Surface segregation of hydrogen in free-standing Pd-H alloy nanofilms

论文摘要

The interaction between mechanics and chemistry plays an essential and critical role in the behaviors and properties of materials,especially in nanoscale alloys. Based on the classical Gibbs and Mc Lean adsorption isotherms, the present study takes the freestanding nanometer thick films of Pd-H solid solutions as a typic example to investigate surface segregation of hydrogen. The surface eigenstress model is further developed here to give analytic formulas, which have the capability to quantitatively predict the size-dependent surface segregation. Molecular dynamics（MD） simulations are conducted on free-standing Pd-H nanofilms.The MD simulations verify the theoretical analytic results and determine the values of parameters involved in the theoretical analysis. The integrated theoretical and numerical study exhibits that both surface excess H concentration and apparent biaxial Young’s modulus of Pd-H thin films depend on the nominal H concentration and the film thickness. The MD simulations determine the values of three parameters involved in the theoretical analysis. Especially, the parameter of the differentiation in reference chemical potential behaves like the molar free energy of segregation in the Mc Lean adsorption isotherm.

论文目录

• 1 Introduction
• 2 Theoretical analysis
•   2.1 Mechanical analysis
•   2.2 Thermodynamic analysis
• 3 Simulation methods
• 4 Results and discussion
• 5 Concluding remarks

文章来源

类型: 期刊论文

作者: CAI Hong,MAI JiaWei,GAO YingXin,HUANG He,SUN Sheng,ZHANG TongYi

来源: Science China(Technological Sciences) 2019年10期

年度: 2019

分类: 工程科技Ⅱ辑,工程科技Ⅰ辑

专业: 材料科学,工业通用技术及设备

单位: Materials Genome Institute, Shanghai University

基金: supported by the National Key R&D Program of China(Grant No.2017YFB0701604),support by the National Natural Science Foundation of China(Grant No.11672168)

分类号: TB383.2

页码: 1735-1746

总页数: 12

文件大小: 1670K

下载量: 8