Reaction Bonded Si3n4 From Si-Polysilazane Mixture

Reaction-bonded Si3N4 has cost-reduction merit because inexpensive silicon powder was used as a start material. But its density was not so high enough to be used for structural materials. So the sintered reaction-bonded Si3N4 techniques were developed to solve the low density problem. In this study the sintered reaction-bonded Si3N4 manufacturing method by using polymer precursor which recently attained significant interest owing to the good shaping and processing ability was proposed. The formations, properties of reaction-bonded Si3N4 from silicon and polysilazane mixture were investigated. High density reaction-bonded Si3N4 was manufactured from silicon and silicon-containing preceramic polymers and post-sintering technique. The mixtures of silicon powder and polysilazane were prepared and reaction sintered in N-2 atmosphere at 1350 degrees C and post-sintered at 1600-1950 degrees C. Density and phase were analyzed and correlated to the resulting material properties.