Using magnesium to maximize heat generated by reactive Al/Zr nanolaminates

Kyle R. Overdeep, Kenneth J.T. Livi, David J. Allen, Nick G. Glumac, Timothy P. Weihs

Research output: Contribution to journalArticlepeer-review

Abstract

In this study, we explore the effect of magnesium content on the ability of reactive nanocomposite foils to generate heat, by comparing three chemistries: Al:Zr, Al-8Mg:Zr, and Al-38Mg:Zr. These correspond to foils with alternating aluminum and zirconium layers where the Al is either pure, an 8. at.%Mg alloy, or a 38. at.%Mg alloy, respectively. Measurements performed in a specially designed bomb calorimeter show that Al-8Mg:Zr foils perform the best, generating the greatest gravimetric heat in air, oxygen, and nitrogen environments. Both Mg-containing foils release a visible plume of particles and vapor upon reacting, which was recorded with a high speed camera. This ejected mass includes Mg vapor and particles of all three metals. Both the vapor and particles oxidize rapidly in air, resulting in single metal-oxide particles. The reacted foils, particularly the Al-8Mg:Zr samples, contain voids and higher levels of oxygen and nitrogen throughout their thicknesses than reacted Al:Zr foils. To explain the higher heats of reaction for the Al-8Mg:Zr foils, we suggest that the out-diffusion and evaporation of Mg generates a high concentration of vacancies that enhance oxygen and nitrogen diffusion throughout the foil, thereby increasing the degree of oxidation and nitridation.

Original languageEnglish (US)
Pages (from-to)2855-2864
Number of pages10
JournalCombustion and Flame
Volume162
Issue number7
DOIs
StatePublished - Jul 1 2015

Keywords

  • Aluminum
  • Bomb calorimetry
  • Magnesium
  • Reactive nanocomposites
  • Zirconium

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Physics and Astronomy(all)

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