Highly reactive spheroidal milled aluminum

Mechanical milling of aluminum powders with two immiscible liquids, acetonitrile and hexane, produced roughly spherical particles increased flowability sizes in the range tens to hundreds microns specific surface areas 15 – 30 m2/g. The near shapes comprised agglomerated flakes. Samples were milled from 0.5 2 hours a planetary mill. Longer times led reduced sizes, while porosity area peaked at intermediate times. Thermal analysis showed that samples heated an oxidizing environment oxidized faster than nonporous micron-size aluminum, oxidation rates comparable those nanopowders. active content these was micron-sized aluminum. Reaction steps respective activation energies consistent other powders. However, unlike regular spheroidal placed on electrically 3500 K/s ignited temperatures ranging 750 900°C. Ignition decreased longer decreasing particle size. In low-temperature, humid environments, lost about half compared reference Al aged under identical conditions. Heterogeneous reactions prepared are interpreted using model comprising reactive shell inert core.