Coating nano-sized aluminum particles with an energetic material such as RDX has several unique advantages. The RDX coating can protect the aluminum surface from developing a growing oxide coating and can potentially improve performance by bringing the two components into closer contact than would conventional mixing. In this investigation, a custom-built rapid expansion of a super-critical solution with a nonsolvent (RESS-N) system was modified to coat nano-sized aluminum (ALEX® ) particles. Particles were coated by entraining them in a solution of supercritical CO2 and RDX and then rapidly expanding the mixture through a nozzle. To achieve this, a particle entrain- ment vessel introduced ALEX® particles into the flow and the suspension was flown through a micro-orifice sapphire nozzle. The rapid expansion of the supercritical solution and the addition of ALEX® particles as nucleation sites created favorable conditions for the RDX to coat the ALEX® particles by heterogeneous nucleation. Tests were run at pre-expansion pressures up to 34.5MPa and pre-expansion temperatures up to 353 K. Particles were successfully coated with RDX and collected by expanding the CO2 until it formed dry ice, which allowed for gravimetric collection. The success- ful coating of the particles was confirmed by field emission scanning electron microscopy (FE-SEM). Environmental scanning electron microscopy (ESEM) with energy disperse spectroscopy (EDS) was used to confirm that only RDX and ALEX® particles were collected and that the coating material was truly RDX.
|Original language||English (US)|
|Number of pages||32|
|Journal||International Journal of Energetic Materials and Chemical Propulsion|
|State||Published - Dec 1 2010|
All Science Journal Classification (ASJC) codes
- Materials Science(all)