Robust and wear resistant in-situ carbon nanotube/Si3N4 nanocomposites with a high loading of nanotubes

Highly homogenous carbon nanotube (CNT)/silicon nitride (Si3N4) nanocomposites with high CNTs loadings, up to 22 vol.%, are developed through the in-situ synthesis of CNTs on the ceramic powders, and further densification using the spark plasma sintering technique. The CNTs dispersion degree, the composite density, and their properties, especially the tribological ones, are evaluated and compared with those obtained for nanocomposites processed by the ex-situ method based on the mixing of nanotubes and ceramic powders in a solvent media. Fully dense in-situ 12 vol.% CNTs nanocomposites are 87% and 65% more wear resistant than monolithic Si3N4 materials and ex-situ nanocomposites, respectively, in the latter case due to the higher nanotubes dispersion and better mechanical properties attained by the in-situ process. These new in-situ CNTs nanocomposites present multifunctionality and are promising for emerging applications, especially for gasoline direct injection systems.