Effect of composition on properties of reactive Al·B·I2 powders prepared by mechanical milling

Ani Abraham, John Obamedo, Mirko Schoenitz, Edward L. Dreizin

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Metal-based fuels producing halogen-containing combustion products are being developed to enable rapid inactivation of harmful aerosolized spores and bacteria. Ternary reactive materials containing aluminum, boron, and iodine were prepared by mechanical milling with systematically varied Al:B ratio. The aluminum mass fraction varied from 0% to 70%, and most materials included 20 wt% of iodine. Prepared powders were inspected by electron microscopy; particle size distributions were measured using low angle laser light scattering. Stability of materials was studied using thermo-gravimetry and differential scanning calorimetry. As-prepared as well as pre-heated and quenched samples were analyzed using x-ray diffraction. Iodine was released upon heating in several stages. Low-temperature iodine release was relatively small. It overlapped with decomposition of B(OH)3 releasing water. The most significant amounts of iodine were released when the samples were heated to 400-500 °C, when AlB2 formed. Both AlB2 formation and iodine release were further accelerated by melting of aluminum. For the boron-rich samples, in which boron remained after all aluminum was used to form AlB2, an additional, high-temperature iodine release stage was observed near 900 °C. The results show that both boron and aluminum are capable of stabilizing substantial quantities of iodine in the metal matrix. The iodine is released at temperatures much greater than its boiling point. The mechanism by which iodine is retained in boron and aluminum remains unclear.

Original languageEnglish (US)
Pages (from-to)1-7
Number of pages7
JournalJournal of Physics and Chemistry of Solids
Volume83
DOIs
StatePublished - Aug 1 2015

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Keywords

  • Alloys
  • Metals
  • Nanostructures
  • Phase equilibria
  • Thermogravimetric analysis

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