Chmielewski Adrian, Nelayah Jaysen, Amara Hakim, Creuze Jérôme, Alloyeau Damien, Wang Guillaume, Ricolleau Christian
Université Paris Diderot, Sorbonne Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162, 75013 Paris, France.
Laboratoire d'Etude des Microstructures, ONERA-CNRS, BP 72, 92322 Châtillon Cedex, France.
Phys Rev Lett. 2018 Jan 12;120(2):025901. doi: 10.1103/PhysRevLett.120.025901.
We use in situ transmission electron microscopy to monitor in real time the evaporation of gold, copper, and bimetallic copper-gold nanoparticles at high temperature. Besides, we extend the Kelvin equation to two-component systems to predict the evaporation rates of spherical liquid mono- and bimetallic nanoparticles. By linking this macroscopic model to experimental TEM data, we determine the surface energies of pure gold, pure copper, Cu_{50}Au_{50}, and Cu_{25}Au_{75} nanoparticles in the liquid state. Our model suggests that the surface energy varies linearly with the composition in the liquid Cu-Au nanoalloy; i.e., it follows a Vegard's rulelike dependence. To get atomic-scale insights into the thermodynamic properties of Cu-Au alloys on the whole composition range, we perform Monte Carlo simulations employing N-body interatomic potentials. These simulations at a microscopic level confirm the Vegard's rulelike behavior of the surface energy obtained from experiments combined with macroscopic modeling.
我们使用原位透射电子显微镜实时监测金、铜以及铜金双金属纳米颗粒在高温下的蒸发情况。此外，我们将开尔文方程扩展到双组分体系，以预测球形液态单金属和双金属纳米颗粒的蒸发速率。通过将这个宏观模型与实验TEM数据相联系，我们确定了液态纯金、纯铜、Cu₅₀Au₅₀和Cu₂₅Au₇₅纳米颗粒的表面能。我们的模型表明，液态铜金纳米合金中的表面能随成分呈线性变化；也就是说，它遵循类维加德规则依赖性。为了在原子尺度上深入了解整个成分范围内铜金合金的热力学性质，我们使用N体原子间势进行蒙特卡罗模拟。这些微观层面的模拟证实了通过实验结合宏观建模得到的表面能的类维加德规则行为。
