Fabrication and Properties of Al2O3-SiC/Sialon Composite Refractories

2012 ◽  
Vol 512-515 ◽  
pp. 908-911
Author(s):  
Ding Yun Ye ◽  
Yan Gai Liu ◽  
Zhao Hui Huang ◽  
Ming Hao Fang ◽  
Yang Yang Liu
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Carbothermal Reduction ◽  
Room Temperature ◽  
Bending Strength ◽  
Raw Materials ◽  
Apparent Porosity ◽  
Low Grade ◽  
Sialon Powder ◽  
Aluminate Cement

Sialon powder was synthesized using low grade bauxite as raw materials by carbothermal reduction-nitridation reaction. The influence of synthesizing temperatures (1300°C, 1350°C, 1400°C, 1450°C, 1500°C and 1550°C) on the phases of the final products was studied by XRD technique. β-Sialon (Z=3) formed at 1350°C and decreased when the temperature was higher than 1450°C. The optimizing reaction temperature for preparing Sialon was 1450°C. The Al2O3-SiC/Sialon composite refractories were prepared at 200°C, 400°C and 600°C for 24h with white corundum, brown corundum, SiC, Sialon powders prepared at 1450°C and calcium aluminate cement. The bulk density, apparent porosity, water absorption and bending strength of the Al2O3-SiC/Sialon composite refractories at room temperature were studied. The results show that the bulk density decreased and then increased with the enhancing of the temperature and reached the highest value of 2.43g/cm3 at 200°C. The apparent porosity and water absorption reached the lowest values of 26.68% and 10.99% at 200°C respectively. The bending strength decreased as the temperature increased, reached the highest value of 0.73MPa at 200°C.

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.

scholarly journals Evaluation of Kalalani vermiculite for production of high strength porcelain insulators

2019 ◽  
Vol 51 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Blasius Ngayakamo ◽  
Eugene Park
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Bending Strength ◽  
Raw Materials ◽  
High Strength ◽  
Microstructural Characterization ◽  
Dielectric Strength ◽  
Raw Material ◽  
Porcelain Insulators

The present work has evaluated Kalalani vermiculite as a potential raw material for the production of high strength porcelain insulators. Three porcelain compositions were prepared to contain 0, 20 and 30 wt% of Kalalani vermiculite. Porcelain samples were fabricated using a semi-drying method. The chemical, mineralogical phases and microstructural characterization of the raw materials were carried out using XRF, XRD, and SEM techniques, respectively. Water absorption, bulk density, dielectric and bending strengths were performed on porcelain samples fired up to 1300?C. However, at the sintering temperature of 1250?C, the porcelain sample with 20 wt% of Kalalani vermiculite gave the dielectric strength of 61.3 kV/mm, bending strength of 30.54 MPa, bulk density of 2.21 g/cm3 and low water absorption value of 0.21 % which is the prerequisite properties for high strength porcelain insulators. It was therefore concluded that Kalalani vermiculite has the potential to be used for the production of high strength porcelain insulators

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.

scholarly journals Studies on the Physico-Chemical Properties of Ceramic Tiles Produced from Locally Available Raw Materials

1970 ◽  
Vol 43 (1) ◽  
pp. 77-88 ◽  
Author(s):  
SA Jahan ◽  
S Parveen ◽  
S Ahmed ◽  
M Moniruz Zaman
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Bending Strength ◽  
Raw Materials ◽  
Chemical Properties ◽  
Cost Effective ◽  
Local Market ◽  
Ceramic Tiles ◽  
Firing Shrinkage ◽  
Increasing Demand

Due to the increasing demand of cost-effective tiles in Bangladesh, using the locally available raw materials five different batches of tiles have been prepared and their physical properties (firing shrinkage, bending strength, water absorption, bulk density etc.) as well as chemical properties were studied in order to evaluate the quality of the products. The present investigation revealed that various properties of the produced tiles are similar to those present in commercial tiles which are available in the local market. Key words: Tiles, Firing shrinkage, Bending strength, Water absorption, Bulk density. DOI: 10.3329.bjsir.v43i1.859 Bangladesh J. Sci. Ind. Res. 43(1), 77-88, 2008

Effects of the Z Value on the Properties of β-Sialon/ZrO2 Composites

2012 ◽  
Vol 476-478 ◽  
pp. 471-474
Author(s):  
Rui Sheng Wang ◽  
Jun Cong Wei ◽  
Jun Hong Zhao ◽  
Yong Wu He ◽  
Fu Hua Peng
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Absorption Rate ◽  
Apparent Porosity ◽  
Modulus Of Rupture ◽  
X Ray Diffraction ◽  
Water Absorption Rate ◽  
Shock Resistance ◽  
Z Value ◽  
Sialon Powder

β-Sialon/ZrO2 composites were prepared using 10 wt. % β-Sialon powder (where the z =1, 2, 3, respectively) and 90 wt. % ZrO2 powder as the starting materials. The effects of the Z value of β-Sialon on the bulk density, apparent porosity, water absorption rate, room temperature modulus of rupture, thermal shock resistance, microstructure and composition of the composites were investigated. The microstructure of sintered specimens was analyzed by scanning electron microscope (SEM), and X-Ray diffraction (XRD). The results revealed that with increase of the Z value of β–Sialon, bulk density gradually increased, apparent porosity and water absorption rate gradually decreased. The specimen possessed a maximum MOR (71.46MPa) when the z=2. In carbon embedded condition, the residual strength ratio of the specimen reached 60% and the lowest thermal expansion rate was obtained (0.55%) when the z=1. The phase compositions were cubic ZrO2 (c-ZrO2) and monoclinic ZrO2 (m-ZrO2). β-Sialon/ZrO2 composites exhibited overall optimum performance when the z equals 2

Mechanical Properties and Thermal Conductivity of Lightweight Clay Bricks Fabricated with a Powdered Marble Dust Additive

2018 ◽  
Vol 777 ◽  
pp. 465-470
Author(s):  
Sutas Janbuala ◽  
Mana Eambua ◽  
Arpapan Satayavibul ◽  
Watcharakhon Nethan
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Bulk Density ◽  
Firing Temperature ◽  
Apparent Porosity ◽  
Clay Brick ◽  
Clay Bricks ◽  
Marble Dust

The objective of this study was to recycle powdered marble dust to improve mechanical properties and thermal conductivity of lightweight clay bricks. Varying amounts of powdered marble dust (10, 20, 30, and 40 vol.%) were added to a lightweight clay brick at the firing temperatures of 900, 1000, and 1100 °C. When higher quantities of powdered marble dust were added, the values of porosity and water absorption increased while those of thermal conductivity and bulk density decreased. The decrease in apparent porosity and water absorption were also affected by the increase in firing temperature. The most desirable properties of the clay bricks were obtained for the powdered marble dust content of 40 vol.% and firing temperature 900 °C: bulk density of 1.20 g/cm3, compressive strength 9.2 MPa, thermal conductivity 0.32 W/m.K, and water absorption 22.5%.

The Influences of Addition of MgCO3 on the Properties of the Magnesia Prepared Using Magnesite

2018 ◽  
Vol 281 ◽  
pp. 230-235
Author(s):  
Wang Nian Zhang ◽  
Li Wang ◽  
Ni Deng
Keyword(s):  
Grain Size ◽  
Bulk Density ◽  
Raw Materials ◽  
Apparent Porosity ◽  
X Ray Diffraction ◽  
Linear Change ◽  
Change Rate ◽  
X Ray ◽  
Before And After ◽  
Calcination Method

Micropowder MgCO3 was added into magnesite as raw materials to prepare magnesia using a two-step calcination method. The sample magnesite was characterized use X-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results showed that the sample insulated at 1600° C for 3 hours before and after sintering presented a linear change rate of 15.6 % in the case of without adding micropowder MgCO3, the prepared magnesia had a bulk density of 2.31 g/cm3 and apparent porosity of 32.8 %, while MgO grain size was 3.11 μm. In the case of adding 8 % micropowder MgCO3, the sample magnesite before and after sintering showed a linear change rate of 17.9 %. The bulk density, apparent porosity of prepared magnesia were 2.46 g/cm3 and 28.1 % respectively, while the grain size of MgO was 5.15 mm.

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.

Quality Technological Properties of Foundry Exhaust Dust as Alternative Ceramic Coating Raw Materials

2015 ◽  
Vol 1088 ◽  
pp. 395-398
Author(s):  
Luiz Oliveira Veriano dalla Valentina ◽  
Marilena Valadares Folgueras ◽  
Wanessa Rejane Knop ◽  
Maria Cristina Pacheco do Nascimento ◽  
Glaucia Aparecida Prates
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Ceramic Coating ◽  
Raw Materials ◽  
Linear Shrinkage ◽  
Inert Atmosphere ◽  
Technological Properties ◽  
Foundry Industry ◽  
Ceramic Manufacturing ◽  
Materials Used

The work evaluates the possibility of the use the exhauster powder generated in the foundry process in ceramic mass atomized semigre type. The raw materials used were semi-stoneware kind atomized powder used on the coating ceramic manufacturing and dust exhaust byproduct supplied by a foundry industry both from brazilian industries . Tests were conducted using a heating rate of 10o.C / min and oxidant and / or inert atmosphere. Specimens contained different amounts of byproduct to the extent of 30% by mass, in order to verify the maximum addition of byproduct and were used in order to analyze the technological properties evaluation (water absorption linear shrinkage, bulk density). at the temperature of 1100 ° C showed higher difference between the results obtained and 1200o C this difference decreased.

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