Simultaneous Decomposition and Dewetting of Nanoscale Alloys: A Comparison of Experiment and Theory
Simultaneous Decomposition and Dewetting of Nanoscale Alloys: A Comparison of Experiment and Theory
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纳米合金的同时分解和去湿：实验与理论的比较
DOI：
10.1021/acs.langmuir.0c02964
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发表时间：
2021
期刊：
影响因子：
3.9
通讯作者：
Kondic, Lou
中科院分区：
文献类型：
--
作者：
Diez, Javier A.;González, Alejandro G.;Garfinkel, David A.;Rack, Philip D.;McKeown, Joseph T.;Kondic, Lou
我们考虑沉积在固体基底上的纳米级厚度的金属合金的相分离和去湿的耦合过程。实验涉及应用纳秒激光脉冲，在两种设置中熔化 Ag40Ni60 合金薄膜：在薄支撑膜上或在块状基板上。这两种设置允许提取所考虑的过程发生的时间和空间尺度。该理论模型涉及用于描述旋节线分解的 Cahn-Hilliard 公式的长波版本，加上渐近一致的基于长波的去湿描述，该去湿是由于合金和基材之间的不稳定相互作用而发生的，使用分离压力方法进行建模。仔细的建模，结合线性稳定性分析和完全非线性仿真，得出与实验一致的结果。特别是，我们发现两种不稳定机制同时发生，相分离发生得更快且时间尺度更短。建模结果显示了相关材料特性的温度依赖性的强烈影响，这意味着这种依赖性对于理解实验结果至关重要。理论与实验之间的一致性表明所提出的理论方法在帮助开发进一步的实验以形成具有所需性能的金属合金纳米粒子方面的实用性。
We consider the coupled process of phase separation and dewetting of metal alloys of nanoscale thickness deposited on solid substrates. The experiments involve applying nanosecond laser pulses that melt the Ag40Ni60alloy films in two setups: either on thin supporting membranes or on bulk substrates. These two setups allow for extracting both temporal and spatial scales on which the considered processes occur. The theoretical model involves a longwave version of the Cahn–Hilliard formulation used to describe spinodal decomposition, coupled with an asymptotically consistent longwave-based description of dewetting that occurs due to destabilizing interactions between the alloy and the substrate, modeled using the disjoining pressure approach. Careful modeling, combined with linear stability analysis and fully nonlinear simulations, leads to results consistent with the experiments. In particular, we find that the two instability mechanisms occur concurrently, with the phase separation occurring faster and on shorter temporal scales. The modeling results show a strong influence of the temperature dependence of relevant material properties, implying that such a dependence is crucial for the understanding of the experimental findings. The agreement between theory and experiment suggests the utility of the proposed theoretical approach in helping to develop further experiments directed toward formation of metallic alloy nanoparticles of desired properties.