title: Nanodiamond for tuning the properties of energetic composites.
abstract: Bismuth oxide (Bi2O3) particles were coated by detonation nanodiamonds. The resulting nanocomposite materials were mixed with an aluminum nanopowder (≈ 100 nm) to prepare nanothermites, with reduced sensitivity to friction and electrostatic discharge (ESD). The use of nanodiamond for this purpose is reported here for the first time. Their numerous qualities such as their small size, antifriction properties and thermal conductivity make them ideal candidates. Small amounts of detonation nanodiamonds allow obtaining impressive desensitization, making thus modified Bi2O3/Al nanothermite safe to handle. A composition containing around 1 wt.% of nanodiamond has a sensitivity threshold to friction superior to 100 N instead of 5 N for the thermite without nanodiamond. Furthermore, the sensitivity threshold to electrostatic discharge increases to 20 times when the nanodiamond content reaches 1.8 wt.%. The antifriction properties of nanodiamond limit the scratching of Bi2O3 surface by Al particles. The desensitization to ESD is observed for a sufficient coverage of the oxide particles (1.8 wt.% of ND), which restrains the effect of the melt dispersion mechanism of aluminum and prevents the mixing of the oxidizing and the reducing parts of the composites. A good reactivity of the thermite could be maintained for nanodiamond content up to 2.6 wt.%. The carburizing of aluminum coming on contact with nanodiamond during the thermite reaction could be evidenced by X-ray Diffraction and calorimetry measurements and also participates to the desensitization of the nanothermite. This kind of desensitization by using detonation nanodiamond can also be applied to other nanothermites having low sensitivity threshold to friction and ESD.
authors.affiliation: NS3E "Nanomatériaux pour les Systèmes Sous Sollicitations Extrêmes" UMR 3208 ISL/CNRS/UNISTRA French German Research Institute of Saint-Louis (ISL), 5 rue du général Cassagnou, 68301, Saint-Louis, France. Electronic address: vincent.pichot@isl.eu.
authors.forename: Vincent
authors.initials: V
authors.lastname: Pichot
authors.affiliation: NS3E "Nanomatériaux pour les Systèmes Sous Sollicitations Extrêmes" UMR 3208 ISL/CNRS/UNISTRA French German Research Institute of Saint-Louis (ISL), 5 rue du général Cassagnou, 68301, Saint-Louis, France. Electronic address: marc.comet@isl.eu.
authors.forename: Marc
authors.initials: M
authors.lastname: Comet
authors.affiliation: NS3E "Nanomatériaux pour les Systèmes Sous Sollicitations Extrêmes" UMR 3208 ISL/CNRS/UNISTRA French German Research Institute of Saint-Louis (ISL), 5 rue du général Cassagnou, 68301, Saint-Louis, France. Electronic address: julien.miesch@isl.eu.
authors.forename: Julien
authors.initials: J
authors.lastname: Miesch
authors.affiliation: NS3E "Nanomatériaux pour les Systèmes Sous Sollicitations Extrêmes" UMR 3208 ISL/CNRS/UNISTRA French German Research Institute of Saint-Louis (ISL), 5 rue du général Cassagnou, 68301, Saint-Louis, France. Electronic address: denis.spitzer@gmail.eu.
authors.forename: Denis
authors.initials: D
authors.lastname: Spitzer
keywords: Detonation nanodiamonds; Energetic compositions; Reactive properties; Sensitivities