Aluminum particle reactivity as a function of alumina shell structure: Amorphous versus crystalline

Renita K. Walzel, Valery I. Levitas, Michelle L. Pantoya

Research output: Contribution to journalArticlepeer-review

Abstract

The objective of this study was to investigate Al particle reactivity as a function of the Al2O3 shell phase. Aluminum particles were thermally treated to transition the shell from amorphous to crystalline and each powder was combined with polytetrafluoroethylene (PTFE). Flame speeds were measured for Al + PTFE powder mixtures for two Al particle sizes that differ from micrometer (μAl) to nanometer (nAl) diameter and for both crystalline and amorphous Al2O3 shells encapsulating Al core particles. Results showed that μAl particles were more sensitive to shell phase than nAl particles. Reactions were modeled according to the melt dispersion mechanism (MDM), and altering the shell phase reduced the thickness, damaged the shell structure, impeded melt dispersion, and reduced flame speed for μAl particles by 45% and nAl particles by 12%.

Original languageEnglish
Pages (from-to)33-39
Number of pages7
JournalPowder Technology
Volume374
DOIs
StatePublished - Sep 2020

Keywords

  • Aluminum
  • Diffusion reactions
  • Flame speed
  • Fluorination reactions
  • Melt dispersion mechanism
  • Thermites

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