Preparation of microstructure controllable CL-20/FOX-7 composite microspheres by microchannel recrystallization technology to enhance safety and combustion performance

Realizing the balance between high energy density and multifunctionality of energetic materials is a hot spot in current research, and its study is of great significance for the application of energetic materials. Regulating microstructure is widely recognized as an effective strategy for solving such problems. In this paper, four different microstructures of Hexanitrohexaazaisowurtzitane(CL-20)/1,1-diamino-2,2-dinitroethylene(FOX-7) composite microspheres, namely, hollow, porous irregular microspheres, porous microspheres, and layered porous microspheres, were prepared by microchannel recrystallization technology. The effects of crystal precipitation rate, binder mechanical properties, and purity of water phase on the microstructure of composite microspheres were systematically investigated. The four prepared samples were spherical particles with regular morphology and uniform particle size. The angle of repose and mechanical sensitivity tests showed that the CL-20/FOX-7 composite microspheres had good dispersibility and mechanical sensitivity. Ignition experiments show that hollow microspheres have the best energy release efficiency, while porous microspheres have higher energy density and more stable energy release efficiency. The results show that the combustion performance and safety of the composite microspheres can be effectively enhanced by adjusting the microstructure. Microchannel recrystallization technology can realize the controllable preparation of the microstructure of composite microspheres, which provides a reference for the design and preparation of other composite microspheres.