Influencing Factors of High-Pressure Discharge Nanothermite Composites Based on Al/Bi₂O₃

To optimize the reactant synthesis and improve the pressure property of Al/Bi₂O₃, the influencing factors in the dynamic pressure discharge of nanothermite reactions are investigated, including the oxide type, Bi₂O₃ particle size, and fuel-to-oxidant mole ratio. All samples are prepared by the ultrasonic mixing method. The synthesized Al/Bi₂O₃ composites are characterized by X-ray diffraction analysis and scanning electron microscopy. By using a closed bomb, the pressure discharge characteristics, including the peak pressure, ignition delay time, and pressurization rate, are obtained. Among the as-prepared nanothermites Al/CuO, Al/Fe₂O₃, and Al/Bi₂O₃, the latter shows the best pressure discharge performance. For the Al (100 nm)/Bi₂O₃ (47 nm) composite with an optimal stoichiometric ratio, the maximum peak pressure, the pressurization rate, and the shortest ignition delay time are 4559 kPa, 11.398 GPa/s, and 27.20 ms respectively. The results indicate that the nano-Bi₂O₃ particle size also produces a significant effect on the pressure output.