Nitrogen-doped-CNTs/Si3N4 nanocomposites with high electrical conductivity

Novel highly electrically conducting nanocomposites consisting of a silicon nitride (Si3N4) ceramic matrix containing up to 13.6 vol.% of nitrogen-doped multi-walled carbon nanotubes (CNx) were fabricated. As-synthesized CNx were treated with hydrogen peroxide in order to efficiently detach/isolate the nanotubes from bundles, then they were mixed with the ceramic powders and fully densified using the spark plasma sintering (SPS) technique. Composites containing 13.6 vol.% CNx reached an electrical conductivity of 2174 S m−1 that is the highest value reported hitherto for carbon nanotubes/Si3N4 nanocomposites. The nitrogen doping also favored a strong mechanical interlocking between the nanotubes and the Si3N4 matrix; when compared to the undoped carbon nanotubes. These novel nanocomposites could be used in devices associated to power generation or telecommunications.