scholarly journals Effect of Al(OH)3 content on the microstructure and strength of porous cordierite-mullite ceramics prepared by an in-situ pore forming technique

2018 ◽  
Vol 50 (2) ◽  
pp. 205-215 ◽  
Author(s):  
Qingjie Chen ◽  
Wen Yan ◽  
Nan Li ◽  
Xiaoli Lin ◽  
Zhenyan Zhang ◽  
...  
Keyword(s):  
Phase Composition ◽  
Pore Size ◽  
Size Distribution ◽  
Porous Ceramics ◽  
X Ray ◽  
Neck Size ◽  
Median Pore ◽  
Porous Cordierite ◽  
Mullite Ceramics

Five porous cordierite-mullite ceramics with similar porosity and different neck characteristics were prepared from Al(OH)3, magnesite, silica and clay using an in-situ pore-forming technique. The phase composition, pore and neck characteristics and strength of the porous ceramics were investigated by an X-ray diffractometer (XRD), a scanning electron microscopy (SEM) and a microscopy measured method, etc. The experimental results showed that Al(OH)3 content had a significant effect on the pore size distribution and neck characteristics (neck size distribution, total value of neck size and phase composition) and then affecting the strength. With an increase in Al(OH)3 content, the median pore size decreased, the total length of necks and the uniformity of neck size increased, also the mullite content of necks increased, resulting in the increase of strength of the porous cordierite-mullite ceramics. When the Al(OH)3 content was 64.9 wt%, the porous cordierite-mullite ceramics had the best performance of high apparent porosity of 45.1 % and high compressive strength of 55.9 MPa.

scholarly journals Effect of particle size on the pore characterization and strength of porous cordierite-mullite ceramics prepared by a pore-forming in-situ technique

2013 ◽  
Vol 45 (2) ◽  
pp. 165-172 ◽  
Author(s):  
W. Yan ◽  
N. Li ◽  
J. Tong ◽  
G. Liu ◽  
J. Xu
Keyword(s):  
Particle Size ◽  
Pore Size ◽  
Average Particle ◽  
Pore Characterization ◽  
Effect Of Particle Size ◽  
Median Pore ◽  
Porous Cordierite ◽  
Mullite Ceramics ◽  
In Situ Technique

The porous cordierite-mullite ceramics were prepared by the pore-forming in-situ technique. The characterizations of porous cordierite-mullite ceramics were determined by an X-ray diffractometer (XRD), a scanning electron microscopy (SEM), and a microscopy measured method, etc., and the effect of particle size on phase composition, pore characterization and strength were investigated. It?s found that particle size affects strongly the formations of cordierite and mullite, and then changes the pore characterization and strength. With the decrease of the particle size, the sintering temperature at which the formations of cordierite and mullite take place extremely fast decreases, the pore size distribution becomes from bi-peak mode to mono-peak mode, the porosity and the median pore size decrease but strength increases. The most opposite mode is the specimen sintered at 1400 ?C from the grinded powder with an average particle size of 10.2 ?m, which consists of cordierite, mullite and minor spinel, and has a high apparent porosity (40 %), a high compressive strength (58.4 MPa), a small median pore size (6.3 ?m) and well-developed necks between particles.

scholarly journals Influences of composition of starting powders and sintering temperature on the pore size distribution of porous corundum-mullite ceramics

2005 ◽  
Vol 37 (3) ◽  
pp. 173-180 ◽  
Author(s):  
Li Shujing ◽  
Li Nan
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Volume Percentage ◽  
Air Atmosphere ◽  
In Situ Decomposition ◽  
Mullite Ceramics

Porous corundum-mullite ceramics were prepared by an in-situ decomposition pore-forming technique. Starting powders were mixtures of milled Al(OH)3 and microsilica and were formed into oblong samples with a length of 100mm and a square cross-section with edge size of 20mm. The samples were heated at 1300?C, 1400?C, 1500?C or 1600?C for 3h in air atmosphere, respectively. Apparent porosity was detected by Archimedes? Principle with water as a medium. Pore size distribution and the volume percentage of micropores were measured by mercury intrusion porosimetry. The results show that the pore morphology parameters in the samples depend on four factors: particle size distribution of starting powders, decomposition of Al(OH)3, the expansion caused by mullite and sintering. The optimum mode which has a higher apparent porosity up to 42.3%, well-distributed pores and more microsize pores up to 16.3% is sample No.3 and the most apposite sintering temperature of this sample is 1500?C.

Evolution of the Pore Size Distribution in Final-Stage Sintering of Alumina Measured by Small-Angle X-ray Scattering

1991 ◽  
Vol 74 (10) ◽  
pp. 2538-2546 ◽  
Author(s):  
Susan Krueger ◽  
Gabrielle G. Long ◽  
David R. Black ◽  
Dennis Minor ◽  
Pete R. Jemian ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Small Angle ◽  
Final Stage ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Synthesis of biomorphic SiC and SiO2 ceramics

2008 ◽  
Vol 73 (7) ◽  
pp. 745-751 ◽  
Author(s):  
Adela Egelja ◽  
Jelena Gulicovski ◽  
Aleksandar Devecerski ◽  
Biljana Babic ◽  
Miroslav Miljkovic ◽  
...  
Keyword(s):  
Porous Ceramics ◽  
X Ray Diffraction ◽  
Pressure Infiltration ◽  
X Ray ◽  
Carbon Template ◽  
Cellular Wall ◽  
Infiltration Technique ◽  
Coniferous Wood ◽  
Biomorphic Ceramics

Coniferous wood (fir) was transformed by pyrolysis into carbon preforms, which were subsequently converted into biomorphic ceramics by the pressure infiltration technique with colloidal silica. An in situ reaction between the silica and the carbon template occurred in the cellular wall at a high sintering temperature. Depending on the employed atmosphere, non-oxide (SiC) or oxide (SiO2) ceramics were obtained. The morphology of the resulting porous ceramics and their phase composition were investigated by scanning electron microscopy (SEM/EDX) and X-ray diffraction (XRD). The experimental results showed that the biomorphic cellular morphology of the wood maintained in both the SiC and silica ceramics, which consisted of only the b-SiC phase and SiO2, respectively. .

scholarly journals X-Ray Tomography Study on Porosity and Particle Size Distribution in In Situ Al-4.5Cu-5TiB2 Semisolid Rolled Composites

JOM ◽  
2019 ◽  
Vol 71 (11) ◽  
pp. 4050-4058 ◽  
Author(s):  
Swapnil Morankar ◽  
Monalisa Mandal ◽  
Nadia Kourra ◽  
Mark A. Williams ◽  
Rahul Mitra ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
X Ray

The Preparation of High-Strength and Micropore Lightweight Bauxite Aggregate by In Situ Polymerization and Decomposition

2011 ◽  
Vol 194-196 ◽  
pp. 2135-2139
Author(s):  
Yi Neng Fang ◽  
Hua Zhi Gu ◽  
Yun Sheng Fen ◽  
Lin Jun Wang ◽  
Yan Jing Li
Keyword(s):  
Phase Composition ◽  
Pore Size ◽  
Aluminium Hydroxide ◽  
Average Pore Size ◽  
High Strength ◽  
Organic Polymer ◽  
Low Grade ◽  
Pore Former ◽  
Average Pore

High-strength and micropore lightweight bauxite aggregate was fabricated by low grade raw bauxite powder, aluminium hydroxide powder and organic polymer (OP). OP was used as consolidator, binder and pore former and aluminium hydroxide was used as pore former. The influence of OP and aluminium hydroxide content on the property of the samples was studied. The phase composition and the microstructure of the sintered samples were characterized by XRD, SEM and the pore size distribution was measured by mercury porosimety. The results demonstrate that the bulk density of the samples decreases linearly and the apparent porosity of the samples increases gradually with the addition of OP. The lowest density reached 1.13g/cm3when adding 35% OP and 10% Al(OH)3. The average pore size is around 5μm, and increases with the addition of OP increased. The XRD showed the main phase of the sample is mullite and some little amount of corundum.

scholarly journals Optimization of the SiC Powder Source Material for Improved Process Conditions During PVT Growth of SiC Boules

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3272
Author(s):  
Ellefsen ◽  
Arzig ◽  
Steiner ◽  
Wellmann ◽  
Runde
Keyword(s):  
Crystal Growth ◽  
Size Distribution ◽  
Growth Conditions ◽  
Source Material ◽  
Process Time ◽  
Process Conditions ◽  
Powder Size ◽  
Growth Interface ◽  
X Ray

We have studied the influence of different SiC powder size distributions and the sublimation behavior during physical vapor transport growth of SiC in a 75 mm and 100 mm crystal processing configuration. The evolution of the source material as well as of the crystal growth interface was carried out using in situ 3D X-ray computed tomography (75 mm crystals) and in situ 2D X-ray visualization (100 mm crystals). Beside the SiC powder size distribution, the source materials differed in the maximum packaging density and thermal properties. In this latter case of the highest packaging density, the in situ X-ray studies revealed an improved growth interface stability that enabled a much longer crystal growth process. During process time, the sublimation-recrystallization behavior showed a much smoother morphology change and slower materials consumption, as well as a much more stable shape of the growth interface than in the cases of the less dense SiC source. By adapting the size distribution of the SiC source material we achieved to significantly enhance stable growth conditions.

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