fracture toughness and hardness. The fracture toughness of an HAP/ o-MWCNT bioceramic processed at 900?C for only 5 min was 30 % higher than that of monophase HAP materials obtained under the same conditions. The addition of MWCNT during SPS processing of HAP materials caused a decrease in the grain size to the nano-dimension, which was one of the reasons for the improved mechanical properties.

Preparation and Magnetic Properties of Dense NiCuZn Ferrite by Spark Plasma Sintering

2008 ◽  
Vol 368-372 ◽  
pp. 601-603
Author(s):  
Xi Wei Qi ◽  
Ji Zhou ◽  
Zhen Xing Yue ◽  
Ming Ya Li ◽  
Xiu Mei Han
Keyword(s):  
Spark Plasma Sintering ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Impurity Phase ◽  
Uniaxial Pressure ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Spark Plasma ◽  
Nicuzn Ferrite

Dense NiCuZn ferrites consisting of fine grains were prepared by spark plasma sintering (SPS) at 750°C for 3 min under a uniaxial pressure of 15 MPa. The powders were densified to >95% of theoretical density by the SPS process, and the average grain size of the prepared NiCuZn ferrite was < 1 /m. The saturation magnetization of prepared specimens (without further annealing treatment) was approximate 50.54 emu/g, which was slightly smaller than that of 52.21 emu/g for specimens prepared by conventional sintering at 980°C for 4 h. Phase identifications indicated that prepared NiCuZn ferrite existed impurity phase (Cu2O), and Cu2O would gradually transform to CuO when annealing temperature increased.

scholarly journals Characterization of Multiwalled Carbon Nanotube-Reinforced Hydroxyapatite Composites Consolidated by Spark Plasma Sintering

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Duk-Yeon Kim ◽  
Young-Hwan Han ◽  
Jun Hee Lee ◽  
Inn-Kyu Kang ◽  
Byung-Koog Jang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Multiwalled Carbon Nanotube ◽  
Multiwalled Carbon ◽  
Pull Out ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Mwnt Content

Pure HA and 1, 3, 5, and 10 vol% multiwalled carbon nanotube- (MWNT-) reinforced hydroxyapatite (HA) were consolidated using a spark plasma sintering (SPS) technique. The relative density of pure HA increased with increasing sintering temperature, but that of the MWNT/HA composite reached almost full density at 900°C, and then decreased with further increases in sintering temperature. The relative density of the MWNT/HA composites increased with increasing MWNT content due to the excellent thermal conductivity of MWNTs. The grain size of MWNT/HA composites decreased with increasing MWNT content and increased with increasing sintering temperature. Pull-out toughening of the MWNTs of the MWNT/HA composites was observed in the fractured surface, which can be used to predict the improvement of the mechanical properties. On the other hand, the existence of undispersed or agglomerate MWNTs in the MWNT/HA composites accompanied large pores. The formation of large pores increased with increasing sintering temperature and MWNT content. The addition of MWNT in HA increased the hardness and fracture toughness by approximately 3~4 times, despite the presence of large pores produced by un-dispersed MWNTs. This provides strong evidence as to why the MWNTs are good candidates as reinforcements for strengthening the ceramic matrix. The MWNT/HA composites did not decompose during SPS sintering. The MWNT-reinforced HA composites were non-toxic and showed a good cell affinity and morphologyin vitrofor 1 day.

Effects of Processing Parameters of SPS on the Densification and Texture of LaPO4 Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1059-1061 ◽  
Author(s):  
Ai Bing Du ◽  
Zhi Xue Qu ◽  
Chun Lei Wan ◽  
Ruo Bing Han ◽  
Wei Pan
Keyword(s):  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Processing Parameters ◽  
Preferred Orientation ◽  
Holding Time ◽  
Plasma Sintering ◽  
Spark Plasma

Spark plasma sintering was used to fabricate the LaPO4 ceramics and the effect of SPS holding time and sintering temperature on the densification and texture of LaPO4 ceramics were studied. The results revealed that holding time had no obvious influence on the densification of LaPO4 ceramics under the present process. The density increases with the increase of sintering temperature, when it reached 1350°C, the relative density kept nearly constant of 98.6 %. The preferred orientation of LaPO4 ceramics approximately increases with the increase of sintering temperature, but contrary impact in holding time.

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