The method for making carbon-coated copper nanoparticles is a simple, one-step for coating copper nanoparticles with a carbon shell to prevent rapid oxidation of the carbon nanoparticle core. The method involves heating or autoclaving thin sheets of copper hydroxide nitrate (Cu.sub.2(OH).sub.3NO.sub.3) under supercritical conditions (a temperature of 300° C. and a pressure of 120 bar) for two hours. The autoclaving may be performed in the presence of an inert gas, such as argon, which may be used to remove any remaining gases, and the pressure may be released in the presence of the inert gas so that the product may be collected in the presence of air.

The present disclosure provides a preparation method of a metal powder material. An alloy sheet composed of a matrix phase and a dispersive phase with different chemical reactivities is prepared by the rapid solidification technique of alloy melt. Metal powder is prepared by the reaction of the alloy sheet and an acid solution. Please refer to the description for the detailed preparation method. This method is simple in operation, can be used to prepare many kinds of metal powder materials of different shapes and at the nanometer scale, the submicron scale and the micron scale, and has a good application prospect in the fields of catalysis, powder metallurgy and 3D printing.

The present disclosure provides a preparation method of a metal powder material. An alloy sheet composed of a matrix phase and a dispersive phase with different chemical reactivities is prepared by the rapid solidification technique of alloy melt. Metal powder is prepared by the reaction of the alloy sheet and an acid solution. Please refer to the description for the detailed preparation method. This method is simple in operation, can be used to prepare many kinds of metal powder materials of different shapes and at the nanometer scale, the submicron scale and the micron scale, and has a good application prospect in the fields of catalysis, powder metallurgy and 3D printing.

The present disclosure provides a preparation method of a metal powder material. An alloy sheet composed of a matrix phase and a dispersive phase with different chemical reactivities is prepared by the rapid solidification technique of alloy melt. Metal powder is prepared by the reaction of the alloy sheet and an acid solution. Please refer to the description for the detailed preparation method. This method is simple in operation, can be used to prepare many kinds of metal powder materials of different shapes and at the nanometer scale, the submicron scale and the micron scale, and has a good application prospect in the fields of catalysis, powder metallurgy and 3D printing.

The present disclosure provides a preparation method of a metal powder material. An alloy sheet composed of a matrix phase and a dispersive phase with different chemical reactivities is prepared by the rapid solidification technique of alloy melt. Metal powder is prepared by the reaction of the alloy sheet and an acid solution. Please refer to the description for the detailed preparation method. This method is simple in operation, can be used to prepare many kinds of metal powder materials of different shapes and at the nanometer scale, the submicron scale and the micron scale, and has a good application prospect in the fields of catalysis, powder metallurgy and 3D printing.

A method for producing a metal powder provided on the surface thereof with a glassy thin film, wherein a glassy substance is produced in the vicinity of the surface of the metal powder by spray pyrolysis from a solution that contains a thermally decomposable metal compound and a glass precursor that produces a glassy substance that does not form a solid solution with the metal produced from the metal compound by thermal decomposition, so as to form the metal powder provided on the surface thereof with the glassy thin film. The metal includes a base metal as a major component, and the solution contains 5 to 30 mass %, as the mass % with reference to the overall solution, of a reducing agent that is soluble in the solution and exhibits a reducing activity during the aforementioned step of heating.

A method for producing a metal powder provided on the surface thereof with a glassy thin film, wherein a glassy substance is produced in the vicinity of the surface of the metal powder by spray pyrolysis from a solution that contains a thermally decomposable metal compound and a glass precursor that produces a glassy substance that does not form a solid solution with the metal produced from the metal compound by thermal decomposition, so as to form the metal powder provided on the surface thereof with the glassy thin film. The metal includes a base metal as a major component, and the solution contains 5 to 30 mass %, as the mass % with reference to the overall solution, of a reducing agent that is soluble in the solution and exhibits a reducing activity during the aforementioned step of heating.

A method for producing a metal powder provided on the surface thereof with a glassy thin film, wherein a glassy substance is produced in the vicinity of the surface of the metal powder by spray pyrolysis from a solution that contains a thermally decomposable metal compound and a glass precursor that produces a glassy substance that does not form a solid solution with the metal produced from the metal compound by thermal decomposition, so as to form the metal powder provided on the surface thereof with the glassy thin film. The metal includes a base metal as a major component, and the solution contains 5 to 30 mass %, as the mass % with reference to the overall solution, of a reducing agent that is soluble in the solution and exhibits a reducing activity during the aforementioned step of heating.

The present invention provides novel silver particles that when used as a conductive adhesive, are satisfactorily sintered at a low temperature without application of pressure during sintering of the conductive adhesive, and form a sintered body with high denseness and high mechanical strength (shear strength). Silver particles comprising silver particles A with an average particle diameter in the range of 50 to 500 nm, and silver particles B with an average particle diameter in the range of 0.5 to 5.5 μm, wherein the silver particles satisfy a relationship in which the average particle diameter of the silver particles B is 5 to 11 times the average particle diameter of the silver particles A.

Disclosed here is a method for making a nanoporous material, comprising aerosolizing a solution comprising at least one metal salt and at least one solvent to obtain an aerosol, freezing the aerosol to obtain a frozen aerosol, and drying the frozen aerosol to obtain a nanoporous metal compound material. Further, the nanoporous metal compound material can be reduced to obtain a nanoporous metal material.