Effects of hollow carbon nanospheres on combustion performance of Al/Fe2O3-based nanothermite sticks

Effects of hollow carbon nanospheres on the combustion behavior of Al/Fe2O3-based thermite sticks are studied in this work. The results from laser ignition experiments confirm that the presence of hollow carbon nanospheres not only can reduce the ignition threshold because of the excellent laser energy absorption capacity, but also play a positive role in heightening the heat transfer efficiency by introducing pores and increasing heat-flow output during the combustion process. The video snapshots indicate that the combustion propagation stages, including ignition, acceleration, and steady combustion, all improved significantly with the suitable inclusion of hollow carbon nanospheres. The modified composites containing 4 wt% hollow carbon nanospheres exhibit a minimum ignition threshold (28 mJ), shorter acceleration duration (76 ms), higher combustion rate (10.10 cm/s) and steady combustion temperature (similar to 2850 K). Furthermore, it exhibits a remarkable enhancement in energy release (537.36 J/g) and pressure output (0.91 Mpa), which are 1.67 and 1.34 times than that of pristine thermite sticks, respectively. Overall, this work demonstrates that the high porosity structure and heat-flow release of thermite sticks facilitate convective heat transfer and eventually improve the combustion behavior, which can provide some reference in the design and optimization of microstructure and composition in micro-energetic devices. (c) 2022 Published by Elsevier B.V.

Automated summary

The effects of hollow carbon nanospheres on the combustion behavior of Al/Fe2O3-based thermite sticks were investigated. It was found that the presence of hollow carbon nanospheres reduced the ignition threshold and enhanced heat transfer efficiency during combustion. The inclusion of hollow carbon nanospheres improved the ignition, acceleration, and steady combustion stages significantly. Modified composites with 4 wt% hollow carbon nanospheres exhibited improved ignition threshold, combustion rate, energy release, and pressure output compared to pristine thermite sticks. Overall, the high porosity structure and heat-flow release of thermite sticks facilitated convective heat transfer and improved combustion behavior.