Understanding and tuning the reactivity of nano-energetic materials

Mixtures of fuel and oxidizers with particle sizes in the nanometer range have been widely used for energy intensive applications like propellants and explosives. Nano- Al is invariably used as fuel, while a host of metal oxide nanoparticles are used as oxidizers. This article aims at understanding and tuning the reactivity of these nano-energetic materials. The first part of this article discusses the oxidative reactivity of aluminum nanoparticles as measured experimentally using single-particle mass-spectrometer (SPMS) and microscopy and then modeled. Experimental evidence suggests that outward diffusion of aluminum is an important phenomenon in the oxidation of aluminum nanoparticle. Also melting of the aluminum core is necessary for the reaction to lake place vigorously. In the second part of the paper we discuss the formation of novel oxidizers, A super-reactive formulation of Al/KMnO₄ has been developed which is shown to be orders of magnitude more reactive than the traditional formulations of Al/Fe₂O₃, Al/MoO₃ and Al/CuO. We demonstrate the formation of novel composite oxidizers to tune the reactivity of the Al/Metal oxide system.