Volume 88, Issue 12 p. 3311-3315

Processing of Microcellular Mullite

Young-Wook Kim

Corresponding Author

Young-Wook Kim

Department of Materials Science and Engineering, the University of Seoul, Seoul 130-743, Korea

*Member, American Ceramic Society.

Author to whom correspondence should be addressed. e-mail: [email protected]Search for more papers by this author
Hai-Doo Kim

Hai-Doo Kim

Ceramic Materials Group, Korea Institute of Machinery and Materials, Changwon, Gyeongnam 641-010, Korea

*Member, American Ceramic Society.

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Chul B. Park

Chul B. Park

Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada M5S 3G8

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First published: 19 August 2005
Citations: 50

R. Bordia—contributing editor

Supported by the Center for Advanced Materials Processing (21C Frontier R&D Program of the Ministry of Commerce, Industry, and Energy, Republic of Korea) under Grant No. PM002-4-00-01.

Abstract

A new processing route for manufacturing partially interconnected open-cell, microcellular mullite ceramics has been developed. The strategy adopted for making microcellular mullite ceramics entailed the following steps: (i) fabricating a formed body from combining polysiloxane, Al2O3 (a reactive filler), polymer microbeads (used as sacrificial templates), and Y2O3 (a sintering additive); (ii) cross-linking the polysiloxane in the formed body; (iii) transforming the polysiloxane by pyrolysis into SiO2; and (iv) synthesizing mullite by reacting SiO2 and Al2O3. By controlling the sintering temperature and the microbead and additive contents, it was possible to adjust the porosity so that it ranged from 38% to 85%.

The compressive strengths of the microcellular ceramics with ∼40% and ∼70% porosities were ∼90 and ∼10 MPa, respectively. The superior compressive strengths were attributed to the homogeneous distribution of small (≤20 μm), spherical cells with dense struts in the microcellular ceramics.