SILICON CARBIDE-BASED HEAT-RESISTANT, ULTRA-LIGHTWEIGHT, POROUS STRUCTURAL MATERIAL AND PROCESS FOR PRODUCING THE SAME

The present invention provides a silicon carbide-based heat-resistant, ultra-lightweight, porous structural material having the same shape as that of a spongy porous body and also provides a process for readily producing the material. In the process of the present invention, slurry containing silicon powder and a resin is applied to the framework of the spongy porous body by an impregnation method in such a manner that interconnected pores of the porous body are not plugged with the slurry; the resulting porous body is carbonized at a temperature of 900 DEG C to 1320 DEG C in vacuum or in an inert atmosphere; the resulting porous body is subjected to reactive sintering at a temperature of 1320 DEG C or more in vacuum or in an inert atmosphere, whereby silicon carbide having high wettability to molten silicon is produced and open pores due to a volume reduction reaction are formed in one step; and molten silicon is infiltrated into the resulting porous body at a temperature of 1300 DEG C to 1800 DEG C in vacuum or in an inert atmosphere, whereby the silicon carbide-based heat-resistant, ultra-lightweight, porous structural material is produced.