Microstructural and mechanical characterization of titanium nitride produced by S.H.S.

Titanium nitride materials were synthesized using Self-propagating High temperature Synthesis (S.H.S.). The syntheses were conducted under high nitrogen gas pressures ranging from 6 to 200 MPa. A microstructural study showed that the material is made of a dense and homogeneous bulk sub-stoichiometric titanium nitride, surrounded by a porous stoichiometric titanium nitride surface layer. Nanoindentation measurements were performed in order to determine the material Young's modulus, which is in the order of 250 GPa in the bulk for the highest nitrogen gas pressures, namely 36 and 200 MPa. Microstructural characterization made it possible to determine the combustion reaction mechanisms. This study evidenced the importance of high nitrogen gas pressures to obtain single-phase and near-stoichiometric titanium nitride through S.H.S.