(547d) Tunability of Nanoenergetic Materials

Expansive research in the area of nanoenergetics over the past several years has led to the discovery and development of a wide array of reactive systems. These reactive systems have many varying properties including: ignition sensitivity, reaction rate, adiabatic reaction temperature, pressure generation, and theoretic maximum density. Additional investigations into the factors affecting ignition and reaction characteristics have shown that many physical and chemical properties of the individual reactants, as well as processing methods, can have a significant effect on the overall behavior of the nanoenergetic system. Application of nanoenergetic materials as components of various products requires that the ignition and reaction characteristics be tailored to have specific sensitivities and energy outputs. This research effort will address how ignition sensitivity thresholds, reaction rate, and pressure generation can be tailored to have a wide range of values. Several different individual reactants are used including: various sizes and morphologies of aluminum powder, nanoporous silicon, and nano-boron as fuels, as well as many different metal oxides as oxidizers. Nanothermite materials can be ignited by several means, most commonly friction, impact, electrostatic discharge, and thermal impulse. Reaction rate and pressure generation can be increased by using reactants with high specific surface area but is also often accompanied by an increase in sensitivity. Degrees of ignition and reaction rate modification can be accomplished by incremental changes in: amounts of additives, sizes and specific surface areas of reactants, consolidation, and combinational use of oxidizers with different reactive properties.