Incorporation of high explosives into nano-aluminum based microspheres to improve reactivity

Nano-aluminum, as a potential replacement of micro-aluminum, has attracted significant research interests in energetic fields due to its high reactivity. However, the intrinsic high surface area of nanoparticles drives nano-aluminum encounter challenges in handling process and prone to large aggregation, significantly impeding the further application of nano-aluminum. In this work, nano-aluminum based microspheres incorporating hexanitrohexaazaisowurtzitane (CL-20) are directly fabricated by electrospray deposition. These as-prepared microspheres were in high monodispersity and their size ranges from 8 to 16 μm. The surface morphology of such microspheres was adjustable by using different polymers as binder. Thermal behavior results show that CL-20 has no appreciable effect on the reactivity of nano-aluminum while the fluoropolymer binder (F2314) facilitates the oxidation of nano-aluminum. Nevertheless, the presence of CL-20 can significantly enhance the reactivity of nano-aluminum in the combustion behavior tests, where electrosprayed microspheres exhibit outstanding performance in comparison to physical mixed sample, presenting a high pressurization rate, peak pressure and short burning time. These excellent properties are possibly attributed to their uniform microstructure. Therefore, the use of electrospray method can offer a promising strategy to fabricate the microstructure controllable microspheres.