temperature is too low the reaction will progress too slowly to be of practical value when the reaction temperature is too high vaporization of the white carbon may occur preferably the reaction time is 1 5 hours at 1550 u00b0 c and 8 hours at 1300 u00b0 c however longer or shorter reaction times may be used silicon carbide powder obtained by this reaction may be heated in an oxidizing atmosphere for instance air to remove the carbon adhered on the surface of the silicon carbide powder temperatures from about 600 u00b0 to 1000 u00b0 c are suitable having generally described this invention a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified the results of examples 1 and 2 are tabulated in the table following example 2 1 wet process white carbon raw material vitasil 550 manufactured by taki chemical company of japan mean particle size of 0 025 micron and a surface area of 250 to 300 m 2 g 4 boat volume to be filled with white carbon and carbon powder 20 cc 9 additional heating condition to remove adhered carbon 700 u00b0 c for 3 hours in air 1 wet process white carbon raw material vitasil 1500 manufactured by taki chemical company of japan mean particle size of 0 018 micron and a surface area of 180 to 230 m 2 g table 1______________________________________phases detected by x ray chemicaldeffraction analysis analysisexample u03b2 sic si sio sub 2 si sub 3 n sub 4 o______________________________________1 99 wt nd 1 wt nd 1 0 wt 2 98 wt nd 2 wt nd 1 6 wt.