Gold−Copper Nano-Alloy, “Tumbaga”, in the era of nano: phase diagram and segregation

Guisbiers, Grégory y Mejía Rosales, Sergio y Khanal, Subarna y Ruiz Zepeda, Francisco y Whetten, Robert L. y Yacamán, Miguel José (2014) Gold−Copper Nano-Alloy, “Tumbaga”, in the era of nano: phase diagram and segregation. Nano Letters, 14 (11). pp. 6718-6726. ISSN 1530-6984

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Gold−Copper Nano-Alloy, Tumbaga, in the Era of Nano Phase Diagram and Segregation.pdf - Versión Aceptada
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Resumen

Gold–copper (Au–Cu) phases were employed already by pre-Columbian civilizations, essentially in decorative arts, whereas nowadays, they emerge in nanotechnology as an important catalyst. The knowledge of the phase diagram is critical to understanding the performance of a material. However, experimental determination of nanophase diagrams is rare because calorimetry remains quite challenging at the nanoscale; theoretical investigations, therefore, are welcomed. Using nanothermodynamics, this paper presents the phase diagrams of various polyhedral nanoparticles (tetrahedron, cube, octahedron, decahedron, dodecahedron, rhombic dodecahedron, truncated octahedron, cuboctahedron, and icosahedron) at sizes 4 and 10 nm. One finds, for all the shapes investigated, that the congruent melting point of these nanoparticles is shifted with respect to both size and composition (copper enrichment). Segregation reveals a gold enrichment at the surface, leading to a kind of core–shell structure, reminiscent of the historical artifacts. Finally, the most stable structures were determined to be the dodecahedron, truncated octahedron, and icosahedron with a Cu-rich core/Au-rich surface. The results of the thermodynamic approach are compared and supported by molecular-dynamics simulations and by electron-microscopy (EDX) observations.

Tipo de elemento: Article
Palabras claves no controlados: Nanothermodynamics, Binary phase diagram, Nanoalloy, Size effect, Polyhedra, Congruent melting
Materias: Q Ciencia > Q Ciencias en General
Q Ciencia > QC Física
Divisiones: Centro de Investigación en Ciencias Físico Matemáticas
Usuario depositante: Dr. Sergio J. Mejia Rosales
Creadores:
CreadorEmailORCID
Guisbiers, GrégoryNO ESPECIFICADONO ESPECIFICADO
Mejía Rosales, SergioNO ESPECIFICADONO ESPECIFICADO
Khanal, SubarnaNO ESPECIFICADONO ESPECIFICADO
Ruiz Zepeda, FranciscoNO ESPECIFICADONO ESPECIFICADO
Whetten, Robert L.NO ESPECIFICADONO ESPECIFICADO
Yacamán, Miguel JoséNO ESPECIFICADONO ESPECIFICADO
Fecha del depósito: 03 Feb 2016 22:44
Última modificación: 17 Feb 2016 17:29
URI: http://eprints.uanl.mx/id/eprint/8907

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