Studies on the Formation of Silicon Nitride and Silicon Carbide from Rice Husk

Rice husk is a potentially useful source material for the production of silicon nitride, silicon carbide or a mixture of both. Pyrolysis of rice husk yields an intimate and homogeneous mixture of carbon and silica which is highly desirable for a good carbonitrothermic or carbothermic reduction process. The formation of Si 3 N 4 occurs on heating the pyrolysed rice husk to 1400°C under nitrogen flow and SiC forms in the presence of excess carbon at temperatures above 1450°C. SEM and XRD results show that the morphology of the nitride product is influenced by the reaction temperature and the presence of additives.