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

TL;DR

This paper introduces a new high-energy fuel by coating aluminum-diboride with a fluoropolymer, which improves its combustion performance and reactivity.

Contribution

A novel core–shell AlB2@HTPFA composite is developed using in situ polymerization to enhance fuel reactivity and combustion efficiency.

Findings

Coated AlB2 showed 4.1% to 7.5% higher combustion efficiency compared to uncoated AlB2.

AlB2@HTPFA (5 wt%) exhibited 1.5 times higher reactivity than raw AlB2.

The HTPFA coating reduced combustion duration and improved ignition characteristics with potassium perchlorate.

Abstract

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.

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