Ammonium Perchlorate as an Effective Additive for Enhancing the Combustion and Propulsion Performance of Al/CuO Nanothermites

Abstract

Nanothermites are attracting much attention because of the high energy density, self-sustained exothermic reaction, and high combustion temperature. However, they suffer from sintering and incomplete combustion, leading to poor reactivity and low energy utilization efficiency. In order to enhance the energy output and combustion performance of nanothermites, ammonium perchlorate (AP) was introduced into the Al/CuO nanothermites. The nanothermites with varied content of AP were prepared by electrospray. The morphological characterization of the nanothermites confirms that the nanoparticles are homogeneously mixed without agglomeration. Heat release, specific impulse, and peak pressure of gaseous products exhibit remarkable enhancement with increasing AP content. Specifically, the nanothermites with 7.5 wt % AP produce specific impulse and heat energy of ∼2.7 and ∼1.4 times higher than those of Al/CuO-based nanothermites without AP. In addition, the ignition delay time of the nanothermites containing AP is not greatly increased, enabling fast response during practical applications. Thermal analysis implies that the thermite reaction between Al and CuO can be divided into two steps in the presence of AP: solid–solid phase and liquid–solid phase diffusion reaction. These results provide facile strategy to enhance the output performance of nanothermites, which may facilitate the practical propulsion and combustion applications of nanothermites.