(547b) Development of High-Efficient Nanoenergetic Gas-Generators

Nanoenergetic thermite materials release energy much faster than conventional energetic materials and have various potential military applications such as rocket propellants, aircraft fuel and explosives. They are likely to become the next-generation explosive materials, as they enable flexibility in energy density and power release through control of particle size distribution, stoichiometry and choice of fuel and oxidizer. The reduction of the reactant powders from micro- to nano-size generates a more intimate contact between the particles. This, in turn, increases the reaction front propagation velocity in some systems by two to three orders of magnitude. Most researchers have investigated the dependence of the temperature evolution and velocity of the thermal front propagation on the thermite reactions. However gas pressure evolution and rate of gas release is not well investigated and understood.

We report here the development of high-efficient Nanoenergetic Gas-Generators (NGG) systems having various potential military applications. We systematically studied micro and nano energetic reactants mixtures such as MoO3-Al, MoO2-Al, WO3-Al, Bi2O3-Al, MnO2-Al, Fe2O3-Al, CuO-Al, some containing boron and carbon additives, to find those generating the highest gas discharge pressure peak. Loose reactant mixtures were loaded (m=0.5 g) into a ceramic boat that was placed inside a cylindrical stainless steel vessel (Parr, V=342 cc) and then ignited. Addition of some boron to the reactant mixture for MoO3/Al and WoO3/Al increased the peak pressure. The maximum combustion temperature during the studied reactions exceeded 2000°C. The thermal front emitted many sparks (hot zones) and small particles. The estimated average rate of temperature rise was ~40,000 C/s. The peak pressure during some nanoenergetic thermite reactions exceeded 1000 psi. Key factors that affect the ignition sensitivity and peak pressure evolution will be discussed.