Gold-silver alloys

Noble Metal Weldments. Noble metal contact buttons, TS—l h p.m thick, are made by resistance welding a rod of the material to the substrate, which usually is a contact spring, and by cutting the rod and forming the button to the desired shape. Pure gold and gold—silver alloys are the most commonly used metals. 

T. Doppler and W Pfeiler, Resistometric investigation of short-range order kinetics in gold-silver alloys, phys. slot. sol. (a) 131 131 (1992). 

MO bonding theory, 1,152 geometrical structure, 1,138 gold-silver alloy, 1,170 iron-sulfur... 

Liu YC, Yang KH, Yang SJ (2006) Sonoelectrochemical synthesis of spike-like gold-silver alloy nanoparticles from bulk substrates and the application on surface-enhanced Raman scattering. Anal Chim Acta 572 290-294... 

Chen YH, Yeh CS (2001) A new approach for the formation of alloy nanoparticles laser synthesis of gold-silver alloy from gold-silver colloidal mixtures. Chem Commun 371-372... 

A professor of medicine at Wittenberg, Daniel Setmert (1572-1637 CE) developed a version of atomism from experimental observations rather than philosophical considerations. Based upon sublimation, solution, and petrifaction, for example, the mixtures of gold-silver alloy and silver dissolved in acid, he concluded that there were corpuscles or minima that were divisible, and the four elements had them (36, 38). 

The first series of experiments was devoted to determination of the effect scale on the slit temperature. In the second series of experiments we used the slits formed by massive plates of gold-silver alloy and pure palladium, varying considerably their microstructure. Namely, they were initially highly cold-hardened samples and later on the ones annealed at the recrystallisation temperature. In other words, we deal with either fine-grained or coarse-grained metal surfaces. 

Quartering.—This designation is applied to the parting with nitric acid mentioned above, although it is also employed to describe the sulphuric-acid process. Usually, the gold-silver alloy is made to contain 2 parts of gold to 5 parts of silver. It is granulated, and boiled with nitric acid. The silver solution produced is either worked up into lunar caustic, or precipitated as chloride by addition of sodium chloride, and then reduced to metal. 

Nair and Pradeep (2002) have reported that common Lactobacillus strains found in buttermilk, when challenged with silver and gold ions, assisted the growth of microscopic gold, silver, and gold silver alloy crystals of well-defined morphology within the bacterial cells. However, the exact reaction mechanism leading to the formation of silver nanoparticles by this species of silver-resistant bacteria was not... 

The separation of silver from gold was a difficult task, and Pliny refers to an essentially chemical method in which the alloy is roasted with iron sulfate and common salt in the presence of brick dust, which absorbs the silver chloride formed and leaves pure gold. However, some 250 years earlier, Hieron, King of Syracuse (200 bc), had asked Archimedes to examine the composition of a new golden crown that he suspected might have been made from a gold-silver alloy. Since the density of gold (19.3) is nearly twice that of silver (10.5) the composition of the crown was easily determined by a purely physical method, probably the first use of a nondestructive method in analysis. 

Figure 6.4 Optical absorbance of pure silver NPs, (A), gold / silver alloy NPs, (dashes) and pure gold NPs (solid line) coated onto polyelectrolyte coated microplate wells analysed under ambient conditions. Forty eight wells were examined in total, sixteen for each NP.

Size Spherical gold/silver alloy nanoparticles, surrounded by a silica spacer shell, to which is attached a fluorescent ruthenium dye, have been studied. The... 

H.M. Lee, M. Ge, B.R. Sahu, P. Tarakeshwar, and K.S. Kim, Geometrical and electronic structures of gold, silver, and gold-silver binary clusters origins of ductility of gold and gold-silver alloy formation. J. Phys. Chem. B 107, 9994—10005, 2003. 

Philip, R., Kumar, G.R., Sandhyarani N.. Pradeep. T. Picosecond optical nonlinearity in monolayer-protected gold, silver, and gold-silver alloy nanoclusters. Phys. Rev. B 62, 13160-13166(2000)... 

Tominaga, M., Shimazoe, T., Nagaashima, M., Kusuda, H., Kubo, A., Kuwahara, Y., and Taniguchi, I. 2006. Electrocatalytic oxidation of glucose at gold-silver alloy, silver and gold nanoparticles in an alkaline solution. Journal of Electroanalytical Chemistry 590, 37-46. 

---