Enhancing solid rocket propellants with nano-additives: a review of thermal and kinetic performance
Rahul Kumar, Deepak Sharma, Yarrapragada K. S. S. Rao, Ashish Kumar, Madan Dubey, Shri Krishna Mishra, Ashu Yadav
Abstract
This study critically focuses on the recent trends concerning ammonium perchlorate (AP) based solid rocket propellants with nano-additives, focusing on their thermal and kinetic parameters such as activation energy, burning rate, thermal decomposition temperature, and apparent heat of thermal decomposition, providing a brief overview of the overall efficiency of the propellant, and can be used as a baseline for further research. Although AP is one of the most widely used solid rocket propellants, it suffers from low burning rates, thermal sensitivity at high temperatures, catalytic decomposition, sensitivity to shock and friction, and lower combustion efficiency as a whole, including environmental concerns due to its emission of hydrochloric acid on combustion, which not only affects its efficiency but also its marketability as industries related to aerospace and defence focus mainly on high-efficiency propulsion solutions. Nano-additives varying between metallic forms, represented by aluminium, iron oxide (Fe 2 O 3 ), and magnesium, and non-metallic forms based on graphene and carbon nanotubes-focus on enhancing the thermal and kinetic parameters of AP while reducing the toxic fumes released. The key findings from this review include a significant reduction in decomposition temperature and activation energy, along with a general increase in burning rate and heat of decomposition, which yields a much more efficient propellant. Using metal-based (e.g., Fe 2 O 3 ) and carbon-based (e.g., graphene oxide, carbon nanotubes) additives can reduce HCl emissions from AP combustion by 35–60% compared to baseline formulations, lowering exhaust chlorine content from 19 wt% to below 8–12 wt%, meeting environmental acceptability thresholds for aerospace applications.