Impact-Induced Reaction Characteristic and the Enhanced Sensitivity of PTFE/Al/Bi₂O₃ Composites

In this paper, the reaction characteristic of a novel reactive material, which introduced bismuth trioxide (Bi₂O₃) into traditional polytetrafluoroethylene/aluminum (PTFE/Al), is studied. The effect of Bi₂O₃ with different content and particle size on the reaction behaviors of PTFE/Al/Bi₂O₃ are investigated by drop-weight test and X-ray diffractometer (XRD), including impact sensitivity, energy release performance under a certain impact, and reaction mechanism. The experimental results show that the content of Bi₂O₃ increased from 0% to 35.616%, the characteristic drop height of impact sensitivity (H₅₀) of PTFE/Al/Bi₂O₃ reactive materials decreased first and then increased, and the minimum H₅₀ of all types of materials in the experiment is 0.74 times that of PTFE/Al, and the particle size of Bi₂O₃ affects the rate of H₅₀ change with Bi₂O₃ content. Besides, with the increase of Bi₂O₃ content, both the reaction intensity and duration first increase and then decrease, and there is optimum content of Bi₂O₃ maximizing the reaction degree of the PTFE/Al/Bi₂O₃. Furthermore, a prediction model for the impact sensitivity of PTFE-based reactive material is developed. The main reaction products include AlF₃, xBi₂O₃·Al₂O₃, and Bi.