A survey on spark plasma sinterability of CNT-added TiC ceramics

The objective of this study was to assess the impacts of carbon nanotubes (CNTs) incorporation on the mechanical characteristics, thermal conductivity, microstructure, and sintering behavior of titanium carbide (TiC) matrix ceramics. To this aim, two samples of TiC-CNTs and monolithic TiC were produced using the SPS process at 1900 °C. The results indicated the obvious deposition of carbon from the crystalline lattice of TiC in the undoped sample; however, the addition of CNTs hindered this phenomenon remarkably. Moreover, in the carbon-doped sample, the areas where CNTs were agglomerated provided suitable places for limited precipitation of carbon from TiC. As a result, no graphite flake was observed in the microstructure of the CNT-doped specimen. Additionally, the amount of residual amorphous TiO₂ in the final microstructure of carbon-doped ceramic was significantly declined by introducing CNTs to TiC. The thermal conductivity of 13.9 W/mK, the flexural strength of 413 MPa, and the hardness of 3016 HV_{0.1 kg} were obtained for the TiC-CNTs ceramic, which all of them were lower than those obtained for the monolithic TiC.