Divide and combust: Effect of morphology of CUO nanowires on the combustion rate of al nanoparticle-CUO nanowire thermite composites

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.