Time-resolved measurements of near infrared emission spectra from explosions: Pure pentaerythritol tetranitrate and its mixtures containing silver and aluminum particles J. Appl. Phys. 108, 036101 (2010); 10.1063/1.3437056 Time-resolved optical measurements of the post-detonation combustion of aluminized explosives Rev. Sci. Instrum. 77, 063103 (2006);

Articles you may be interested inUsing time-frequency analysis to determine time-resolved detonation velocity with microwave interferometry Rev. Sci. Instrum. 86, 044705 (2015); 10.1063/1.4916733Influence of explosive density on mechanical properties of high manganese steel explosion hardened Time-resolved measurements of near infrared emission spectra from explosions: Pure pentaerythritol tetranitrate and its mixtures containing silver and aluminum particles Time-resolved emission spectroscopy and high-speed photography were used to study the chemical dynamics and thermal history of aluminized hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) charges following detonation. The aluminized RDX charges contained 20 wt. % of either 30-70 nm or 16-26 lm Al particles. Non-aluminized RDX charges were also studied for comparison. Spectra collected from the aluminized charges exhibited Al and AlO emissions during the first 60 ls, followed by a broadband emission that evolved over two time scales: one in the early time, 0-200 lsec, and another on late time, 0.5-10 ms. The apparent temperatures of the early-time fireballs were obtained using barium atom thermometry and were found to be 2900 K for the RDX-only charges, 3600 K for the RDX-micron Al charges, and 4000 K for the RDX-nano Al charges. In both types of aluminized samples, once Al and AlO emissions ceased, the fireballs began to cool and approached the temperature obtained for the non-aluminized RDX charges. For aluminized charges, a late-time luminescence was also observed, with the intensity and duration dependent upon the size of the Al particles. Aluminum nanoparticles yielded a higher early-time temperature, but a less intense and shorter duration late-time emission, while micron-sized particles produced a lower early-time temperature, but a longer-lived and more intense late-time energy release. These results indicate that post-detonation Al combustion occurs in multiple stages during the evolution of the fireball.

Aluminum nanoparticles and explosive formulations that incorporate them have been a subject of ongoing interest due to the potential of aluminum particles to dramatically increase energy content relative to conventional organic explosives. We have used time-resolved atomic and molecular emission spectroscopy to monitor the combustion of aluminum nanoparticles within the overall chemical dynamics of post-detonation fireballs. We have studied the energy release dynamics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) charges incorporating three types of aluminum nanoparticles: commercial oxide-passivated nanoparticles, oleic acid-capped aluminum nanoparticles (AlOA), and nanoparticles in which the oxide shell of the particle has been functionalized with an acrylic monomer and copolymerized into a fluorinated acrylic matrix (AlFA). The results indicate that the commercial nanoparticles and the AlFA nanoparticles are oxidized at a similar rate, while the AlOA nanoparticles combust more quickly. This is most likely due to the fact that the commercial nano-Al and the AlFA particles are both oxide-passivated, while the AlOA particles are protected by an organic shell that is more easily compromised than an oxide layer. The peak fireball temperatures for RDX charges containing 20 wt. % of commercial nano-Al, AlFA, or AlOA were ∼3900 K, ∼3400 K, and ∼4500 K, respectively.