Study on the effect of graphite-based materials on the reactivity of activated aluminum composites in different forms of water

Abstract

For further energy enhancement of water-reactive metal fuels, it is crucial to find aluminum composites that can react synchronously and quickly with multiple types of water (ice, steam, and water). In this paper, two graphite-based aluminum composites, aluminum/bismuth/graphite (Al/Bi/GI) and aluminum/bismuth/graphene nanosheets (Al/Bi/GE), were prepared. The morphology and crystal structure of the composites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The reactivity of Al/Bi/GI and Al/Bi/GE with water from 20 °C to 80 °C and ice at 0 °C and −15 °C was characterized using hydrogen generation properties. Their ignition and combustion properties in high-temperature water steam from 300 °C to 900 °C were also investigated. The results show that Al/Bi/GI and Al/Bi/GE composites prepared by ball milling have blocky and multilayered lamellar structures, respectively. That ball milling does not result in the formation of new alloys. The thickness of graphite material affects the reactivity of activated aluminum composites. The hydrogen generation rates of Al/Bi/GE in water and ice are much higher than that of Al/Bi/GI. The maximum hydrogen generation rates of Al/Bi/GE were 28.8 and 46.6 times higher than those of Al/Bi/GI in water at 20 °C and ice at −15 °C, respectively. In high-temperature water steam, the ignition temperature and ignition delay time of Al/Bi/GE are lower than those of Al/Bi/GI. Al/Bi/GE achieves a rapid reaction that can be synchronized with three forms of water and is expected to be applied to water-reactive metal fuel propellants.