Novel design of elongated mullite reinforced highly porous alumina ceramics using carbonized rice husk as pore-forming agent

Micromechanical calculations and elasticity standard relations are used to predict the elastic properties of porous alumina, zirconia and kaolin-based ceramics, as well as the high-temperature Young moduli of alumina-zirconia and alumina-mullite composites. The predictions are compared with experimental results obtained via impulse excitation. It is found that the Young moduli of highly porous (cellular) alumina ceramics can be predicted via the Gibson-Ashby power-law relation, whereas for partially sintered kaolin-based ceramics our exponential relation, albeit better than the Gibson-Ashby relation, does not give a satisfactory prediction. However, once the Young moduli are known, the shear and bulk moduli can be reliably predicted in both cases, based on rough information on the Poisson ratio. The temperature dependence of the Youngs moduli of two-phase composites can be quite precisely predicted as soon as the master curves of the constituent phases and the type of porosity (convex, concave, or saddle-point) are known.

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Effect of starch addition on microstructure and properties of highly porous alumina ceramics

Ceramics International ◽

10.1016/j.ceramint.2013.04.072 ◽

2013 ◽

Vol 39 (8) ◽

pp. 8833-8839 ◽

Cited By ~ 72

Author(s):

Sa Li ◽

Chang-An Wang ◽

Jun Zhou

Keyword(s):

Porous Alumina ◽

Alumina Ceramics ◽

Microstructure And Properties ◽

Highly Porous

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Preparation of Porous Alumina Ceramics by Spark Plasma Sintering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1056 ◽

2007 ◽

Vol 336-338 ◽

pp. 1056-1059

Author(s):

Won Seung Cho ◽

Yeon Chul Yoo ◽

Chin Myung Whang ◽

Nam Hee Cho ◽

Woon Suk Hwang ◽

...

Keyword(s):

Spark Plasma Sintering ◽

Rapid Heating ◽

Porous Alumina ◽

High Porosity ◽

Alumina Ceramics ◽

Porous Bodies ◽

Plasma Sintering ◽

Conventional Sintering ◽

Spark Plasma ◽

Highly Porous

Porous alumina bodies were successfully prepared by spark plasma sintering of alumina powders with different amounts of graphite, and by subsequently burning out the graphite. Highly porous bodies were fabricated by spark plasma sintering at 1000°C for 3 min under a pressure of 30 MPa. The heating rate was 80°C/min, and the pulse pattern (on-off) was 12:2. For example, alumina bodies prepared by the addition of 10 ~ 30 vol% graphite showed high porosity of 50 ~ 57%. Porous alumina bodies prepared by the addition of 10 ~ 30 vol% graphite had a high compressive strength of 200 ± 55 MPa, about 35 times higher than those obtained on samples prepared by pressureless sintering, and about 2.5 times higher than those in samples prepared by hot-pressing. The significant improvement in strength relative to values obtained with conventional sintering was attributed to better sintering resulting from the rapid heating between particles.

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Fabrication and Biological Properties of Bionic Structure Porous Alumina Ceramics with Spherical/Lamellar Pores

Materials Science Forum ◽

10.4028/www.scientific.net/msf.815.367 ◽

2015 ◽

Vol 815 ◽

pp. 367-372 ◽

Cited By ~ 4

Author(s):

Yu Fei Tang ◽

Qian Miao ◽

Ying Liu ◽

Zi Xiang Wu ◽

Wei Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Porous Alumina ◽

Porous Ceramic ◽

Biological Properties ◽

Alumina Ceramics ◽

Pore Connectivity ◽

Bionic Structure ◽

Pass Through ◽

Fabrication Parameters ◽

Highly Porous

In order to solve the problem that low pore connectivity of the spherical porous ceramic, bionic structure porous alumina ceramics with spherical/lamellar pores were fabricated combining the adding pore-forming agent and two step freeze casting. The effects of fabrication parameters of the samples on morphologies, porosity and pore connectivity are investigated. The mechanical and biological properties of bionic structure porous alumina ceramics are also characterized. Results show that porous alumina ceramics with spherical/lamellar pores are obtained, and the lamellar pores pass through the spherical pores, which prove the pore connectivity reach 86.2 %. The mechanical properties are improved by porosity gradient from the inside (highly porous) to the outside (less porous) of porous alumina. Bionic structure porous alumina ceramics with spherical/lamellar pores have better cell growth and absorbance than those with spherical or lamellar pores only since its high pore connectivity.

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