coil 2 and the surface of the nucleating silicon carbide crystals is heated at 1600 to 2300 u00b0 c along with the carrier gas argon gas the following raw materials used as the superfine silicon dioxide particles and superfine carbon particles were supplied to the crucible under the following conditions along with the silicon dioxide particles and superfine carbon particles a certain amount of silicon powder for preventing carbonization was simultaneously added by a feeding device not shown in the drawing while the superfine particles were supplied the nucleating crystals were rotated on a horizontal plane by the nucleating silicon carbide crystal storing bar 3 as a result growth of the nucleating silicon carbide crystals having a thickness of more than 250 u03bcm was observed on the surface of the nucleating silicon carbide crystals aerosil 380 nippon aerosil co ltd average diameter of primary particles 7 nm bet specific surface area 380 m 2 g superfine carbon c particles carbon black ma600 mitsubishi kagaku co ltd average diameter of primary particles 18 nm specific surface area by a nitrogen absorption method 140 m 2 g the fine silicon dioxide particles and fine carbon particles described above had been dried in the air at 200 u00b0 c for 3.