Electro-static discharge ignition of monolayers of nanocomposite thermite powders prepared by Arrested Reactive Milling

Ian Monk, Rayon Williams, Xinhang Liu, Edward Dreyzin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Reactive nanocomposite powders with compositions 2Al·3CuO, 2.35Al·Bi2O3, 2Al·Fe2O3, and 2Al·MoO3 were prepared by arrested reactive milling, placed in monolayers on a conductive substrate and ignited by an electro-static discharge (ESD) or spark in air, argon, and vacuum. The ESD was produced by discharging a 2000 pF capacitor charged to a voltage varied from 5 to 20 kV. Emission from ignited particles was monitored using a photomultiplier equipped with an interference filter. Experimental variables included particle sizes, milling time used to prepare composite particles, surrounding environment, and starting ESD voltage. All materials ignited in all environments, producing individual burning particles that were ejected from the substrate. The spark duration varied from 1 to 5 μs; the duration of the produced emission pulse was in the range of 80 - 250 μs for all materials studied. The longest emission duration was observed for the nanocomposite thermite using MoO3 as an oxidizer. The reaction rates of the ESD-initiated powders were defined primarily by the scale of mixing of and reactive interface area between the fuel and oxidizer in composite materials rather than by the external particle surface or particle dimensions. In vacuum, particles were heated by ESD while remaining on the substrate until they began generating gas combustion products. In air and argon, particles initially pre-heated by ESD were lifted and accelerated to ca. 100 m/s by the generated shock wave; the airborne particles continued self-heating due to heterogeneous redox reactions.

Original languageEnglish (US)
Title of host publicationRecent Advances in Reactive Materials
EditorsD. Adams, K. Sullivan, E. Dreizin, H. H. Hng
PublisherMaterials Research Society
Pages19-24
Number of pages6
ISBN (Electronic)9781510806320
DOIs
StatePublished - Jan 1 2015
Event2014 MRS Fall Meeting - Boston, United States
Duration: Nov 30 2014Dec 5 2014

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1758
ISSN (Print)0272-9172

Other

Other2014 MRS Fall Meeting
Country/TerritoryUnited States
CityBoston
Period11/30/1412/5/14

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Keywords

  • Heterogeneous reactions
  • Ignition delay
  • Reactive materials
  • Spark ignition

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