(547c) Aluminum Burn Rate Modifiers Based on Reactive Nanocomposite Powders

Aluminum powders have long been used in reactive materials for such applications as propellants, pyrotechnics and explosives. Aluminum has a high enthalpy of combustion but relatively low combustion rate. Addition of reactive nanocomposite powders can increase the burn rate of aluminum and thus the overall reaction rate. Replacing a small fraction of the fuel by a nanocomposite material can enhance the reaction rate with little change to the thermodynamic performance of the energetic formulation. This research showed the feasibility of the above concept using nanocomposite powders prepared by Arrested Reactive Milling (ARM), a scalable “top-down” technique for manufacturing reactive nanocomposite materials. The nanocomposite materials used in this study were based on B-Ti, Al-CuO and Al-MoO3 compositions. The reactive nanocomposite pareticles were added to micron sized aluminum powder and the mixture was burned in a constant volume chamber. The combustion atmosphere was varied using mixtures of oxygen, nitrogen, and methane to imitate the environments produced in practical applications. The resulting pressure traces were recorded and processed to compare different types and amounts of modifiers. Results indicated that the 8Al+MoO3 and 2B+Ti nanocomposites were most effective in improving both the rate and efficiency of aluminum combustion.