Interfacial engineering of aluminum powder with a tannic acid/Fe³⁺ complex and fluorosilane for high-performance energetic composites

Constructing a multifunctional coating on aluminum (Al) powder is crucial for enhancing its energy release in propellants. However, existing methods face challenges such as complex processes, high costs, and poor controllability. This study proposes a simple self-assembly strategy to construct a dual core-shell structure on aluminum powder surfaces, consisting of an inner tannic acid-Fe³⁺ (TA-Fe) network and an outer fluorosilane (PDTTS) layer, thus successfully fabricating the Al@TA-Fe@PDTTS composite. Molecular dynamics simulations reveal a strong binding energy among the coating components, providing theoretical support for the successful realization of the self-assembly process. The resulting Al@TA-Fe@PDTTS composite exhibits excellent hydrophobicity (contact angle up to 123.7°) and significantly promotes the cracking of the inert alumina shell. Serving as a combined fuel and catalyst, the composite significantly lowers the high-temperature decomposition peak of ammonium perchlorate (AP) by 41.9 °C. Furthermore, laser ignition tests confirm a substantially shortened ignition delay (from 13.2 ms for aluminum/AP mixtures to only 4.8 ms for the composite material) and a more intense combustion process, highlighting its great potential for advanced energetic applications.