DEVELOPMENT OF SI2N2O, SI3N4 AND SIC CERAMIC MATERIALS USING RICE HUSK

The presence of silicon in rice husk has been established by its chemi cal and thermal degradation. The bonding between Si and C have been st udied by IR spectroscopy. The existence of IR peak at similar to 800 c m(-1) shows SI-C bonding in raw rice husk, which is shifted to 790 cm( -1) during coking and pyrolysis. ESCA study of surface showed Si, C, O and F to be present; Si in the form of SICx and SiOx and C as SiCx an d CHx. On sputtering, the SiOx and CHx species decrease with increase of SiCx level. The formation of SiC from coked rice husk and Si3N4 and Si2N2O from HCl treated rice husk has been observed at 1200-1400 degr ees C under N-2 and NH3 atmosphere, respectively. The chemical analysi s of raw rice husk and products are tabulated. The XRD analyses shows the presence of different phases in the products. A new mechanism for the development of these ceramic materials has been proposed.