Synthesis of Al/B/graphite fluoride microspheres with enhanced energetic properties

Aluminum (Al) is one of the most widely used metal fuels in the fields of automotive airbags, solid propellants, explosives and pyrotechnics. Unfortunately, it is hard to meet further demand of practical applications owing to the comparatively low calorific value. Herein, graphite fluoride (CF) and boron (B) are employed to construct Al/B/CF microspheres through self-assembly in emulsion to obtain high energy density and significantly improved combustion performance resulted from synergistic reaction between Al and B reacted with fluorine. The Al/B/CF microspheres with pore structure have uniformly distribution of components and the average size range from 60 to 600 μm. Based on the experimental results, CF content and Al/B mass ratio have significant important effects on the combustion behavior and pressure output. The highest burning rate (301.74 m/s) and pressurization rate (77.78 MPa/s) are obtained for the Al/B/CF microspheres with CF content of 50 wt% and Al/B mass ratio of 3 to 1, respectively. Furthermore, the combustion reaction process of single Al/B/CF microsphere are studied for the first time to understand the synergistic reaction between high reactivity of Al and high energy of B reacted with fluorine. This work demonstrates that introducing CF and B to construct Al/B/CF microspheres is an efficient strategy to achieve high energy density and reactivity for the practical applications.