Energetic nano-materials: Opportunities for enhanced performances

This paper deals with the contribution of nano-materials to the contemporary pyrotechnics science. The breakthroughs in this domain are illustrated by several examples of energetic nano-materials recently studied in our laboratory. The solidification of energetic phases in a porous matrix (Cr2O3) Was used to prepare and to stabilize at nano-scale explosive particles. The thermo-chemical behaviour of RDX nano-particles strongly differs from the one of micron-sized RDX. For instance, the temperature at which the decomposition occurs is significantly lowered and the melting point is removed. The effect of the decomposition of RDX nanoparticles on the matrix in which they are trapped was observed for the first time by the atomic force microscopy. The Cr2O3/RDX nano-composite materials were mixed with aluminium nano-particles in order to formulate gas-generating nano-thermites (GGNT). The combustion of GGNT involves a synergy mechanism in which the decomposition of RDX nano-particles fragments the Cr2O3 matrix and primes the thermite reaction. "Classical" nano-thermites were obtained by mixing nano-particles (diameter < 100 nm) of metallic oxides (WO3) with a reducing metal (Al). These materials were used to demonstrate that nano-particles (i) significantly lower the ignition delay time and (ii) remarkably increase the combustion rate. Finally, pure RDX nano-particles are prepared by a continuous process of crystallization. (C) 2009 Elsevier Ltd. All rights reserved.