Divide and Combust: Effect of Morphology of CuO Nanowires on the Combustion Rate of Al Nanoparticle-CuO Nanowire Thermite Composites

Abstract

We examined the combustion rate of thermite composites of Al nanoparticles (NPs) and CuO nanowires (NWs). CuO NWs were synthesized by directionally attaching Cu(OH)(2) NPs, followed by oxidation process with heating at elevated temperatures. An X-ray diffraction analysis revealed that increasing the aging time of Cu(OH)(2) synthesis gives rise to CuO NWs of higher aspect ratio, while electron microscopy images showed that CuO NWs have similar diameter regardless of the aging time. A mixture of Al NPs and CuO NWs of varying aspect ratios was ignited in a closed-bomb pressurization chamber, where the pressure change was monitored within millisecond resolution. The pressurization rate upon the ignition of Al NPs/CuO NWs shows the highest value when CuO NWs appear to have a certain aspect ratio, which implies that both the homogeneity of the Al/CuO mixture and oxygen diffusivity within CuO crystals are relevant factors. The NWs provide a platform for systematic studies of the effects of dimensionality of nanomaterials for energy-efficient propulsion and explosive materials design