Abstract: A method of making a perforated silicon carbide product in a shorter time and with less labor work to achieve a lower cost and high yield. Openings 13a, 13b are previously formed in a mold 11, and inserts 14 are inserted into the openings to project toward the inside of the mold. A slurry 15 composed of a mixture of a silicon carbide powder, an organic binder and water is put in the mold to conduct a slip casting molding method whereby a molded green product with perforation 16 is obtained.

Abstract: High purity silicon carbide parts for a heat treating apparatuses for semiconductors; composed mainly of .alpha.-type silicon carbide and silicon; characterized in that a particle sizes of the .alpha.-type silicon carbide crystals composing the high purity silicon carbide parts are not larger than 44 .mu.m; a weight mean particle size of the .alpha.-type silicon carbide crystals is in a range from 2 to 25 .mu.m; high purity silicon is filled up among the particles of the .alpha.-type silicon carbide crystals; and a content of iron as an impurity element contained in the high purity silicon carbide parts is not larger than 5 ppm.