“This work is focused on materials designed to be used in energetic materials for a variety of applications,” she said. “In addition to military technologies, these materials can be used in automotive airbags, for spacecraft propulsion, in industrial or specialized heaters, and for in-situ welding. Future applications can include materials for hydrogen generation and advanced catalysts.”

Multiple aluminum-based (AL) nano-composite reactive materials were explored  including thermite compositions, coated powders and multilayered foils. In most cases, a highly exothermic reaction is expected to occur between the aluminum and one of the additional components resulting in an accelerated ignition. However, additional solid oxidizers inevitably reduce the overall energy density of the metal fuel additives. 

This project explored a new type of Al-based reactive composite material.  In these materials, aluminum was mixed, but not alloyed, with a metal, rather than an oxide.  The bulk compositions are aluminum-rich to take advantage of the high aluminum combustion enthalpy. 

Composite materials in the systems of Al-Zn, Al-Fe, and Al-Ni were prepared by mechanical milling of aluminum powders mixed with powders of the respective metal additives.  For each material, structure and composition were characterized using electron microscopy and x-ray diffraction.  Reactivity of the prepared powders was studied using thermal analysis and heated filament ignition experiments. 

It was observed that oxidation kinetics of the prepared aluminum-metal reactive composite materials differ substantially from the kinetics of aluminum oxidation.  It was also observed that reduced ignition temperatures are achieved for different Al-metal composite materials.  Detailed studies of the reaction processes werer carried out to establish mechanisms of accelerated oxidation kinetics and reduced ignition temperatures for different materials.