A method, and systems in which such method may be practiced, allow for the separation of elemental metals from metal alloy. A metal alloy is atomized to form metal alloy particulates. The metal alloy particulates are exposed to an oxidizing agent, such as chlorine gas in the presence of a salt, such as NaCl, an acid, such as HCl, and water. The resulting solution may be filtered to remove particulates, reduced, filtered, reduced, filtered, and so on. In aspects, the method is used to refine gold alloy by oxidation of elemental sponge gold to gold chloride followed by reduction to pure elemental gold.

The present invention provides a silver coating composition that develops excellent conductivity (low resistance value) by low-temperature and short-time calcining and that has excellent printability. A silver particle coating composition including: silver nano-particles whose surfaces are coated with a protective agent including an aliphatic hydrocarbon amine; and a dispersion solvent, wherein the dispersion solvent includes a solvent selected from the group consisting of a glycol ether-based solvent and a glycol ester-based solvent. The silver particle coating composition is suitable for various printing methods such as intaglio offset printing and screen printing.

A method for preparing gold metal nanoparticles, e.g., nanospheres and nanoprisms, includes combining an extract of red algae with chloroauric acid (HAuCl.sub.4). The red algae can be Laurencia papillosa. The extract can include a water solvent extract. The chloroauric acid (HAuCl.sub.4) can be in an aqueous solution. The method can include providing chloroauric acid

(HAuCl.sub.4), providing a red algae extract, and combining the chloroauric acid (HAuCl.sub.4) and the red algae extract to produce gold nanoparticles.

The invention provides a green chemistry, aqueous method to synthesize gold nanoparticles directly from bulk gold sources. The method involves the ultrasonication of bulk gold in water in the presence of an alkythiol species and a quaternary ammonium surfactant. An organic bilayer forms on the surface of the gold which renders it susceptible to material ejection from the violent collapse of cavitation bubbles. This ejected material is stabilized in solution by the formation of an organic bilayer and can be easily separated. It can then be subjected to an aqueous digestive ripening step to give a gold nanoparticle ensemble with a well-defined plasmon resonance. This method is applicable to a number of different sources of bulk gold. The method can be applied to an environmentally important problem; the recovery of gold from electronic waste streams. For example, gold nanoparticles can be extracted directly from the surface of SIM cards, with no prior manipulation of the cards necessary.

A metal sintering preparation containing (A) 50 to 90% by weight of at least one metal that is present in the form of particles having a coating that contains at least one organic compound, and (B) 6 to 50% by weight organic solvent. The mathematical product of tamped density and specific surface of the metal particles of component (A) is in the range of 40,000 to 80,000 cm.sup.−1.

A heat radiating member includes: a composite portion composed of a composite material which contains particles of a satisfactorily thermally conductive material in a metal matrix; and a metal layer formed on at least one surface of the composite portion and composed of a metal. A method for producing a heat radiating member includes: a preparation step to prepare a composite material which contains particles of a satisfactorily thermally conductive material in a metal matrix; a powder arrangement step to dispose a metal powder composed of metal particles on at least one surface of the composite material; and a heating step to heat the composite material and the metal powder, with the metal powder disposed on the composite material, to form a metal layer composed of a metal of the metal powder on a composite portion composed of the composite material.

The present disclosure relates generally to wires and more particularly to textured powder wires containing nanoscale metallic silver powder. The invention presents an improvement of the process of making compressed cores of textured-powder high-temperature superconductor previously using the micaceous high-temperature superconductor Bi-2212. Embodiments of the claimed methods are useful with the micaceous high-temperature superconductors, notably Bi2Sr2CaCu208+x (Bi-2212) and Bi2S-r2Ca2Cu3O10+x (Bi-2223) and rare earth barium copper oxide (REBCO).

There is a problem that when a silver powder sintering paste that is substantially free from resin is used, an organic solvent used as a dispersion medium bleeds, which results in contamination and wire bonding defects. In order to solve the problem, provided is a metal powder sintering paste that contains, as a principal component, silver particles having an average particle diameter (a median diameter) of 0.3 μm to 5 μm and further contains an anionic surfactant but is substantially free from resin.

The present invention provides a silver nano-particle production method which is safe and simple also in terms of scaled-up industrial-level production, in a so-called thermal decomposition method in which a silver-amine complex compound is thermally decomposed to form silver nano-particles. A method for producing silver nano-particles comprising: mixing an aliphatic hydrocarbon amine and a silver compound in the presence of an alcohol solvent having 3 or more carbon atoms to form a complex compound comprising the silver compound and the amine; and thermally decomposing the complex compound by heating to form silver nano-particles.

The present invention discloses a method for continuously preparing noble metal and alloy nanoparticles thereof, and belongs to the technical field of preparation of inorganic nanomaterials. A three-way quartz tube microreactor is designed; noble metal solutions used as raw materials are continuously inputted into the microreactor by injection pumps; and a plasma technology is coupled to form discharge in the microreactor to directly prepare noble metal and alloy nanoparticles thereof. The device and the method of the present invention have low energy consumption, wide operation range, safety, high efficiency, green and environmental protection. The synthesized nanoparticles have high purity, small size, narrow particle size distribution and adjustable components.