Fabrication of Bulk Chromium Nitrides Using Self-Propagating High-Temperature Synthesis and Hot Isostatic Pressing

抄録

Cr₂N, CrN and their mixtures with desired fractions were prepared by self-propagating high-temperature synthesis (SHS) under controlled nitrogen pressure and then followed by hot isostatic pressing at 1300°C and 196 MPa under argon gas. The combustion temperature increased with increasing nitrogen pressure. Single-phase Cr₂N and CrN were formed at 1040° under 0.18 MPa N₂ and 1730°C under 2 MPa N₂, respectively. The mechanical properties of chromium nitride ceramics with relative density of 99.2% were examined; Vickers hardness H_v(CrN:11.2 GPa and Cr₂N: 14.5 GPa) linearly increased with increasing fraction of Cr₂N, whereas fracture toughness K_IC (-4.7 MPa⋅m^1/2) and bending strength σ_b (-355 MPa) were constant regardless of the fraction of Cr₂N/CrN.