Abstract
Abstract A mechanism of self-propagating high-temperature synthesis (SHS) of TiCNi cermet was studied by means of a combustion front quenching method. Microstructural evolution in the quenched sample was observed using a scanning electron microscope (SEM) with energy dispersive X-ray (EDX) spectrometry, and the combustion temperature and velocity were measured. The results showed that the combustion reaction started with a local formation of a TiNi liquid solution and could be described with a dissolution–precipitation mechanism, namely, Ti, Ni, and C particles dissolved into the TiNi solution and TiC particles precipitated in the saturated TiNiC liquid solution. The local formation of the TiNi solution resulted from a solid diffusion between the Ti and Ni particles, and it was found that the dissolving rate of Ti particles is higher than the Ni particles. In addition, the combustion synthesis has incompleteness and it was attributed to a usage of the coarser Ni and Ti powders. Again, a model corresponding to the dissolution–precipitation mechanism was drawn, and an ignition temperature of the combustion reaction was prophesied as about 942 °C.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have