The Ag−Au (Silver-Gold) system

Okamoto, H.; Massalski, T. B.

doi:10.1007/bf02880317

Cited by 67 publications

(40 citation statements)

References 78 publications

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“… Bulk phase diagram of the gold–silver alloy. Experimental points are taken from ref ( 63 ). The liquidus–solidus curves are plotted using the regular solution model ( eq 1 ).…”

Section: Results and Discussionmentioning

confidence: 99%

Electrum, the Gold–Silver Alloy, from the Bulk Scale to the Nanoscale: Synthesis, Properties, and Segregation Rules

et al. 2015

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The alloy Au–Ag system is an important noble bimetallic phase, both historically (as “Electrum”) and now especially in nanotechnology, as it is applied in catalysis and nanomedicine. To comprehend the structural characteristics and the thermodynamic stability of this alloy, a knowledge of its phase diagram is required that considers explicitly its size and shape (morphology) dependence. However, as the experimental determination remains quite challenging at the nanoscale, theoretical guidance can provide significant advantages. Using a regular solution model within a nanothermodynamic approach to evaluate the size effect on all the parameters (melting temperature, melting enthalpy, and interaction parameters in both phases), the nanophase diagram is predicted. Besides an overall shift downward, there is a “tilting” effect on the solidus–liquidus curves for some particular shapes exposing the (100) and (110) facets (cube, rhombic dodecahedron, and cuboctahedron). The segregation calculation reveals the preferential presence of silver at the surface for all the polyhedral shapes considered, in excellent agreement with the latest transmission electron microscopy observations and energy dispersive spectroscopy analysis. By reviewing the nature of the surface segregated element of different bimetallic nanoalloys, two surface segregation rules, based on the melting temperatures and surface energies, are deduced. Finally, the optical properties of Au–Ag nanoparticles, calculated within the discrete dipole approximation, show the control that can be achieved in the tuning of the local surface plasmon resonance, depending of the alloy content, the chemical ordering, the morphology, the size of the nanoparticle, and the nature of the surrounding environment.

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“… Bulk phase diagram of the gold–silver alloy. Experimental points are taken from ref ( 63 ). The liquidus–solidus curves are plotted using the regular solution model ( eq 1 ).…”

Section: Results and Discussionmentioning

confidence: 99%

Electrum, the Gold–Silver Alloy, from the Bulk Scale to the Nanoscale: Synthesis, Properties, and Segregation Rules

et al. 2015

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“…The nominal porosity P of NPG is accessible from the amount of dissolved Ag (determined from the residual content of Ag) and taking into account the volume of the monolith after shrinkage during the dealloying (Table , Line 1) . In case of NPG, this estimation is especially intuitive as Au and Ag have almost identical atomic volumes: The lattice parameters of Au (407.8 pm) and Ag (408.6 pm) differ by merely 0.2 % …”

Section: Resultsmentioning

confidence: 99%

“…[23] In case of NPG, this estimation is especially intuitive as Au and Ag have almost identical atomic volumes: The lattice parameters of Au (407.8 pm) and Ag (408.6 pm) differ by merely 0.2 %. [24] The porosity can also be determined from the effective diffusion coefficients determined from the approach curves in Figure 4. The effective diffusion coefficient describes the diffusion when considering the pores and the ligaments as one continuous domain so that the porosity, P', may be estimated from D eff /D.…”

Section: Comparison Of Different Approaches For Porosity Determinationmentioning

confidence: 99%

Mass Transport in Porous Electrodes Studied by Scanning Electrochemical Microscopy: Example of Nanoporous Gold

et al. 2019

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Scanning electrochemical microscopy (SECM) approach curves were measured above different samples of nanoporous gold (NPG) using ascorbic acid as an irreversible redox mediator. Under these circumstances, the microelectrode current is informative in terms of the diffusive mass transport inside the network of pores in the sample, because mediator regeneration at NPG is not possible for an irreversible mediator. The reaction–transport problem was solved by finite element simulation for a wide variety of working distances, film thicknesses, and microelectrode geometries. The Bruggeman equation was used to relate transport properties and porosity. The simulation leads to an analytical expression that allows the determination of porosity values corrected by the tortuosity of insulating and conducting materials. The validity of the approach was demonstrated by applying it to NPG samples for which structural parameters can be varied by the particular dealloying protocol. This procedure is potentially applicable for following coarsening processes in porous electrodes and other materials, because the SECM procedure avoids emersion from electrolyte solution for those determinations.

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“…The thermodynamic properties and phase diagrams of all the three binary systems, Ag-Au [4][5][6][7][8], Ag-Bi [9][10][11] and Au-Bi [12][13][14] are well known. These have already been calculated by authors [7,11,13,14], and compiled in the Scientific Group of Thermodata Europe (SGTE) [15] database or COST 531 database.…”

Section: The Boarding Binary Systemsmentioning

confidence: 99%