Ignition of air suspensions of metal borides

The critical ignition parameters of an air suspension of promising energy-intensive compounds of $\mathrm{MgB}_{12}$, $\mathrm{AlB}_2$, $\mathrm{ZrB}_2$, $\mathrm{TiB}_2$ metal borides and the mechanical mixtures of initial components, which simulate the composition of compounds, are experimentally studied. It is established that magnesium borides ignite at temperatures much lower than those for boron, which indicates the active role of magnesium in the ignition process. For other borides, the ignition temperatures are close to those for boron, i.e., the governing factors are the diffusion of oxygen through a liquid boron oxide film and the oxide evaporation rate.