Reactive and Metastable Nanomaterials Prepared by Mechanical Milling

Reactive materials prepared by mechanical milling are discussed. First, mechanical milling equipment, process parameters and materials characterization techniques are reviewed. In addition, experimental methods used to assess reactive and energetic properties of the prepared metal-based materials are introduced. Two types of materials are then described. Mechanically alloyed, aluminum-based powders designed to achieve enhanced ignition and combustion performance are prepared and characterized. Effect of milling parameters on the powder properties and correlations between powder properties and their ignition and combustion characteristics are discussed. Further, nanocomposite reactive powders comprising at least two components capable of a highly exothermic reaction and mixed on the scale of about 100 nm are described. Their reactivity is substantially enhanced compared to conventional composite materials. Reactions in nanocomposite powders are discussed for both individual particles and consolidated pellets. Ignition kinetics and combustion dynamics of the nanocomposite and mechanically alloyed powders are compared to those of reference pure aluminum powders.