Abstract
The effects of adding a small amount of Si3N4 less than 0.1mass% as seed crystals on the particle size and the α-content in resulting Si3N4 powders were investigated. A small quantity of only 0.02mass% seed increased the α-content to more than 90%. This seems to be due to the high partial pressure of gaseous SiO evolved by reduction of SiO2. The particle sizes of the products decreased as the amount of seed increased. Finer particles were obtained when a kind of seed powder produced through pulverization process was used, which can be ascribed to significantly finer particles in the seed. With addition of less than 0.1mass% seed, the relation between the number of seed (N) and the resultant particle size (D) was confirmed to obey the equation, D=k(1/N)1/3, where k is a constant.
