Aluminum-Rich Al-MoO3 Nanocomposite Powders Prepared by Arrested Reactive Milling

2008 ◽  
Vol 24 (2) ◽  
pp. 192-198 ◽  
Author(s):  
Swati M. Umbrajkar ◽  
Soumitri Seshadri ◽  
Mirko Schoenitz ◽  
Vern K. Hoffmann ◽  
Edward L. Dreizin
Keyword(s):  
Reactive Milling ◽  
Nanocomposite Powders ◽  
Arrested Reactive Milling

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

2015 ◽  
Vol 1758 ◽  
Author(s):  
Ian Monk ◽  
Rayon Williams ◽  
Xinhang Liu ◽  
Edward L. Dreizin
Keyword(s):  
Particle Surface ◽  
Combustion Products ◽  
Reaction Rates ◽  
Interference Filter ◽  
Gas Combustion ◽  
Reactive Milling ◽  
Discharge Ignition ◽  
Reactive Interface ◽  
Arrested Reactive Milling ◽  
Static Discharge

AbstractReactive 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.

scholarly journals Preparation and Characterization of Silicon-Metal Fluoride Reactive Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2367
Author(s):  
Siva Kumar Valluri ◽  
Mirko Schoenitz ◽  
Edward Dreizin
Keyword(s):  
Metal Fluoride ◽  
Composite Powders ◽  
Particle Combustion ◽  
Reactive Milling ◽  
Lower Temperature ◽  
Thermoanalytical Measurements ◽  
Arrested Reactive Milling ◽  
Heated Filament ◽  
Measured Particle

Fuel-rich composite powders combining elemental Si with the metal fluoride oxidizers BiF3 and CoF2 were prepared by arrested reactive milling. Reactivity of the composite powders was assessed using thermoanalytical measurements in both inert (Ar) and oxidizing (Ar/O2) environments. Powders were ignited using an electrically heated filament; particle combustion experiments were performed in room air using a CO2 laser as an ignition source. Both composites showed accelerated oxidation of Si when heated in oxidizing environments and ignited readily using the heated filament. Elemental Si, used as a reference, did not exhibit appreciable oxidation when heated under the same conditions and could not be ignited using either a heated filament or laser. Lower-temperature Si fluoride formation and oxidation were observed for the composites with BiF3; respectively, the ignition temperature for these composite powders was also lower. Particle combustion experiments were successful with the Si/BiF3 composite. The statistical distribution of the measured particle burn times was correlated with the measured particle size distribution to establish the effect of particle sizes on their burn times. The measured burn times were close to those measured for similar composites with Al and B serving as fuels.

Nano-Composite Energetic Powders Prepared by Arrested Reactive Milling

2005 ◽  
Author(s):  
Trent Ward ◽  
Wenliang Chen ◽  
Mirko Schoenitz ◽  
Edward Dreizin ◽  
Rajesh Dave
Keyword(s):  
Nano Composite ◽  
Reactive Milling ◽  
Arrested Reactive Milling

Zirconium-boron reactive composite powders prepared by arrested reactive milling

2019 ◽  
Vol 38 (2) ◽  
pp. 142-161 ◽  
Author(s):  
Daniel Hastings ◽  
Mirko Schoenitz ◽  
Edward L. Dreizin
Keyword(s):  
Composite Powders ◽  
Reactive Milling ◽  
Arrested Reactive Milling
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