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Sulfates‐Based Nanothermites: An Expanding Horizon for Metastable Interstitial Composites
Author(s) -
Comet Marc,
Vidick Geoffrey,
Schnell Fabien,
Suma Yves,
Baps Bernard,
Spitzer Denis
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201410634
Subject(s) - sulfur , sulfate , decomposition , metal , combustion , metastability , standard enthalpy of formation , materials science , chemistry , inorganic chemistry , chemical engineering , composite material , metallurgy , organic chemistry , engineering
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 (SO 3 2− , S 2 O 3 2− , S 2 O 8 2− ) which opens up new horizons in the domain of metastable interstitial composites.