Preparation and Performance of Neutron Absorbing Dysprosium Oxide Ceramic

2016 ◽  
Vol 697 ◽  
pp. 404-408
Author(s):  
Yu Bai Zhang ◽  
Yu Jun Zhang ◽  
Jia Xing Zhao
Keyword(s):  
Fracture Toughness ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Oxide Ceramic ◽  
Absorption Property ◽  
Neutron Absorption ◽  
Dysprosium Oxide ◽  
And Performance ◽  
Increasing Temperature

Dysprosium is a kind of potential neutron absorption material with the thermal neutron absorption cross area of 950 Barn. In this paper, dysprosium oxide (Dy2O3) ceramic was prepared by pressureless sintering. The density, bending strength, fracture toughness and hardness of Dy2O3 ceramics under different sintering schedule were analyzed. The density of Dy2O3 ceramics was enhanced accompanied with the increase in sintering temperature, and it was close to the theoretical value when heated at 1630 °C. Bending strength reached a maximum of 117 MPa when sintering temperature was 1570 °C. However, fracture toughness was inversely proportional to the hardness approximately. As a consequence, the optimum sintering temperature for mechanical property of Dy2O3 ceramics was 1570 °C. The morphology of fracture surface was examined by SEM. The results showed that the porosity of Dy2O3 ceramics decreased with increasing temperature. Meanwhile, the Monte-Carlo software was used to simulate the neutron absorption property. The absorbtivity was about 99.13% when the neutron source was uniform energy spectrum of 10-11 Mev~10-5 Mev and the thickness of Dy2O3 was of 20 mm.

Effect of Sintering Temperature on Microstructure and Performance of Ti(C,N)-Based Cermets

2012 ◽  
Vol 430-432 ◽  
pp. 556-560 ◽  
Author(s):  
Li Yan Zou ◽  
Zhi Ping Sun ◽  
Guo Jun Zhang
Keyword(s):  
Fracture Toughness ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Low Cost ◽  
Shrinkage Rate ◽  
Excellent Performance ◽  
And Performance ◽  
Microstructure And Performance

In order to find a way which is low cost in preparation of Ti (C,N)/Fe composites. Ti (C,N)/Fe composites were prepared from TiFe (w (Ti)=30%), FeNCr (w (N)=5%,w (Cr)=60%) and toner by Vacuum Hot-pressed Sintering. The effect of sintering temperature on microstructure and performance of Ti (C,N)/Fe composites and the reason of it were studied. The results show that the Ti (C,N)/Fe composites prepared by Vacuum Hot-pressed Sintering have excellent performance, when the temperature was less than 1150°C, shrinkage rate of material was low,and reaction was slow. When the temperature was higher than 1150°C, material shrunk obviously,and reaction became faster, fracture toughness and bending strength rised rapidly at 1150°C-1200°C, rised slowly at 1200°C-1250°C, hardness was maximum at 1200°C.

Pressureless Sintering and Characterization of Al2O3-SiO2-ZrO2 Composite

2012 ◽  
Vol 329 ◽  
pp. 113-128 ◽  
Author(s):  
G. Mebrahitom Asmelash ◽  
Othman Mamat
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Pressureless Sintering ◽  
Oxide Ceramic ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
X Ray Diffraction ◽  
X Ray

An Oxide Ceramic-Based Composite in the Al2o3-Sio2-Zro2(ASZ) System Was Developed and Investigated Using a Pressureless Sintering Route. the Effect of the Content of each Component and Sintering Temperature upon the Microstructure, Density, Hardness and Strength Was Studied. X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) Were Used to Investigate the Phase Transformation Sequences of the ASZ Composite System. the Flexural Strength Was Measured Using Three-Point Bending Method on a Universal Testing Machine, while the Indentation Fracture (IF) Method Was Used to Determine the Fracture Toughness of the Composite. the Results Showed that, with Varying Zro2Content, Keeping the Silica Content Constant and the Alumina as a Matrix, Densification Tends to Decrease as the Content of Zirconia Increases from 20 Wt. % of the Composition. X-Ray Diffraction Peaks Indicated Fully Developed Alumina, Mullite and Zirconia Phases due to Solid-Phase Reaction and Liquid-Phase Sintering of the System. the Experimental Results Also Revealed that, for a Sintering Temperature of 1500°C, the Hardness Value Ranged from 12 Gpa to 14 Gpa and the Flexural Strength Was 420±31MPa.The Fracture Toughness (KIc) Was Also Reported to Be between 4.5 and 5.1 Mpa.m1/2, for Samples Sintered at a Temperature of 14500C.

Effects of TiN Content on Mechanical Properties and Microstructure of ATN Materials

2013 ◽  
Vol 589-590 ◽  
pp. 590-593 ◽  
Author(s):  
Min Wang ◽  
Jun Zhao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Hot Press ◽  
Hot Press Sintering ◽  
Tin Content

In order to investigate the effects of TiN content on Al2O3/TiN ceramic material (ATN), the ATN ceramic materials were prepared of TiN content in 30%, 40%, 50%, 60% in the condition of hot press sintering. The sintering temperature is 1700°C, the sintering press is 32MPa, and the holding time are 5min, 10min, 15min. The effects of TiN content on mechanical properties and microstructure of ATN ceramic materials were investigated by analyzing the bending strength, hardness, fracture toughness. The results show that ATN50 has the best mechanical property, its bending strength is 659.41MPa, vickers hardness is 13.79GPa, fracture toughness is 7.06MPa·m1/2. It is indicated that the TiN content has important effect on microstructure and mechanical properties of ATN ceramic materials.

scholarly journals Study of the Comparative Effect of Sintering Methods and Sintering Additives on the Microstructure and Performance of Si3N4 Ceramic

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2142 ◽  
Author(s):  
Liangliang Yang ◽  
Allah Ditta ◽  
Bo Feng ◽  
Yue Zhang ◽  
Zhipeng Xie
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Fracture Toughness ◽  
Relative Density ◽  
Transition Rate ◽  
Bending Strength ◽  
Si3n4 Ceramic ◽  
Sintering Additives ◽  
The Difference ◽  
And Performance

The Si3N4 ceramics were prepared in this study by gas pressure sintering (GPS) and spark plasma sintering (SPS) techniques, using 5 wt.% Yb2O3–2 wt.% Al2O3 and 5 wt.% CeO2–2 wt.% Al2O3 as sintering additives. Based on the difference in sintering methods and sintering additive systems, the relative density, phase composition, phase transition rate, microstructure, mechanical properties, and thermal conductivity were comparatively investigated and analyzed. SPS proved to be more efficient than GPS, producing higher relative density, bending strength, hardness, and thermal conductivity of Si3N4 ceramic with both additive systems; however, the phase transition rate and fracture toughness were lower. Similarly, higher bending strength, hardness, and thermal conductivity were achieved with Yb2O3–Al2O3 than CeO2–Al2O3 in the case of GPS and SPS, and only the relative density, fracture toughness, and phase transition rate were lower.

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.

Pressureless Sintering and Properties Investigation of Silicon Nitride

2011 ◽  
Vol 194-196 ◽  
pp. 1464-1469
Author(s):  
Bin Li ◽  
Yi Feng ◽  
Hui Qiang Liu ◽  
Yan Fang Zhu ◽  
Dong Bo Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Bending Strength ◽  
Fracture Morphology ◽  
Pressureless Sintering ◽  
Sintering Aids ◽  
Α Phase ◽  
Different Grain Size ◽  
Si3n4 Ceramics

Different grain size of starting powder was choosed and different sintering additives were used to fabricate Si3N4 ceramics by pressureless sintering. Samples’ relative density and mechanical properties including Vickers hardness, bending strength and fracture toughness were tested. Then XRD, SEM and EDS were carried out to identify phase and observe microstructure and fracture morphology. The result shows that high purity α phase Si3N4 powder of 5 μm is suitable for sintering and combination of 5 wt.% MgO +5 wt.% Y2O3 is most effective within six kinds of sintering aids.

SILICON CARBIDE SC-221

Alloy Digest ◽  
1991 ◽  
Vol 40 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
High Temperature ◽  
Mechanical Strength ◽  
Physical Properties ◽  
Bending Strength ◽  
Beta Phase ◽  
Pressureless Sintering ◽  
Bend Strength ◽  
Sintering Method

Abstract SILICON CARBIDE SC-221 is a beta-phase silicon carbide made from the pressureless sintering method. It possesses excellent mechanical strength at high temperature (4-point bending strength of 71ksi [490 MPa] at 1400 C [2552 F]). This datasheet provides information on physical properties, hardness, elasticity, and bend strength as well as fracture toughness. Filing Code: Cer-5. Producer or source: Kyocera America Inc..

Mechanical and Wear Properties of Al2O3-15wt%ZrO2 Composites

2007 ◽  
Vol 280-283 ◽  
pp. 1049-1052
Author(s):  
Ping Gen Rao ◽  
Jian Qing Wu ◽  
Jian Dong Ye ◽  
Ying Jun Wang ◽  
Mikio Iwasa
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Precipitation Method ◽  
Alumina Powder ◽  
Wear Properties ◽  
Temperature Range ◽  
Al2o3 Matrix

A commercial a-alumina powder was mixed with Zr(OH)4 gel synthesized by a precipitation method. The mixture was calcined at 600°C for 2h. The Al2O3−15 wt% ZrO2 composites were sintered for 2 h in the temperature range between 1400°C and 1650°C in air. At the sintering temperature of 1550°C the highest density, the best wear resistance, the maximum bending strength of 708 MPa and the highest fracture toughness of 5.8 MPa×m1/2 were achieved, respectively. Improvement of the mechanical and wear properties of the Al2O3 matrix should mainly be attributed to the addition of ZrO2.

Effect of Nano-Al2O3 on Mechanical Properties and Microstructure of Al2O3/Si3N4 Compound Ceramics

2010 ◽  
Vol 168-170 ◽  
pp. 1846-1849 ◽  
Author(s):  
Shi Ming Hao ◽  
Hui Fang Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Bending Strength ◽  
Nitrogen Atmosphere ◽  
Pressureless Sintering ◽  
X Ray ◽  
Ceramics Matrix

The specimens of Al2O3/Si3N4 compound ceramics which contain 3%, 6%, 9%, 12%, 15%, and 18% nano-Al2O3 additions respectively were obtained by pressureless sintering at 1650 in the nitrogen atmosphere. The bending strength and fracture toughness (KIC) were detected. The microstructure and phase composition of the specimens were analyzed by the means of SEM and X-ray. The results show that Al2O3/Si3N4 compound ceramics can be made only using pressureless sintering. With 9-12% nano-Al2O3addition, the specimens have the top mechanical properties. The bending strength reach 710.86MPa, KIC reach 8.61MPa•M1/2. These excellent properties come from many interwoven nitride distributed uniformly in the Al2O3/Si3N4 compound ceramics matrix, which composed of big and firmly plate-like β- Si3N4, hexagonal Sialon and sheet Si2N2O.

The Influence of Sintering Temperature on Properties and Microstructure of TiN/Si3N4 Composite

2012 ◽  
Vol 512-515 ◽  
pp. 878-882
Author(s):  
Lan Er Wu ◽  
Yong Jiang
Keyword(s):  
Fracture Toughness ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Fine Particles ◽  
Electrical Discharge Machining ◽  
Sintering Temperature ◽  
Sintered Sample ◽  
Β Phase ◽  
Fine Grain ◽  
The Difference

Electrical discharge machining can be used easily for the materials which has good conductivity. In order to improve conductivity of Si3N4 based ceramics, TiN/Si3N4 composite was sintered by adding TiN into Si3N4 powder. In the present research, influence of sintering temperature (1535-1925°C, 8 temperatures) on properties and microstructure of the TiN/Si3N4 composite were investigated with La2O3, AlN as sintering additives, liquid phase pressure less sintering used. Densities of the sintered sample were measured. Bending strength, hardness, fracture toughness and electrical resistively of the sample were tested. Phase composition and microstructure of the samples were analyzed by XRD, SEM and EDX. The results showed that the density and fracture toughness of the sintered bodies reached maximum at temperature of 1760°C (relative density of 97.9%; fracture toughness of 8.5 MPa•m1/2) in the sintering temperature range of 1535~1925°C. With increasing of temperature, the bending strength and hardness of the samples kept raising, reached maximum at temperature of 1925°C (bending strength of 634MPa and Vickers hardness of 1869). But the weight lost at the highest temperature was the severe. Microstructure and EDX showed that crystals of the Si3N4 transferred into complete β phase from α + β both phases. The grain of Si3N4 grew up into long columnar from equiaxial fine particles. The fine grain of TiN grew up also. The comprehensive performances of the samples are better at sintering temperature of 1760°C. The long columnar β-Si3N4 grains interweaved with conductive TiN particles, formed conductive nets through sintering. At this sintering temperature, the bending strength of TiN/Si3N4 sintered body was 560MPa，Vickers hardness 1708MPa. The conductivity of the sintered bodies was irregular with the difference of temperature. The minimum of the conductivity is 20Ω.

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