Study on combustion characteristics and pyrotechnic cutting effects of bimetal thermite Ni/Al/Fe2O3 system

Abstract

Nano‐thermite has become a subject of significant interest in the composite energetic materials field due to its high energy release rate. To cater to diverse engineering needs, thermite formulations are often customized to fulfill specific criteria. This study investigates the potential of metal nickel (Ni) as an additive to modify nano‐thermite formulations, selected for its optimal calorific values and chemical reactivity. The base materials, nano‐aluminum (Al) and iron oxide (Fe2O3), are blended with varying mass ratios of Ni (1 %, 3 %, 5 %, 7 %, 9 %) using the wet ball milling method. Pre‐reaction and post‐reaction morphological and compositional alterations in the resultant thermite samples are scrutinized through SEM and XRD characterization tests. Moreover, DSC analysis and combustion experiments were conducted to examine the pyrolysis and combustion behaviors of the evaluated samples. The results reveal a reduced exothermic peak on the DSC curves with the introduction of Ni, making the liquid‐solid (L‐S) phase reaction more challenging compared to the Al/Fe2O3 thermite. Intriguingly, Ni addition progressively decreases the combustion temperature of thermites as the Ni's mass ratio increases, with a peak efficiency at 7 % in the perforation tests on stainless‐steel plates. This research further reveals that the thermite reaction mechanism is a combined consequence of the “pre‐ignition‐fusion” and “fusion‐diffusion” mechanisms. These insights can provide valuable guidance for designing thermite formulations for potential applications in storage, management, and pyrotechnic cutting areas.