Nanostructured TiC–TiB2 composites obtained by adding carbon nanotubes into the self-propagating high-temperature synthesis process

The synthesis of nanostructured TiC–TiB2 by self-propagating high-temperature synthesis (SHS) has been investigated by using carbon nanotubes as precursor materials in partial substitution of graphite according to the following reaction: 6Ti + B4C + (3−x)C + x CNT → 4TiC + 2TiB2.Different amounts of CNTs addition have been studied in order to achieve structural refinement of the SHS products. The CNT molar content was varied in order to define the optimal composition, which allows to obtain nanostructured TiC–TiB2 powders morphologically homogenous.The optimized composition has been chosen for the further densification step. The Pressure Assisted Fast Electric Sintering (PAFES) technique gave bulk composites with ultrafine grained microstructure. The mechanical characterization showed very high hardness and good fracture toughness values if compared to literature data.

The synthesis of nanostructured TiC–TiB2 by self-propagating high-temperature synthesis (SHS) has been investigated by using carbon nanotubes as precursor materials. Different amounts of CNTs addition have been studied in order to achieve structural refinement of the TiC and TiB2 phases. The densified composites showed ultrafine grained microstructure, very high hardness and good fracture toughness values.Figure optionsDownload as PowerPoint slideHighlights
► We investigated the effect of the CNT in the SHS synthesis of TiC–TiB2 powders.
► We tested different substitution of graphite with CNT.
► The optimal CNT amount was proved to refine the TiC and TiB2 phases.
► We densified the optimized powder through an ECAS technique.
► The bulk TiC–TiB2 composite showed very high hardness and good fracture toughness.