Nanostructured energetic materials using sol-gel methodologies

We have utilized a sol-gel synthetic approach in preparing nano-sized trans ition metal oxide components for new energetic nanocomposites. Nanocomposit es of Fe2O3/Al(s), are readily produced from a solution of Fe(lll) salt by adding an organic epoxide and a powder of the fuel metal. These materials c an be processed to aerogel or xerogel monolithic composite solids. High res olution transmission electron microscopy (HRTEM) of the dried energetic nan ocomposites reveal that the metal oxide component consists of small (3-10 n m) clusters of Fe2O3 that are in intimate contact with ultra fine grain (UF G) similar to 25 nm diameter Al metal particles. HRTEM results also indicat e that the Al particles have an oxide coating similar to5 nm thick. This va lue agrees well with analysis of pristine UFG Al powder and indicates that the sol-gel synthetic method and processing does not significantly perturb the fuel metal. Both qualitative and quantitative characterization has show n that these materials are indeed energetic. The materials described here a re relatively insensitive to standard impact, spark, and friction tests. re sults of which will be presented. Qualitatively, it does appear that these energetic nanocomposites burn faster and an mon sensitive to thermal igniti on than their conventional counterparts and that aerogel materials are more sensitive to ignition than xerogels. We believe that the sol-gel method wi ll at the very least provide processing advantages over conventional method s in the areas of cost, purity, homogeneity, and safety and potentially yie ld energetic materials with interesting and special properties. (C) 2001 Pu blished by Elsevier Science B.V.