Aiming at providing a metal particle, an electro-conductive paste, a formed article, and a laminated article that are able to form a highly reliable and high-quality electric interconnect, an electro-conductive bonding portion, or a three-dimensional structure that is less likely to produce the Kirkendall void, this invention discloses a metal particle which include an outer shell and a core part, the outer shell including an intermetallic compound and covering the core part.

Nanocages are formed by etching nancubes. The nanocubes are added to an aqueous system having an amphiphilic lipid dissolved in an organic solvent (e.g. a hydrophobic alcohol) to form reverse micelles. As the water evaporates the micelles shrink as etching of the flat surface of the nanocubes occurs. In this fashion hollow nanocages are produced. In one embodiment, the nanocage is covalently attached to a polymer shell (e.g. a dextran shell).

The present invention relates to a soft magnetic metal powder which contains B and has Fe and Ni as the main components, wherein the content of Ni in the soft magnetic metal powder is 30 to 80 mass %, the total content of Fe and Ni in the soft magnetic metal powder is 90 mass % or more, the content of B inside the metal particle of the soft magnetic metal powder is 10 to 150 ppm, and the particle has a film of boron nitride on the surface. The present invention also relates to a soft magnetic metal powder core prepared by using the soft magnetic metal powder.

A solder-coated ball (10A) includes a spherical core containing Ni and P; and a solder layer (12) formed to coat the core (11). A solder-coated ball (10B) further includes a Cu plating layer (13) formed between the core (11) and the solder layer (12). A solder-coated ball (10C) further includes an Ni plating layer (14) formed between the Cu plating layer (13) and the solder layer (12).

Provided is a dendritic silver-coated copper powder which is capable of effectively ensuring a contact, while having excellent electrical conductivity by having the surface coated with silver. A silver-coated copper powder according to the present invention is obtained by coating the surface of a copper powder 1, which is an assembly of copper particles 2 and has a dendritic form having a plurality of branches, with silver. Each copper particle 2, the surface of which is coated with silver, is an ellipsoid that has a breadth within the range of from 0.2 μm to 0.5 μm and a length within the range of from 0.5 μm to 2.0 μm. The average particle diameter (D50) of the copper powder 1, which is obtained by coating the surface of the assembly of the ellipsoidal copper particles 2 with silver, is from 5.0 μm to 20 μm.

Provided are a Cu ball, a Cu core ball, a solder joint, solder paste and foamed solder, which are superior in the impact resistance to dropping and can inhibit any occurrence of poor joints a junction defect. An electronic component 60 is constructed by joining a solder bump 30 of a semiconductor chip 10 to an electrode 41 of a printed circuit board 40 with solder paste 12, 42. The solder bump 30 is formed by joining an electrode 11 of the semiconductor chip 10 to the Cu ball 20. The Cu ball 20 according to the present invention contains purity which is equal to or higher than 99.9% and equal to or lower than 99.995%, sphericity which is equal to or higher than 0.95, and Vickers hardness which is equal to or higher than 20 HV and equal to or less than 60 HV.

A method of making a transparent conductive material includes: preparing a reactive solution that contains a solvent, a metal salt which is dissolved in the solvent, and a powder of graphene oxide which is dispersed in the solvent; and simultaneously reducing metal ions of the metal salt and the graphene oxide in the reactive solution to form a plurality of core-shell nanowires, each of which includes a core of a metal reduced from the metal ions, and a shell of graphene surrounding the core.

Provided are processes for preparing a thermodynamically stable PtBi.sub.2 alloy nanoparticle. In certain aspects, the process comprises preparing an aqueous mixture, with the aqueous mixture comprising: an inorganic compound comprising SnCl.sub.2; an inorganic compound comprising Bi; and HCl. The process further comprises adding PtCl.sub.4 to the mixture. The process results in the spontaneous reduction of Bi and Pt. Excess SnCl.sub.2 is adsorbed as a ligand at the surface of the PtB.sub.2 alloy nanoparticle, which serves to stabilize the nanoparticle. Another aspect provides a thermodynamically stable PtBi.sub.2 nanoparticle. The nanoparticle comprises a core comprising a PtBi.sub.2 alloy. The nanoparticle further comprises a shell at least partially encapsulating the core, with the shell comprising stannous chloride. The thermodynamically stable PtB.sub.2 nanoparticle has a negative charge.

Novel nanoparticle-coated multilayer shell microstructures are disclosed herein. Some variations of the invention provide a material comprising a plurality of hollow microstructures characterized by an average shortest diameter from about 5 microns to about 1 millimeter, wherein each of the microstructures comprises multiple shells, including at least an inner shell and an outmost shell, with a combined thickness that is less than one-tenth of the average shortest diameter. The inner shell and the outmost shell have different composition. The outmost shell comprises nanoparticles sized between about 10 nanometers to about 500 nanometers, and the nanoparticles each contain an oxide and/or are surrounded by an oxide layer having a layer thickness of at least 1 nanometer. Several microstructure configurations are illustrated in the drawings.

A Cu core ball and a method of manufacturing such a Cu core ball. Purity of the Cu internal ball is at least 99.9% and not greater than 99.995%. A total contained amount of Pb and/or Bi in impurity contained in the Cu ball is equal to or larger than 1 ppm. Its sphericity is at least 0.95. A solder plating film coated on the Cu ball is of Sn solder or a lead free solder alloy whose primary component is Sn. In the solder plating film, a contained amount of U is not more than 5 ppb and that of Th is not more than 5 ppb. A total alpha dose of the Cu ball and the solder plating film is not more than 0./0200 cph/cm2. An arithmetic average roughness of the Cu core ball is equal to or less than 0.3 μm.