title: Sulfates-based nanothermites: an expanding horizon for metastable interstitial composites.
abstract: Metal sulfates (Ba, Bi, Ca, Cu, Mg, Mn, Na, Zn, Zr) were used as oxidizers in reactive compositions with Al nanopowder. These new kinds of nanothermites have outstandingly high reaction heats (4-6 kJ g(-1) ) compared to conventional Al/metal oxides (1.5-4.8 kJ g(-1) ) and also have good combustion velocities (200-840 m s(-1) vs 100-2500 m s(-1) ). These compositions are extremely insensitive to friction making their preparation and handling easy and safe. The sulfate hydration water increases the reaction heats and has a significant effect on the sensitivity to impact and to electrostatic discharge. The reaction of Al with water is easier to initiate than the one with sulfate which leads to two possible decomposition modes for samples exposed to an open flame. The pyrotechnical properties observed with sulfates have also been found for other sulfur oxygenates (SO3 (2-) , S2 O3 (2-) , S2 O8 (2-) ) which opens up new horizons in the domain of metastable interstitial composites.
authors.affiliation: NS3E-ISL-CNRS-Unistra (Nanomatériaux pour les Systèmes Sous Sollicitations Extrêmes) UMR 3208, French-German Research Institut of Saint-Louis, 5 rue du Général Cassagnou, B.P. 70034, 68301 Saint-Louis Cedex (France).
authors.forename: Marc
authors.initials: M
authors.lastname: Comet
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Vidick
authors.forename: Fabien
authors.initials: F
authors.lastname: Schnell
authors.forename: Yves
authors.initials: Y
authors.lastname: Suma
authors.forename: Bernard
authors.initials: B
authors.lastname: Baps
authors.forename: Denis
authors.initials: D
authors.lastname: Spitzer
keywords: aluminum; metastable compounds; nanoparticles; reactivity; sulfur