Atomic-Scale Reaction Mechanism of Impact Ignition in Al/Si/PTFE Reactive Materials.

Non-metallic polytetrafluoroethylene (PTFE)-based reactive materials (RMs) exhibit relatively high energy density; however, the low shock sensitivity hinders their widespread application in space debris protection. To develop lightweight, high-energy PTFE-based RMs with superior shock-induced energy-release performance, Al/Si/PTFE ternary RMs were produced by a cold pressing and sintering process with additions of Aluminum (Al) and Silicon (Si) powders. The effect of Al and Si content on the impact ignition and energy release of Al/Si/PTFE was investigated by split Hopkinson pressure bar (SHPB) experiments. High-speed photography shows that the addition of Al powder can effectively lower the reaction threshold of Si/PTFE and enhance its energy release efficiency. The critical reaction temperature threshold of Al1.2Si1PTFE is lower than that of other Al/Si/PTFE RMs, and its primary and secondary ignition intensities are the highest. The micro-ignition mechanism of the Al/Si/PTFE RMs was revealed by molecular dynamics (MD) simulations and differential scanning calorimetry (DSC) experiments. The synergistic effect of Al and Si particles in Al1.2Si1PTFE under a shock wave produces a more pronounced local temperature rise and more hotspots, ultimately releasing the greatest extent of reaction.