Effect of Molar Ratio of Al2O3 to Fe2O3 on the Sintering and Thermal Shock Resistance of Al2O3-Fe2O3 Composite

2011 ◽  
Vol 194-196 ◽  
pp. 1745-1748
Author(s):  
Zhi Fa Wang ◽  
Jian Sheng Wang ◽  
Yue Jun Chen ◽  
Li Xue Yu ◽  
Jing Long Bu ◽  
...  
Keyword(s):  
Composite Materials ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Raw Materials ◽  
Sem Analysis ◽  
Molar Ratio ◽  
Alumina Powder ◽  
Linear Change ◽  
Shock Resistance

The Al2O3-Fe2O3 composite was prepared at 1550°C for 3h with alumina powder and ferric oxide powder as raw materials and with magnesia powder as additive. The effect of molar ratio of Al2O3 to Fe2O3 on the sintering and thermal shock resistance of the composite materials was studied. The results showed that the apparent porosity and bulk density of the samples both decreased with the molar ratio of Al2O3 to Fe2O3 increase, as a result, the linear change ratio and bending strength both increased. When the molar ratio of Al2O3 to Fe2O3 equals to 3, the sample exhibits excellent thermal shock resistance. The XRD and SEM analysis results indicated that the mechanical and thermal proprieties are relative to the microstructure and crystal phases of the composite materials.

Microstructure and Thermal Shock Behaviour of Alumina Composite Ceramic for Heat Transmission Pipeline

2014 ◽  
Vol 692 ◽  
pp. 217-223 ◽  
Author(s):  
Xiao Hong Xu ◽  
Xiao Yang Xu ◽  
Jian Feng Wu ◽  
Yang Zhou ◽  
De Zhi He
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Raw Materials ◽  
Composite Ceramic ◽  
Alumina Powder ◽  
Monoclinic Zirconia ◽  
Heat Transmission ◽  
Transmission Pipeline ◽  
Shock Resistance

Al2O3 composite ceramics materials used for heat transmission pipeline were prepared by pressureless sintering in air. Calcined bauxite, talc and commercial alumina powder were used as the main raw materials, partially stabilized zirconia was also added to improve the thermal shock resistance of the samples. The effects of composition and sintering temperature on density, phase composition, microstructure and thermal shock behavior of samples were evaluated. It shows that the B2 sample which was sintered at 1400 °C for 2 h has optimal properties with porosity 0.4%, bulk density 3.2 g•cm-3.The bending strength increases 19.46 MPa after 30 times thermal shock cycles from 1100 °C to room temperature. The main phases of B2 are corundum and spinel, meanwhile, a small amount of monoclinic zirconia and α-quartz are also detected according to XRD pattern. Microstructure analysis reveals that spinel crystals are interlocked by prismatic corundum crystals, bright white beaded monoclinic zirconia particles are distributed uniformly, and it is beneficial to improve the thermal shock resistance of sample.

Effect of Molar Ratio of MgO/Al2O3 on the Performance of MgO-Al2O3-Fe2O3 Composite

2011 ◽  
Vol 284-286 ◽  
pp. 242-245
Author(s):  
Yan Qing Cai ◽  
Zhi Fa Wang ◽  
Li Xue Yu ◽  
Jing Long Bu ◽  
Rong Lin Wang ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Raw Materials ◽  
Molar Ratio ◽  
Alumina Powder ◽  
Primary Crystal ◽  
Shock Resistance ◽  
Crystal Phases ◽  
Magnesia Powder ◽  
High Temperature Gas

The MgO-Al2O3-Fe2O3 composite was prepared at 1600°C for 3h with magnesia powder and alumina powder as raw materials and with ferric oxide powder as additive. The effect of the molar ratio of MgO/Al2O3 on the sintering and thermal shock resistance of the composite materials was studied. The results showed that increasing the molar ratio of MgO/Al2O3 could improve the densification of the Al2O3-Fe2O3 composites, with the molar ratio of MgO/Al2O3 increased from 3 to 5, densification of the composites didn't increased but decreased. The optimum molar ratio of MgO/Al2O3 of the Al2O3-Fe2O3 composite is equal to 3, the sample MA-3 exhibits better sintering densification and thermal shock resistance. Its primary crystal phases are spinel and periclase, and less amount of sosoloid 20MgO·19Al2O3·Fe2O3. So, the MgO-Al2O3-Fe2O3 composite is acceptable for application in cement rotary kiln linings and high temperature gas filter support.

Effect of Sintering Temperatures on the Sintering Performance and Thermal Shock Resistance of MgO-Al2O3-Fe2O3 Composite

2011 ◽  
Vol 194-196 ◽  
pp. 1755-1758
Author(s):  
Jing Long Bu ◽  
Yan Qing Cai ◽  
Li Xue Yu ◽  
Zhi Fa Wang ◽  
Rong Lin Wang
Keyword(s):  
Bulk Density ◽  
Thermal Shock ◽  
Rotary Kiln ◽  
Ferric Oxide ◽  
Potential Application ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Raw Materials ◽  
Linear Change ◽  
Shock Resistance

The composites in the MgO-Al2O3-Fe2O3 system were prepared using high pure magnesia and alumina as raw materials and ferric oxide powder as additive. The effect of sintering temperatures on the sintering performance and thermal shock resistance of the composites was studied. The results showed that both the apparent porosity and linear change ratio of the samples decreased with the increase of sintering temperatures, and their bulk density and bending strength increased accordingly. The sample sintered at 1550°C exhibits excellent thermal shock resistance. The XRD and SEM results indicated that the crystal phase of the samples remained the same, but their microstructure became denser as the sintering temperatures increased from 1500°C to 1600°C. As a result, the composites could be sintered at about 1550°C, which has a potential application in cement rotary kiln linings.

Effect of MgO/CuO on the Microstructure and Thermal Properties of Cordierite–Alumina Ceramics

2012 ◽  
Vol 509 ◽  
pp. 240-244
Author(s):  
Li Ying Tang ◽  
Xi Cheng ◽  
Ping Lu ◽  
Fang Yue
Keyword(s):  
Thermal Conductivity ◽  
Bulk Density ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Raw Materials ◽  
Laser Flash ◽  
Alumina Powder ◽  
Alumina Ceramics ◽  
Conductivity Increase ◽  
Shock Resistance

Abstract: Cordierite–alumina ceramics were prepared with the raw materials of cordierite and α-alumina powder, and TiO2，CuO and MgO were added as composite additives. The effect of MgO/ CuO ratios on the microstructure, thermal conductivity and thermal shock resistance of cordierite–alumina ceramics were researched by X-ray diffraction, scanning electron microscopy and laser flash analyzer; the bulk density and the porosity of cordierite – alumina ceramics were measured. The results show that with increasing of MgO/CuO ratios, the bulk density and thermal conductivity increase firstly and then decrease, and have a minimum with 0.4wt% MgO and 0.667 MgO/CuO; and the porosity of ceramics decreases firstly and then increases and has a maximum with 0.4wt% MgO and 0.667 MgO/CuO;There are little changes in the size of the grain of the ceramics, and a small amount of magnesium aluminate spinel precipitate; the thermal shock resistance performance of the ceramics is developed with the increasing of MgO/CuO ratios.

Improvement in the Thermal Shock Resistance of Zirconia Ceramic by the Addition of Aluminium Titanate

2011 ◽  
Vol 194-196 ◽  
pp. 1724-1727 ◽  
Author(s):  
Heng Yong Wei ◽  
Li Xue Yu ◽  
Zhi Fa Wang ◽  
Jing Long Bu ◽  
Shu Long Ma ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Sem Analysis ◽  
Precipitation Method ◽  
Zirconia Ceramic ◽  
Aluminum Titanate ◽  
Sintering Properties ◽  
Shock Resistance ◽  
Co Precipitation

ZrO2-Al2TiO5 composite materials with high bending strength and good thermal shock resistance expansion were prepared using partially stabilized zirconia (Y-PSZ) powders coated with Al2TiO5 by co-precipitation method. The effects of Al2TiO5 content on the sintering properties, phase composition, microstructure and thermal shock resistance of the zirconia ceramic were investigated．The results show that the apparent porosity of the samples decreased and their bending strength increased with the content of aluminum titanate increasing from 0 to 8 wt%. The samples with 5 and 8 wt% aluminum titanate addtion have excellent thermal shock resistance. The results showed that the addtion of aluminum titanate could enhance the mechanical strength and improve the thermal shock resistance of zirconia ceramic. The XRD and SEM analysis results indicated that the propriety improvement is relative with the change of the microstructure and the increase of tetragonal ZrO2 phase in the composites.

The Preparation and Properties of MgO-CaO-ZrO2 System Composite Materials

2012 ◽  
Vol 535-537 ◽  
pp. 161-164
Author(s):  
Rong Lin Wang ◽  
Yan Ping Wang ◽  
Yi Cui ◽  
Li Xue Yu
Keyword(s):  
Composite Materials ◽  
Calcium Oxide ◽  
Thermal Shock Resistance ◽  
Volume Expansion ◽  
Bending Strength ◽  
Raw Materials ◽  
Thermal Expansivity ◽  
Stabilized Zirconia ◽  
Shock Resistance ◽  
Two Phases

MgO-CaO-ZrO2 composite materials were prepared in oxidizing atmosphere at 1550 oC with sintered magnesia, calcium oxide and partial stabilized zirconia as raw materials. Sintering performance of the composites was measured by the checking of the bending strength, the apparent porosity, the thermal expansivity and the thermal shock resistance of samples, respectively. The phase compositions and microstructures of the composites were investigated by XRD, SEM and EDS. The results showed that CaZrO3 phase was formed by high temperture reaction between ZrO2 and CaO, and phase compositions of the composites consisted of two phases of CaZrO3 and MgO. The sintering performance of composites were promoted further with increasing the content of ZrO2 due to the volume expansion caused by the reaction of the added ZrO2 and CaO to form CaZrO3 phase in the refractories.

Effect of Ferric Oxide Addition on the Performance of MgO-Al2O3 System Materials

2011 ◽  
Vol 399-401 ◽  
pp. 805-808
Author(s):  
Jian Sheng Wang ◽  
Zhi Fa Wang ◽  
Jing Long Bu ◽  
Jun Xing Chen
Keyword(s):  
Thermal Shock ◽  
Ferric Oxide ◽  
Thermal Shock Resistance ◽  
Raw Materials ◽  
Spinel Phase ◽  
Alumina Powder ◽  
Primary Crystal ◽  
Oxide Addition ◽  
Shock Resistance ◽  
Crystal Phases

The MgO-Al2O3 system materials were prepared at 1600°C for 3h with magnesia powder and alumina powder as raw materials and with ferric oxide powder as additive. The effect of the ferric oxide additive on the sintering and thermal shock resistance of the composite materials was studied. The results showed that increasing the ferric oxide dosage could improve the densification of the MgO-Al2O3 system materials. In sample MAF-0, crystal phases all are spinel phase. With the ferric oxide dosage increased from 2% to 6% in MAF-2, MAF-4 and MAF-6, the MgAl2O4 (spinel) became the primary crystal phases, and less amount of sosoloid 20MgO•19Al2O3•Fe2O3. In comparison with samples MAF-0, MAF-2, MAF-6, sample MAF-4 has better structure compactness and thermal shock resistance, the optimum ferric oxide dosage was added in MgO-Al2O3 system material is equal to 4%. The MgO-Al2O3 system material is acceptable for application in cement rotary kiln linings and high temperature gas filter support.

Preparation Cordierite-Mullite Composites with Iron Tailing

2011 ◽  
Vol 393-395 ◽  
pp. 902-906
Author(s):  
Feng Feng Li ◽  
Wei Chao Yang ◽  
Ming Xi Zhang ◽  
Li Fang Zhang ◽  
Yi Shen
Keyword(s):  
Bending Strength ◽  
Sintered Material ◽  
Raw Materials ◽  
Sintered Sample ◽  
Molar Ratio ◽  
Alumina Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Shock Resistance ◽  
Sintered Temperature

Cordierite–mullite composites were prepared by using iron tailing, burn talc, suzhou soil, knar clay and alumina powder as raw materials. The main influencing factors such as the molar ratio of cordierite to mullite, amount of iron tailing and calcination temperature were discussed. The microstructure of the sintered sample was analyzed with X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The results show that the optimal prescription was V sample (36.4635wt% of iron tailings, 13.6813 wt % of burn talc, 10.2154 wt % of suzhou soil, 3.8405 wt % of knar clay and 35.7984 wt% of alumina), and its sintered material contains about 50% of mullite and 50% of cordierite;The optimal sintered temperature was 1250°C and the holding time was 2 hours. The bending strength of the sample is 29.79MPa and the thermal shock resistance expriments are above 60 times.

Improvement of Thermal Shock Resistance Performance of High Alumina Ceramic Filter Support

2013 ◽  
Vol 750-752 ◽  
pp. 525-528
Author(s):  
Yue Chao Tian ◽  
Xi Liu ◽  
Hui Tang ◽  
Jing Long Bu ◽  
Dong Mei Zhao ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Raw Materials ◽  
Ceramic Materials ◽  
Raw Material ◽  
Ceramic Filter ◽  
High Alumina ◽  
Gas Cleaning ◽  
Shock Resistance

Mullite-corundum multiphase ceramic materials were prepared at 1400°C for 2h with bauxite chamotte and clay clinker as raw material (size<74 μm), molded at pressure of 50 MPa. Effect of raw materials composition on sintering and themal shock resistance of composite were researched by measurements of apparent porosity, bending strength，thermal shock resistance and thermal expansion rates, and analysed by XRD and SEM. The results showed that the best weigh percentage of raw materials with better sintering and themal shock resistance are bauxite chamotte 50 wt%, clay clinker 50wt% for mullite-corundum multiphase ceramic materials. The test results for high temperature gas cleaning dust removal technology development and the application of the composite ceramic material has important application value.

Study of Thermal Shock Resistance of Sagger Plate Used in Floppy Magnets Sintering

2007 ◽  
Vol 280-283 ◽  
pp. 1667-1670 ◽  
Author(s):  
Feng Cao ◽  
Xing Rong Wu ◽  
Rainer Telle
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Rapid Development ◽  
Particle Surface ◽  
Sem Analysis ◽  
Sintering Process ◽  
Kiln Furniture ◽  
Dense Structure ◽  
Zircon Powder ◽  
Shock Resistance

The rapid development of magnetic materials has witnessed a sustained consumption increase in corundum-mullite kiln furniture application, yet a comparatively short duration of them. In this view, the thermal shock resistance of sagger plate in floppy magnets sintering turns out a factor of critical importance. This paper makes a study concerning the influence of factors including the size of critical electro-melted mullite particles, the electro-melted corundum or mullite as medium particles and the addition of upon the thermal shock resistance. The result shows that, with critical particles of 2 mm, the sheet of about 10mm thickness is characterized by better performance in modulus of rapture and thermal shock resistance. The latter proves to be more outstanding in samples rather than mullite. When zircon powder is added in a two-hour sintering process at the temperature of 1550°C, a remarkable improvement is made by the sample in terms of its thermal shock resistance. SEM analysis shows the existence of micropores in the section of samples with corundum as medium particles, whereas the glasses phase in that of mullite sample, resulting in a dense structure. Finally, zircon powder added makes for the improvement of thermal shock resistance due to the formation of baddeleyite on the particle surface of the corundum.

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