Perovskite fluoride NH₄MnF₃ as a dual-functional reaction modifier for aluminum-based energetic composites

The design and fabrication of energetic composites with high energy output and tunable combustion behavior hold great promise for expanding their advanced applications. Aluminum powder, while widely used as metal fuel in energetic composite due to its high oxidation heat, faces limitations in reaction kinetics and efficiency resulted from the surface oxide barrier. To address this challenge, herein a perovskite fluoride NH₄MnF₃ was introduced as a novel dual-functional component to overcome this oxide barrier through interfacial fluorination, leveraging its unique thermal decomposition into reactive HF gas and solid MnF₂. On one hand, the fluorides produced from NH₄MnF₃ can exothermically react with Al at relatively low temperature, demonstrating its capability as a moderate oxidizer. On the other hand, the incorporation of NH4MnF3 is found to enhance the oxidation efficiency of Al in various scenarios, whether by a solid oxidizer (MnO₂) or by atmospheric oxygen. The optimized ternary composites containing 20 wt% NH₄MnF₃ exhibited high heat releases (2.86 kJ/g in argon and 6.32 kJ/g in air) and declined ignition temperature, attributed to the synergy between fluorination and oxidation. This work pioneers the functionality of ammonium metal fluoride in oxidation of Al, offering constructive insight into the design of advanced energetic composites. © 2025 Elsevier B.V.