Energy Release Characteristics of Laser Ignited Al/PTFE Reactive Materials

In this study, the energy release mechanism in aluminum/polytetrafluoroethylene (Al/PTFE) reactive materials was investigated through combustion experiments employing laser ignition. Al/PTFE specimens with different Al particle sizes and different ratio were prepared by molding and sintering. The combustion processes and temperature fluctuations were documented using high-speed cameras and temperature sensors. It was found that specimens with micron Al failed to sustain combustion following the cessation of laser energy, whereas specimens with nano Al displayed a lower ignition threshold and sustained self-propagating reactions. The high surface reactivity and extensive specific surface area increased the susceptibility of specimens with nano Al to oxidation, which, following initial reactions, resulted in diminished reactivity and reduced energy release compared to specimens with micron Al. As the Al content increases in the specimens, the time required to reach the highest reaction temperature is reduced, concurrently with an augmentation in energy liberated. This correlation substantiates that within specified boundaries, an elevation in Al content precipitates an enhancement in both the efficacy and magnitude of the energy release.