scholarly journals Si3N4-SiCpComposites Reinforced byIn SituCo-Catalyzed Generated Si3N4Nanofibers

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Juntong Huang ◽  
Zhaohui Huang ◽  
Shaowei Zhang ◽  
Minghao Fang ◽  
Yan’gai Liu
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Network Connection ◽  
Opposite Trend ◽  
Low Sintering Temperature ◽  
Co Addition

Si3N4-SiCpcomposites reinforced byin situcatalytic formed nanofibers were prepared at a relatively low sintering temperature. The effects of catalyst Co on the phase compositions, microstructures, and physicochemical-mechanical properties of samples sintered at 1350°C–1450°C were investigated. The results showed that the catalyst Co enhanced the nitridation of Si. With the increase of Co addition (from 0 wt% to 2.0 wt.%), the apparent porosity of as-prepared refractories was initially decreased and subsequently increased, while the bulk density and the bending strength exhibited an opposite trend. TheSi3N4-SiCpcomposites sintered at 1400°C had the highest strength of 60.2 MPa when the Co content was 0.5 wt.%. The catalyst Co facilitated the sintering ofSi3N4-SiCpcomposites as well as the formation of Si3N4nanofibers which exhibited network connection and could improve their strength.

Fabrication and Properties of CaAl12O19-Al2O3 Composite Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 539-542 ◽  
Author(s):  
Xue Yin Liu ◽  
Yan Gai Liu ◽  
De Xin Yang ◽  
Ding Yun Ye ◽  
Zhao Hui Huang ◽  
...  
Keyword(s):  
Solid State ◽  
Bulk Density ◽  
Solid State Reaction ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Composite Ceramics ◽  
Final Composite

CaAl12O19-Al2O3 composite ceramics were synthesized by in situ solid state reaction using CaCO3 and industrial α-Al2O3 powders. The effects of sintering temperature and ratio of CA6 (CaAl12O19) content on phases and microstructure of the final composite ceramics were studied by XRD and SEM. The result showed that sheet-like CA6 appeared in the materials when sintering temperature was higher than 1400°C and grew up with the increased of the sintering temperature. The optimum sintering temperature was 1600°C, when the sample containing 20wt% CA6 was sintered at 1600°C, the bulk density was 3.21g/cm3, the apparent porosity achieved 9.94% and the bending strength gained 149.88MPa. With the increasing of CA6 content in the final composite ceramics, the bulk density and the bending strength increased firstly and then decreased. The lowest apparent porosity 1.42%, a density of 3.60g/cm3 and the highest bending strength of 265.10MPa were achieved for the sample containing 10wt% CA6 sintered at 1600°C.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

In Situ Formation of Mullite-Al2O3 Refractory Ceramic from Al-Matrix Mixtures

2014 ◽  
Vol 602-603 ◽  
pp. 628-631
Author(s):  
Xing Yong Gu ◽  
Ping Li ◽  
Wei Xia Dong ◽  
Ting Luo
Keyword(s):  
Thermal Expansion ◽  
Bulk Density ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Bending Strength ◽  
Potential Effect ◽  
Apparent Porosity ◽  
Mullite Phase ◽  
Two Samples

Two types of mullite-Al2O3 composites were designed and sintered in situ from different composition containing Al composites e.g. kaolin, alumina hydroxide and calcined bauxite etc, and auxiliary additives. The phase composition and microstructure were studied using X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. Bulk density, apparent porosity, thermal expansion coefficient and bending strength were also measured. The two samples exhibited XRD reflections characteristic of alumina and mullite phases. The amount of these phases depended on starting batch compositions, and reaction of starting and auxiliary materials together to form mullite. Because of in-situ formation of mullite fiber, the bulk density and bending strength were improved and apparent porosity was decreased for the composites with uniform microstructure. The presence of high mullite phase was found to decrease the thermal expansion coefficient. The potential effect of these morphologies and phase on properties was discussed. These mullite-Al2O3 composite was expected to have major applications in the areas of refractory material.

Influence of Sintering Temperature on Physical and Mechanical Properties of Hydroxyapatite-Calcium Titanate Composite

2019 ◽  
Vol 805 ◽  
pp. 65-70
Author(s):  
Suchittra Inthong ◽  
Denis Russell Sweatman ◽  
Sukum Eitssayeam ◽  
Tawee Tunkasiri
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Bulk Density ◽  
Vickers Microhardness ◽  
Sintering Temperature ◽  
Physical And Mechanical Properties ◽  
Calcium Titanate ◽  
Apparent Porosity

This research is concerned with the effect of sintering temperature on physical and mechanical properties. This Hydroxyapatite-calcium titanate (HA-CT) composites were synthesized using conventional route technique. The HA-CT composites were sintered between 1200 up to 1300 °C. The effect of sintering temperature on the physical and mechanical properties of HA-CT composites was discussed. The physical properties were studied in term of densification and apparent porosity. As well as, the mechanical properties were determined in term of Vickers microhardness. The increasing of the sintering temperature increased both of the bulk density and the Vickers microhardness properties. However, the apparent porosity was decreased with increasing sintering temperature. The highest bulk density was found at 0.15 mol.% of CT in HA-CT composites which was sintered at 1300 °C for 3 h. Moreover, the mechanical properties as a function of the sintering temperature and the CT contents were also discussed and compared with other related work.

Co-Catalyzed Si3N4/Sialon Nanofibers Reinforced SiC Refractories

2018 ◽  
Vol 281 ◽  
pp. 316-322
Author(s):  
Meng Zhang ◽  
Jun Tong Huang ◽  
Xi Bao Li ◽  
Zhi Hui Hu ◽  
Ming Qiang Liu ◽  
...  
Keyword(s):  
Bulk Density ◽  
Bending Strength ◽  
Apparent Porosity ◽  
Structure And Properties ◽  
Co Addition

SiCp matrix refractories reinforced by Si3N4/Sialon nanofibers in-situ catalytic formed were prepared at 1400 °C. The roles of catalyst Co on the structure and properties of as-prepared products were studied. We found that the catalyst Co enhanced the nitridation of Si and/or Al. With the increasing of Co addition (from 0-2.0 wt.%), the apparent porosity of the products decreased first and then increased, while the bending strength and the bulk density were exactly the opposite. The as-prepared Si3N4/Sialon bonded SiC refractories exhibited the highest strength of 61.1 MPa as the Co content was 1.0 wt.%. The addition of Co was beneficial to the formation of Si3N4/Sialon nanofibers and the sintering of Si3N4/Sialon bonded SiC matrix refractories, which effectively improved the strength of the samples.

Effect of Z Values on the Microstructure and Mechanical Properties of Post-sintered Reaction Bonded β-SiAlON

2017 ◽  
Vol 36 (5) ◽  
pp. 453-458 ◽  
Author(s):  
Yanjun Li ◽  
Donghua Liu ◽  
Han Jin ◽  
Donghai Ding ◽  
Guoqing Xiao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Bulk Density ◽  
Grain Growth ◽  
Bending Strength ◽  
Raw Materials ◽  
Apparent Porosity ◽  
Reaction Bonding ◽  
Microstructure And Mechanical Properties ◽  
Before And After

Abstractβ-SiAlON materials with different Z values (Z=0.5–3) were fabricated by a reaction bonding combining post-sintering route using raw materials of Si, Al2O3, AlN, etc. The reaction bonded β-SiAlON (RB-β-SiAlON) were post-sintered at 1,750 °C for 6 h. Apparent porosity, bulk density, bending strength and Vicker’s hardness of the samples before and after post-sintering were tested. XRD results showed that the phase composition of both RB-β-SiAlON and post-sintered RB-β-SiAlON (PSRB-β-SiAlON) were β-SiAlON. For RB-β-SiAlON, the apparent porosity was decreased with the increase of Z values, while the strength and hardness was increased accordingly. After the post-sintering procedure, nearly full densified PSRB-β-SiAlON was obtained and the mechanical properties were significantly improved. The bending strength and Vicker’s hardness of the PSRB-β-SiAlON (Z=0.5) achieved 510 MPa and 16.5 GPa, respectively, which were as 2.7 and 6.7 times high as those of the corresponding RB-β-SiAlON. However, the strength and hardness of PSRB-β-SiAlON decreased with the increase of Z value due to the grain growth.

Microstructure and Mechanical Properties of In Situ Al2O3- Ti(C,N) Composites

2011 ◽  
Vol 239-242 ◽  
pp. 1243-1247
Author(s):  
Xiu Mei Feng ◽  
Xiao Qing Lian ◽  
Ming Xue Jiang ◽  
Yi Ner He
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Raw Materials ◽  
In Situ Synthesis ◽  
Apparent Porosity ◽  
Composite Ceramics ◽  
Comprehensive Properties ◽  
Microstructure And Mechanical Properties ◽  
Metal Aluminum

Al2O3-Ti(C,N)composite ceramics were prepared by in situ aluminothermic reduction and pressureless sintering. The effects of different Ti(C,N) contents and sintering temperatures on microstructure and mechanical properties (bulk density ,apparent porosity and blending strength)of samples were investigated through experiments.The results show that Al2O3-Ti(C,N) composite ceramics with 10 wt.% Ti(C,N) prepared using titanium dioxide and metal aluminum powder as raw materials and sintered at 1300 °C for 3h under a flowing nitrigen stream have good properties ,with bulk density 2.94g/cm3,apparent porosity 26.4%, and blending strength reaches to 28.04 MPa. According to the microstructure analysis,the fine in situ synthesis Ti(C,N) particles are uniformly dispersed in tabular alundum matrix. Ti(C,N) and tabular alundum phases are closely combined and can inhibit grain growth each other,which is benefical in improving the comprehensive properties of composite ceramics.

Sintering of Silicon Carbide Ceramics with Co-Addition of Gadrinium Oxide and Silica and their Mechanical Properties

2011 ◽  
Vol 484 ◽  
pp. 117-123
Author(s):  
Toyohiko Yano ◽  
Yasutaka Horie ◽  
Masamitsu Imai ◽  
Katsumi Yoshida
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Boundary Phase ◽  
Homogeneous Distribution ◽  
Carbide Ceramics ◽  
Co Addition ◽  
Silicon Carbide Ceramics

Effects of simultaneous addition of SiO2 and gadrinium oxide on densification of SiC ceramics were examined, and relation between microstructure and their mechanical properties were discussed. Total 11wt% of Gd2O3 and SiO2 were mixed with fine -SiC powder. The weight of Gd2O3 in (Gd2O3 + SiO2) were set as 0, 20, 40, 60, 80 and 100%. The mixture was hot-pressed at 1950oC under 40 MPa applied pressure for 1 h. In the case of 40Gd2O3 and 80Gd2O3 compositions, the effect of sintering temperature from 1900 to 2000oC was also examined. The bulk density increased with increasing Gd2O3 content at the sintering temperature of 1950oC. Bending strength of the sintered bodies also improved with increasing Gd2O3 content generally, but at 40Gd2O3 composition, the maximum over ~800 MPa was observed. Young’s modulous, Vickers hardness and fracture toughness also increased with increasing Gd2O3 content. The distribution of grain boundary phase was not homogeneous. Evaporation of additives, mainly SiO2, caused non-homogeneous distribution of grain boundary phase between outside and inside of sintered bodies. High temperature bending strength of 80Gd2O3 specimen was superior than that of 40Gd2O3 specimen.

The Optimal Ratio of Mixed Talc Silica and Narathiwat Clay for Cordierite-Mullite Refractories

2018 ◽  
Vol 766 ◽  
pp. 223-227
Author(s):  
Nattawut Ariyajinno ◽  
Sakdipown Thiansem
Keyword(s):  
Mechanical Properties ◽  
Optimum Condition ◽  
Water Absorption ◽  
Bulk Density ◽  
Bending Strength ◽  
Raw Materials ◽  
Apparent Porosity ◽  
Kiln Furniture ◽  
Firing Shrinkage ◽  
Xrd Patterns

In this paper, effects of incorporation of Narathiwat clay (NT), talc and silica on the mechanical properties of cordierite-mullite refractories were investigated. The starting raw materials were mixed in different ratios and fired at 1300 °C for 2 hours. XRD patterns of fired refectories indicated cordierite and mullite phases. The fired samples were studied the firing shrinkage, water absorption, bulk density, apparent porosity and bending strength of the cordierite-mullite refractories. The optimum condition was achieved for the composition of 20% Talc that had shrinkage: 11.78%, water absorption: 4.16%, bulk density: 2.28 g/cm3, apparent porosity: 9.2% and bending strength: 330.82 kg/cm2. The results thus showed that Narathiwat clay, talc and silica was a potential materials for use kiln furniture cordierite-mullite refractories.

Effects of Sintering Temperature on Phases, Microstructures and Properties of Fused Silica Ceramics

2017 ◽  
Vol 726 ◽  
pp. 399-403 ◽  
Author(s):  
Shi Hua Liu ◽  
Peng Chen ◽  
Dan Hua Xu ◽  
Qing Dan Yuan
Keyword(s):  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Fused Silica ◽  
High Density ◽  
Apparent Porosity

Fused silica ceramics, named fused silica articles by means of ceramics fabrication processes, had been widely used in metallurgy, refractory, aviation and many other areas. How to get fused silica ceramics with high density and less cristobalite is on the focus. In this paper, effects of sintering temperature (1150°C, 1200°C, 1250°C, 1300°C, 1350°C) on phases, microstructures and properties of fused silica ceramics were investigated. The results showed that the bulk density of samples increased and the apparent porosity of samples minished gradually, with the increase of sintering temperature. However, the bending strength increased to maximum firstly and then decreased because the emergency of cristobalite at 1300°C. When the sintering temperature was 1250°C, the bulk density, apparent porosity and bending strength was 1.71g·cm-3, 17.6% and 38.87MPa, respectively.

Sign in / Sign up

Export Citation Format

Share Document