Reactive Materials with Burn Rate Adjusted by Initiation Method
Technical Report,15 Jun 2016,30 Mar 2020
New Jersey Institute of Technology Newark United States
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This work investigates combustion of nanocomposite thermite powders prepared by arrested reactive milling ARM. The focus is on how ARM as a top-down approach to nano-thermite building generating fully-dense nanocomposite particles with dimensions of 1100 m affects the rates and mechanism of their combustion. A variety of thermites are milled using both aluminum and zirconium as fuels combined with several oxidizers WoO3, MoO3, CuO, Fe2O3, and Bi2O3. The powders are ignited using both an electrostatic discharge ESD and a CO2 laser beam. A range of parameters vary in the first set of experiments in order to broadly understand the underlying combustion mechanisms of nanocomposite thermite powders. Only the aluminum thermites are considered in these experiments and had their particle sizes, preparation method milled, mixed, or electrosprayed, and milling times adjusted in order to see their effects on combustion. Additionally the ESD ignition experiments vary the environment between air, argon, and vacuum, as well as varying the ignition voltages from 5 up to 20 kV at a constant capacitance of 2000 pF. The ignited particles are monitored using a photomultiplier tube PMT equipped with an interference filter. It is observed that the reaction rates of the ESD-initiated powders are unaffected by their particle size but are affected by their scale of mixing between their fuel and oxidizer within the particles themselves. The different preparation methods play a significant role in determining the powders performance. Mixed nano-powders agglomerated quite easily, which hinder their combustion performance. The electrosprayed powders perform well in all environments, and the milled powders perform best in oxidizer-free environments when no reoxidation of the oxidizer could occur.
- Combustion and Ignition
- Miscellaneous Materials