The Effects Of Non-stoichiometric TiN_0.3 On The Interfacial Microstructure And Mechanical Properties Of Refractory Material

This paper proposed a new way to solve the difficulty of poor sintering ability forrefractory materials in the sintering process. Non-stoichiometric titanium nitride （TiN） wasadded into the refractory materials to improve their sintering abilities through elementaldiffusion between vacancies. Non-stoichiometric TiN_0.3/AlN, TiN_0.3/Si₃N₄, andTiN_0.3/Al₂O₃composites were investigated, and the interfacial diffusion was carried out toreduce the sintering temperatures and improve the sintering abilities.The experiments were carried out by SPS which with specimen of TiN_0.3/AlN,TiN_0.3/Si₃N₄, or TiN_0.3/Al₂O₃in separate layers. The result revealed that an interfacialreaction between non-stoichiometric TiN_0.3and AlN was conformed. N and Al atomdecomposed from AlN migrated in TiN_0.3via the vacancy diffusion mechanism. As aresult of the existence of a large proportion of N vacancies in TiN_0.3lattice, N atomsincorporated into N vacancies in TiN_0.3lattice where a stoichiometric TiN layer formedclosed to the AlN substrate. Al atoms crossed the TiN layer and formed hexagonal AlN;The interfacial diffusion of TiN_0.3/Si₃N₄revealed that Si₃N₄decomposed into Si and Natoms, N atoms diffused into TiN_0.3and formed stoichiometric TiN, A small amount ofTiSi2formed in Si₃N₄substrate as a result of the large amount of Si residue; TheTiN_0.3/Al₂O₃interface had no obvious interfacial reaction zone, whereas a small amount ofTi（O）Nxsolid solution formed as a result of the diffusion of O atoms in TiN_0.3lattice.TiN_0.3/Al₂O₃composites within various Al₂O₃contents were sintered by SPS atdifferent sintering temperatures. The results show that TiN_0.3/Al₂O₃composite, which with30vol.%TiN_0.3addition, had the high hardness of20.9GPa and fracture toughness of5.25MPa·m^1/2with the sintering parameters of1400℃and10min.