High Heating Rate Reaction Dynamics of Al/CuO Nanolaminates by Nanocalorimetry-Coupled Time-of-Flight Mass Spectrometry
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- 作者：Jeffery B. DeLisio ; Feng Yi ; David A. LaVan ; Michael R. Zachariah
- 刊名：Journal of Physical Chemistry C
- 出版年：2017
- 出版时间：February 9, 2017
- 年：2017
- 卷：121
- 期：5
- 页码：2771-2777
- 全文大小：441K
- ISSN：1932-7455
文摘
Highly tunable reactive nanolaminates have been of recent interest for various “on chip” energetic applications. The reaction dynamics of Al/CuO nanolaminates were investigated by nanocalorimetry-coupled time-of-flight mass spectrometry, capable of simultaneous measurement of temporal thermal dynamics and detection of evolved gas phase species at heating rates up to ∼106 K/s. The nanolaminates were synthesized by alternately sputtering Al and CuO onto the heater of nanocalorimeter sensors. For thin films of 80 nm with one bilayer, the stoichiometric ratio of fuel to oxidizer significantly affected the reaction mechanism: initial reactions occurred between 300 and 400 °C, and main reactions varied based on stoichiometry. For thicker films of 199 and 266 nm, a series of samples with varying bilayer numbers were analyzed to determine the effect of diffusion distance and interfacial area. Only one reaction step was observed for a sample with a bilayer thickness of 33 nm. A two-step reaction mechanism is observed as the bilayer thickness was increased to 66 nm and beyond: solid-state reaction occurring at the interfaces of Al and CuO before the melting of Al and a much faster liquid–solid reaction right after the melting of Al. At the same time, interfacial premixed distance during the deposition was also estimated from parallel experiments. Furthermore, the power data from nanocalorimetry provides a more direct method, compared to optical emission and mass spectrometry based methods, in determining the ignition temperature in addition to being able to measure actual energy output for films with nanoscale thicknesses.