A method for producing nickel powder sequentially includes: a mixing step of adding, to a nickel ammine sulfate complex solution, an insoluble solid as seed crystals and a polyacrylate or lignosulfonate as a dispersant to form a mixed slurry; and a reduction and precipitation step of charging a reaction vessel with the mixed slurry and blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions in the mixed slurry to form nickel precipitate on the surface of the insoluble solid, wherein the amount of the dispersant added in the mixing step is controlled to control the number of the nickel powder obtained by formation of the nickel precipitate in the reduction and precipitation step. (120 words)

A method for producing nickel powder sequentially includes: a mixing step of adding, to a nickel ammine sulfate complex solution, an insoluble solid as seed crystals and a polyacrylate or lignosulfonate as a dispersant to form a mixed slurry; and a reduction and precipitation step of charging a reaction vessel with the mixed slurry and blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions in the mixed slurry to form nickel precipitate on the surface of the insoluble solid, wherein the amount of the dispersant added in the mixing step is controlled to control the number of the nickel powder obtained by formation of the nickel precipitate in the reduction and precipitation step. (120 words)

A method to achieve full densification and grain size control for sintering metal materials, wherein raw material powder is deagglomerated to obtain deagglomerated powder with dispersion. The deagglomerated powder is granulated by spray granulation. The granulated particles are processed by high-pressure die pressing and cold isostatic pressing. The powder compact is sintered by two-step pressureless sintering. The first step is to heat up the powder compact to a higher temperature and hold for a short time to obtain 75-85% theoretical density; the second step is to cool down powder compact to a lower temperature and hold for a long time. The two-step sintering can decrease the sintering temperature, so that the powder compact can be densified at a lower temperature. Thus, the obtained refractory metal product is densified, with ultrafine grains, uniform grain size distribution, and outstanding mechanical properties.

A protein template dispersion solution of the present embodiment includes a protein template containing two or more types of heterogeneous metal ions or alloy nanoparticles; and a solvent in which the protein template is dispersed, wherein alloy nanoparticles are obtained by removing the protein template. A method of producing a protein template dispersion solution according to the present embodiment includes: a step in which a protein template is added to a solution in which heterogeneous metal ions are dissolved and metal ions are introduced into the protein template; and a step in which the protein template and metal ions that are not incorporated into the protein template are separated. A method of producing alloy nanoparticles according to the present embodiment includes a step in which a dispersion solution of heterogeneous metal-ion-containing protein templates is subjected to a heat treatment under a reducing atmosphere to remove a protein template.

A protein template dispersion solution of the present embodiment includes a protein template containing two or more types of heterogeneous metal ions or alloy nanoparticles; and a solvent in which the protein template is dispersed, wherein alloy nanoparticles are obtained by removing the protein template. A method of producing a protein template dispersion solution according to the present embodiment includes: a step in which a protein template is added to a solution in which heterogeneous metal ions are dissolved and metal ions are introduced into the protein template; and a step in which the protein template and metal ions that are not incorporated into the protein template are separated. A method of producing alloy nanoparticles according to the present embodiment includes a step in which a dispersion solution of heterogeneous metal-ion-containing protein templates is subjected to a heat treatment under a reducing atmosphere to remove a protein template.

The invention relates to nano-particles comprising metallic ferromagnetic nanocrystals combined with either amorphous or graphitic carbon in which or on which chemical groups are present that can dissociate in aqueous solutions.

According to the invention there is provided nano-particles comprising metal particles of at least one ferromagnetic metal, which metal particles are at least in part encapsulated by graphitic carbon.

The nano-particles of the invention are prepared by impregnating carbon containing bodies with an aqueous solution of at least one ferromagnetic metal precursor, drying the impregnated bodies, followed by heating the impregnated bodies in an inert and substantially oxygen-free atmosphere, thereby reducing the metal compounds to the corresponding metal or metal alloy.

To provide a metal-based structure or nanoparticles whose homogeneity is not deteriorated and whose sticking formation is easy, and a production method thereof with a high safety. A metal-based structure comprises a hydrogen compound, cluster, or an aggregate thereof, represented by the general formula: M.sub.mH. The M is a metal-based atom. The m is an integer of 3 or more and 300 or less. H is a hydrogen atom.

To provide a metal-based structure or nanoparticles whose homogeneity is not deteriorated and whose sticking formation is easy, and a production method thereof with a high safety. A metal-based structure comprises a hydrogen compound, cluster, or an aggregate thereof, represented by the general formula: M.sub.mH. The M is a metal-based atom. The m is an integer of 3 or more and 300 or less. H is a hydrogen atom.

A method of forming a metal nanomaterial comprises forming a precursor solution comprising a metal precursor and a metal oxide precursor. A complexing agent is added to the precursor solution, and the metal precursor and the metal oxide precursor are hydrolyzed to form a sol. The sol is heated to form a gel, which is calcined to incorporate metal cations from the metal precursor into a metal oxide lattice from the metal oxide precursor. The calcined gel is exposed to a reducing agent to exsolve the metal from the metal oxide lattice and to form a metal nanomaterial comprising a metal and a metal oxide is formed. Additional methods of forming a metal nanomaterial are also disclosed.

A method of forming a metal nanomaterial comprises forming a precursor solution comprising a metal precursor and a metal oxide precursor. A complexing agent is added to the precursor solution, and the metal precursor and the metal oxide precursor are hydrolyzed to form a sol. The sol is heated to form a gel, which is calcined to incorporate metal cations from the metal precursor into a metal oxide lattice from the metal oxide precursor. The calcined gel is exposed to a reducing agent to exsolve the metal from the metal oxide lattice and to form a metal nanomaterial comprising a metal and a metal oxide is formed. Additional methods of forming a metal nanomaterial are also disclosed.