Preparation And Properties Of Energetic Aluminum Nanocomposite Particles

With the increasing requirements of efficient damage and rapid assault-defense and other performances for modern weapons, energetic materials, as the weapon energy carrier, also need to constantly upgrade. Nano-aluminum become an important component of Energetic Materials due to its characteristics of high activity, high calorific value and a high burning rate, and it has great prospects in energetic field, for example, solid propellant and super thermite, however, nano-aluminum can easily be oxidized and become inactivated, so the study of nano aluminum surface coating technology is particularly important.In this paper, high-activity Al nanopowder was prepared by a DC arc discharge plasma, then the active powders were collected under the protection of inert gas and sealed by anhydrous ethanol to separate from air. The surface modification of the nanopowders was carried out by KH-550, while an organic components propellant of hydroyl-terminated polybutadiene (HTPB) as the coating agent, and isophorone diisocyanate (IPDI) as the curing agent, to prepare a well covered core-shell structure of Al/HTPB composite particles. The composite particles were coated with uniformly dense layers in the thickness of about 4nm. It is indicated by FTIR and TG-DSC analysis that the cladding layer is cured by HTPB, and the overall exotherm has recahed 5.229 KJ/g. the dispersion tests show that HTPB-coated aluminum nanopowders have the changed physical and chemical properties of the their surface, as a result the aluminum nanopowders changed from an oleophobic to the lipophilic state, which greatly improve the moisture resistance and organic solvent dispersion abilities, and the compatibility between aluminum nanopowders and the propellants.In order to achieve a high activealuminum in the applications of super thermite, using the HTPB-coated aluminum nanopowders as the raw material and Fe(NO3)3·9H2O ethanol solution as a precursor, the Fe2O3/HTPB/Al nanocomposite energetic materials were fabricated by a sol-gel method. XRD analysis indicates that such nanocomposite is protected by the HTPB polymer cladding layer, and can not be corroded by a low pH and high temperature condition. TEM shows that the aluminum nanoparticles is in spherical or quasi-spherical shapes with the diameter of about 40 nm, and tightly coated by Fe2O3 fine particles, without serious reunion. FTIR shows that the presence of Fe2O3 and HTPB in composite particles. BET analysis shows that the specific surface area of Fe2O3/HTPB/Al nanocomposite is 24.842 m2/g.A hybrid-spray method was utilized for polymeric coating of the hydroxyl terminated polybutadiene (HTPB) on the surface of high active Al NPs. It is indicated that the HT coating can be completely carried out to form high-quality assemblies in micrometers scalesizes, which can prevent circumambient oxygen from infiltration and reaction with the active Al NPs, meanwhile, favors to preserve the assemblies for a long-term.