Hammons Joshua A, Nielsen Michael H, Bagge-Hansen Michael, Bastea Sorin, May Chadd, Shaw William L, Martin Aiden, Li Yuelin, Sinclair Nicholas, Lauderbach Lisa M, Hodgin Ralph L, Orlikowski Daniel A, Fried Laurence E, Willey Trevor M
Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 United States.
Dynamic Compression Sector, Washington State University, 9700 South Cass, Lemont, Illinois 60439, United States.
J Phys Chem Lett. 2021 Jun 10;12(22):5286-5293. doi: 10.1021/acs.jpclett.1c01209. Epub 2021 Jun 1.
Detonation nanodiamond (DND) is known to form aggregates that significantly reduce their unique nanoscale properties and require postprocessing to separate. How and when DND aggregates is an important question that has not been answered experimentally and could provide the foundation for approaches to limit aggregation. To answer this question, time-resolved small-angle X-ray scattering was performed during the detonation of high-explosives that are expected to condense particulates in the diamond, graphite, and liquid regions of the carbon phase diagram. DND aggregation into low fractal dimension structures could be observed as early as 0.1 μs, along with a separate scattering population also observed from an explosive that produces primarily graphitic products. A counterexample is the case of a high-explosive that produces nano-onions, where no hierarchical scattering was observed for at least 10 μs behind the detonation front. These results suggest that DND aggregation occurs on time scales comparable to particle formation.
已知爆轰纳米金刚石（DND）会形成聚集体，这会显著降低其独特的纳米级特性，并且需要进行后处理以分离。DND如何以及何时聚集是一个重要问题，尚未通过实验得到解答，而这可能为限制聚集的方法提供基础。为了回答这个问题，在预期会在碳相图的金刚石、石墨和液相区域凝聚颗粒的高爆炸药爆轰过程中进行了时间分辨小角X射线散射。早在0.1微秒时就可以观察到DND聚集成低分形维结构，同时还从主要产生石墨产物的炸药中观察到了单独的散射群体。一个反例是产生纳米洋葱的高爆炸药的情况，在爆轰前沿之后至少10微秒内未观察到分层散射。这些结果表明，DND聚集发生的时间尺度与颗粒形成相当。
