Making nanostructured pyrotechnics in a beaker
Controlling composition at the nanometer scale is well known to alter material properties in sometimes highly desirable and dramatic ways. In the field of energetic materials component distributions, particle size, and morphology, effect both sensitivity and reactivity performance. To date nanostructured energetic materials are largely unknowns with the exception of nanometer-sized reactive powders now being produced at a number of laboratories. We have invented a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. The ease of this synthetic approach along with the inexpensive, stable, and benign nature of the metal precursors and solvents permit large-scale syntheses to be carried out. This approach can be accomplished using low cost processing methods. We will describe here, for the first time, this new synthetic route for producing metal-oxide-based pyrotechnics. The procedure employs the use of stable and inexpensive hydrated-metal inorganic salts and environmentally friendly solvents such as water and ethanol. The synthesis is straightforward and involves the dissolution the metal salt in a solvent followed by the addition of an epoxide, which induces gel formation in a timely manner. Experimental evidence suggests that the epoxide acts as an irreversible proton scavenger that induces the hydrated-metal species to undergo hydrolysis and condensation to form a sol that undergoes. further condensation to form a metal-oxide nanostructured gel. Both critical point and atmospheric drying have been employed to produce monolithic aerogels and xerogels, respectively. Using this method we have synthesized metal-oxide nanostructured materials using Fe{sup 3+}, Cr{sup 3+}, Al{sup 3+}, Ga{sup 3+}, In{sup 3+}, Hf{sup 4+}, Sn{sup 4+} and Zr{sup 4+} inorganic salts. Using related methods we have made nanostructured oxides of Mo, Ti, V, Co, Ni, Cu, Y , Ta, W, Pb, B, Pr, Er, Nd and Si. These materials have been characterized using optical and electron microscopy, infrared spectroscopy, surface area, pore size, and pore volume analyses. The epoxide addition sol-gel technique is amenable the addition of insoluble materials (e.g., metals or polymers) to the viscous sol, just before gelation, to produce a uniformly distributed and energetic nanocomposite upon gelation. As an example energetic nanocomposites of Fe{sub x}O{sub y} and metallic aluminum are easily synthesized. The compositions are stable, safe and can be readily ignited. Production and characterization data of these novel energetic materials will be presented.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15007525
- Report Number(s):
- UCRL-JC-137593; TRN: US200419%%61
- Resource Relation:
- Conference: International Pyrotechnics Seminars, Grand Junction, CO (US), 07/17/2000--07/21/2000; Other Information: PBD: 10 Apr 2000
- Country of Publication:
- United States
- Language:
- English
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