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.

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.

Sintering Properties of Fused Silica/Nano-Zirconia Composite Ceramic

2013 ◽  
Vol 750-752 ◽  
pp. 81-84
Author(s):  
Yong Wu He ◽  
Jing Long Bu ◽  
Rui Sheng Wang ◽  
Dong Mei Zhao ◽  
Jun Xing Chen ◽  
...  
Keyword(s):  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Composite Ceramic ◽  
High Energy ◽  
Fused Silica ◽  
Raw Material ◽  
Composite Powders ◽  
Wet Chemical Synthesis ◽  
Sintering Properties

Zirconyl chloride was used as zirconium source and fused silica particles were used as main raw material. First of all, the composite powders were prepared by wet chemical synthesis using ammonia as the precipitator and polyethylene glycol as the dispersant. Then, fused silica nanozirconia composite ceramic containing nanometer particle zirconia with different contents (5%, 15%, 25% and 35%) were fabricated in reduction atmosphere at 1300°C, 1350°C and 1400°C for 1 h. The bulk density and bending strength were measured, microstructure was observed by SEM. The result indicated bulk density and bending strength of composite ceramic increase and microstructure becomes denser with content of zirconia increasing. Bulk density of composite ceramic increases and bending strength which reaches maximum at 1350°C firstly increases then decreases with the increase of sintering temperature. Both high sintering temperature and nanozirconia possessing high energy interface can improve the composite ceramic sintering.

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.

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.

Research on the Sinterability of MgAl2O3/SiC Composites in Air Atmosphere

2011 ◽  
Vol 399-401 ◽  
pp. 834-837
Author(s):  
Chun Hui Cao ◽  
Jun Cong Wei ◽  
Jian Kun Huang ◽  
Jun Bo Tu
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
National Standards ◽  
Crushing Strength ◽  
Air Atmosphere ◽  
Cold Crushing Strength ◽  
Sic Composites

MgAl2O4-SiC composites were prepared by using MgAl2O4 and SiC powder as main starting materials, being pressed to cylindrical specimens of Φ30mm×30mm at 200 MPa and heated respectively at 1400°C and 1500°C for 3 hours in air atmosphere. The room temperature physical properties of sintered samples were tested according to related national standards. The phase compositions were analyzed by XRD. The microstructure of the fracture of the samples was observed by SEM. The results showed that MgAl2O4-SiC materials could sintered well in air atmosphere. The mechanism is that SiC was oxidized to form active SiO2, which reacted with MgAl2O4 to produce liquid cordierite promoting the sintering of the materials. The sinterability of MgAl2O4-SiC materials was overall improved with increasing the sintering temperature. When the content of SiC of MgAl2O4-SiC materials was 10%, the cold crushing strength and bulk density of the samples reached maximums and apparent porosity reached a minimum; the content of SiC was more than 10%, the sinterability of samples deteriorated.

Effect of Sintering Temperature on Membrane Properties of Sayong Ball Clay

2013 ◽  
Vol 315 ◽  
pp. 349-353 ◽  
Author(s):  
Norhayati Ahmad ◽  
Nurhanna Binti Mohd Zaidan
Keyword(s):  
Water Quality ◽  
Bulk Density ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Membrane Properties ◽  
Casting Technique ◽  
Gel Casting ◽  
Physical Measurements ◽  
Ball Clay ◽  
Clay Membrane

Sayong ball clay membrane can be fabricated as a cheap membrane material and available commonly at Malaysia. This work was concerned with the study of Sayong ball clay membrane as a water filtration by gel casting technique. Gel casting involves mixing process of Sayong ball clay with the solvent, monomer, dispersant, initiator and catalyst in a certain composition. Tubular membrane was fabricated by controlling the sintering temperature (1000, 1100, 1200, 1300°C). The physical measurements (shrinkage, apparent porosity, and bulk density), microstructure analysis, filtration process (flow rate) and water quality assessments (pH, color, Chemical Oxygen Demand (COD), solid suspended (SS)) were carried out at different sintering temperature. Apparent porosity and bulk density of the samples were measured by using Archimedes method. The effect of sintering temperature on microstructure of the membranes has been investigated using SEM. The experimental results showed that the shrinkage and bulk density increase with increasing sintering temperature. It gives the improvement in water quality with the lowest SS (192 mg/L), lowest COD (4 mg/L) and most colorless (1.1 Gardner units) filtered wastewater as compared to others.

Preparation of Bauxite-Based Homogenized Mullite Grogs with Bauxite and Coal Gangue

2011 ◽  
Vol 199-200 ◽  
pp. 1940-1944 ◽  
Author(s):  
Zhong Zheng Yang ◽  
Zhen Xian Xing ◽  
Zhan Fang Gai ◽  
Huan Qiang Liu
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Bulk Density ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Heat Processing ◽  
Sintering Behavior ◽  
Sintering Aids ◽  
Homogenization Process ◽  
Three Stages

The sintering behavior, physical properties and heat processing changes of bauxite-based homogenized grogs prepared by homogenization process and high temperature sintering using bauxite as starting material were investigated. Results show that the bauxite-based mullite can be synthesized by the method, sintering temperature with and without MgO/CeO2sintering aids are 1600°C and 1700°C separately, the mullite with apparent porosity of＜1.0% and 2.5%, bulk density of ≥2.87g•cm-3and 2.75g•cm-3, Refracteriness-Under-Load(RUL) 1600°C and 1620С; changes in the heat processing is divided into three stages: dehydration stage(400°С~900°С ), primary mullitization stage(1000°С ~1200°С) and secondary mullitization stage(>1200°С).

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.

Research of Thermal Shock Resistance of Si3N4 and SiC

2012 ◽  
Vol 549 ◽  
pp. 691-694
Author(s):  
Fang Zhang ◽  
Zhi Liang Huang
Keyword(s):  
Bulk Density ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Silicon Powder ◽  
Nitrogen Atmosphere ◽  
Production Practice ◽  
Shock Resistance ◽  
Powder Content

The study is carried out combing with the production practice in Danjiangkou Hongyuan SiC limited. Si3N4 and SiC were prepared successfully from SiC and Silicon power in nitrogen atmosphere at 1425°C and 1375°C sintering temperature by the serial of techniques, such as ingredients, mixing, molding and drying, respectively. In the actual production, silicon powder content and sintering temperature will directly influence the products of the bending strength and thermal shock resistance. By measuring bending strength, porosities, bulk density, XRD and FESEM, the bending strength and thermal shock resistance of samples were studied mainly by changing sintering temperature and silicon powder content. The results show that bending strength and thermal shock resistance of sample which was added 16% Si powder is best. And bending strength and thermal shock resistance of sample of 1425°C sintering temperature is higher than that of 1375°C sintering temperature.

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