|Acquisition Program: ||PM Future Combat Systems Brigade Combat Team|| Objective: ||The overall objective of this proposal is to design and develop new advanced Reactive Materials (RM) with reduced electrostatic discharge (ESD) sensitivity for ammunition applications. To promote safe handling of this advanced RMs, suitable coating methods will be developed to reduce their electrostatic discharge (ESD) sensitivity. The energetic material will, in general, consist of nanothermite materials and composites thereof. The coated safe material can be both in the form of pallets and powders.
|| Description: ||Reactive materials have major defense applications in developing futuristic weapon systems. In an integrated device, energy release at the target are related to the structural components such as payload casing, bomb casing (for fragment formation) etc. If these components can be made out of energetic materials, then, total energy delivered to the target can be increased . Metal-Metal/Oxide (nanothermite) composition in nanoscale is an excellent choice for use as the initiator for secondary energetic materials, because of its ability to exhibit tunable performance and generate high temperatures during chemical reactions between the oxidizer and the fuel [2-5]. The use of thermite materials as a structural element of weapon system can increase energy delivered to the target and increase efficiency of hit the target factor. The synthesis of self assembled nanocomposite consisting of oxidizer and fuel will produce nanoenergetic materials with superior combustion characteristics. One of the key problems preventing the extensive use of this kind of energetic material is the extremely high sensitivity of nanothermites to electrostatic discharge (ESD). Typically values of ESD sensitivity for bare nanothermite composition are less than 1 mJ. Special additives and formulation techniques can increase energy of spark discharge to initiate nanothermite compositions. For example, suitable composition of copper oxide / aluminum nanothermites, selective polymers and electrically conducting materials can pass up to a safe energy level of accidental spark discharge. This level of insensitivity is expected to be acceptable for safe handling such as for military and commercial application. The Electrostatic Sensitivity Test is described in MIL-STD-1751A, dated 11 December 2001, Method 1032, "ESD (Electrostatic Discharge) Sensitivity Test (ARDEC(Picatinny Arsenal)Method)". The formulated sample containing these RM should not react in 20 trials at 0.25 joule (the maximum energy level of the test apparatus) if used in HE applications. Pass/Fail safety criteria for primary, booster, or main charge explosive formulations are listed in MIL-STD_1751A including: impact sensitivity, friction sensitivity, electrostatic sensitivity, stability at constant temperature, self-heating, compatibility, detonation velocity, critical diameter, shock sensitivity, hot wire ignition, exudation and growth safety tests.
|| ||PHASE I: Development of Reactive Materials and evaluation of their performance in terms of combustion wave speed, pressure, reactivity and ESD Sensitivity will be undertaken in the Phase I. The formulations will be developed for composites of nanothermites with polymers, explosives and electrically conducting polymers. The novel materials should produce desired combustion performance and safe handling level. The integration of nanothermite composition with advanced materials like carbon nanotubes, graphite nanoparticles etc will also be carried out. The phase I plan will include development of the right combination of materials’ compositions and optimize their synthesis procedures to solve the most important problem (high ESD sensitivity of bare nanothermites) limiting the practical use of the nanothermite compositions. The proof of concept will be established during this effort. If the optimized formulations including these RMs pass the ESD test according to the pass/fail criteria stated in MIL-STD 1751A for any or all of the specified applications (ie. booster explosives, primary explosives, etc.), Phase II can begin.
|| ||PHASE II: Systematic investigation of the performance and aging studies of the developed RMs with reduced sensitivity in Phase I will be performed The Scale-up of the most successful composition preparation technology to produce 1-50 pounds (lb.) of advanced RMs in the shape of pallets and powders for testing at ARDEC Facility and its affiliates in this cooperative program will be explored in Phase II.
|| ||PHASE III: Commercialization of the technology will be undertaken in the third phase through strategic partnership. Other than defense needs, the business plan is expected to include dual-use applications as for military and commercial technology.
|| References: ||
1. “Advanced Energetic Materials”, Committee on Advanced Energetic Materials and Manufacturing Technologies, National Research Council, ISBN: 0-309-09160-8, 64 pages, 8 1/2 x 11, (2004) Source: http://www.nap.edu/catalog/10918.html and the references therein.
2. MRS Proceedings Volume 896: “Multifunctional Energetic Materials”, 2006 and the references therein.
3. Richard H. B. Bouma, Denise Meuken, Ries Verbeek, Maria Martinez Pacheco, and Laurens Katgerman, “Shear Initiation of Al/MoO3-Based Reactive Materials”, Propellants, Explosives, Pyrotechnics 32(6), 2007, 447 – 453.
4. Prakash, A., McCormick, A.V, Zachariah, M.R "Thermo-kinetic study of core-shell nanothermites”, 845 II, 2006, 1006-1009 AIP Conference Proceedings
5. Puszynski J.A, Buhan, C.J., Swiatkiewicz, J.J, “Processing and ignition characteristics of aluminum-bismuth trioxide nanothermite system”. Journal of Propulsion and Power 23(4) 2007, 698-706.
|Keywords: ||Nanoenergetics, Nanothermites, ESD sensitivity, Reactive Materials, Coating methods, Performance, Aging |