The mechanism of synthesis of titanium nitride by self-sustaining reactions

The mechanism of formation of titanium nitride by the self-propagating high-temperature synthesis was investigated. Samples were quenched in liquid argon at different stages of the reaction and analyzed by x-ray diffraction and electron microprobe methods. A mechanism is proposed in which the propagation of the reaction wave results in the formation of a thin surface layer of TiN and an unsaturated solid solution. The layer then dissolves to form a solid solution of nitrogen in titanium and then re-forms with continued reaction. On the basis of phase equilibria and diffusion information, an analysis is made in which the feasibility of the proposal mechanism is demonstrated.