The present invention relates to a magnetic material containing a magnetic alloy particle having an ordered crystal structure. The magnetic material according to the present invention is the one composed of a magnetic alloy particle having crystal magnetic anisotropy and being composed of an FePt alloy, a CoPt alloy, an FePd alloy, a Co.sub.3Pt alloy, an Fe.sub.3Pt alloy, a CoPt.sub.3 alloy, an FePt.sub.3 alloy, or the like, and a silica carrier covering the magnetic alloy, in which the silica carrier contains an alkali-earth metal compound such as an oxide, hydroxide or silicate compound of Ba, Ca, or Sr. The magnetic material according to the present invention is excellent in magnetic properties such as coercive force.

The present invention relates to a magnetic material containing a magnetic alloy particle having an ordered crystal structure. The magnetic material according to the present invention is the one composed of a magnetic alloy particle having crystal magnetic anisotropy and being composed of an FePt alloy, a CoPt alloy, an FePd alloy, a Co.sub.3Pt alloy, an Fe.sub.3Pt alloy, a CoPt.sub.3 alloy, an FePt.sub.3 alloy, or the like, and a silica carrier covering the magnetic alloy, in which the silica carrier contains an alkali-earth metal compound such as an oxide, hydroxide or silicate compound of Ba, Ca, or Sr. The magnetic material according to the present invention is excellent in magnetic properties such as coercive force.

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.

Provided is a method of producing a nickel nanopowder, the method capable of preventing coagulation between particles and, accordingly, providing a nickel nanopowder having a small average particle size and a low coagulation rate. According to an embodiment of the present invention, the method of producing a nickel nanopowder includes providing a nickel salt and a shell-forming material; nucleating and growing nickel core particles from the nickel salt; forming a shell layer on surfaces of the nickel core particles using the shell-forming material; and removing the shell layer to form the nickel nanopowder.

Provided is a method of producing a nickel nanopowder, the method capable of preventing coagulation between particles and, accordingly, providing a nickel nanopowder having a small average particle size and a low coagulation rate. According to an embodiment of the present invention, the method of producing a nickel nanopowder includes providing a nickel salt and a shell-forming material; nucleating and growing nickel core particles from the nickel salt; forming a shell layer on surfaces of the nickel core particles using the shell-forming material; and removing the shell layer to form the nickel nanopowder.

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.

Process to decrease silicon content of metal powder produced by hydrogen reduction from ammoniacal ammonium sulphate solutions containing metal ammine complexes, wherein metal (Me) is Ni, Co, or Cu. The process controls the precipitation of metal hydroxide, which is found to be an effective scavenger for silicon. Silicon is preferentially removed from metal diammine sulphate-containing solutions by precipitating with a small amount of a metal hydroxide, and then separating the silicon-bearing metal hydroxide precipitate from the solution. This solution, from which the silicon impurity has been removed with the metal hydroxide precipitate, can then be reduced in one or more densification cycles with a reducing gas to produce an elemental metal powder having a decreased silicon content. Alternatively, the solution is reduced to produce a low silicon metal powder seed material for the first of the one or more densification cycles.

Process to decrease silicon content of metal powder produced by hydrogen reduction from ammoniacal ammonium sulphate solutions containing metal ammine complexes, wherein metal (Me) is Ni, Co, or Cu. The process controls the precipitation of metal hydroxide, which is found to be an effective scavenger for silicon. Silicon is preferentially removed from metal diammine sulphate-containing solutions by precipitating with a small amount of a metal hydroxide, and then separating the silicon-bearing metal hydroxide precipitate from the solution. This solution, from which the silicon impurity has been removed with the metal hydroxide precipitate, can then be reduced in one or more densification cycles with a reducing gas to produce an elemental metal powder having a decreased silicon content. Alternatively, the solution is reduced to produce a low silicon metal powder seed material for the first of the one or more densification cycles.