Enhancing Micrometric Aluminum Reactivity by Mechanical Activation

The pursuit of solid rocket motor and hybrid rocket engine performance enhancements is pushing toward the research of novel energetic materials replacing the conventional micron-sized aluminum. Nanotechnology opened the way to new concepts, introducing very promising ingredients like nanoaluminum (nAl). Their effectiveness in increasing energetic system performance has been already proven. However, the high cost, the dispersion difficulties and the increased handling risk, hinder a widespread application. On the other hand, activation techniques offer the possibility of micron-sized additives reactivity enhancement while maintaining high safety levels and reduced costs. This work deals with design, production, and characterization of mechanically activated ingredients for solid propellants (SPs) and hybrid rocket fuels (HFs). General guidelines for implementation of powder processing are critically discussed. Additives are characterized in the pre-burning phase, and their effects on the ballistic response of SPs and HFs are investigated. Activated powders improved HF regression rate and reduced the size of the condensed combustion products of SPs, confirming their suitability for micron-sized aluminum replacement.