Ignition and phase formation in the $\mathrm{Zr}$–$\mathrm{Al}$–$\mathrm{C}$ system

The ignition mechanism and the dependence of the composition of the products of combustion or thermal explosion in a mixture of $2\mathrm{Zr}+\mathrm{Al}+\mathrm{C}$ on the initiation temperature and heat transfer conditions were studied. Heat transfer conditions were changed by varying the size of the samples and the gaseous medium in which the experiments were performed. Two contusion regimes were found: a low-temperature regime in which zirconium aluminides formed and carbon and part of the zirconium remained unreacted and a high-temperature regime in which the reaction products were carbide and zirconium aluminide. Upon reinitiation, the low-temperature combustion products reacted in the high-temperature combustion mode. The observed dependences are due to parallel reactions in the three-component system.