Palladium-gold

White gold is an alloy of gold decolorized by the addition of palladium. Like gold, palladium can be beaten into leaf as thin as 1 /250,000 in. The metal is used in dentistry, watchmaking, and... 

The ideal electroless solution deposits metal only on an immersed article, never as a film on the sides of the tank or as a fine powder. Room temperature electroless nickel baths closely approach this ideal electroless copper plating is beginning to approach this stabiHty when carefully controUed. Any metal that can be electroplated can theoretically also be deposited by electroless plating. Only a few metals, ie, nickel, copper, gold, palladium, and silver, are used on any significant commercial scale. 

Palladium and gold Palladium electrodeposition is of special interest for catalysis and for nanotechnology. It has been reported [49] that it can be deposited from basic chloroaluminate liquids, while in the acidic regime the low solubility of PdCl2 and passivation phenomena complicate the deposition. In our experience, however, thick Pd layers are difficult to obtain from basic chloroaluminates. With different melt compositions and special electrochemical techniques at temperatures up to 100 °C we succeeded in depositing mirror-bright and thick nanocrystalline palladium coatings [10]. 

For electronic micrographs, samples were taken from fresh beads and 72 hour beads from the ICR column. The samples were dipped into liquid nitrogen for 10 minutes, then freeze dried for 7 horns (EMITECH, model IK750, Cambridge, UK). The sample was fixed on an aluminium stub and coated with gold-palladium by a Polaron machine model SD515... 

Gold-palladium alloys, see Palladium-gold alloys... 

Gold palladium binuclear complexes [141] can be synthesized by reaction of [Au (C6F5)(tht)] with the palladium derivative trans-[pdRR (dppm)2] where R = R = QF5 R = R = CgCls R = C Fs, R = Cl. It was however not possible to distinguish the two structures for these complexes shown in Figure 3.20 ... 

Uson, R., Fomies, J., Laguna, A. and Valenzuela, J.I. (1982) Pseudohalo-bridged pentafiuorophenyl gold-palladium complexes. Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, 12(7), 935-946. 

Fievet et al. [225] have prepared and isolated metallic nanopowders of gold, palladium, iridium, osmium, copper, silver, nickel, cobalt, lead, and cadmium via polyol... 

Hinds MW (1993) Determination of gold, palladium and platinum in high purity silver by different solid sampling graphite furnace atomic absorption spectrometry methods, Spectrochim Acta 48B 435-445. 

Mizukoshi Y, Okitsu K, Yamamoto T, Oshima J, Nagata Y, Maeda Y (1997) Sonochemical preparation of bimetallic nanoparticles of gold/palladium in aqueous solution. J Phys Chem B 101 7033-7037... 

Mizukoshi Y, Fujimoto T, Nagata Y, Oshima R, Maeda Y (2000) Characterization and catalytic activity of core-shell structured gold/palladium bimetallic nanoparticles synthesized by the sonochemical method. J Phys Chem B 104 6028-6032... 

Harada M, Asakura K, Toshima N (1993) Catalytic activity and structural analysis of polymer-protected gold/palladium bimetallic clusters prepared by the successive reduction of hydrogen tetrachloroaurate(ffl) and palladium dichloride. J Phys Chem 97 5103-5114... 

A section of the film was removed from the bag and was immersed in liquid nitrogen. The section was then freeze-fractured and mounted on the SEM stage with the outside surface of the bag section facing downward. The sample was sputter coated prior to SEM/EDS analysis. Sputtering was performed to deposit approximately 20 nm of gold/palladium onto the sample. Double-sided conductive tape was used to ensure that the sample was sufficiently grounded to... 

Yordanov, A. T. Roundhill, D. M. Electronic absorption spectroscopy for the investigation of the solution binding of gold, palladium, mercury and silver salts to the lower rim substituted calix[4]arenes 25,26,27,28-(2-N,N-dimethyl-dithiocarbamoylethoxy)calix[4]arene and 25,26,27,28-(2-methylthioethoxy)calix[4]arene. Inorg. Chim. Acta 1998, 270, 216-220. 

In addition, a number of other deep level impurities have been hydrogen passivated. They include nickel, cadmium, tellurium, zirconium, titanium, chromium, and cobalt (Pearton et al., 1987). Most of these studies have been qualitative, and important work remains to be done if the hydrogenation of these and most probably additional impurities, such as gold, palladium, platinum and iron, is to be fully understood. 

Dehydrate in a graded alcohol series series (30%, 50%, 70%, 90%, 100%), for 100% use in 200 proof alcohol Freon or amyl acetate (use a graded series, e.g., 1 3, 1 2, 1 1 Freon/alcohol and then pure Freon) Critically point dry using liquid C02 soaks and flushes Mount on aluminum stubs using silver paint or double-stick tape0 Sputter coat with gold/palladium in a sputter coater flushed with argon... 

A metallic electrode consisting of a pure metal in contact with an analyte solution develops an electric potential in response to a redox reaction occurring at its metal surface. Common metal electrodes such as platinum, gold, palladium or carbon are known as inert metal electrodes whose sole function is to transfer electrons to or from species in solution. Metal electrodes corresponding to the first kind are pure metal electrodes such as Ag, Hg and others that respond directly to a change in activity of the metal cation in the solution. For example, for the reaction... 

Schmid, G. et al., Catalytic properties of layered gold-palladium colloids, Chem. Eur. J., 2,1099,1996. 

The scanning electron microscopy micrographs shown in the body of this manuscript were taken by AMR-1000 and Jeol C-35 instruments. All specimens were gold-palladium coated. To obtain the cross-section morphologies, the membranes were fragmented in liquid nitrogen. 

Tan, Y., Dai, X., Li, Y., Zhu, D. 2003. Preparation of gold, palladium and silver nanoparticles by the reduction of their salts with a weak reductant - potassium bitartrate. Journal of Materials Chemistry, 13, 1069-1075. 

Figure 1 shows experimental reaction curves obtained in the absence of added catalyst and in the presence of various colloidal catalysts. The reaction has a pronounced induction period in the absence of added catalyst, and the curve shows the typical shape expected for an auto-catalytic reaction. Addition of colloidal silver, gold, palladium, and silver sulfide markedly decrease the magnitude of the induction period. 

In 1824 del Rio published an analysis of a gold-rhodium alloy from the smelting house in Mexico which was similar to the gold-palladium ingot previously reported by Joseph Cloud, director of the Philadelphia Mint (21). Three years later he published a translation of Berzelius s New mineral system (22). He served for some time on a committee appointed to inspect the money and improve working conditions at the Mint. 

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