The purpose of this article is to alert our peers on the danger faced by those who carry out experiments involving molten ammonium dinitramide (ADN). In recent experiments aiming at preparing submicron particles of this compound, a preliminary study of the sensitivity to impact of molten ADN was performed. These first tests have shown that the sensitivity threshold of molten ADN to impact is more than one order of magnitude lower that the one on solid ADN (< 0.25 J vs. 4 J) and similar to the one of nitroglycerin (< 0.25 J), making liquid ADN extremely hazardous to handle. Detonation tests, which were performed in strong steel sheaths open to one end, have shown that the initiation of the detonation and its subsequent propagation occur both in solid and liquid ADN charges, having a diameter of only 4 mm. The critical diameter of solid ADN which is between 25 and 40 mm according to literature, is therefore decreased by at least an order of magnitude when ADN is placed in strong metallic confinement. On the other hand, the detonation of liquid ADN produces stronger destructive effects than the detonation of solid ADN, meaning that the detonation mechanisms of this explosive are different in its two physical states. In conclusion, liquid ADN must be considered in practice as a more hazardous and powerful explosive than solid ADN. This raises the issue of all experiments in which ADN is likely to be formed in molten state.
This article reports on a new family of detonating compositions in which ammonium dinitramide (ADN) is used as an explosive oxidizer, and red phosphorus (P r ) or titanium hydride (TiH 2 ) as fuels. At optimized ADN/fuel ratios, these compositions have typical explosion heats higher than 7 kJ/g, detonation velocities in 3 mm diameter tubes ranging from 1.2 to 2.0 km/s at~40 % of their theoretical maximum density, with a run to detonation distance between 20 and 40 mm. Both compositions are insensitive to electrostatic discharge, but are very sensitive to impact and friction, ADN/P r mixtures being the most sensitive to these stress. The shockwave released by the reaction of these materials, efficiently initiates the detonation of high explosives such as pentaerythritol tetranitrate (PETN) or hexogen (RDX). In view of these characteristics, ADN-based detonating compositions must be considered as "green" substitutes for primary explosives containing heavy metals.
Composite energetic nanomaterials, otherwise known as nanothermites, consist of physical mixtures of fuel and oxidizer nanoparticles. When a combustion reaction takes place between both components, extremely impressive conditions are created, such as high temperatures (>1000 °C), intense heat releases (>kJ/cm3), and sometimes gas generation. These conditions can be adjusted by modifying the chemical nature of both reactants. However, these energetic composites are extremely sensitive to electrostatic discharge. This may lead to accidental ignitions during handling and transportation operations. This study examines the use of a n-type semiconductor ITO material as an alternative oxidizer combined with aluminum fuel. Indium tin oxide (ITO) ceramic is widely used in the elaboration of conducting coatings for antistatic applications because of its ability to conduct electrical charges (n-type semiconductor). The energetic performance of the Al/ITO thermite was determined, i.e., the sensitivity threshold regarding mechanical (impact and friction) and electrostatic discharge (ESD) stresses, as well as the reactive behavior (heat of reaction, combustion front velocity). The results demonstrate insensitivity toward mechanical stresses regardless of the ITO granulometry. As regards the spark sensitivity, using ITO microparticles considerably raises the sensitivity threshold value (<0.21 mJ vs. 13.70 mJ). A combustion velocity of nearly 650 m/sec was also determined.
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