Palladium-copper alloy

Silver-copper-palladium alloys with liquidus temperatures of 800-1 000°C have very low vapour pressures combined with good wetting and flow characteristics and are widely employed in vacuum work. They exhibit a lower tendency to stress corrosion than silver-copper, and do not form brittle alloys with other metals. 

Simonet, J., Poizot, P. and Laffont, L. (2006) A copper-palladium alloy usable as cathode material mode of formation and first examples of catalytic cleavages of carbon-halide bonds. J. Electroanal. Chem. 591, 19-26. 

Zetkin AS, Kagan GY, Levin YS. Influence of structural transformations on the diffusion parameters of deuterium in palladium-copper alloys. Phys Met Metall. 1987 64(5) 130. Piper J. Diffusion of hydrogen in copper-palladium alloys. J Appl Phys. 1966 37(2) 715. Levin ES, Zetkin AS, Kagan GE. Solubility of deuterium in Pd-Cu alloys. Russ J Phys Chem... 

Piper J. Diffusion of hydrogen in copper-palladium alloys. J Appl Phys. 1966 37(2) 715-21. 

J. Piper, Diffusion ofhydrogen in copper-palladium alloys, L Appl. Phys. 1966, 37(2), 715-721. 

Taylor R. (1934), Transformations in the copper-palladium alloys ,/ Institute Metals, 54,255-272. 

EXAFS analysis of colloidal metals has begun to shed light on this complex state of affairs. In the few examples reported so far for bimetallic colloids, a nonuniform distribution of metals has been observed. Ibshima [164, 165] has studied a series of bimetallic PtPd catalysts, and concluded that the distribution of the two metals in the particles is nonuniform on the basis of differences in their respective mean coordination numbers. In our laboratory, colloidal 4.0 nm PdCu/PVP has been analyzed by this method and the distribution of the metals in the alloy particles shown to be nonuniform. However the component which is enriched at the surface appears to be palladium, in contrast to the segregation of copper to the surface of bulk copper-palladium alloys. [203] In addition, the ability of surface deposited copper to dissolve in a preformed palladium particle has been clearly demonstrated on the basis of the analysis of the coordination sphere of the copper. [204]... 

Metal powder—glass powder—binder mixtures are used to apply conductive (or resistive) coatings to ceramics or metals, especially for printed circuits and electronics parts on ceramic substrates, such as multichip modules. Multiple layers of aluminum nitride [24304-00-5] AIN, or aluminay ceramic are fused with copper sheet and other metals in powdered form. The mixtures are appHed as a paste, paint, or slurry, then fired to fuse the metal and glass to the surface while burning off the binder. Copper, palladium, gold, silver, and many alloys are commonly used. 

Copper-palladium-nickel-manganese brazes give very low erosion of the parent metals to be brazed, and are therefore used to join thin sections of stainless steels and high-nickel alloys. 

It should be noted that, in the interpretation of activity patterns of alloy catalysts, extreme care is needed to ensure that the surface composition is known. It has been shown [321,322] with copper—nickel alloys, which show two phases in the composition range 2—80% copper, that, within this miscibility gap, the surface composition remains constant at 80% Cu—20% Ni, independent of the nominal bulk composition. Furthermore, the surface composition may vary depending upon the catalyst pretreatment [322], No miscibility gap occurs with palladium—gold or palladium-silver alloys [323]. 

Between 1980 and about 2000 most of the studies on the electrodeposition in ionic liquids were performed in the first generation of ionic liquids, formerly called room-temperature molten salts or ambient temperature molten salts . These liquids are comparatively easy to synthesize from AICI3 and organic halides such as Tethyl-3-methylimidazolium chloride. Aluminum can be quite easily be electrode-posited in these liquids as well as many relatively noble elements such as silver, copper, palladium and others. Furthermore, technically important alloys such as Al-Mg, Al-Cr and others can be made by electrochemical means. The major disadvantage of these liquids is their extreme sensitivity to moisture which requires handling under a controlled inert gas atmosphere. Furthermore, A1 is relatively noble so that silicon, tantalum, lithium and other reactive elements cannot be deposited without A1 codeposition. Section 4.1 gives an introduction to electrodeposition in these first generation ionic liquids. 

Concentrated hydrochloric acid attacks the compact metal but slowly, whilst aqua regia rapidly effects its solution. Dilute nitric acid has but little action, although, when present in certain alloys, such as those with silver or copper, palladium will dissolve in it. Concentrated nitric acid readily attacks the metal. Boiling concentrated sulphuric acid converts it into palladous sulphate. Palladium is unique in that it displaces mercury from its cyanide. 

Thus the palladium alloy with 53% copper proved to be more permeable than palladium [37]. However, the maximal operating temperature for membranes of this alloy is 623 K. Palladium-ruthenium alloys are more thermostable and may be used up to 823 K. At the increase in ruthenium content from 1 to 9.4 at.%, the hydrogen permeability of the alloys attained a maximum at a ruthenium content of about 4.5%. The long-term strength of this alloy at 823 K after service for lOOOhr was greater by a factor of almost 5 than that of pure palladium [35]. 

An alloy is made by mixing two or more melted metals. The solid mixture has properties different from those of the individual metals. Palladium is commonly alloyed with gold, silver, and copper. The alloys... 

Methods involving triphenylmethane dyes were applied in determination of antimony in air [74], water [44], silicates, plants, sewage and waste waters [25], copper-zinc and copper-nickel alloys [48], steel [50], lead [12], silver and gold [42], palladium [45], and tellurium [27]. Antimony was determined in duralumin alloys and steel with the use of Rhodamine 6G... 

In Raney s method a catalytically active metal is alloyed with a catalytically inactive one and then treated with a reagent that dissolves out the inactive metal. The catalytically inactive component that is to be dissolved out may be aluminum, silicon, magnesium, or zinc. The catalytically active metal is usually nickel, cobalt, copper, or iron. Noble-metal catalysts can, however, also be produced by Raney s method if an aluminum-platinum alloy (40% of platinum) or a zinc-palladium alloy (40% of palladium) is decomposed by hydrochloric acid.153... 

Another striking example of the decisive role of the mode of preparation may be found in the behavior of Cu-Pd alloys [Rienacker et al. (65)] (see Fig. 18). When copper is alloyed with palladium the activation energy remains practically constant up to 65% Pd on further addition of Pd, E falls rapidly down to the low value of Pd. This is only true, however, for normally prepared, disordered alloys. If, by tempering, the so-called ordered alloys are prepared, in which the Pd-atoms have definite crystallographic positions, the result is essentially different (see Fig. 18) now the activation energy of the alloys is nearly additively composed of the contributions of the components in the alloy. Analogous results were obtained for the system Cu-Pt [Rienacker (69)]. 

Juda W, Krueger CW, Bombard TR. Method of producing thin palladium-copper and the hke, palladium alloy membranes by solid-solid metallic interdifiusion, and improved membrane. US Patent 6238465,2001. 

Complex substrate modifications involving intermediate layers and palladium alloy deposition methods are often required for superior membrane performance. Modification of a membrane support surface before palladium deposition by sintering on smaller particles can create a smoother surface with smaller pores, facilitating the deposition of a defect-free palladium layer. Nickel microparticles have been sintered together to form a porous support that was sputter-coated with palladium and then copper [118]. Thermal treatment at 700 °C for 1 h promoted reflow to create a durable, pinhole-free membrane with a Pd-Cu-Ni alloy film. In another case, starting with commercially available PSS with a 0.5 pm particle filtration cut-ofF, submicron nickel particles were dispersed on the surface, vacnium sintered for 5 h at 800 °C, and then sputtered with UN [159]. The nickel particles created a smoother surface with smaller pores, so a thinner palladium alloy layer... 

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