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 nano-particles 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.