Combustion synthesis of well‐dispersed rod‐like β‐Si3N4 crystals by the addition of carbon

Abstract The well‐dispersed rod‐like β‐Si 3 N 4 crystals have been prepared by combustion synthesis with the addition of carbon. The added carbon helps to separate Si particles and remove the SiO 2 oxide layer, and thus reduces the agglomeration of β‐Si 3 N 4 crystals. By adding carbon, the reaction temperature and the width of β‐Si 3 N 4 crystals are decreased, but the aspect ratio of β‐Si 3 N 4 crystals is increased. The well‐dispersed β‐Si 3 N 4 crystals with an average width of 0.84 μm 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.