Probing the Reaction Dynamics of Thermite Nanolaminates

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• 作者：Garth C. Egan ; Edward J. Mily ; Jon-Paul Maria ; Michael R. Zachariah
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：September 3, 2015
• 年：2015
• 卷：119
• 期：35
• 页码：20401-20408
• 全文大小：417K
• ISSN：1932-7455

文摘

Al/CuO reactive nanolaminate ignition was studied using temperature jump (T-Jump) heating for rates greater than 10⁵ K/s. Multilayer samples were sputter deposited onto thin platinum filaments in alternating layers of Al and CuO. The filaments were resistively heated in a time-of-flight mass spectrometer (ToF-MS), while ignition and reaction were observed with high-speed video. A total deposited thickness of 1800 nm was maintained for all samples, while the number of bilayers was varied from 1 to 12. Increasing this value decreased the diffusion distances and increased the amount of interfacial area across which reaction could occur, while keeping the overall energy of the system constant. From 2 to 6 bilayers, the ignition temperature decreased from 1250 to 670 K and the overall reactivity increased. Past 6 bilayers, the ignition temperature only decreased slightly and there was little impact on the overall reactivity. This behavior is consistent with a mass-transport model where the predominant diffusing species exhibits a low activation energy (50 kJ/mol). Ignition temperature, which depends upon bilayer thickness, is found to be a good predictor of flame speed.