Comparison of Performance of Fast‐Reacting Nanothermites and Primary Explosives

Abstract

ionel Borne 724 Solid-Liquid Adhesion Energies of Composite Propellant Components Determinedb yS olution Calorimetry Michael M. Nardai, ManfredA .B ohn 728 Modeling, Simulation and Characterization of Complex Shaped Solid PropellantC ombustion Sebastian Wurster 736 Evaluationo ft he James Initiation Criterion in the 21 mm and 50 mm PMMAG ap Te st Sebastian Wurster 749 R Re ev vi ie ew w The cover picture shows as even-hole propellant of type NK 1074 that was aged for 36 years at 35 8C, 40 8C, 45 8C, and 50 8C. The 50 8Cs ample shows serious decomposition with completel oss of the grain structure. The other samples do not show alarge differenceinoptical appearance. Periodic mass loss oscillationsf or A5020 propellant can be observed over the temperature range of 30 8Ct o7 08Cw ithout temperature dependence. Additionally the Arrheniusp lot for decompositionv ia mass loss for an A5200 propellant is shown. It shows av ery good correlation of the formal and the simplified model applied in mass loss analysis. Details are discussed in the article by Moritz Heil et al. on page7 06.

Nanothermites: A short Review. Factsheet for Experimenters, Present and Future Challenges

“…However, mixtures made from aluminum nanopowder stand out from energetic compositions, which are prepared from other nanosized fuels. The reaction of nano-sized aluminothermic mixtures gives particularly strong combustions, which are not detonations [23], but that still propagate at high velocities (0.1 to 2.5 km/s) [24]. The particular behavior of nano-Al based compositions could arise from the explosion of the core-shell structure of the aluminum nanoparticle upon ultrafast heating.…”

“…In the state of loose powder, nanothermites burn actually faster than any other micrometer-sized pyrotechnic composition, but they do not detonate and have lower flame propagation velocity (FPV) than explosives [23]. The main challenge is to increase their reactivity, either by playing on the nature of the oxidizer or by adding energetic gas generating substances.…”

“…Measuring the pressure and the temperature produced by the reaction of nanothermites and hybrid compositions, with high spatial and time resolution, is necessary for understanding the reaction mechanisms [105]. Determining the sound velocity in such compositions could give valuable information to define whether nanothermites can detonate or not, even though the analysis of existing data, which was performed by Khasainov et al, has led to conclude this was not possible [23]. Recently, Gottfried et al have inferred extremely high detonation velocity on hybrid nanocomposite materials Al/CuO/nitrocellulose (11.7 km/s) primed by a laser-induced air shock [106].…”

Emission Spectroscopy of the Combustion Flame of Aluminium/Copper Oxide Thermite

“…Thermites composed from aluminium and copper(II) oxide have interesting combustion properties because of the intermediate vaporization of copper formed by the reduction of CuO [12]. Nanometric types of this thermite are predominantly investigated for different applications [13] because of higher burning rates [14][15][16]. Mostly, the disadvantage of higher sensitivity in comparison to micrometric thermites [17] and the problems resulting from the occupational and environmental impact of nano-materials [18] is accepted.…”

Detailed Chemical Kinetic Models for Nanothermites Combustion

“…As underlined by Jian et al, another unresolved question is the way they react depending on the heating rates [5]. Issues concerning reaction mechanisms are also related to the propagation regimes because such materials support deflagration athigh flame propagation velocity [6,7]. However, the occurence of detonation in nanothermites is not nowadays assessed but because lots of different nanothermites are feasible this issue remains to be worked out, numerically and/or experimentally.…”