Fabrication, Microstructure and Properties of Nitrides Bonded Alumina Castables by In Situ Nitridation Reaction

2011 ◽  
Vol 284-286 ◽  
pp. 69-72 ◽  
Author(s):  
Quan Li Jia ◽  
Fang Bao Ye ◽  
Yu Cui Zhang
Keyword(s):  
Phase Composition ◽  
Physical Properties ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Modulus Of Rupture ◽  
Hot Strength ◽  
Nitridation Reaction ◽  
Shock Resistance ◽  
Alumina Castables

Nitrides(Si3N4/Sialon) bonded alumina castables were fabricated by in situ nitridation reaction. Effects of the formation of nitrides on the physical properties, hot strength and thermal shock resistance were investigated. The results show that the phase composition of castables is alumina, a-Si3N4, b-Si3N4and Si2N2O after fired at 1400ºC and 1450ºC, and is alumina, b-Sialon and O’-Sialon after fired at 1500ºC. Hot modulus of rupture and thermal shock resistance of specimens are noticeably improved due to the formation of nitrides.

Utilization of Fly Ash in the Synthesis of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 321 ◽  
pp. 131-140
Author(s):  
Martin Nguyen ◽  
Radomír Sokolař
Keyword(s):  
Thermal Expansion ◽  
Fly Ash ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Power Plants ◽  
Linear Thermal Expansion ◽  
Aluminium Oxide ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Shock Resistance

Forsterite refractory ceramics is utilized in the metallurgical and cement industries as a lining of metallurgical furnaces and rotary kilns for its high refractoriness up to 1850°C and refractoriness under load above 1600°C. Another significant property of forsterite is its coefficient of linear thermal expansion utilized in the electrotechnical industry for ceramic-metal joints. Addition of aluminium oxide into the raw material mixture results in creation of magnesium-alumina spinel (MgO·Al2O3) which improves sintering, thermal shock resistance and mechanical properties in comparison with pure forsterite ceramics. Inexpensive source of aluminium oxide is fly ash. Utilization of fly ash, secondary energetic product of coal-burning power plants, is important for the environment and sustainable development. This paper evaluated properties of fly ash-based forsterite-spinel ceramics in comparison with alumina-based forsterite-spinel ceramics. Forsterite-spinel ceramics was synthesized from olivine, calcined magnesite and fly ash/alumina powders. XRD analysis was used to determine mineralogical composition, thermal analyses were used to determine the behaviour during firing and scanning electron microscopy to determine the morphology of crystal phases. Refractoriness of pyrometric cones, refractoriness under load, thermal shock resistance, coefficient of linear thermal expansion, water absorption, porosity and modulus of rupture were also determined on fired test samples.

Viability of Some Kano-Nigerian Clays for Refractory Applications

2013 ◽  
Vol 315 ◽  
pp. 477-481 ◽  
Author(s):  
I.A. Rafukka ◽  
B. Onyekpe ◽  
Y. Tijjani
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Bulk Density ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Linear Shrinkage ◽  
Chemical Compositions ◽  
Shock Resistance ◽  
Materials Used ◽  
Refractory Bricks

The physical properties of some materials used by local foundries were investigated with a view to assessing their suitability for use as low heat duty refractory bricks. The samples were collected from Malamai village, Gezawa Local Government, Kano state; they are Gezawa clay and Burji (Clay). The samples were crushed, ground, sieved and the chemical compositions were determined. The clay samples were treated separately as well as blended with Gezawa clay in different proportions and molded in to bricks. The bricks were dried and fired to 1100. Test for refractoriness, thermal shock resistance, linear shrinkage; bulk density, porosity and compressive strength were carried out on each of the specimen. Burji blended with 50% to 90% Gezawa clay gave improved thermal shock resistance with a refractoriness of 1300 and hence could be used for non ferrous melting cupolas.

Sic Based Ceramic Foams Reinforced by In Situ Mullite Whisker

2009 ◽  
Vol 79-82 ◽  
pp. 1983-1986 ◽  
Author(s):  
Xiao Li Ji ◽  
Fei Xu ◽  
Hai Ya Chen
Keyword(s):  
Compressive Strength ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Ceramic Foams ◽  
Sic Ceramic ◽  
Influence Of Temperature On ◽  
Shock Resistance ◽  
Mullite Whiskers ◽  
Maximum Compressive Strength

Prepared silicon carbide(SiC) ceramic foams combined with mullite whiskers which synthesized by in-situ reaction. Studied on the influence of temperature on the synthesis of mullite whisker, and the influence of mullite content on the compressive strength, thermal shock resistance of SiC ceramic foams. The results indicate that the performance of mullite whiskers synthesized at 1400°Cwere best, when mullite content was 25%, SiC ceramic foams could reach the maximum compressive strength for 1.75MP, the most thermal shock resistance for14 times.

Thermo-Mechanical Properties and Microstructure of Al2O3-SiC-SiAlON Composites

2011 ◽  
Vol 295-297 ◽  
pp. 161-164 ◽  
Author(s):  
Xin Hong Liu ◽  
En Xia Xu ◽  
Chao Jie Zhou
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Thermal Shock Resistance ◽  
Modulus Of Rupture ◽  
Increase With Increase ◽  
Shock Resistance ◽  
Si Content ◽  
Sialon Powder ◽  
Skeleton Structure

The composite specimens have been prepared using fused corundum, silicon and bauxite-based β-SiAlON powder as starting materials. The physical properties, high temperature modulus of rupture (HMOR), thermal shock resistance (TSR), phase composition and microstructure of the specimens after firing at 1500°C have been studied. The results show: (1) Al2O3-SiC-SiAlON composites are sintered well at 1500°C. (2) HMOR and TSR of the specimens increase with increase of Si content, high temperature properties are further increased with appropriate β-SiAlON addition. (3) The in-situ formed SiC and O’-SiAlON fill in the interstices of corundum skeleton structure, forming interlocking network structure, thus creating strengthening and toughening effects.

KUBOTA ALLOY KHR35CL

Alloy Digest ◽  
1999 ◽  
Vol 48 (9) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Thermal Shock ◽  
Tensile Properties ◽  
Thermal Fatigue ◽  
Thermal Shock Resistance ◽  
Temperature Performance ◽  
Shock Resistance ◽  
Lower Carbon

Abstract Kubota alloy KRH35CL is similar to KHR35C but contains lower carbon for applications requiring good thermal fatigue and thermal shock resistance. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as casting. Filing Code: SS-761. Producer or source: Kubota Metal Corporation.

Thermal and Thermomechanical Properties of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 325 ◽  
pp. 174-180
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář
Keyword(s):  
Fly Ash ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Raw Materials ◽  
Thermal Analyses ◽  
Aluminium Oxide ◽  
Thermomechanical Properties ◽  
Modulus Of Rupture ◽  
Shock Resistance

This article examines the utilization of fly ash in comparison with alumina as raw materials and sources of aluminium oxide for synthesis of forsterite-spinel refractory ceramics. Raw materials were milled, mixed in different ratios into two sets of mixtures and sintered at 1500°C for 2 hours. Sintered samples were characterized by X-ray diffraction analysis and scanning electron microscopy. Samples were also subjected to determination of porosity, water absorption and bulk density. Thermal and thermomechanical properties were determined by thermal analyses, refractoriness, refractoriness under load, thermal shock resistance and thermal dilatometric analysis with determination of thermal expansion coefficient. Mixtures with 10 wt.% and 20 wt.% of fly ash had the most promising results compared to alumina mixtures. Thermal shock resistance and modulus of rupture were improving with increasing content of aluminium oxide in the mixture.

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