One-step preparation of dense TiC1 − xNx–Ni3Ti cermet by combustion synthesis

Highlights: • Dense TiC_1−xN_x–Ni₃Ti cermet is prepared in one step of only a few seconds by combustion synthesis. • The TiC_1−xN_x–Ni₃Ti cermet shows homogeneous microstructure and a hardness of 12.1 ± 0.3 GPa. • The deficiency of C is important for in-situ densification in combustion synthesis. - Abstract: TiC_1−xN_x-based cermets are attractive for high-speed cutting operations, and are usually produced by powder sintering at high temperatures and for a long time. In this paper, dense TiC_1−xN_x–Ni₃Ti cermet is directly prepared in one step by combustion synthesis in 2 MPa N₂ atmosphere, from the reactant of (Ti + C + Ni) with a molar ratio of Ti:C:Ni = 1:0.7:0.4. The as-prepared TiC_1−xN_x–Ni₃Ti cermet shows a homogeneous microstructure, in which equiaxed TiC_1−xN_x grains of a few microns are bounded by Ni₃Ti grain-boundary phase, and a Vickers hardness of 12.1 ± 0.3 GPa. It is proposed that the deficiency of C in the starting reactant plays a key role in simultaneous densification during combustion synthesis. Compared with the conventional powder sintering approach, combustion synthesis may provide a one-step, ultrafast, and furnace-free way to prepare TiC_1−xN_x-based cermets with reduced time and energy consumption.