Au-Cu alloys

Chen S J, Sanz F, Ogletree D F, Hallmark V M, Devine T M and Salmeron M 1993 Selective dissolution of copper from Au-rich Au-Cu alloys an electrochemical STS study Surf. Sc . 292 289... 

Table 7.4. Crystal structure data of Au-Cu alloys (after Okamoto et al. (1987).

It may be of interest to note that as far back as 1934 Rienhcker (47) reported that the decomposition of formic acid over Au-Cu alloys is influenced by long-range ordering of the alloys. 

Ghetta, V., Fouletier, J. and Chatain, D., Oxygen adsorption isotherms at the surfaces of liquid Cu and Au-Cu alloys and their interfaces with A1203 detected by wetting experiments , Acta. Mater., 1996 44(5) 1927-1936. 

Figure 8. Gold-cadmium-copper alloy obtained by dissolution of CdS in molten Au-Cu alloy. The black earthy deposit is easily separated from the...

Rapid alloying (RA) is a fast diffusion process that was experimentally discovered by Yasuda, Mori, and co-workers (YM) in binary microclusters. By using an evaporator, they deposited individual solute atoms (Cu) on the surface of host nano-sized clusters that are supported by amorphous carbon him at room temperature. YM observed the alloying behavior with a transmission electron microscope in in situ condition as schematically described in Fig. 1. In Ref. 7 it is demonstrated that Au clusters promptly changed into highly concentrated, homogeneously mixed (Au-Cu) alloy clusters. RA is similarly observed in various nano-sized binary clusters, such as (Au-Ni), (In-Sb), (Au-Zn), and (Au-Al) [7]. They examined the presence and absence of RA for clusters of different sizes. Consequently, YM summarize the unusual features of RA as follows ... 

Kang, Q. Wang, T. Li, P. Liu, L. Chang, K. Li, M. Ye, J. Photocatalytic Reduction of Carbon Dioxide by Hydrous Hydrazine over Au-Cu Alloy Nanoparticles Supported on SrTi03/Ti02 Coaxial Nanotube Arrays. Angew. Chem. Int. Ed., 2015, 54, 841-845. 

A major driving force in the development of the ion beam mixing process is the process s ability to produce ion-modified materials with higher solute concentrations at lower irradiation doses than can be achieved with conventional high-dose implantation techniques. A case-in-point is the formation of Au-Cu alloys on Cu substrates (Fig. 13.2). 

In general, the constituent atoms of substitutional solid solutions will be randomly positioned at any site in the lattice. However, as the temperature is lowered, each lattice position may no longer be equivalent, and ordered arrays known as superlattices may be formed. Examples of superlattice behavior are found for Au-Cu alloys used in jewelry, gold fillings, and other applications (Figure 2.47). 

Solid Au-Cu alloys are regular in their thermodynamic behaviour. The integral enthalpy of mixing, at 447°C (720 K) is given below as a function of composition. 

The partial molar entropy of mixing of gold in solid Au-Cu alloys, determined at 500°C (773 K) over the complete solution range, is tabulated below. 

VoeUcer, E., Williams, F.J., Calvo, E.J., Jacob, T., and Schiffrin, D.J. Oj induced surface segregation in Au-Cu alloys studied by angle resolved XPS and DFT modelling. Physical Chemistry Chemical Physics, 14, 7448-7455, 2012. 

FIGU RE 7.6 Effect of heat treatment on the tensile strength of binary Au-Cu alloys [33]. (From A plain man s guide to alloy phase diagrams their use in jewellery manufacture - Part 2, M. Grimwade, Gold Technology, 2000,30, 8. With permission.)... 

Electrodeposited Au-Cu alloys Structural analysis, thermal stability measurements and mechanical characterization, L. Battezzati, M. Baricco, S. Barhero, A. Zambon, I. Calliari, A. Variola, B. Bozzini, P. L. Cavallotti, G. Giovannelli, and S. Ti r taE, La metallurgia italiana 93(2) (2001) 17. (In Italian)... 

Microstructure and thermal stability of nanocrystaUine electrodeposited Au-Cu alloys, L. Battezzati, M. Baricco, M. Belotti, and V. Brunella, Mater. Sci. Fontm, 2001, 360-362, 253. 

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