(491c) Reactive Nanocomposite Materials Prepared by Cryogenic Milling

Nanocomposite materials of reactive components are of interest for many applications in pyrotechnics, explosives, and propellants. Several such materials have been recently prepared by Arrested Reactive Milling (ARM), a method based on mechanical milling of µm-sized component powders to form µm-sized composite particles in which the components are mixed on a scale of 100 nm or finer. The temperature at which the milling is performed affects significantly both the rate at which the material is refined and the final properties of the product. In the present paper we report on an effort to process Al-CuO and Al-MoO3 reactive nanocomposite at cryogenic temperatures. A SPEX Certiprep 6815 Freezer/Mill was used to prepare the nanocomposites with aluminum-rich compositions from µm-sized component powders. The material was processed in steel vials using steel balls of different sizes as milling medium. The number and dimensions of the milling balls as well as the milling time were systematically varied. The prepared powders were characterized by X-ray diffraction, scanning electron microscopy, ignition and combustion testing, and differential scanning calorimetry. Preliminary results show that the uniformity of mixing and reactivity of the nanocomposite powders can be substantially improved using milling at cryogenic temperatures. A detailed overview of this project will be presented.