Preparation of 10B Enriched B4C Ceramics by Pressureless Sintering

2014 ◽  
Vol 602-603 ◽  
pp. 540-543
Author(s):  
Yu Jun Zhang ◽  
Sha Li Tan ◽  
Ru Bin Wei ◽  
Shu He Ai ◽  
Hai Bin Sun
Keyword(s):  
Flexural Strength ◽  
Boron Carbide ◽  
Relative Density ◽  
Sintering Temperature ◽  
Raw Material ◽  
Carbide Powder ◽  
Average Particle ◽  
Strength Increase ◽  
Pressureless Sintering ◽  
Water Reactors

Boron carbide is an attractive neutron absorbing material used both in Fast Breeder Reactors (FBR) and in Pressurised Water Reactors (PWR) owing to its very high absorption cross section for thermal neutrons, chemical stability and refractory character. In the present paper, 10B enriched B4C ceramics are prepared by pressureless sintering at 19602160°C, under argon, using 10B boron carbide powder as raw material, 18 wt% phenolic resin as sintering aid. In the sintering temperature range, with the increasing of sintering temperature, both the relative density and flexural strength increase linearly, the average particle sizes increase from about 3μm at 1960°C to more than 30μm at 2160°C. The sample sintered at 1960°C has a 91.7% of relative density and 192 MPa of flexural strength and a homogeneous texture with 3-4μm particle size, which are enough for pellet application of reactors.

Preparation and Thermal Properties of Pressureless Sintered AIN/SiC Composites

2015 ◽  
Vol 655 ◽  
pp. 78-81
Author(s):  
Shu He Ai ◽  
Yu Jun Zhang ◽  
Hong Yu Gong ◽  
Qi Song Li
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Property ◽  
Thermal Properties ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Temperature Range ◽  
Sic Composites

AlN/SiC composites with 5 wt.% Y2O3addition were fabricated by pressureless sintering at 1700-1950 oC. The influences of sintering temperature and SiC content on the relative density, mechanical property and thermal conductivity were studied. With sintering temperature increasing from 1700 oC to 1750 oC, the relative density increased significantly to about 98.0%, without evident changes from 1750 oC to 1900 oC, and then decreased slightly at 1950 oC. As SiC content increased, the flexural strength of composites sintered at 1750 oC increased firstly, and then decreased, obtaining a maximum flexural strength of 337 MPa at 20 wt.% SiC content. Meanwhile, the thermal conductivity decreased from 60 W/(m∙K) to 40 W/(m∙K) with SiC content increasing from 0 wt.% to 30 wt.%. Moreover, in the sintering temperature range from 1750 oC to 1950 oC, the thermal conductivity increased from 45 W/(m∙K) to 55 W/(m∙K) for AlN-10 wt.% SiC composites, but decreased from 40 W/(m∙K) to 36 W/(m∙K) for AlN-30 wt.% SiC composites.

scholarly journals Fabrication of Cu Based Metallic Binder for Diamond Tools by Microwave Pressureless Sintering

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1453 ◽  
Author(s):  
Shenghui Guo ◽  
Xiaolei Ye ◽  
Liang Wang ◽  
Sivasankar Koppala ◽  
Li Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Relative Density ◽  
Metallic Matrix ◽  
Strength Increase ◽  
Pressureless Sintering ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Mps Method ◽  
Diamond Tools

Microwave pressureless sintering (MPS) method is successfully applied in the fabrication of Cu based metallic matrix for diamond tools. The main purpose of this work is to obtain better mechanical properties when the metal binder of the diamond tools was prepared by the MPS method. The orthogonal experimental method is adopted to design the sintering process parameters. The optimized experimental conditions are suggested as 880 °C of sintering temperature, 375 MPa of cold pressure, and 35 min of withholding time. The contrastive investigation of the MPS and conventional pressureless sintering (CPS) are performed under optimized conditions. The microstructures information are obtained by scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe microanalysis (EPMA), and the necessary mechanical properties, such as relative density, hardness, and flexural strength are tested. Experimental results show that the MPS method, compared with CPS, can significantly improve the mechanical properties of the metallic matrix. The factors of relative density, hardness, and flexural strength increase 1.25%, 3.86%, and 6.28%, respectively. The possible sintering mechanism of the MPS method is also discussed. This work may provide a reference for the fabrication of metal-based diamond tools by microwave heating method.

Pressureless Sintering and Properties of Boron Carbide-Titanium Diboride Composites by In Situ Reaction

2012 ◽  
Vol 525-526 ◽  
pp. 321-324 ◽  
Author(s):  
Ai Dong Liu ◽  
Ying Jie Qiao ◽  
Ying Ying Liu
Keyword(s):  
Flexural Strength ◽  
Boron Carbide ◽  
Titanium Diboride ◽  
Sintering Temperature ◽  
High Density ◽  
Sintering Behavior ◽  
Pressureless Sintering ◽  
In Situ Reaction

Pressureless sintering to obtain high density boron carbide-titanium diboride composites by in-situ reaction was studied. Pressureless sintering behavior of this material was investigated between 1800-2150 .The effects of composition, sintering temperature and tine were examined. Density up to 98.5% T.D. was reached at 2150. Maximum values of flexural strength (502 MPa), hardness (33 Gpa) and fracture toughnes (4.6 MPa·m1/2) were observed in the specimens containing 15 vol.% TiB2.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3-TiC-ZrO2 Ceramic Composites

2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.

Pressureless Sintering of Boron Carbide-Based Superhard Materials

2010 ◽  
Vol 159 ◽  
pp. 145-148 ◽  
Author(s):  
Dimitar D. Radev
Keyword(s):  
Transition Metal ◽  
Boron Carbide ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Vacuum Furnace ◽  
Pressureless Sintering ◽  
Metal Carbides ◽  
Sintering Aids ◽  
Transition Metal Carbides

Boron carbide-based materials B4C-MexBy were densified by pressureless sintering in a vacuum furnace. Some transition metal carbides (TiC, ZrC, HfC, Cr3C2 and WC) from groups IV-VI were used as sintering aids. The optimal sintering temperature in the range 2220-2250oC was used for any composition. Here we show the possibilities to activate the mass transport of the B4C by the mechanism of liquid phase sintering. The method of reactive sintering of B4C in the presence of additives of some transition metal carbides allows in situ synthesis of dense B4C-MexBy materials. Structural properties and fracture toughness of the B4C-based composite materials were discussed. The properties of some of these materials and the possibilities for their application are also discussed.

Purification of Attrition Milled Nano-size Boron Carbide Powder

2012 ◽  
Vol 05 ◽  
pp. 94-101 ◽  
Author(s):  
A. Sokhansanj ◽  
A.M. Hadian
Keyword(s):  
Chemical Analysis ◽  
Boron Carbide ◽  
Sintering Temperature ◽  
Milled Powder ◽  
Carbide Powder ◽  
Sintering Behavior ◽  
Sintered Ceramic ◽  
Weight Percentage ◽  
Wide Range ◽  
Nano Size

Boron carbide is one of the advanced ceramic materials which is used in a wide range of applications. However, this material needs a high sintering temperature (~2200°C). Using nano-size powders for producing ceramic parts results in lowering sintering temperature and also enhances toughness and hardness of the material. One of the methods for producing ceramic nano powders is attrition milling. However, as the milling balls and wall are made of steel, some impurities specially iron will be introduced to the powder during milling. Chemical analysis of the milled powder shows that more than 33wt% of the powder consists of iron. These uncontrolled impurities affect the mechanical and physical properties of sintered ceramic parts that are made of such a powder. Therefore, these impurities must be removed from the powder. Hydro metallurgical beneficiation technique with two different solvents has been used for purification of the powder. The result of chemical analysis after purification showed that the weight percentage of iron in powder dropped to 9% and 0.8% (depending on the solvents). Moreover, the sintering behavior of hot-pressed boron carbide powder with different percentages of iron as sintering aid has been studied. The results showed excellent densification and hardness of the sintered parts.

Effect of Y2O3 on the Sintering, Mechanical and Dielectric Properties of Mullite/h-BN Composites

2016 ◽  
Vol 848 ◽  
pp. 28-31
Author(s):  
Han Jin ◽  
Yong Feng Li ◽  
Zhong Qi Shi ◽  
Hong Yan Xia ◽  
Guan Jun Qiao
Keyword(s):  
Fracture Toughness ◽  
Dielectric Constant ◽  
Phase Composition ◽  
High Temperature ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Different Temperatures

Mullite/10 wt. %h-BN composites with 5 wt. % Y2O3 additive were fabricated by pressureless sintering at different temperatures. The densification, phase composition, microstructure, mechanical and dielectric properties of the mullite/h-BN composites were investigated. With the addition of Y2O3, the sintering temperature of the mullite/h-BN composites declined, while the density, mechanical and dielectric properties all increased. The addition of Y2O3 promoted the formation of liquid phase at high temperature, which accelerated the densification. Besides, Y2O3 particles which were located at the grain boundaries inhibited the grain growth of mullite matrix. For the mullite/h-BN composites with Y2O3 additive, the appropriate sintering temperature was about 1600°C. The relative density, flexural strength, fracture toughness and dielectric constant of the Y2O3 doped mullite/h-BN composite sintered at 1600 °C reached 82%, 135 MPa, 2.3 MPa·m1/2 and 4.9, respectively.

Study on Structure and Properties of Porous Copper Alloy

2013 ◽  
Vol 833 ◽  
pp. 301-304
Author(s):  
Hao Zhong ◽  
Yun Zhou
Keyword(s):  
Compressive Strength ◽  
Relative Density ◽  
Pore Size ◽  
Alloy Powder ◽  
Sintering Temperature ◽  
Raw Material ◽  
Structure And Properties ◽  
Pore Former ◽  
Porous Copper ◽  
Increasing Trend

CuSn6Zn6 alloy powder and a pore former were used as raw material. Porous bronze was successfully prepared by the sintering and dissolution process (SDP). The porosity is in range of 76%~88%, and the pore size is in range of 0.8~3.3mm. The effect of the porosity and cell sizes of specimens on its mechanical property was investigated, and the effect of sintering temperature on its relative density and porosity was also studied. The experimental results indicate that under the condition of the same pore size, the compressive strength decreases with the increase of porosity, the compressive strength changes from 10Mpa to 2Mpa with the porosity from 76% to 88%; under the same porosity condition, the compressive strength does not change significantly with the pore size, but it has a slightly increasing trend with the decrease of the pore size. The relative density of the specimens increases with the increase of the sintering temperature.

Effect of Iron Additive on the Sintering Behavior of Hot-Pressed ZrC-W Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1764-1766 ◽  
Author(s):  
Yu Jin Wang ◽  
Lei Chen ◽  
Tai Quan Zhang ◽  
Yu Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Hot Press ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties ◽  
Hot Press Sintering

The ZrC-W composites with iron as sintering additive were fabricated by hot-press sintering. The densification, microstructure and mechanical properties of the composites were investigated. The incorporation of Fe beneficially promotes the densification of ZrC-W composites. The relative density of the composite sintered at 1900°C can attain 95.3%. W2C phase is also found in the ZrC-W composite sintered at 1700°C. The content of W2C decreases with the increase of sintering temperature. However, W2C phase is not identified in the composite sintered at 1900°C. The flexural strength and fracture toughness of the composites are strongly dependent on sintering temperature. The flexural strength and fracture toughness of ZrC-W composite sintered at optimized temperature of 1800°C are 438 MPa and 3.99 MPa·m1/2, respectively.

Combustion Synthesis and Two-Time Densification of TiB2-Cu Composites

2007 ◽  
Vol 280-283 ◽  
pp. 1433-1436
Author(s):  
Chang Qing Hong ◽  
Xing Hong Zhang ◽  
Jie Cai Han ◽  
Qiang Xu ◽  
Xiao Dong He
Keyword(s):  
Flexural Strength ◽  
Relative Density ◽  
Combustion Synthesis ◽  
Hot Pressing ◽  
Hot Isostatic Pressing ◽  
Strength Increase ◽  
Pressing Temperature ◽  
Copper Powders ◽  
Hot Pressing Sintering ◽  
Thermal Physical Properties

TiB2 -Cu cermet with the relative density of 92% was produced from titanium, boron and copper powders by combustion synthesis and subsequently pseudo hot isostatic pressing. To improve its mechanical and thermal physical properties, the two-time hot pressing sintering test was carried out at 1050°, 1090° and 1150°C respectively. The deformation behavior and variation of micro- structure and mechanical properties were investigated in detail. The results showed that the relative density and the flexural strength increase remarkably after two-time hot pressing. The relative density reaches 605.5MPa and the flexural strength reaches 96% when the two-time pressing temperature is at 1090°C, and the values increase 12% and 6% compared to that before two-time pressing.

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