Preparation and characterization of carbon nanotube reinforced silicon nitride composites

Multiwall carbon nanotube (MWNT) reinforced silicon nitride ceramics matrix composites have been prepared. The hot isostatic press (HIP)-sintering method was used for composite processing. Bending strength and elastic modulus of MWNT-silicon nitride composites showed a considerable improvement compared to matrices with added carbon fiber, carbon black or graphite. However, the silicon nitride samples without any carbon addition, because of higher densities present an even higher value. In the case of carbon fibers addition, a deterioration during sintering has been observed. The increasing pressure and sintering time resulted in carbon nanotube free structures.