Phase stabilization of ammonium nitrate-based propellants using ferric oxide and manganese dioxide catalysts

Abstract Traditional booster rockets typically use solid propellants with Ammonium Perchlorate (AP) as the oxidizer. However, AP releases toxic chlorine gas during combustion, raising concerns about environmental impact and prompting the exploration of greener alternatives, such as Ammonium Nitrate (AN). Despite its potential, AN faces challenges due to phase transitions at room temperature. This study aims to stabilize AN’s phases to improve the performance of AN/AP-based composite solid propellants (CSPs) by adding ferric oxide (Fe 2 O 3 ) and manganese dioxide (MnO 2 ). The partial substitution of AP with AN is examined to overcome the limitations of pure AN-based propellants. Theoretical analyses are conducted to assess the effects of AN/AP-based propellants on performance parameters such as specific impulse (I sp ). Experimental studies involving burning rate, density measurements, and flame characterization reveal that the presence of AP and catalysts Fe 2 O 3 and MnO 2 , significantly enhances the burning rate and flame temperature, ensuring complete combustion. Additionally, these catalysts stabilize AN’s endothermic phase transitions and accelerate the decomposition of its breakdown products, leading to improved combustion in AN/AP-based propellants.