Effect of Additives and Carbon Resources on Thermal Shock Resistance of Spinel-C Material

2017 ◽  
Vol 726 ◽  
pp. 440-444 ◽  
Author(s):  
Zheng Wei ◽  
Guo Qi Liu ◽  
Jin Song Yang
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Expanded Graphite ◽  
Silicon Powder ◽  
Particle Sizes ◽  
Flake Graphite ◽  
Good Corrosion Resistance ◽  
Effect Of Additives ◽  
Shock Resistance ◽  
Quenching Method

Spinel-C material is important for monolithic stopper and submerged nozzle, which usually determine the application effects. Spinel-C specimens with 8% flake graphite is characterized by good corrosion resistance but poor thermal shock resistance. The effects of additives (Al-Si alloy, silicon powder, B4C and SiC), flake graphite (+199/-199), ultrafine flake graphite, expanded graphite and nickel nitrate + pitch powder on thermal shock resistance of spinel-C material were investigated by using water-quenching method. The results show that: (1) The addition of Al-Si alloy and B4C can significantly decrease the residual strength ratios (RSR) of the specimens. The addition of SiC and silicon powder can improve the RSR obviously. (2) The flake graphite of different particle sizes has little effect on the RSR of the specimens. With the increasing of the expanded graphite content, the RSR of the specimens increases. (3) The addition of mesophase pitch and Carboresâ P can receive the RSR rise of 74% and 59% respectively.

Research on the Performance of SiAlON-Graphite-SiC Composites

2011 ◽  
Vol 284-286 ◽  
pp. 73-77
Author(s):  
Wen Wu Wang ◽  
Hui Yan Cao ◽  
Zhi Ping Zhang ◽  
Jing Xiang Wang
Keyword(s):  
Blast Furnace ◽  
Thermal Shock Resistance ◽  
Fine Powder ◽  
Silicon Powder ◽  
Alkali Resistance ◽  
Flake Graphite ◽  
Shock Resistance ◽  
Composition Structure ◽  
And Performance ◽  
Sic Composites

Based on SiC grains and powder, flake graphite, AlN powder, Silicon powder, sintered alumina ultra-fine powder as the starting materials, the sample of SiAlON-Graphite-SiC composites was prepared by firing under N2 atmosphere at 1 550°C and then analyzed in terms of high temperature performances by XRD, SEM and EDAX etc. The interrelation between composition, structure and performance of the material was also investigated. It indicates that this material provides excellent thermal shock resistance and molten alkali resistance, also proper oxidation resistance and applicable as the inner lining of the blast furnace.

Improvement on Thermal Shock Resistance of Ceramic Components by Using Self-Healing

2010 ◽  
Author(s):  
Wataru Nakao
Keyword(s):  
Thermal Stress ◽  
High Temperature ◽  
Thermal Shock ◽  
Stress Fracture ◽  
Thermal Shock Resistance ◽  
Self Healing ◽  
Quenching Rate ◽  
Ceramic Components ◽  
Shock Resistance ◽  
Quenching Method

Availability of self-healing on the thermal shock resistance of ceramic components was investigated. Using gas quenching method, the crack-healed alumina-18 vol% SiC composite, which has excellent self-healing ability, was applied to thermal shock of the arbitrary quenching rate. The procedure could give rise to the thermal stress fracture at high temperature. The critical quenching rate at thermal stress fracture of the healed specimen was found to be 6.47 K/s, corresponding to the thermal stress of 452.3 MPa. Alternatively, that of the cracked specimen was found to be 5.02 K/s, corresponding to the thermal stress of 350 MPa. From the obtained results, usage of self-healing was confirmed to improve extremely thermal shock resistance. The present result suggests that usage of self-healing gives a large advantage to design the high temperature ceramic components, because the mechanically reliable design and thermal shock resistance cannot coexist due to low thermal conductivity.

Investigation of Microstructure and Thermal Shock Resistance of the B4C/BN Composites Fabricated by Hot-Pressing Process

2012 ◽  
Vol 512-515 ◽  
pp. 748-752 ◽  
Author(s):  
Tao Jiang ◽  
Chen Chao Tian
Keyword(s):  
Mechanical Property ◽  
Thermal Shock ◽  
Hot Pressing ◽  
Thermal Shock Resistance ◽  
High Fracture ◽  
Pressing Process ◽  
Low Elastic Modulus ◽  
Shock Resistance ◽  
Quenching Method ◽  
Better Than

The B4C/BN composites were fabricated by hot-pressing process. The B4C/BN composites included the B4C/BN microcomposites and B4C/BN nanocomposites. The B4C/BN microcomposites were fabricated by hot-pressing process, and the B4C/BN nanocomposites were fabricated by chemical reaction and hot-pressing process. In this research, the phase composition, microstructure, mechanical property and thermal shock resistance of the B4C/BN microcomposites and B4C/BN nanocomposites were investigated. The B4C/BN microcomposites and the B4C/BN nanocomposites exhibited the homogenous and compact microstructure, and the h-BN particles were homogenously distributed in the B4C matrix. The mechanical property of the B4C/BN microcomposites and B4C/BN nanocomposites decreased gradually with the increase of h-BN content, but the B4C/BN nanocomposites exhibited the higher mechanical property than that of the B4C/BN microcomposites. The thermal shock resistances of the B4C monolith and the B4C/BN composites were measured by water-quenching method. The thermal shock resistances of the B4C/BN microcomposites and the B4C/BN nanocomposites were remarkably improved in comparison with the B4C monolith. The thermal shock resistance of the B4C/BN nanocomposites was much better than that of the B4C/BN microcomposites. The thermal shock temperature difference (ΔTc) of the B4C monolith was about 300oC, the ΔTc of the B4C/BN microcomposites was about 500oC and the ΔTc of the B4C/BN nanocomposites was about 600oC. The B4C/BN composites exhibited the high thermal shock resistance due to the high fracture strength and low elastic modulus. The microstructure showed that the weak interface of B4C/BN and cleavage behavior of laminate structured h-BN particles would remarkably improve the thermal shock resistance of the B4C/BN composites.

Fabrication, Microstructure, and Properties of Zirconium Diboride Matrix Ceramic

2013 ◽  
pp. 354-412 ◽  
Author(s):  
Zhi Wang ◽  
Zhanjun Wu
Keyword(s):  
Thermal Stress ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Zirconium Diboride ◽  
Isothermal Oxidation ◽  
Rate Of Change ◽  
Oxide Layers ◽  
Sic Ceramic ◽  
Shock Resistance ◽  
Quenching Method

The crystal structure, synthesis, and densification of zirconium diboride (ZrB2) are summarized in detail. In this chapter, ZrB2-ZrC-SiC ceramic was synthesized by reactive hot pressing a mixture of Zr, B4C, and Si powders. The thermal shock resistance of the ZrB2-SiC-ZrC ceramic was estimated by the water-quenching method and was significantly greater than that of a ZrB2-15vol.% SiC ceramic. The isothermal oxidation of the ZrB2-SiC-ZrC ceramic was carried out in static air at constant temperatures of 1000±15, 1200±15, and 1400±15 ºC for different amounts of time at each temperature. The mechanism of strength increase for the oxidized specimen indicated that the strength increased with the reaction rate, which was related to the rate of change in volume induced by reaction, initial crack geometry, elastic modulus, and surface free energy. The formation of oxide layers resulted in (I) repair of surface flaws, (II) increase in flexural strength, (III) appearance of a compressive stress zone beneath the surface oxide layers, (IV) decrease in thermal stress, and (V) consumption of thermal stress. These five aspects were favorable to the improvement of the thermal shock resistance of the ZrB2-SiC-ZrC ceramic. The isothermal oxidation of the ZrB2-SiC-ZrC ceramic was carried out in static air at 1600±15 ºC. In the different oxidation stages, quantitative models were proposed for predicting oxidation kinetics.

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.

Preparation and Properties of MgO-MgAl2O4-FeAl2O4 Bricks in Cement Kiln

2011 ◽  
Vol 250-253 ◽  
pp. 554-560 ◽  
Author(s):  
Shu Long Ma ◽  
Yong Li ◽  
Jia Lin Sun ◽  
Yue Li ◽  
Wen Bin Xia
Keyword(s):  
Compressive Strength ◽  
Thermal Shock ◽  
Adhesion Strength ◽  
Thermal Shock Resistance ◽  
Raw Materials ◽  
Volume Density ◽  
Cement Kiln ◽  
Particle Sizes ◽  
Tunnel Furnace ◽  
Shock Resistance

Sintered magnesia with different particle sizes, fused MgAl2O4and FeAl2O4were used as the raw materials. FeAl2O4is added in MgO-MgAl2O4bricks at different ratios to gradually replace MgAl2O4. After the raw materials were molded and sintered at the tunnel furnace with the temperature 1 530°C for 10 hours, the MgO-MgAl2O4-FeAl2O4bricks could be made. After the analysis of the phase composition, microstructure and routine performance of the specimens, the influence by adding FeAl2O4to the samples on the properties such as thermal shock resistance, adhesion strength of kiln crust are discussed as the key point. The result shows that the addition of FeAl2O4has no evidently influence on the apparent porosity and volume density. The cold compressive strength of the samples reduces gradually with the addition of FeAl2O4, and it decreases obviously when the amount of FeAl2O4is more than 8%. When the addition of FeAl2O4is 5% FeAl2O4in the MgO-MgAl2O4-FeAl2O4bricks, MgAl2O4and FeAl2O4can combine each other’s advantages. The thermal shock resistance not only decreased obviously but the adhesion strength to kiln crust is increased.

Effect of Additives on Thermal-Shock Resistance of W∕Cu FGMs

2008 ◽  
Author(s):  
Zhang Ke ◽  
Shen Weiping ◽  
Ge Changchun ◽  
Glaucio H. Paulino ◽  
Marek-Jerzy Pindera ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Effect Of Additives ◽  
Shock Resistance

Effect of additives on the thermal-shock resistance of corundum-zircon refractories

Refractories ◽  
1981 ◽  
Vol 22 (5-6) ◽  
pp. 344-347
Author(s):  
I. G. Orlova ◽  
A. I. Gudilina ◽  
M. E. Drizheruk
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Effect Of Additives ◽  
Shock Resistance

Study on Thermal Shock Resistance of Alumina Composite Ceramics by Indention Quenching Method

2015 ◽  
Vol 655 ◽  
pp. 92-96
Author(s):  
Fen Ling Qian ◽  
Zhi Yong He ◽  
Zhi Peng Xie ◽  
Xiao Bo Wang ◽  
Qi Fu Zhang
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Covalent Bond ◽  
Alumina Ceramics ◽  
Composite Ceramics ◽  
Mullite Fiber ◽  
Alumina Composite ◽  
Shock Resistance ◽  
Quenching Method ◽  
Industry Area

Alumina ceramics are the most widely used structural ceramics, especially in aviation, spaceflight and war industry area. However, alumina is of covalent bond, with low fracture toughness and poor thermal shock resistance, which baffle the application of the alumina ceramics in engineering. In this paper, mullite fiber was used to improve its toughness and thermal shock resistance. Alumina-mullite composite ceramics were prepared by hot press sintering. The effect of mullite fiber on thermal shock resistance of ceramics was investigated through indention quenching method. Meanwhile, the mechanism of its reinforcing and toughening and the relationship between mechanical properties and addition of mullite fiber were also discussed.

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