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.

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.

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.

scholarly journals Reactive sintering of B4c-TiB2 composites from B4 and TiO2 precursors

2020 ◽  
Vol 14 (4) ◽  
pp. 329-335
Author(s):  
Pavol Svec ◽  
Zuzana Gábrisová ◽  
Alena Brusilová
Keyword(s):  
Fracture Toughness ◽  
Boron Carbide ◽  
Titanium Diboride ◽  
Sintering Temperature ◽  
Secondary Phase ◽  
Ceramic Composites ◽  
Reactive Sintering ◽  
Different Temperatures ◽  
Carbide Matrix

The effect of sintering temperature in the interval from 1775 to 1850?C on the density, microstructure, hardness and fracture toughness of ceramic composites consisting of a boron carbide matrix and titanium diboride secondary phase was studied. The composites were hot pressed using in situ reaction between boron carbide and 40 wt.% of titanium dioxide additive. The samples were hot pressed at different temperatures but for the constant time of 60min, under the pressure of 35MPa in vacuum of 10 Pa. Both Vickers hardness and fracture toughness of the composites increased with the sintering temperature.Maximal hardness of 29.8GPa and fracture toughness of 6.9MPa?m1/2 were achieved for the composite with 29.6 vol.% of titanium diboride secondary phase sintered at the highest sintering temperature of 1850?C.

Effect of TiO2 and MgO on Microstructure of α-Alumina Ceramics and its Sintering Behavior

2015 ◽  
Vol 1112 ◽  
pp. 519-523 ◽  
Author(s):  
Jarot Raharjo ◽  
Sri Rahayu ◽  
Tika Mustika ◽  
Masmui ◽  
Dwi Budiyanto
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Physical And Mechanical Properties ◽  
Basic Material ◽  
Sintering Behavior ◽  
Pressureless Sintering ◽  
Alumina Ceramics ◽  
Density Measurements ◽  
Technical Alumina ◽  
Platelet Structure

Observation on the effect of adding titanium oxide (TiO2) and magnesium oxide (MgO) on the sintering of α-alumina (Al2O3) has been performed. In this study, technical alumina used as basic material in which the sample is formed by the pressureless sintering/cold press and sintered at 1500°C which is lower than alumina sintering temperature at 1700°C. Elemental analysis, observation of microstructure, hardness, fracture toughness and density measurements were carried out to determine the physical and mechanical properties of alumina. The results indicate a change in the microstructure where the content of the platelet structure are much more than the equilateral structure. At sintering temperature of 1500°C, neck growth occurs at ceramics grain, supported by the results of the density test which indicate perfect compaction has occurred in this process.

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.

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.

A Comparative Study on Sintering Behaviour of Low and High Density Pellets of Ni-YSZ by Electrochemical Impedance Spectroscopy

2017 ◽  
Vol 17 ◽  
pp. 237-245
Author(s):  
P. Kuppusami ◽  
T. Dharini ◽  
Ajith Kumar Soman ◽  
A.M. Kamalan Kirubaharan ◽  
Arul Maximus Rabel
Keyword(s):  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Sintering Temperature ◽  
Systematic Investigation ◽  
High Density ◽  
Oxygen Atmosphere ◽  
Sintering Behavior ◽  
Low Density ◽  
Oxygen Environment ◽  
Ac Impedance Spectra

In this study, a systematic investigation on in-situ sintering behavior of Ni-YSZ (50: 50wt. %) pellets of density of 4.2 (low density) and 4.9 g/cm3 (high density) in ambient and oxygen environment by impedance spectroscopy is presented. X-ray diffraction indicated the formation of cubic phases of NiO and YSZ. The low density pellet sintered for 16 h showed low content of monoclinic phase when compared to high density pellet. The microstructure of the high density pellet revealed finer and homogenous distribution of Ni in YSZ matrix due to longer sintering duration when compared with the low density pellet. AC impedance spectra were recorded for both low and high density pellets during sintering in ambient and oxygen environment in the temperature range 873-1173 K. The results indicate that for both the pellets, the impedance values decreased when sintering temperature increased from 873 to 1173 K in both ambient and oxygen environment. However, the impedance was low while sintering in oxygen atmosphere than in ambient. Besides these observation, impedance of the high density pellet was much lower than that of the low density pellet at all sintering temperature in both ambient and oxygen atmosphere. While the impedance decreased with increasing sintering temperature, the capacitance increased slowly in both the ambient and oxygen atmosphere. The change in the impedance behavior due to grain interior and grain boundaries is explained in relation with the microstructural changes that occur during sintering in different environments.

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