Energy release characteristics of Al/PTFE reactive materials under laser ignition experiment

Al/PTFE (Aluminum/Polytetrafluoroethylene) is a typical kind of reactive material, which has a variety of potential applications in weapon systems. In this paper, laser ignition experiments were carried out for a pressed and sintered mixture of Al and PTFE powder, and the parameters of Al/PTFE combustion process was measured by infrared thermometer , C-type corundum thermocouple and high-speed camera. The results show that Al particle size and Al content have a significant impact on energy release behavior. As particle size decreases, energy release increases in Al/PTFE specimens with micron-sized Al particles. However, for nano-sized particles, 500 nm particles release more energy than 50 nm particles, likely due to greater oxidation . Besides, increasing Al content enhances the reaction rate of Al/PTFE, but excess Al reduces the energy release. Moreover, in the specimens prepared with mass ratio of 26.5/73.5, self-propagating combustion can be achieved in the specimens with nano Al particles, whereas it fails to occur in the specimens with micron Al particles. And intense chemical reactions were detected in Al/PTFE specimens with smaller particle sizes, with a temperature variation of up to 1763.85 K in 1 s. The highest temperature can reach 2523.45 K. Based on the above experiments, an Al/PTFE laser ignition combustion model was established to characterize the temperature dynamics and combustion mechanisms during the reaction process.