Oxidation Kinetics of Aluminum Nanoparticles

1
Zachariah
Oxidation Kinetics of Aluminum Nanoparticles
Goal Understand the nature of single
nanoparticle reactivity. A. How reactive are
nanoparticles ? B. How can we moderate there
reactivity through changes in
composition, size, morphology ?
Technical Approach 1. Develop reproducible
aluminum sources. 2. Develop the necessary
methods, including tools to study reactivity
at the single-particle level. 3. Compare
reactivity with atomistic and phenomenological
models.
2
Zachariah (cont.)
Progress

• Developed two reliable and reproducible sources
  of nanoaluminum
• laser ablation
• DC arc more reactive nanoparticles because
  smaller
• Measured the composition of individual
  nanoparticles using single-particle mass
  spectrometry.
• Measured rates of aluminum nanoparticle
  oxidation.
• Studied the internal pressure and surface tension
  of bare and oxide coated aluminum.
• Developed a connection between the melting of
  aluminum and the onset of oxidation

3
Zachariah (cont.)
Results from this year
Completed determination of size-dependent
kinetics for aluminum nanoparticle oxidation
(875-1175 K). less than 50 nm fast, low
activation energy 100-150 nm slow, high
activation energy

• Developed a phenomenological model for how the
  internal pressure of oxide coated nanoparticles
  can retard the oxidation rate.
• Developed method for coating aluminum
• with carbon and studied the oxidative
• and thermal stability as a function of size.

Carbon-coated aluminum
20 nm

• Developed a plasma-hydrodynamics model for the
  interaction for an intense laser pulse with a
  single nanoparticle, for application to
  quantification of single particle
  mass-spectrometry.