Preparation of core-shell structured Al-5Li@HTPB powders with improved stability and combustion performance by using perfluoroalkylsilane as a surfactant

Aluminum-lithium alloy powder exhibits better thermal properties and combustion performances than aluminum, thus showing promising applications in the field of energetic materials such as explosives and propellants. However, the high activity of lithium also raises issues of stability and compatibility with propellant components, deteriorating the powder's overall performance. In this study, a facile coating method is presented using 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTS) as a surfactant to coat hydroxyl‑terminated polybutadiene (HTPB) on the surface of Al-5Li powder, forming the core-shell composite Al-5Li@HTPB. The microstructure and chemical composition characterized by SEM, EDS, XPS, FT-IR, and nano-CT demonstrated that a uniform and dense layer was successfully coated on the surface. The thermal analysis results showed a significant improvement in the thermal properties and stability compared to pure Al-5Li. In addition, ignition tests were conducted, and the results showed that Al-5Li@HTPB could reduce the ignition delay time and significantly reduce agglomeration. Overall, our strategy provides a novel method to solve the stability issues of Al-Li powders and simultaneously enhance combustion performance.