Cordierite ceramic
AssigneeNGK Insulators, Ltd.
InventorsTadaaki Matsuhisa, Shigeo Soejima
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Abstract
Cordierite ceramic consisting mainly of cordierite in crystal phase after fired and having a mean pore size of 2-50 microns and a thermal expansion coefficient of not more than 16.times.10.sup.-7 (1/.degree. C.) over the range of 25-1000.degree. C. and being produced by starting from a batch including a magnesia raw material with an average particle size of 5-150 microns.
Claims5
A process for the preparation of cordierite ceramic consisting mainly of cordierite in crystal phase after fired, and having a mean pore size of 2-50 microns and a thermal expansion coefficient of not more than 16.times.10.sup.-7 (1/.degree.C.) in the range of 25.degree.-1000.degree. C., characterized in that a starting material having a chemical composition consisting of 42-52% by weight of silica, 34-48% by weight of alumina and 10-18% by weight of magnesia, in which an average particle size of magnesia starting material is 5-150 microns, is fired by raising temperature at a rate of 30.degree.-300.degree. C./hr in the temperatures above 1100.degree. to control formation of a liquid phase appearing during firing and then keeping a peak temperature for sufficient time to attain crystallization of cordierite from the liquid phase.
Dependencies are inferred from the claim text.