Morphological and technological characteristics of silicon nitride powder prepared by self-propagating high-temperature synthesis

Silicon nitride produced by self-propagating high-temperature synthesis is ground in planetary and ball mills successively in both devices. The size distribution of particles, specific surface, shape factor, structure, and bulk density are evaluated. The behavior of powder pelletized with synthetic rubber under compaction and sintering in a nitrogen atmosphere in a charge containing magnesium oxide is studied. Powder after ball milling appears to be the most technologically efficient. Empirical equations are obtained which connect bulk density and shrinkage during sintering of powders with their morphological characteristics. The increase in density during compaction governed by the physicomechanical properties of silicon nitride powder and the plastifier is similar for all of the powders tested.Translated from Poroshkovaya Metallurgiya, No. 11(359), pp. 16–21, November, 1992.