Reactive Hot Pressing of TiC0.5 Ceramic at Low Applied Pressure with 1 Wt% Ni Additive

Densification in non-stoichiometric TiC0.5 ceramic has been studied by reactive hot pressing (RHP) of Ti:0.5C composition at 4-40 MPa, 1200 degrees C for 60 min. Incomplete reaction and 94% relative density (RD) at a pressure of 4 MPa changed to 99% RD and a negligible amount of residual Ti at 40 MPa. In contrast, the addition of 1 wt% Ni in the starting Ti-0.5C powder mixture resulted in full density at a lower pressure of 4 MPa, leading to comparable hardness. It is argued that both, reaction as well as densification, were improved by the formation of transient Ti-Ni liquid phase. The enhanced RD and residual metallic phase in the nickel-containing non-stoichiometric TiC0.5 showed high flexural strength (537 +/- 79 MPa), which is comparable to values obtained from materials processed at high temperature and pressure.