Aluminium Titanate-Aluminia Composites Synthesized by Heterogeneous Precipitation Method

2012 ◽  
Vol 217-219 ◽  
pp. 3-7
Author(s):  
Chun Xia Feng ◽  
Jing Hua Chen ◽  
Wei Guo ◽  
Bao Xiang Jiao ◽  
Hong Bin Lu
Keyword(s):  
Thermal Expansion ◽  
Crystalline Phase ◽  
Bending Strength ◽  
Sol Gel ◽  
Precipitation Method ◽  
Aluminium Titanate ◽  
Heterogeneous Precipitation ◽  
Blending Method ◽  
Sintering Properties ◽  
Precursor Powders

Aluminium titanate-alumina (AT-A) composites were sintered from the precursor powders prepared by two different methods: a simple sol-gel based heterogeneous precipitation method and a traditional blending method. The crystalline phase, microstructure, mechanical strength, sintering properties, and thermal expansion coefficient (TEC) of the sintered AT-A composites were investigated and compared. The heterogeneous precipitation method increases the homogeneity of the precursor powders and improves the mechanical and sintering properties of the AT-A composites. The AT-A composites with a Al:Ti ratio of 2.2 achieve the optimal performance where the bending strength is high and the TEC remains low.

Tunability and dielectric properties of Ba0.55Sr0.45TiO3/MgO composites prepared by heterogeneous precipitation method and sol-gel method

2017 ◽  
Vol 520 (1) ◽  
pp. 75-82
Author(s):  
Hai Jiang ◽  
Xiao-Hong Wang ◽  
Jing Tao ◽  
Hua-Bo Wang ◽  
Fang-yuan Chen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Sol Gel ◽  
Precipitation Method ◽  
Gel Method ◽  
Sol Gel Method ◽  
Heterogeneous Precipitation

Effects of Heat-Treatment Temperature on the Properties of Negative CTE Eucryptite Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 123-125 ◽  
Author(s):  
Yong Li ◽  
Qi Hong Wei ◽  
Ling Li ◽  
Chong Hai Wang ◽  
Xiao Li Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Heat Treatment Temperature ◽  
Bending Strength ◽  
Sol Gel ◽  
Negative Thermal Expansion ◽  
Treatment Temperature ◽  
Heat Treated

In this paper, negative thermal expansion coefficient eucryptite powders were prepared by sol-gel method using silica-sol as starting material. The raw blocks were obtained by dry pressing process after the powder was synthesized, and then the raw blocks were heat-treated at 600º, 1150º, 1280º, 1380º, 1420º and 1450°C, respectively. Variations of density, porosity and thermal expansion coefficient at different heat treatment temperatures were investigated. Phase transformation and fracture surface morphology of eucryptite heat-treated at different temperatures, respectively, were observed by XRD and SEM. The results indicate that, with the increasing heat- treatment temperature, the grain size and the bending strength increased, porosity decreased, thermal expansion coefficient decreased continuously. Negative thermal expansion coefficient of -5.3162×10-6~-7.4413×10-6 (0~800°C) was obtained. But when the heat-treatment temperature was more than 1420°C, porosity began to increase, bending strength began to decrease, which were the symbols of over-burning, while the main crystal phase didn’t change.

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.

Effect of LaCl3 on the Properties of LAS Ceramics

2009 ◽  
Vol 66 ◽  
pp. 112-114
Author(s):  
Yong Li ◽  
Xiao Li Zhang ◽  
Ling Li ◽  
Hong Sheng Wang ◽  
Hong Yi Jiang
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Sol Gel ◽  
Aluminum Silicate ◽  
Lithium Aluminum ◽  
Gel Method ◽  
Sol Gel Method

In this research, different amounts of LaCl3 were added to the lithium aluminum silicate (LAS) ceramics and the sample powder was prepared by sol-gel method. The effect of LaCl3 on the density, bending strength and the thermal expansion of the obtained ceramics was mainly investigated because LaCl3 is heavier than the lithium aluminum silicate (LAS) ceramics and the superfluous of La2O3 can be introduced into the sol solution.

Low-Temperature Preparation of Porous Cordierite-Mullite Ceramics Using Rice Husk as Silica Source and Pore-Forming Agent

2012 ◽  
Vol 217-219 ◽  
pp. 86-90
Author(s):  
Wei Guo ◽  
Hong Bin Lu ◽  
Chun Xia Feng ◽  
Jian Sun ◽  
Hai Feng Sun ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Bending Strength ◽  
Mullite Ceramic ◽  
Silica Source ◽  
Low Thermal Expansion ◽  
Low Temperature Preparation ◽  
Sintering Properties ◽  
Mullite Ceramics

Si and C of rice rusk were used as silica source and pore-forming agent to prepare cordierite-mullite ceramics at 1380°C for 5 h soaking. The Nd2O3 additive was added to improve the sintering properties. The bending strength, porosity, and thermal expansion coefficient were measured. The composition was characterized by X-ray diffraction (XRD). The microstructures of the sintered samples were observed by scanning electron microscopy (SEM). The cordierite-mullite ceramic doped with 2% Nd2O3 have high prorosity and low thermal expansion coefficient, its bending strength reaches 20.55 MPa. The addition of Nd2O3 decreases the mullite formation temperature to 1200 °C

Sintering Properties of Apatite-Type Lanthanum Silicate Electrolytes

2015 ◽  
Vol 814 ◽  
pp. 65-70 ◽  
Author(s):  
Qing Le Shi ◽  
Hua Zhang ◽  
Tian Jing Li ◽  
Fang Li Yu ◽  
Hai Jun Hou ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Plasma Sintering ◽  
Sol Gel Process ◽  
Spark Plasma ◽  
One Step ◽  
Sintering Properties ◽  
Lanthanum Silicate ◽  
Apatite Type

The sintering properties of appetite-type lanthanum silicate La10Si6O27prepared by sol-gel process were studied. The precursor powder was sintered by one-step sintering (OSS) process, two-step sintering (TSS) process and spark-plasma sintering (SPS) process. The phase structure, microstructure, relative density, thermal expansion properties, electrochemical properties of the samples were investigated by means of the techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes method, dilatometer, and AC impedance spectroscopy. The experimental results show that the samples sintered by SPS process can decrease the sintering temperature, shorten the sintering time, increase the density, and reduce the particle size. The appetite-type lanthanum silicate La10Si6O27 sintered by SPS process shows better sintering properties than of sintered by OSS process and TSS process, which can beneficial to the thermal expansion properties and conductivity.

scholarly journals Phase Transition and Coefficients of Thermal Expansion in Al2−xInxW3O12 (0.2 ≤ x ≤ 1)

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4021
Author(s):  
Andrés Esteban Cerón Cerón Cortés ◽  
Anja Dosen ◽  
Victoria L. Blair ◽  
Michel B. Johnson ◽  
Mary Anne White ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Thermal Shock ◽  
Monoclinic Phase ◽  
Ceramic Materials ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Co Precipitation

Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties.

scholarly journals Spray‐dried sol‐gel glass‐ceramic powders based on the tunable thermal expansion of quartz and keatite solid solutions

2021 ◽  
Author(s):  
Alessio Zandona ◽  
Gundula Helsch ◽  
Aurina Martínez Arias ◽  
Alfred P. Weber ◽  
Joachim Deubener
Keyword(s):  
Thermal Expansion ◽  
Solid Solutions ◽  
Glass Ceramic ◽  
Sol Gel ◽  
Ceramic Powders ◽  
Spray Dried

Mechanical and thermal expansion properties of β-eucryptite prepared by sol–gel methods and hot pressing

2011 ◽  
Vol 32 (5) ◽  
pp. 2526-2531 ◽  
Author(s):  
L. Xia ◽  
G.W. Wen ◽  
C.L. Qin ◽  
X.Y. Wang ◽  
L. Song
Keyword(s):  
Thermal Expansion ◽  
Hot Pressing ◽  
Sol Gel

Novel Infrared Stealth Properties of Cotton Fabric with ZnO: (Al, In) Coating

2014 ◽  
Vol 936 ◽  
pp. 1031-1034 ◽  
Author(s):  
Xi Li Yu ◽  
Lin Ping Zhang ◽  
Yi Zhong ◽  
Hong Xu ◽  
Zhi Ping Mao
Keyword(s):  
Thin Film ◽  
Crystalline Phase ◽  
Sol Gel ◽  
Infrared Emission ◽  
Cotton Fabrics ◽  
Dual Band ◽  
Infrared Emissivity ◽  
Measuring Instrument ◽  
Coated Fabric ◽  
Doped Zno

In this paper, we report a study on the infrared stealth properties of cotton fabrics with ZnO: (Al,In) coating. Al, In doped ZnO samples were prepared through sol-gel method. The crystalline phase of the ZnO: (Al, In) solids were determined by XRD. IR-2 Dual-Band Infrared Emissivity Measuring Instrument was used to test the infrared emissivity of the coated fabric. Infrared stealth effect of ZnO: (Al, In) coated fabric was measured using thermal infrared photospectrometry instrument. It was found that the ZnO: (Al, In) thin film has a low infrared emission in the range of 8 ~ 14μm wavelengths, and the addition of Al and In leaded to a better infrared stealth effect.

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