Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.13/809086

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Title
Surface-sandwich segregation phenomena in bimetallic Ag-Ni and Pd-Ni nanoparticles: a molecular dynamics study
Author/Creator
Levchenko, E. V.;  Evteev, A. V.;  Belova, I. V.;  Murch, G. E.
Institution
The University of Newcastle. Faculty of Engineering & Built Environment, School of Engineering
Description
By molecular dynamics simulation it is shown that interdiffusion in the initial f.c.c. Agcore (≈ 28 at. %) – Ni-shell (≈ 72 at. %) and Ni-core (≈ 34 at. %) – Pd-shell (≈ 66 at. %) nanoparticles can lead to surface–sandwich segregation. It is observed that there is a separation of the initial Ag-Ni core-shell structure into Ag-core – Ni-intermediate shell – Ag-disperse surface monolayer. The initial crystal Ni-Pd core-shell structure transforms to the core of a non-crystalline Pd-rich solid solution with quite strongly developed icosahedral short-range order, which is covered by a surface–sandwich shell, where Ni atoms are located in the centres of interpenetrating icosahedra of a subsurface Kagomé net layer while the Pd atoms occupy the vertices of the icosahedra and cover this Ni layer from inside and outside. We demonstrate that under certain conditions a surface–sandwich segregation phenomenon at the nanoscale can be observed in systems with completely different phase diagrams in the bulk states: in systems displaying the extremely low mutual solubility as in the Ag-Ni system, or in systems exhibiting a continuous mutual solid solubility like the Pd-Ni system.
Relation
Defect and Diffusion Forum Vol. 289-292, p. 657-664
Publisher Link
http://dx.doi.org/10.4028/www.scientific.net/DDF.289-292.657
Date
2009
Publisher
Trans Tech Publications
Keyword(s)
molecular dynamics;  embedded atom method;  interdiffusion;  surface segregation;  silver;  palladium;  nickel;  alloy nanoparticles
Resource Type
journal article
Identifier
http://hdl.handle.net/1959.13/809086
Identifier
ISSN:1012-0386
Reviewed
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Subject
"Defect and Diffusion Forum"
 
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