HTPFA-Coated AlB₂ with Enhanced Combustion Performance as a High-Energy Fuel

High-energy boron-based fuel aluminum-diboride (AlB₂) has attracted much attention in the field of solid propellants. However, the low reactivity of AlB₂ hindered its further application. In this study, highly reactive AlB₂@hydroxyl-terminated perfluoropolyether alcohol (AlB₂@HTPFA) composites with a core-shell structure were prepared by coating AlB₂ with functionalized fluoropolymers by using a facile one-step in situ polymerization method. AlB₂@HTPFA composites with varying polymer contents (0, 5, 10, and 15 wt%) were obtained. The in situ polymerization strategy enables precise control over the polymer coating thickness and interfacial interactions, which is critical for optimizing the reactivity and thermal stability of composites. The morphology and structure were characterized, and the microcore-shell structure of AlB₂@HTPFA was obtained. Compared with raw AlB₂, the combustion efficiency of coated fuel increased by 4.1%, 5.6%, and 7.5%, respectively, with varying polymer contents. Meanwhile, the reactivity of AlB₂@HTPFA (5 wt%) was 0.65 MPa/s, which is ~1.5 times that of AlB₂. Additionally, the ignition and combustion characteristics of AlB₂@HTPFA were investigated by laser ignition experiments with potassium perchlorate (KP) as an oxidant. The results revealed that AlB₂@HTPFA/KP composites showed a greatly reduced combustion duration compared to uncoated AlB₂. The ignition and combustion enhancement mechanism of AlB₂@HTPFA was proposed. During the ignition process, the existence of HTPFA can result in a pre-ignition reaction, thus raising its reaction activity. This work provided a promising candidate for high-energy fuel that can be used in energetic materials.