氧气氛下核壳Al / Al <sub>2</sub> O <sub>3</sub>纳米粒子的点火和氧化：分子动力学模拟的启示,The Journal of Physical Chemistry C

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氧气氛下核壳Al / Al ₂ O ₃纳米粒子的点火和氧化：分子动力学模拟的启示
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2018-12-18 , DOI: 10.1021/acs.jpcc.8b09858
Qingzhao Chu ₁ , Baolu Shi ₁ , Lijuan Liao ₂ , Kai H. Luo ₃ , Ningfei Wang ₁ , Chenguang Huang ₂

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这项研究利用反作用力场分子动力学来捕获铝纳米颗粒（ANP）在高温高压氧气氛中氧化的原子级传热和传质以及反应过程，揭示了ANP氧化的详细机理。系统地检查了ANP的温度，密度，均方位移，原子消耗率和放热率的时间变化。此外，还评估了环境对ANP氧化的影响。结果表明，在整个氧化过程中，ANPs经历了四个阶段的预热，熔化，快速的Al核和适度的壳氧化。铝核开始从核-壳界面熔化，随着核铝原子向外扩散到壳中。熔融结束时，在外壳O和界面周围的核心Al原子之间会发生激烈反应，从而导致Al核心快速氧化。Al核完全氧化后，氧化物壳继续与周围的O原子反应。初始环境温度和等效压力均会显着影响预热。相反，熔化阶段似乎几乎独立于其中的任何一个。但是，快速的铝芯氧化对环境等效压力表现出更高的敏感性。

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Ignition and Oxidation of Core–Shell Al/Al2O3 Nanoparticles in an Oxygen Atmosphere: Insights from Molecular Dynamics Simulation

This study employed the reactive force field molecular dynamics to capture atomic-level heat and mass transfer and reaction processes of an aluminum nanoparticle (ANP) oxidizing in a high temperature and pressure oxygen atmosphere, revealing detailed mechanisms for oxidation of ANPs. Temporal variations of temperature, density, mean square displacement, atom consumption rate, and heat release rate of ANPs have been systematically examined. In addition, the effects of environment on ANP oxidation were also evaluated. The results show that ANPs undergo four stages of preheating, melting, fast Al core, and moderate shell oxidations during the whole oxidation process. The Al core starts to melt from a core–shell interface with outward diffusion of core Al atoms into the shell. Intense reaction occurs between shell O and core Al atoms around the interface at the end of melting, leading to fast Al core oxidation. After complete oxidation of the Al core, the oxide shell continues to react with ambient O atoms. Both the initial environmental temperature and the equivalent pressure significantly influence the preheating. Conversely, the melting stage seems almost independent of any of them. However, fast Al core oxidation presents more sensitivity to the ambient equivalent pressure.

更新日期：2018-12-18

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