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Research on the origin of the thermodynamically stable amorphous phase in nm-sized particles

纳米颗粒中热力学稳定非晶相的起源研究

基本信息

批准号：
15206070
负责人：
MORI Hirotaro
金额：
$ 20.8万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15206070/
关键词：
alloy nano-particle thermodynamic calculation interface surface 界面エネルギー

项目摘要

In this research, the origin of the thermodynamically stable amorphous phase formed in nanometer-sized alloy particles was studied by both experiment and thermodynamic calculation.First, the effect of surface and interface on the stability of nanometer-sized particles was examined using particles of the Sn-Bi system. An approximately 8-nm-sized particle of the terminal tin solid solution directly changed into a particle of the liquid phase with increasing concentration of bismuth. On the other hand, an approximately 8-nm-sized particle of the terminal bismuth solid solution changed first to a particle with a crystal/liquid two-phase microstructure and eventually to a particle of the liquid phase, with increasing concentration of tin. Even in the bismuth-rich side, an approximately 5-nm-sized particle of the terminal bismuth solid solution, however, directly changed into the liquid phase, without taking a stage of crystal/liquid coexistence. These experimental results were discussed fro … More m a thermodynamic viewpoint. As a result, it was confirmed that not only surface but also interface is a governing factor of the thermodynamical stability of nanometer-sized alloy particles. Namely, the existence of the heterointerface between two crystalline solids stabilizes the liquid phase.Next, the relative stability of solid solution and liquid in nanometer-sized particles was examined using particles of the Pb-Sn system. Approximately 15-nm-sized particles of a lead-56at.%Sn solid solution were formed at 110℃ by tin deposition onto nanometer-sized pure lead particles. This fact indicates that the solubility limit of tin in 15-nm-sized lead particle is almost five times higher than the solubility limit of tin in bulk lead (i.e., 10at% Sn). It was confirmed that the relative stability between the highly concentrated solid solution and the amorphous phase governs the structure of nanometer-sized alloy particles.Conclusions obtained are given below.(1)In nanometer-sized alloy particles, the liquid phase becomes relatively stable as compared with the crystalline phase due to both surface and interface.(2)As a result, in nanometer-sized alloy particles the eutectic point becomes to be suppressed down to a temperature even below the glass transition temperature. This results in the formation of the thermodynamically stable amorphous phase over a temperature range between these two temperatures. Less

本研究从实验和热力学计算两个方面研究了纳米合金颗粒中形成非晶稳定相的原因。首先，以Sn-Bi系合金颗粒为研究对象，考察了表面和界面对纳米颗粒稳定性的影响。随着铋浓度的增加，末端锡固溶体的约8 nm大小的颗粒直接变成液相的颗粒。另一方面，随着锡浓度的增加，最终铋固溶体的约8 nm尺寸的颗粒首先变为具有晶体/液体两相微结构的颗粒，并最终变为液相的颗粒。然而，即使在富铋侧，最终铋固溶体的约5 nm尺寸的颗粒也直接变为液相，而不采取晶体/液体共存的阶段。并对实验结果进行了讨论 ...更多信息我是从热力学的角度来看的。结果表明，纳米合金颗粒的热力学稳定性不仅取决于表面，还取决于界面。即，两种结晶固体之间的异质界面的存在使液相稳定。接着，使用Pb-Sn系的粒子，对纳米粒子中固溶体和液体的相对稳定性进行了研究。约15 nm大小的铅颗粒-56 at.%在110℃下，锡沉积在纳米级纯铅颗粒上形成锡固溶体。这一事实表明锡在15 nm尺寸的铅颗粒中的溶解度极限几乎是锡在块状铅中的溶解度极限的五倍（即，10at%Sn）。结果表明，高浓度固溶体和非晶相之间的相对稳定性决定了纳米合金颗粒的结构。(1)In在纳米尺寸的合金颗粒中，由于表面和界面，液相与晶相相比变得相对稳定。(2)As结果，在纳米尺寸的合金颗粒中，共晶点被抑制到甚至低于玻璃化转变温度的温度。这导致在这两个温度之间的温度范围内形成结晶稳定的非晶相。少