Energetic intermetallic materials formed by cold spray

Cold spray was used to synthesize three intermetallic energetic materials from powders composed of mixed Ni/Al, mixed Ni/Al/MoO₃, and Ni-clad Al. After bulk samples were produced, characterization was performed to determine their composition and reactivity. Ignition was achieved with a 30 W CO₂ laser and propagation rates were measured using a high speed digital video camera. Differential scanning calorimetry was used to obtain energetic properties of the composites at slow heating rates. The energetic properties of cold sprayed samples were compared with lower density axially pressed pellets of identical composition. Samples composed of a mechanical blend of Ni and Al powders had higher reaction propagation rates at lower densities; with the near fully-dense cold spray samples having the lowest propagation rates. The opposite was found in samples composed of Ni-clad Al powders, with propagation rate increasing with increasing density for pellets, and reaching a maximum in the cold sprayed samples. The samples containing MoO₃ had mixed results, with pellets experiencing higher propagation rates for all MoO₃ contents' with increasing density, but cold sprayed samples having lower propagation rates as the MoO₃ content increased.