Si//3N//4 FORMATION IN THE CARBOTHERMAL REDUCTION PROCESS OF A MAGADIITE-POLYACRYLONITRILE INTERCALATION COMPOUND.

Silicon nitride was formed from a magadiite (layered polysilicate)-polyacrylonitrile (PAN) intercalation compound through a novel process of carbothermal reduction. SiO2 from magadiite was reduced above 1400°C without the formation of any crystalline oxides. On heating above 1400°C, both α-and β-Si3N4 were detected, and the additional formation of α-and β-SiC was observed by heating at 1600°C. On the other hand, the reactions for the synthesis from a magadiite-carbon mixture involved the formation of cristobalite as well as α-and β-Si3N4, and β-SiC. In addition, it was also indicated that the mixture was less reactive for the formation of Si3N4. These observations suggest that the reaction process of the magadiite-PAN complex was different from that of the magadiite-carbon mixture, and that the use of the intercalation compound was favorable for Si3N4 production.