CATALYTIC PROCESS FOR PRODUCING HIGH PURITY SILICON NITRIDE

SILICON NITRIDE IS A CERAMIC MATERIAL KNOWN FOR ITS HIGH TEMPERATURE STRENGTH, TOUGHNESS AND THERMAL SHOCK RESISTANCE. SILICON NITRIDE (SI3N4) POWDER IS COMMERCIALLY PRODUCED BY HIGH TEMPERATURE REACTIONS BETWEEN NITROGEN AND SILICON OR SILICA AND CARBON. THE OBJECTIVE OF THIS PROGRAM IS TO DEVELOP AN IMPROVED METHOD FOR PRODUCING HIGH PURITY, FINE GRAINED SILICON NITRIDE POWDER. VARIOUS TRANSITION METAL CATALYSTS WILL BE EVALUATED BY THERMOGRAVIMETRIC ANALYSIS FOR THEIR EFFECT ON REACTION KINETICS. THE REACTED SILICON POWDERS WILL BE EVALUATED FORCOMPOSITION, PARTICLE SIZE AND MORPHOLOGY. THE EXTENT OF CATALYST REMOVAL FROM THE SILICON NITRIDE BY CHEMICAL TECHNIQUES WILL BE DETERMINED. PRINCIPLE ADVANTAGES OF THE PROCESS WILL BE DECREASED ENERGYREQUIREMENTS AND PRODUCTION OF A FINER, MORE SINTERABLE POWDER. FINE SILICON NITRIDE WILL BE MORE EASILY CONSIDATEDINTO DENSE, FLAW FREE CERAMICS.