Ceramic porous body and method for preparing the same

摘要

A ceramic porous body for a filter or a catalyst carrier, having a structure in which voids each having the same volume as that of a sphere of 10 mu m to 500 mu m in diameter are formed and the voids are communicated with each other through smaller fine pores, the ceramic porous body having a volume fraction of the voids and the fine pores of from 15% to 60% and being formed of components 70% or higher by volume of which is silicon nitride. The ceramic porous body is prepared by mixing coarse silicon nitride powder with fine silicon nitride powder(s) at a mixing ratio by volume of the fine silicon nitride powder to the combined volume of the fine and coarse silicon nitride powders in the range of +E,fra 1/99+EE to +E,fra 1/2+EE ; adding one or more compounds of the group IIa elements, the group IIIa elements, transition metals, Al and Si in a range of 1% to 30% by volume as their oxides to the silicon nitride powder mixture; molding the resultant powder mixture; and sintering the molded body in a non-oxidizing atmosphere of at least 0.9 atm at a temperature ranging from 1100 DEG C. to 2000 DEG C.