Comparative investigations of ternary thermite Al/Fe₂O₃/CuO and Al/Fe₂O₃/Bi₂O₃ from pyrolytic, kinetics and combustion behaviors

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 degrees C and 564.5 degrees C, respectively. The corresponding activation energies are similar. The corresponding mechanism functions are set as G(a) = [-ln(1 -a)]3=4 and G(a) = [-ln(1 -a)]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 degrees 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 com-bustion performance of ternary thermite.(c) 2023 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).