Combustion Synthesis Of Well-Dispersed Rod-Like Beta-Si3n4 Crystals By The Addition Of Carbon

The well-dispersed rod-like beta-Si3N4 crystals have been prepared by combustion synthesis with the addition of carbon. The added carbon helps to separate Si particles and remove the SiO2 oxide layer, and thus reduces the agglomeration of beta-Si3N4 crystals. By adding carbon, the reaction temperature and the width of beta-Si3N4 crystals are decreased, but the aspect ratio of beta-Si3N4 crystals is increased. The well-dispersed beta-Si3N4 crystals with an average width of 0.84 mu m and aspect ratio of 2.3 are produced by adding 2 wt% carbon. When 5 wt% carbon is added, the reaction temperature is too low and the nitridation of Si becomes incomplete, and at the same time much SiC occurs in the product.