Pyrophoricity of nascent and passivated aluminum particles at nano-scales

Dilip Srinivas Sundaram, Puneesh Puri, Vigor Yang

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

Pyrophoricity of nascent and passivated nano-aluminum particles in air is studied theoretically using energy balance analyses. The work incorporates size-dependence of physicochemical properties of particles at nano-scales, and considers free-molecular and radiation heat exchange with the surrounding environment. The heterogeneous oxidation process is modeled using the Mott-Cabrera mechanism. Nascent aluminum particles with diameters lower than 32. nm are predicted to be pyrophoric. The critical diameter for particles passivated with 0.3-nm thick oxide layer is calculated as 3.8. nm. Particles with oxide layers thicker than 0.3. nm are found to be non-pyrophoric. The sensitivity analysis suggests that the model results are significantly affected by the choice of physicochemical properties, polymorphic state of the oxide layer, parameters of the Mott-Cabrera oxidation kinetics, and heat-transfer correlation. The critical particle size increases by 40%, when bulk material properties calculated at room temperature are used and the oxide layer is assumed to be in a crystalline form. It decreases by 43%, when free-molecular effects are neglected.

Original languageEnglish
Pages (from-to)1870-1875
Number of pages6
JournalCombustion and Flame
Volume160
Issue number9
DOIs
Publication statusPublished - 2013 Sep

All Science Journal Classification (ASJC) codes

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

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