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 nano-sized aluminum powders. Their effectiveness in increasing energetic system performance has been already proven at lab-scale level. However, the high cost, the dispersion difficulties, and the increased handling risk hinder a widespread application of nanomaterials. 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 the design, the production, and the characterization of mechanically activated ingredients for solid propellants and hybrid rocket fuels. General guidelines for the powder processing implementation are critically discussed. Additives are characterized in the pre-burning phase, and their effects on the ballistic response of solid propellants and hybrid fuels are investigated. Activated powders improved hybrid fuel regression rate and reduced the size of the condensed combustion products of solid propellants, confirming their suitability for the micron-sized aluminum replacement.