Method of making porous silicon carbide bodies

Porous silicon carbide bodies are obtained by starting with a powder of particle size falling within a single sieve mesh range fraction and consisting either entirely of carbon particles or a mixture of carbon and silicon carbide particles of the same mesh fraction is mixed or coated with 15 to 30% by weight of a binder, moulded to shape, warmed in the temperature range from 40 DEG to 200 DEG C. to vaporize volatile material and then coked at a temperature rising to 850 DEG C. Then it is siliconized by raising the temperature to the range from 1650 DEG to 1950 DEG C. with gaseous silicon or impregnated with silicon by dipping the body into a silicon melt and convert it to carbide, with the excess silicon thereafter being removed by vaporizing out or by boiling in lye. Sieve mesh fractions in the region of a few hundred mu m are preferred, and the density of the porous body after pressing but before siliconizing should lie in the neighborhood of 0.6 to 0.7 g/cm3.