Campus Units

Aerospace Engineering, Mechanical Engineering, Ames Laboratory

Document Type


Publication Version

Accepted Manuscript

Publication Date


Journal or Book Title

Powder Technology




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 are 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%.


This is a manuscript of an article published as Walzel, Renita K., Valery I. Levitas, and Michelle L. Pantoya. "Aluminum particle reactivity as a function of alumina shell structure: Amorphous versus crystalline." Powder Technology (2020). DOI: 10.1016/j.powtec.2020.06.084. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

Elsevier B.V.



File Format


Available for download on Sunday, July 03, 2022

Published Version