Combustion characteristics of a high-energy material containing particulate aluminum, boron, and aluminum borides

Dispersed metallic fuels are energy-intensive components of various gel-like and mixed solid fuels, which significantly increase the performance of propulsion systems. This article presents the combustion characteristics of a high-energy material (HEM) containing an oxidizer, a polymeric combustible and a dispersed metallic fuel – aluminum Al, aluminum borides AlB$_2$ and AlB$_{12}$, amorphous boron. In a constant-pressure bomb, the combustion rates of HEM were measured in the pressure range of 0.7–4.0 MPa, the effect of aluminum dispersion and the nature of the metallic fuel on the combustion rate and temperature, the fuel sensitivity to pressure changes in the chamber, and the composition of condensed combustion products was established. An increase in the fineness of Al particles in the HEM significantly increases the burning rate and the sensitivity of the fuel composition to pressure changes. Replacing microsized Al powder with amorphous boron, AlB$_2$ or AlB$_{12}$ in HEM increases the combustion rate by 2.1–2.2 times at a pressure of 4.0 MPa, while the power exponent in the combustion rate law $u(p) = Bp^\nu$ increases from 0.22 to 0.45.