Design and Characterization of Tannic Acid-Iron and Metal Oxides Functionalized Aluminum Powders for Improved Ignition and Combustion Efficiency

A dense tannic acid-iron (TA-Fe) and metal oxide layer was successfully encapsulated on the surface of spherical aluminum powder via in situ polymerization and liquid-phase deposition. This process yielded core-shell composites (Al@TA-Fe@M_xO_y) designed to address the challenges of poor combustion performance and extended ignition delays associated with raw aluminum powder. After characterization, it was found that the Al@TA-Fe@M_xO_y composites exhibit a well-defined core-shell structure with uniform and compact cladding layers. These composites displayed lower activation energies (1.925 × 10⁵ and 2.021 × 10⁵ J/mol for Al@TA-Fe@CoO and Al@TA-Fe@CuO, respectively) than that of raw aluminum (3.326 × 10⁵ J/mol), alongside reduced initial reaction temperatures (400-470 °C), no ignition delay, and smaller condensed-phase residues. Collectively, these attributes significantly enhanced the ignition and combustion performance of aluminum powder. This study underscores the potential of functionalized aluminum-based fuels in solid propellants, offering promising applications in energetic material systems.