The Microstructure and thermal diffusivity of carbon nanostructures/Si3N4 composites processed using spark plasma sintering

Graphene nanoribbons (GNRs) were obtained by unzipping multiwall carbon nanotubes (MWCNTs). Three different silicon nitride-carbon nanostructures were prepared by spark plasma sintering (SPS): ceramic composites that contained 1 wt% carbon nanofibers (CNFs), 1 wt% MWCNTs and 1 wt% GNRs respectively. The α to β-Si3N4 transformation ratio and thermal diffusivity of GNR/Si3N4 composites were higher than both CNF/Si3N4 composites and MWCNT/Si3N4 composites. Furthermore, the higher thermal diffusivities of GNR/Si3N4 composites can primarily be attributed to the higher number of elongate β-Si3N4 grains.