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Analysis of the spontaneous alloying mechanism in metal clusters

金属团簇自发合金化机理分析

基本信息

批准号：
10640375
负责人：
SATOKO Chikatoshi
金额：
$ 1.79万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640375/
关键词：
molecular dynamics alloying mechanism metal cluster interaction between metal atoms

项目摘要

We carried out the investigation of a spontaneous alloying mechanism by the theoretical methods such as the molecular dynamics (the interaction between the atoms uses the two-body Morse potential, Petiffor potential and embedded atom model potential), the electronic structure calculation, and the experiments such as electron microscope observation etc. We get the following results : If the size of the clusters is less than the critical radius and the temperature is not so low, the inside atoms are in solid-phase state, and the outside atoms are in the melting state and moves furiously around the surface. As the number of the surface atoms is more in comparison with the atom number of the whole cluster, the local exchange between the atoms around the surface region occurs so frequently that the inside atom is pushed out from the inside region. It is conceivable that spontaneous alloying is breaking out with the mechanism that calls the skin-peeling dynamics. On the other hand, alloying behavior and phase stability has been studied by transmission electron microscopy experiments using clusters in the Au-Sn, Au-Sb, Au-Sn-Pb alloy-nano-particles. We observed the following fine structure : although the composition of alloy clusters falls in the two-phase region for the bulk alloy, the fine structure is in the amorphous-like phase stabilized in nm-sized alloy clusters. We continue to study the theoretical and experimental research that the nano-alloy particle has the unique complicated behavior dependent on the chemical property between the constitution atom.

我们通过分子动力学（原子之间的相互作用使用二体莫尔斯势、Petifor势和嵌入式原子模型势）、电子结构计算以及电镜观察等实验等理论方法对自发合金化机理进行了研究。我们得到以下结果：如果团簇的尺寸小于临界半径并且温度不太低，则内部原子处于固相状态，外部原子处于熔化状态并在表面剧烈运动。由于表面原子的数量与整个团簇的原子数量相比较多，表面区域周围的原子之间的局部交换发生得如此频繁，以至于内部原子被从内部区域推出。可以想象，自发合金化正在以一种称为剥皮动力学的机制爆发。另一方面，通过透射电子显微镜实验使用 Au-Sn、Au-Sb、Au-Sn-Pb 合金纳米颗粒中的团簇研究了合金化行为和相稳定性。我们观察到以下精细结构：虽然合金团簇的成分落在大块合金的两相区域内，但精细结构是稳定在纳米尺寸合金团簇中的类非晶相。我们继续进行理论和实验研究，纳米合金颗粒具有依赖于构成原子之间的化学性质的独特的复杂行为。