Publicou 6 edições por ano
ISSN Imprimir: 2150-766X
ISSN On-line: 2150-7678
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SYNTHESIS AND CHARACTERIZATION OF COATED ENERGETIC MATERIALS USING A RESS-N SYSTEM
RESUMO
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 supercritical 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 entrainment 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 34.5 MPa 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 successful 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.