Thermal conductivity of highly porous mullite material

authors	Barea, R; Osendi, MI; Ferreira, JMF; Miranzo, P
nationality	International
journal	ACTA MATERIALIA
author keywords	thermal conductivity; porous material; mullite; modelling
keywords	CERAMICS; FABRICATION
abstract	The thermal diffusivity of highly porous mullite materials (35-60 vol.% porosity) has been measured up to 1000 degrees C by the laser flash method. These materials were fabricated by a direct consolidation method based on the swelling properties of starch granules in concentrated aqueous suspensions and showed mainly spherical shaped pores of about 30 pin in diameter. From the point of view of heat conduction, they behave as a bi-phase material of voids dispersed in the continuous mullite matrix. The temperature dependence of thermal conductivity for the different porosities was modeled by a simple equation that considers the contribution to heat conduction of the mullite matrix and the gas inside the pores, as well as the radiation. The thermal conductivity of the matrix was taken from the measurements done in a dense mullite while the conductivity in the voids was assumed to be that of the testing atmosphere. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
publisher	PERGAMON-ELSEVIER SCIENCE LTD
issn	1359-6454
year published	2005
volume	53
issue	11
beginning page	3313
ending page	3318
digital object identifier (doi)	10.1016/j.actamat.2005.03.040
web of science category	Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering
subject category	Materials Science; Metallurgy & Metallurgical Engineering
unique article identifier	WOS:000229791100019