Influence of compaction and degassing on the properties of submicron WCCo produced by the PPS method

2019 ◽  
Vol 108 ◽  
pp. 5-12
Author(s):  
JOANNA WACHOWICZ ◽  
MARCIN ROSIŃSKI ◽  
RADOSŁAW ZIELIŃSKI ◽  
TOMASZ TRUSZKOWSKI
Keyword(s):  
Fracture Toughness ◽  
Heating Rate ◽  
Final Stage ◽  
Sintering Temperature ◽  
Cobalt Content ◽  
Operation Temperature ◽  
Plasma Sintering ◽  
Initial Stage ◽  
Temperature Load ◽  
Pulse Plasma Sintering

Influence of compaction and degassing on the properties of submicron WCCo produced by the PPS method. The present study is concerned with the effect of the parameters of the degassing operation (temperature, load and heating rate) conducted at the initial stage of the Pulse Plasma Sintering (PPS) process and the sintering temperature at the final stage of the process, on the properties and microstructure of WCCo with a 6wt% cobalt content sintered by this method. The results of the study have shown that when the heating rate is too high, the material obtained is porous. In most experiments, the sintering temperature of 1050°C appeared to be too low to obtain WCCo composites with density close to the theoretical value (GT). Sintering at the temperature increased to 1070°C yielded sinters with density above 99%GT, with hardness of about 1900 HV30 and fracture toughness KIC=9.3 MNm-3/2.

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.

Nanocrystalline Cemented Carbides Sintered by the Pulse Plasma Method

2006 ◽  
Vol 114 ◽  
pp. 245-250
Author(s):  
Andrzej Michalski ◽  
D. Siemiaszko ◽  
Jakub Jaroszewicz ◽  
Marcin Rosiński ◽  
M. Psoda
Keyword(s):  
Fracture Toughness ◽  
Relative Density ◽  
Crystallite Size ◽  
Sintering Temperature ◽  
Pulse Plasma ◽  
Cemented Carbides ◽  
Plasma Method ◽  
Plasma Sintering ◽  
Pulse Plasma Sintering

Nanocrystalline WC-12wt.%Co was consolidated by Pulse Plasma Sintering (PPS) at various temperatures between 900 and 1200oC for 6 minutes under a pressure of 60MPa. Cemented carbides sintered at 1100oC have a relative density of 99%, a hardness of 2248HV30, the fracture toughness, KIC=12.5 MPa*m1/2, and have a structure containing 50nm WC crystallites. Increasing the sintering temperature to 1200oC causes an increase in the size of the WC crystallite size to about 110 nm, reduces the hardness to 2198HV30, and decreases the KIC to 9.7 MPa*m1/2.

scholarly journals Characterization of Al2O3 Samples and NiAl–Al2O3 Composite Consolidated by Pulse Plasma Sintering

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3398
Author(s):  
Katarzyna Konopka ◽  
Marek Krasnowski ◽  
Justyna Zygmuntowicz ◽  
Konrad Cymerman ◽  
Marcin Wachowski ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Mechanical Alloying ◽  
Ceramic Composites ◽  
Pulse Plasma ◽  
High Plasticity ◽  
Composite Powders ◽  
Microstructural Investigation ◽  
Al2o3 Powder ◽  
Plasma Sintering ◽  
Pulse Plasma Sintering

The paper describes an investigation of Al2O3 samples and NiAl–Al2O3 composites consolidated by pulse plasma sintering (PPS). In the experiment, several methods were used to determine the properties and microstructure of the raw Al2O3 powder, NiAl–Al2O3 powder after mechanical alloying, and samples obtained via the PPS. The microstructural investigation of the alumina and composite properties involves scanning electron microscopy (SEM) analysis and X-ray diffraction (XRD). The relative densities were investigated with helium pycnometer and Archimedes method measurements. Microhardness analysis with fracture toughness (KIC) measures was applied to estimate the mechanical properties of the investigated materials. Using the PPS technique allows the production of bulk Al2O3 samples and intermetallic ceramic composites from the NiAl–Al2O3 system. To produce by PPS method the NiAl–Al2O3 bulk materials initially, the composite powder NiAl–Al2O3 was obtained by mechanical alloying. As initial powders, Ni, Al, and Al2O3 were used. After the PPS process, the final composite materials consist of two phases: Al2O3 located within the NiAl matrix. The intermetallic ceramic composites have relative densities: for composites with 10 wt.% Al2O3 97.9% and samples containing 20 wt.% Al2O3 close to 100%. The hardness of both composites is equal to 5.8 GPa. Moreover, after PPS consolidation, NiAl–Al2O3 composites were characterized by high plasticity. The presented results are promising for the subsequent study of consolidation composite NiAl–Al2O3 powder with various initial contributions of ceramics (Al2O3) and a mixture of intermetallic–ceramic composite powders with the addition of ceramics to fabricate composites with complex microstructures and properties. In composites with complex microstructures that belong to the new class of composites, in particular, the synergistic effect of various mechanisms of improving the fracture toughness will be operated.

Effects of Powder Microscopic Defects on Densification and Mechanical Properties of WC via Spark Plasma Sintering

2021 ◽  
Vol 1016 ◽  
pp. 1770-1777
Author(s):  
Liu Zhu ◽  
Jin Fang Wang ◽  
Zhi Biao Tu ◽  
Na Xue ◽  
Wei Wei Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Free Energy ◽  
Composite Powder ◽  
Sintering Temperature ◽  
Chemical Activation ◽  
Activation Technique ◽  
Specific Chemical ◽  
Plasma Sintering ◽  
Spark Plasma

The WC composite powder was synthesized by a new specific chemical activation technique. A large number of lattice defects such as surface humps, dislocations and stacking fault exist in the surface of the WC powder after chemical activation technique. By using such activated WC powder, the binderless WC cemented carbide with high density (15.54 g/cm3), super hardness (average 26.29 GPa) and excellent fracture toughness (8.9 MPa.m1/2) can be fabricated by SPS at 1700 °C and 50 MPa pressure. The improvement in density, hardness and fracture toughness are respectively 4.5%, 15.3% and 17.1% compared to when using the original WC powder. This improvement is because microscopic defects on the surface of the WC powder can greatly improve surface free energy of the powder, which improves the sintering activity and reduces the sintering temperature of the WC powder.

Spark Plasma Sintering and Characterization of WC-Co-cBN Composites

2014 ◽  
Vol 616 ◽  
pp. 194-198 ◽  
Author(s):  
Jian Feng Zhang ◽  
Rong Tu ◽  
Takashi Goto
Keyword(s):  
Fracture Toughness ◽  
Phase Transformation ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Moderate Pressure ◽  
Plasma Sintering ◽  
Spark Plasma

WC-Co-cBN composites were consolidated by SPS at 1373 to 1673 K under a moderate pressure of 100 MPa. The addition of cBN increased the starting and finishing temperature of shrinkage and decreased the relative density of WC-Co. The relative density of WC-(10-20 vol%) cBN composites was about 97-100% at 1573 K and decreased with increasing the sintering temperature to 1673 K due to the phase transformation of cBN to hBN. The highest hardness and fracture toughness of WC-Co-20 vol% cBN composite sintered at 1573 K were 23.2 GPa and 8.0 MP m1/2, respectively.

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.

Influence of Powder Characteristics on Sintering of AlN Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 1409-1412 ◽  
Author(s):  
Jin Yu Qiu ◽  
Koji Watari ◽  
Yuji Hotta ◽  
Kenshi Mitsuishi
Keyword(s):  
Final Stage ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Particle Sizes ◽  
Sintering Aid ◽  
Surface Areas ◽  
Initial Stage ◽  
Primary Particles ◽  
Powder Characteristics ◽  
Specific Surface Areas

The sintering behavior of AlN powders with different particle sizes and specific surface areas was investigated in the present work. 4.5-8.0mass% of the as-synthesized sintering aid from the Li2O-Y2O3-CaO system was added to these AlN powders, and they were then fired at 1400-1650oC for 6h. At the initial stage of sintering the fine AlN powder, it was recognized that sintering of primary particles occurred in agglomerations. With an increase of firing temperature, particles were rearranged and grains grew rapidly at the final stage. On contrary, in sintering of samples using the coarse AlN powder, the densification increased with raising sintering temperatures slowly, and the sintering temperature higher than 1650oC was required to obtain densified specimens.

Effect of Sintering Schedule on the Microstructure of Carbon Nanotubes Reinforced Alumina Fabricated by SPS Method

2009 ◽  
Vol 66 ◽  
pp. 288-291
Author(s):  
Li Wei Huang ◽  
Zheng Yi Fu ◽  
Jin Yong Zhang ◽  
Wei Min Wang ◽  
Hao Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Raman Spectrum ◽  
Sintering Temperature ◽  
Alumina Ceramics ◽  
Pure Alumina ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Method

Carbon nanotubes reinforced alumina was fabricated by spark plasma sintering method. When adding 0.2wt% nanotubes, the fracture toughness of the composites prepared increases 19% compared with the pure alumina ceramics. The effect of sintering schedule on microstructure and mechanical properties is investigated systematically. Microstructure studies reveal that at high sintering temperature, the nanotubes tend to gather in the gaps surrounded by three or more grains in a flocculent state, which leads to poor mechanical properties. Raman spectrum indicates that long sintering duration may cause serious nanotubes destruction and lower the mechanical properties.

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.

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.

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