Synergy BiF3 and Bi2O3 to enhance the ignition and combustion performance of boron

Abstract

Boron (B), a frequently utilized metalloid fuel, has been garnering growing attention due to its elevated calorific value. However, the inert oxide layer (B₂O₃) on the surface of B powder obstructs the transfer of oxygen, resulting low combustion efficiency and long ignition delay time. In this study, a range of binary oxidizers BiF₃-Bi₂O₃ is developed to enhance the ignition and combustion performance of B by leveraging the synergistic effect of the shell-breaking effect of BiF₃ and the rapid reaction kinetics of Bi₂O₃. A comprehensive investigation is conducted on the influence of the BiF₃/Bi₂O₃ ratio on thermal reaction, ignition delay time, burning rate, and pressure output. The TG-DSC data indicate that the B-BiF₃ reaction exhibits superior gas production capability, while the B-Bi₂O₃ reaction offers greater advantages in terms of heat release. Furthermore, the combination of binary oxidizers (10 wt.%-20 wt.% BiF₃) is more efficient in promoting the ignition and combustion of B than a single metal oxidizer. The B-BiF₃-Bi₂O₃ composite materials exhibit a remarkably high burning rate of 14.81 m/s and a rapid pressurization rate of 1622.45 kPa/s. The enhanced ignition and combustion performance of B-BiF₃-Bi₂O₃ composite materials arises from the synergistic effect between the reactions of B-BiF₃ and B-Bi₂O₃. This study illustrates that the combination of BiF₃ and Bi₂O₃, two types of oxidizers, is an effective method to improve the combustion efficiency of boron.