Invited Paper: Photoignited Aluminum Nanopowder Combustion in Air

Metal combustion has recently received renewed interest as a result of the ability to manufacture and characterize nanoparticles. These nanoparticles are known to exhibit desirable traits, mainly their high specific surface area. The objective of this work was to investigate experimentally the oxidation behavior of nanosized aluminum powders in air under white light photo-ignition conditions. Powder samples with three different nominal size particles of 20, 50, and 70 nm were characterized with HRSEM and TEM. The results showed that the reactivity of photo-ignited powder decreased with increasing size whereas the energy threshold for ignition had the opposite trend. The presence of a natural oxide coating and changes in the optical properties of the powder are proposed as the cause of this behavior.