Effect of C particle size on the mechanism of self-propagation high-temperature synthesis in the Ni–Ti–C system

Abstract: Effect of C particle size on the mechanism of self-propagation high-temperature synthesis (SHS) in the Ni–Ti–C system was investigated. Fine C particle resulted in a traditional mechanism of dissolution-precipitation while coarse C particle made the reaction be controlled by a mechanism of the diffusion of C through the TiC x layer. The whole process can be described: C atoms diffusing through the TiC x layer dissolved into the Ni–Ti liquid and TiC were formed once the liquid became supersaturated. Simultaneously, the heat generated from the TiC formation made the unstable TiC x layer break up. However, with the spread of Ti–Ni liquid, a new TiC x layer was formed again at the interface between spreading liquid and C particle. This process cannot stop until all the C particles are consumed completely. [Copyright &y& Elsevier]