Plasma surface treatment of aluminum nanoparticles for energetic material applications

Aluminum nanoparticles (nAl) have great potential for energetic applications. However, the native oxide shell (amorphous alumina, Al2O3) inhibits efficient energy release and acts as a barrier for aluminum (Al) oxidation. An energetic oxidizer, aluminum iodate hexahydrate (AIH), has recently been demonstrated as an effective coating for nAl. However, the current chemical synthesis method has led to widely varying AIH concentrations on nAl particles. Plasma surface treatment of nAl is a novel energy coupled to material technique which alters the nAl surface properties without changing the bulk active Al core. This work explores a new approach to engineering the nAl surface using atmospheric argon (Ar) plasma to accomplish two objectives: (1) reduce the nAl oxide shell thickness, and (2) synthesize AIH on the treated particle surface. Transmission electron microscopy (TEM) reveals more than 40% reduction in the oxide thickness after 10min Ar plasma treatment. Laser-induced air shock from energetic materials (LASEM) experiments show significant energy release enhancements for the plasma-treated nAl with AIH coating (UT-nAl-AIH) compared to commercial nAl as well as untreated nAl with AIH coating (UT-nAl-AIH). The results demonstrate the potential of applying atmospheric plasma techniques to modify nAl for enhanced reactivity. Published by Elsevier Inc. on behalf of The Combustion Institute.