Examination of carbon nanotube reinforced silicon nitride composites

Carbon nanotubes have been found to posses superior mechanical, thermal, and electrical properties, therefore, there are high expectations concerning the improvement of quality of carbon nanotube reinforced micro and nanocomposites. In the use of nanotubes to form advanced composites a critical issue was identified that would be further clarified, namely the interfacial bonding of the nanotubes to different matrices. Addressing to this critical issue, in this work an attempt has been made to improve the properties of silicon nitride matrix with the help of multiwall carbon nanotube (MWNT) addition. Carbon black, graphite, and carbon fiber added samples were also prepared. Bending strength and elastic modulus of MWNT-silicon nitride composites gave better values than matrices with added carbon fiber, carbon black, or graphite. The silicon nitride samples without any carbon addition, however, presented an even higher value due to their higher densities. At higher pressure and longer sintering time the complete depart of carbon nanotubes have been observed.