Comparative investigations of ternary thermite Al/Fe2O3/CuO and Al/Fe2O3/Bi2O3 from pyrolytic, kinetics and combustion behaviors
Shi Li, Jialin Chen, Tao Guo, Wen Ding, Lin Jiang, M. Yao, Jiaxing Song, Lifeng Xie, Yiming Mao
Abstract
To develop new energy enhancement energetic materials with great combustion performance and thermal stability, two kinds of ternary thermite, Al/Fe2O3/CuO and Al/Fe2O3/Bi2O3, were prepared and analyzed via mechanical ball milling. The samples were characterized by SEM, XRD, TG-DSC, constant volume and constant pressure combustion experiments. The first exothermic peaks of Al/Fe2O3/CuO and Al/Fe2O3/Bi2O3 appear at 579 °C and 564.5 °C, respectively. The corresponding activation energies are similar. The corresponding mechanism functions are set as G(α)=[−ln(1−α)]3/4 and G(α)=[−ln(1−α)]2/3, respectively, which belong to the Avrami-Erofeev equation. Al/Fe2O3/CuO has better thermal safety. For small dose samples, its critical temperature of thermal explosion is 121.05 °C higher than that of Al/Fe2O3/Bi2O3. During combustion, the flame of Al/Fe2O3/CuO is spherical, and the main products are FeAl2O4 and Cu. The flame of Al/Fe2O3/Bi2O3 is jet-like, and the main products are Al2O3, Bi and Fe. Al/Fe2O3/Bi2O3 has better ignition and gas production performance. Its average ignition energy is 4.2 J lower than that of Al/Fe2O3/CuO. Its average step-up rate is 28.29 MPa/s, which is much higher than 6.84 MPa/s of Al/Fe2O3/CuO. This paper provides a reference for studying the thermal safety and combustion performance of ternary thermite.