Role of TiCN addition on the characteristics of reactive spark plasma sintered ZrB2-based novel composites

Abstract The present investigation was carried out to illustrate the effect of TiCN on the microstructure development of spark plasma sintered fully dense ZrB2-based ceramics. The microstructural observations, X-ray diffraction patterns, and field emission-electron probe microanalysis revealed the presence of the (Zr,Ti)B2 and ZrCN phases in the final microstructures of the prepared composites. The advancement of a chemical reaction between TiCN and ZrB2 was suggested over the sintering process through the ZrCN and TiB2 phases formation. Although the ZrCN compound was stable during the sintering process, the generated TiB2 was dissolved into the ZrB2 matrix, forming a (Zr,Ti)B2 solid solution. The composition of this solid solution was roughly uniform in the ternary samples, thanks to the role of SiC in grain-refining, contrary to the ZrB2-TiCN composite with a heterogenous composition. Ultimately, the Vickers hardness and elastic modulus of the (Zr,Ti)B2 matrix in the ternary system were measured to be 29.3 GPa and 450.8 GPa, respectively.