Microstructure–property correlation in nano-diamond and TiN added TiC-based ceramics

In this paper, the effect of TiN and nano-diamond additives on the microstructure and properties of TiC-based composites, produced by spark plasma sintering method, was investigated. The thermal conductivity of TiC ceramic was improved significantly due to the incorporation of nano-diamond additive. Although the introduction of diamond worsened the sintering behavior of the sintered TiC ceramic, it enhanced the formation of continuous network of the graphitized diamond at the grain boundaries. However, the addition of TiN to the TiC-diamond sample led to the formation of nitrogen gas at high temperatures, resulting in a semi-porous ceramic containing ~13% porosity. Furthermore, the unreacted TiN was dissolved in the matrix, creating a solid solution of Ti(C,N). Despite the beneficial influence of nano-diamond on the thermal conductivity of TiC, the incorporation of TiN and nano-diamond in TiC ceramics decreased the flexural strength and hardness.