Impact-Induced Reaction Characteristic and the Enhanced Sensitivity of PTFE/Al/Bi 2 O 3 Composites.

In this paper, the reaction characteristic of a novel reactive material, which introduced bismuth trioxide (Bi ₂ O ₃ ) into traditional polytetrafluoroethylene/aluminum (PTFE/Al), is studied. The effect of Bi ₂ O ₃ with different content and particle size on the reaction behaviors of PTFE/Al/Bi ₂ O ₃ 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 Bi ₂ O ₃ increased from 0% to 35.616%, the characteristic drop height of impact sensitivity ( H ₅₀ ) of PTFE/Al/Bi ₂ O ₃ reactive materials decreased first and then increased, and the minimum H ₅₀ of all types of materials in the experiment is 0.74 times that of PTFE/Al, and the particle size of Bi ₂ O ₃ affects the rate of H ₅₀ change with Bi ₂ O ₃ content. Besides, with the increase of Bi ₂ O ₃ content, both the reaction intensity and duration first increase and then decrease, and there is optimum content of Bi ₂ O ₃ maximizing the reaction degree of the PTFE/Al/Bi ₂ O ₃ . Furthermore, a prediction model for the impact sensitivity of PTFE-based reactive material is developed. The main reaction products include AlF ₃ , xBi ₂ O ₃ ·Al ₂ O ₃ , and Bi.