(605i) Preparation and Characterization Al-I Composite as Fuel Additives with Biocidal Combustion Products

ABSTRACT Multifunctional materials combining the high energy density of metal fuels with the biocidal activity of halogens are of interest for practical applications aiming to defeat stockpiles of chemical and biological weapons. This project is focused on development of nanocomposite Al-halogen materials to replace pure Al as a fuel additive in explosives. A simple and scalable synthesis technique based on mechanical alloying is used enabling preparation of hundreds of grams of powder-like materials necessary for testing of their energetic and biocidal characteristics. A previous study showed that aluminum-iodine composites with iodine concentrations from about 4 to 17 wt% can be prepared using elemental aluminum and iodine as starting materials by mechanical milling. In this work, different samples of an Al-I2 composite with about 10 wt % of iodine stabilized in the Al matrix were prepared and characterized. Materials with different properties were synthesized by varying milling conditions. The prepared powders were initially characterized by electron microscopy and x-ray diffraction. Both the decomposition (iodine release) and oxidation kinetics of such materials were studied using thermogravimetry at heating rate range of 5 ? 200 K/min. The activation energies for both decomposition and oxidation of the materials were calculated using Kissinger and Vyazovkin methods. Ignition temperatures of the prepared powders were determined at the heating rates of 2000 - 35000 K/s using an electrically heated filament. The correlations between ignition and oxidation kinetics are being analyzed. For selected samples, constant volume explosion experiments were used to characterize combustion performance of the produced powders. The burn time as a function of particle size was measured using a laser ignition measurement. Results will be presented and discussed in this paper.