Accession Number:

ADA622821

Title:

Comparison of Post-detonation Combustion in Explosives Incorporating Aluminum Nanoparticles: Influence of the Passivation Layer (Postprint)

Descriptive Note:

Journal article

Corporate Author:

AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE

Report Date:

2013-01-31

Pagination or Media Count:

9.0

Abstract:

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.

Subject Categories:

  • Physical Chemistry
  • Laminates and Composite Materials
  • Metallurgy and Metallography
  • Plastics
  • Ammunition and Explosives
  • Explosions
  • Combustion and Ignition

Distribution Statement:

APPROVED FOR PUBLIC RELEASE