Diffusion of hydrogen atom (1); argon (2)

2007 ◽  
pp. 315-315
Author(s):  
J. Winkelmann
Keyword(s):  
Hydrogen Atom ◽  
Diffusion Of Hydrogen

Frist-Principles Study of Hydrogen Atom Diffusion on Transition Metal Doped Mg(0001) Surface

2013 ◽  
Vol 873 ◽  
pp. 101-109 ◽  
Author(s):  
Zhi Wen Wang ◽  
Xin Jun Guo ◽  
Wei Yuan ◽  
Zhi Yan Ding
Keyword(s):  
Hydrogen Atom ◽  
Transition Metals ◽  
Density Functional ◽  
Atom Diffusion ◽  
Charge Density Difference ◽  
The Density Functional Theory ◽  
Diffusion Paths ◽  
The Stability ◽  
Metal Doped ◽  
Diffusion Of Hydrogen

First-principles calculations within the density functional theory (DFT) have been carried out to study the interaction of hydrogen atom with transition metals (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) doped Mg (0001) surfaces. First we have calculated the stability of the transition metals atom on the Mg surface, On the basis of the energetic criteria, all the elements except Zn prefer to substitute one of the Mg atoms from the second layer, while Zn tend to substitute one of the Mg atoms from the first layer. In the second step, we have studied the interaction between hydrogen atom and the transition metals doped Mg (0001) surface.we have studied the interaction of a hydrogen atom with the transition metals doped Mg (0001) surface. The results show that for transition metals atoms doped Mg (0001) surface in the second layer, it not only enhances the chemisorption interaction between hydrogen atom and Mg surface, but also it benefits hydrogen atom diffusion in Mg bulk with relatively more diffusion paths. However, when the Mg surface doped by elements such as Sc, Ti, V, Cu and Zn, hydrogen atom chooses to bond with transition metals atom and block the diffusion of hydrogen atom into Mg bulk, while when the Mg surface doped by elements such as Cr, Mn, Fe, Co and Ni, hydrogen atom chooses to leave from transition metals atom thereby promoting the diffusion of hydrogen atom diffusion into Mg bulk. Charge density difference plots shows that electrons are transferred from electronic states of transition metals atom to the orbital of hydrogen atom which cause attractive interactions between hydrogen atom and transition metals atom and reduce the energy barrier of the hydrogen atom diffusion into Mg bulk. Our results show that useing transition metals (Cr, Mn, Fe, Co and Ni) as catalysts for the hydrogenation/dehydrogenation of Mg bulk samples and provide more diffusion paths of hydrogen atom, they are beneficial for the diffusion of hydrogen atom to Mg bulk and improve significantly the hydrogenation kinetics property of Mg surface.

Interaction of Hydrogen Atom with Edge Dislocation in Pd and Ni

2018 ◽  
Vol 30 ◽  
pp. 46-51
Author(s):  
Irina V. Zorya ◽  
Gennady M. Poletaev ◽  
Mikhail D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Atom ◽  
Sorption Capacity ◽  
Edge Dislocation ◽  
Dislocation Core ◽  
Hydrogen Impurity ◽  
Hydrogen Atoms ◽  
Energy Characteristics ◽  
Method Of Molecular Dynamics ◽  
Diffusion Of Hydrogen

The energy characteristics of interaction of hydrogen impurity with ½<110> edge dislocation in Pd and Ni were calculated by the method of molecular dynamics. It is shown that the dislocation is effective trap for hydrogen. At the same time the dislocation jogs increases its sorption capacity with respect to hydrogen, but reduces the diffusion mobility of hydrogen along the dislocation. The diffusion of hydrogen atoms in the dislocation region occurs mainly along the dislocation core. The energy of hydrogen migration along the dislocation, as our calculations have shown, is almost two times lower than in a defect-free crystal.

Adsorption and Diffusion of Hydrogen Atom on Pd Loe Index Surfaces

1996 ◽  
Vol 12 (09) ◽  
pp. 773-779 ◽  
Author(s):  
Zhang Ji-Shu ◽  
◽  
Zhang Wen-Xia ◽  
Wang Ze-Xin
Keyword(s):  
Hydrogen Atom ◽  
And Diffusion ◽  
Diffusion Of Hydrogen

Research on Hydriding Reaction Kinetics Mechanism of Mg2-xNdxNi (x = 0-0.3) Alloys

2012 ◽  
Vol 512-515 ◽  
pp. 2250-2256 ◽  
Author(s):  
Qi Wan ◽  
Ping Li ◽  
Li Qun Cui ◽  
Wei Na Zhang ◽  
Yun Long Li ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Storage ◽  
Diffusion Path ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Hydrogenation Rate ◽  
Hydrogen Storage Capacity ◽  
Ni Alloys ◽  
Hydrogen Storage Performance ◽  
Diffusion Of Hydrogen

Mg2-xNdxNi (x=0.1, 0.2, 0.3) alloys, along with Mg2Ni for comparison, were prepared by vacuum induction melting, The influent of content of Nd on the microstructure and hydrogen storage performance were studied, the hydrogenation mechanism of Mg2-xNdxNi alloys was explored. The results showed that: the hydriding-dehydriding kinetics performance of Mg2Ni were improved by adding Nd, but the hydrogen storage capacity of alloys decreased. Mg2Ni, Nd2Ni7, NdMg12, Nd5Mg41 and other minor phases were observed in Mg-Nd-Ni alloys. Mg-Nd-Ni alloys had favorable kinetics performance. Compared with Mg2Ni alloy, the desorption rate and desorption ratio decreased with the increase of the amount of Nd, the hydriding-dehydriding kinetics performance Mg1.9Nd0.1Ni was the best. The hydrogenation mechanism of Mg2-xNdxNi alloy was nucleation and grown up mechanism controlled by diffusion ([-ln(1-ξ)]n=kt), the nucleation and grown up process was decided by the diffusion of hydrogen atom in alloy. Hydrogenation rate increased with the increase of hydrogen pressure and adding Nd, it was because the diffusive rate of hydrogen atom in alloy increased. According to the analysis of kinetics mechanism, methods to improve kinetics performance was put forward by reducing the diffusion path of hydrogen atom in alloy.

scholarly journals Influence of single axis strain on site occupation and diffusion of hydrogen atom in α-Fe

2017 ◽  
Vol 66 (18) ◽  
pp. 187101
Author(s):  
Li Shou-Ying ◽  
Wang Yong ◽  
Zhao Wei-Min
Keyword(s):  
Hydrogen Atom ◽  
Site Occupation ◽  
And Diffusion ◽  
Diffusion Of Hydrogen

Discussion on the Mechanism of Corrosion Resistance of High Temperature QPQ Treated Specimens in H2S Environment

2011 ◽  
Vol 66-68 ◽  
pp. 665-668
Author(s):  
Yuan Hui Li ◽  
Shi Ping Zhang ◽  
Yi Chao Ding ◽  
Zi Lian Jiang
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Hydrogen Atom ◽  
Volume Expansion ◽  
Steel Specimen ◽  
Compound Layer ◽  
Corrosion Layer ◽  
Corrosion Mechanism ◽  
Diffusion Of Hydrogen ◽  
Coefficient Of Diffusion

By constant stress tensile test, the corrosion mechanism of high temperature QPQ treated 25CrMnMo steel specimen in H2S environment was analyzed and discussed. The γ′-Fe4N in the ε compound layer turns into corrosion substance in the test and expands. At the surface of the ε compound layer, the corrosion layer is visible. The compound layer breaks off in little blocks for volume expansion of the corrosion substance and the exterior tensile stress. The coefficient of diffusion of hydrogen atom in the ε compound layer is very low, that decrease the probability of the hydrogen-induced corrosion of high temperature QPQ treated specimens in H2S environment.

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