Characterization of Commercial Aluminum Powders for Use in Energetic Applications, Part II: Structural, Chemical, and Thermal Analyses

Author(s):

C-C Wu, L Giri, D Thapa, and RA Pesce-Rodriguez

Abstract:

This work aims to study the structure, composition, and thermal behavior of several commercially acquired aluminum (Al) powders with varying sizes using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and simultaneous thermogravimetric analysis and differential scanning calorimetry. Four samples of Al powders in the ranges of 40‒60 nm, 60‒80 nm, 100‒130 nm, and less than 5 μm are specially examined by TEM and XPS to investigate their surface properties. Significant numbers of particles with their sizes outside the range of the given range are found for all samples. The sample labeled as “< 5 μm” in particular is essentially a mixture of nano- and micron-sized powders. All samples also contain significant crystalline alumina deposits that presumably are γ-Al₂O₃. X-ray photoelectron survey spectra revealed the significant carbon content for the 60‒80-nm nanopowder sample. The results from thermal analyses suggest the active Al content of the nanopowders is as much as 15 wt% lower than that of the micron-sized powders.