Comparison of CVD-deposited Ni and dry-blended Ni powder as sintering aids for TiN powder

摘要

Ni nanoparticles were precipitated on TiN powder via a rotary chemical vapour deposition (RC VD) method. The sintering behaviour and mechanical properties of the TiN, mixture of TiN and Ni, noted as TiN-Ni(blended), and Ni-precipitated TiN, noted as TiN-Ni(CVD), powders sintered by spark plasma sintering (SPS) were compared. The effects of O_2 gas partial pressure (P_(O_2)) in RC VD and of sintering temperature in SPS (T_s) on the crystalline phase, relative density (D_r), Vickers hardness (H_v) and fracture toughness (K_(IC)) of TiN-Ni(CVD)-sintered bodies were investigated. The mechanical properties of TiN ceramic were improved as CVD-deposited Ni as sintering aid for sintering. TiN-Ni(CVD) body-sintered at T_s= 1600℃ from TiN-Ni(CVD) powder prepared at P_(O_2)= 160 Pa exhibited the highest D_r of 97.9% and H_y = 15.5 GPa, higher than those of TiN- and TiN-Ni(blended)-sintered bodies, and relatively high K_(IC)= 3.8 MPam~(1/2).