Activating Aluminum Reactivity with Fluoropolymer Coatings for Improved Energetic Composite Combustion

Jena McCollum, Michelle L. Pantoya, Scott T. Iacono

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Aluminum (Al) particles are passivated by an aluminum oxide (Al2O3) shell. Energetic blends of nanometer-sized Al particles with liquid perfluorocarbon-based oxidizers such as perfluoropolyethers (PFPE) excite surface exothermic reaction between fluorine and the Al2O3 shell. The surface reaction promotes Al particle reactivity. Many Al-fueled composites use solid oxidizers that induce no Al2O3 surface exothermicity, such as molybdenum trioxide (MoO3) or copper oxide (CuO). This study investigates a perfluorinated polymer additive, PFPE, incorporated to activate Al reactivity in Al-CuO and Al-MoO3. Flame speeds, differential scanning calorimetry (DSC), and quadrupole mass spectrometry (QMS) were performed for varying percentages of PFPE blended with Al/MoO3 or Al/CuO to examine reaction kinetics and combustion performance. X-ray photoelectron spectroscopy (XPS) was performed to identify product species. Results show that the performance of the thermite-PFPE blends is highly dependent on the bond dissociation energy of the metal oxide. Fluorine-Al-based surface reaction with MoO3 produces an increase in reactivity, whereas the blends with CuO show a decline when the PFPE concentration is increased. These results provide new evidence that optimizing Al combustion can be achieved through activating exothermic Al surface reactions. (Figure Presented).

Original languageEnglish
Pages (from-to)18742-18749
Number of pages8
JournalACS Applied Materials and Interfaces
Volume7
Issue number33
DOIs
StatePublished - Aug 26 2015

Keywords

  • aluminum fluoride
  • aluminum powder
  • combustion
  • energetic materials
  • exothermic surface chemistry
  • fluorine
  • oligomers
  • preignition reaction

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