Combustion Characteristics of High-Energy Material Containing Dispersed Aluminum, Boron, and Aluminum Borides

Dispersed metallic fuels are energy-intensive components of various gel-like and composite solid propellants, which significantly improve the performance of propulsion systems. This study describes the combustion characteristics of a high-energy material (HEM) containing an oxidizer, a polymeric combustible binder, and a dispersed metallic fuel (aluminum Al), aluminum borides (AlB₂ and AlB₁₂), and amorphous boron. In a constant-pressure bomb, the burning rates of HEMs in a ressure range of 0.7–4.0 MPa are measured and it is revealed how aluminum dispersity and the nature of the metallic fuel affect burning rate, temperature, HEM sensitivity to pressure changes in the chamber, and the composition of condensed combustion products. An increase in the fineness of Al particles in HEMs significantly increases the burning rate and the HEM sensitivity to pressure changes. Replacing the microsized Al powder with amorphous boron (AlB₂ or AlB₁₂) in the HEM causes a (2.1–2.2)-fold increase in the burning rate at a pressure of 4.0 MPa, while the power exponent in the burning rate law \(u(p)=B p^{\nu}\) increases from 0.22 to 0.45.