Development of metal cluster-based energetic materials at NSWC-IHD

Current research efforts at NSWC-IHD are utilizing gas-phase molecular beam studies, theoretical calculations, and condensed-phase production methods to identify novel metal cluster systems in which passivated metal clusters make up the subunit of a molecular metal-based energetic material. The reactivity of Ni _xAl _y ⁺ clusters with nitromethane was investigated using a gas-phase molecular beam system. Results indicate that nitromethane is highly reactive toward the Ni _xAl _y ⁺ clusters and suggests it would not make a good passivating ligand for these cluster systems. To date, small amounts of a metal-based compound with a subunit containing four aluminum atoms and four Cp* ligands has been produced and was characterized using DSC and TGA. Results indicate this cluster material is more reactive than micron- and nano-sized aluminum. However lack of stability in air precludes it from being a viable replacement for current aluminum particles. Volumetric heat of combustion of Al ₅₀Cp* ₁₂ was determined using thermodynamic data obtained from first principles calculations. The Al50 cluster is found to have a heat of combustion near 60% that of pure aluminum.