Effects of Oxidizer and Architecture on the Thermochemical Reactivity, Laser Ignition and Combustion Properties of Super-Thermite

Abstract

Energetic materials have been widely employed in both military and aerospace fields. Super-thermite has superior energy properties and better combustion performance compared with conventional organic energetic materials. In this paper, a novel nitrocellulose coated aluminum/copper ferrite (Al/CuFe₂O₄@NC) thermite composite with controllable energy release was assembled via electrospray. The intimate contact and uniform distribution between the fuel (Al) and oxidizer (CuFe₂O₄) nanoparticles are achieved in Al/CuFe₂O₄@NC microparticles. The thermochemical reactivity, laser ignition and combustion performance of Al/CuFe₂O₄@NC were investigated and compared with those of Al/CuO or Fe₂O₃@NC and physical mixtures of Al and CuFe₂O₄. The heat release of Al/CuFe₂O₄@NC reaches up to 960.7 J·g^-1 and increases by 78.1%, 32.7% and 26.3% compared with Al/CuO@NC (539.4 J·g-1), Al/Fe₂O₃@NC (724.1 J·g^-1) and Al + CuFe₂O₄ (760.8 J·g^-1) under the same conditions, respectively. Al/CuFe₂O₄@NC composites show a short ignition delay time of ~ 4.5 ms and a controllable combustion process. Moreover, the burning rates of Al/CuFe₂O₄@NC can be adjusted in the range of ~ 0.38-1.72 m·s^-1 by varying the NC content in composites. These results indicate that the oxidizer and architecture have considerable effect on the thermochemical reactivity, energy release and combustion performance of thermite composites. The large heat release and superior combustion performance can be achieved by electrospray technology which is an effective approach for enhancing interfacial contact and improving reactivity.

Keywords: electrospray, super-thermite, thermochemical reactivity, laser ignition, Combustion