On the reactive spark plasma sinterability of ZrB2-SiC-TiN composite

In the present research, the influence of TiN addition on the ZrB2-SiC composite was studied. Hereof, TiN-doped ZrB2-SiC composite was manufactured via the route of reactive spark plasma sintering under an applied load of 40 MPa at the peak temperature of 1850 degrees C for 360 s. Mechanical properties, microstructure evaluation, and sinterability were investigated and compared to the non-doped ZrB2-SiC. X-ray diffraction analysis, thermodynamic appraisal, energy dispersive spectroscopy, and scanning electron microscopy di-vulged the formation of in-situ h-BN, ZrO2, and ZrN as well as the (Zr,Ti)B-2 solid solution in TiN-doped ZrB2-SiC. Comparing the relative density of 95% for the TiN-free sample with the relative density of 94.1% for the sample containing TiN, the addition of TiN increased porosity content owing to the formation of in-situ BN with layered structure. Flexural strength decreased from 460.2 MPa for TiN-free ZrB2-SiC to 435.9 MPa for TiN-doped ZrB2-SiC, due to matrix grain growth and relative density drop. In contrast, in-dentation fracture toughness and Vickers hardness increased to 6.1 MPa.m(1/2) and 29.1 GPa, respectively, as the result of TiN addition. (c) 2022 Elsevier B.V. All rights reserved.