Provided are a method for producing nickel seed crystals that maintains and improves the quality of nickel powder at a low cost while suppressing production cost and environmental load in the production of nickel powder, by optimizing the amount of hydrazine added when producing fine nickel powder as seed crystals using hydrazine; and a method for producing nickel powder using the nickel seed crystals. The method for producing seed crystals used for producing hydrogen-reduced nickel powder, including adding, to an acid solution containing nickel ions that is maintained at a temperature of 50 to 60 C., hydrazine of 1 to 1.25 mol per 1 mol of a nickel component contained in the acid solution to produce the seed crystals.

Provided are a method for producing nickel seed crystals that maintains and improves the quality of nickel powder at a low cost while suppressing production cost and environmental load in the production of nickel powder, by optimizing the amount of hydrazine added when producing fine nickel powder as seed crystals using hydrazine; and a method for producing nickel powder using the nickel seed crystals. The method for producing seed crystals used for producing hydrogen-reduced nickel powder, including adding, to an acid solution containing nickel ions that is maintained at a temperature of 50 to 60 C., hydrazine of 1 to 1.25 mol per 1 mol of a nickel component contained in the acid solution to produce the seed crystals.

An aqueous suspension for producing porous metallic structures comprises 2-49 vol % of a mixture of at least one chemical compound comprising a metal atom, wherein said at least one compound is solid at room temperature, has the form of a powder, and is suspended in water, and 10-9) to 0.1 mol of a surfactant per mol of said chemical compound comprising a metal atom. The aqueous suspension is part of a foam and/or is part of an oil-in-water emulsion, comprising 30-90 vol % of a lipophilic phase, said lipophilic phase not comprising a polymerizable compound.

An aqueous suspension for producing porous metallic structures comprises 2-49 vol % of a mixture of at least one chemical compound comprising a metal atom, wherein said at least one compound is solid at room temperature, has the form of a powder, and is suspended in water, and 10-9) to 0.1 mol of a surfactant per mol of said chemical compound comprising a metal atom. The aqueous suspension is part of a foam and/or is part of an oil-in-water emulsion, comprising 30-90 vol % of a lipophilic phase, said lipophilic phase not comprising a polymerizable compound.

Provided is a process for preparing a molybdenum alloy by ultra-high-temperature rolling. The molybdenum alloy is an ultra-high strength and toughness molybdenum alloy, and includes 95 wt % to 99.9 wt % of molybdenum and 0.1 wt % to 5 wt % of a nano-ceramic oxide particle. The process includes: (1) preparing an MOxSO.sub.3H aqueous solution; (2) preparing a precursor composite powder; (3) preparing a nano-ceramic oxide-reinforced molybdenum alloy powder by reduction; and (4) preparing the ultra-high strength and toughness molybdenum alloy by pressing and sintering.

Provided is a process for preparing a molybdenum alloy by ultra-high-temperature rolling. The molybdenum alloy is an ultra-high strength and toughness molybdenum alloy, and includes 95 wt % to 99.9 wt % of molybdenum and 0.1 wt % to 5 wt % of a nano-ceramic oxide particle. The process includes: (1) preparing an MOxSO.sub.3H aqueous solution; (2) preparing a precursor composite powder; (3) preparing a nano-ceramic oxide-reinforced molybdenum alloy powder by reduction; and (4) preparing the ultra-high strength and toughness molybdenum alloy by pressing and sintering.

A method for synthesizing pure metallic nanoparticles (MNPs) uses a direct electric arc process. The method involves arranging a pair of tungsten filament electrodes within a reaction chamber, connected via a graphite rod passed through a quartz tube. An aqueous solution of a metal nitrate precursor, preferably Fe(NO.sub.3).sub.3.Math.9H.sub.2O, is introduced into the quartz tube. An inert gas, preferably argon, is supplied to maintain an oxygen-free atmosphere. A high voltage is applied across the electrodes to generate an electric arc, which creates a localized plasma, vaporizing the metal ions in the solution. The vaporized metallic species are rapidly cooled and condensed in the inert atmosphere, forming metallic nanoparticles with high purity. The resulting nanoparticles are then collected and washed with water to remove residual contaminants. This method provides a scalable, efficient, and environmentally friendly approach to produce MNPs with controlled size and morphology, suitable for various industrial and scientific applications.

A method for synthesizing pure metallic nanoparticles (MNPs) uses a direct electric arc process. The method involves arranging a pair of tungsten filament electrodes within a reaction chamber, connected via a graphite rod passed through a quartz tube. An aqueous solution of a metal nitrate precursor, preferably Fe(NO.sub.3).sub.3.Math.9H.sub.2O, is introduced into the quartz tube. An inert gas, preferably argon, is supplied to maintain an oxygen-free atmosphere. A high voltage is applied across the electrodes to generate an electric arc, which creates a localized plasma, vaporizing the metal ions in the solution. The vaporized metallic species are rapidly cooled and condensed in the inert atmosphere, forming metallic nanoparticles with high purity. The resulting nanoparticles are then collected and washed with water to remove residual contaminants. This method provides a scalable, efficient, and environmentally friendly approach to produce MNPs with controlled size and morphology, suitable for various industrial and scientific applications.

A method of forming a nanoparticle can include admixing an aqueous solution into an oil-phase to thereby form an emulsion of droplets of the aqueous solution in the oil phase, the aqueous solution comprising a nanostructure precursor and a polymer, adding a silane precursor and catalyst to form a silica shell around each of the droplets to nanoreactors; annealing at a first temperature below the decomposition temperature of the polymer to aggregate the nanostructure precursor within the nanoreactor; and annealing at a second temperature above the decomposition temperature of the polymer to convert the aggregated nanostructure precursor to the nanostructure and decompose the polymer.

A method of forming a nanoparticle can include admixing an aqueous solution into an oil-phase to thereby form an emulsion of droplets of the aqueous solution in the oil phase, the aqueous solution comprising a nanostructure precursor and a polymer, adding a silane precursor and catalyst to form a silica shell around each of the droplets to nanoreactors; annealing at a first temperature below the decomposition temperature of the polymer to aggregate the nanostructure precursor within the nanoreactor; and annealing at a second temperature above the decomposition temperature of the polymer to convert the aggregated nanostructure precursor to the nanostructure and decompose the polymer.