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. SiO//2 from magadiite was reduced above 1400 degree C without the formation of any crystalline oxides. On heating above 1400 degree C, both alpha - and beta -Si//3N//4 were detected, and the additional formation of alpha - and beta -SiC was observed by heating at 1600 degree C. On the other hand, the reactions for the synthesis from a magadiite-carbon mixture involved the formation of cristobalite as well as alpha - and beta -Si//3N//4, and beta -SiC. In addition, it was also indicated that the mixture was less reactive for the formation of Si//3N//4.