Fabrication of Hot Pressed C/Si3N4 Nanocomposites

Silicon nitride based nanocomposites have been manufactured by carbon black addition. Hot pressing sintering method has been applied for composite processing. A low (20 bar) and a high (400 bar) uniaxial pressure have been used. The amount of carbon black introduced in silicon nitride matrix increased the porosity and influenced the bending strength, elastic modulus and hardness of composites. The microstructure of fully dense and porous samples consisted mainly of alpha and beta silicon nitride grains. Inclusions of silicon carbide have been formed by applying a low uniaxial pressure. The silicon carbide phase was not observed at higher uniaxial pressure.