Importance of Phase Change of Aluminum in Oxidation of Aluminum Nanoparticles

Aluminum nanoparticles have increasingly gained attention because of their potential incorporation in explosive and propellant mixtures. This letter reports on a qualitative study on the oxidation of aluminum nanoparticles containing a passivating oxide coating. Hot-stage transmission electron microscopy (TEM) studies were performed to understand the stability of the oxide coating in nanoaluminum, and oxidation was investigated using a single particle mass spectrometer (SPMS). We find that the oxidation of oxide-coated nanoaluminum coincides with and therefore is presumably initiated by melting of the aluminum core and subsequent mechanical rupture of the oxide coating.