One embodiment of the present invention is that in samarium-iron-nitrogen magnet powder, a non-magnetic phase is formed on a surface of the samarium-iron-nitrogen magnet phase, and an arithmetic mean roughness Ra of the surface is 3.5 nm or less.

One embodiment of the present invention is that in samarium-iron-nitrogen magnet powder, a non-magnetic phase is formed on a surface of the samarium-iron-nitrogen magnet phase, and an arithmetic mean roughness Ra of the surface is 3.5 nm or less.

A graphene-reinforced alloy composite material and a preparation method thereof are disclosed. The method includes preparing a porous graphene colloid, smelting a first-part alloy, pouring it into the porous graphene colloid to be formed, subjecting the formed product to a hot extrusion, and pulverizing into a powder I; smelting a second-part alloy into an alloy melt II, adding a high-purity silicon powder therein, mixing by stirring, and atomizing to obtain a powder II; mixing the powder I and the powder II, to obtain a pretreated alloy powder; placing the pretreated alloy powder in a high-purity ark, transferring the high-purity ark to a high-temperature tubular furnace, subjecting the pretreated alloy powder to a redox treatment, and introducing methane and hydrogen to grow graphene, to obtain a coated alloy powder; subjecting the coated alloy powder to a pre-compressing molding and sintering, to obtain the graphene-reinforced alloy composite material.

A graphene-reinforced alloy composite material and a preparation method thereof are disclosed. The method includes preparing a porous graphene colloid, smelting a first-part alloy, pouring it into the porous graphene colloid to be formed, subjecting the formed product to a hot extrusion, and pulverizing into a powder I; smelting a second-part alloy into an alloy melt II, adding a high-purity silicon powder therein, mixing by stirring, and atomizing to obtain a powder II; mixing the powder I and the powder II, to obtain a pretreated alloy powder; placing the pretreated alloy powder in a high-purity ark, transferring the high-purity ark to a high-temperature tubular furnace, subjecting the pretreated alloy powder to a redox treatment, and introducing methane and hydrogen to grow graphene, to obtain a coated alloy powder; subjecting the coated alloy powder to a pre-compressing molding and sintering, to obtain the graphene-reinforced alloy composite material.

Methods for preparing a layered metal nanocomposite and a layered metal nanocomposite. The method includes mixing a magnesium salt and an aluminum salt to form a Mg.sup.2+/Al.sup.3+ solution. The Mg/Al has a molar ratio of between 0.5:1 to 6:1. Then a diamondoid compound is added to the Mg.sup.2+/Al.sup.3+ solution to form a reactant mixture. The diamondoid compound has at least one carboxylic acid moiety. The reactant mixture is heated at a reaction temperature for a reaction time to form a Mg/Al-diamondoid intercalated layered double hydroxide. The Mg/Al-diamondoid intercalated layered double hydroxide is thermally decomposed under a reducing atmosphere for a decomposition time at a decomposition temperature to form the layered metal nanocomposite.

Provided are: a novel magnetic material having high magnetic stability, in particular, having an extremely high saturation magnetization; and a method for producing the same, wherein the magnetic material, due to having a higher saturation magnetization than ferrite magnetic materials and a higher electrical resistivity than existing metallic magnetic materials, resolves problems such as eddy current loss. According to the present invention, Co-ferrite nanoparticles obtained by wet synthesis are reduced in hydrogen and subjected to grain growth, and bcc- or fcc-(Fe, Co) phases and Co-enriched phases are nano-dispersed using phase separation via a disproportionation reaction to prepare a magnetic material powder. In addition, the magnetic material powder is sintered into a solid magnetic material.

Provided are: a novel magnetic material having high magnetic stability, in particular, having an extremely high saturation magnetization; and a method for producing the same, wherein the magnetic material, due to having a higher saturation magnetization than ferrite magnetic materials and a higher electrical resistivity than existing metallic magnetic materials, resolves problems such as eddy current loss. According to the present invention, Co-ferrite nanoparticles obtained by wet synthesis are reduced in hydrogen and subjected to grain growth, and bcc- or fcc-(Fe, Co) phases and Co-enriched phases are nano-dispersed using phase separation via a disproportionation reaction to prepare a magnetic material powder. In addition, the magnetic material powder is sintered into a solid magnetic material.

A production method for silver fine particles retain capabilities such as conductivity and make it possible to form wiring at even lower temperatures; and silver fine particles. A silver fine particle production method in which silver powder is used to produce silver fine particles by means of a gas phase method. The silver fine particle production method has a step for supplying an organic acid to the silver fine particles. The gas phase method is, for example, a plasma method or a flame method. The silver fine particles have a surface coating that includes at least a carboxyl group.

A production method for silver fine particles retain capabilities such as conductivity and make it possible to form wiring at even lower temperatures; and silver fine particles. A silver fine particle production method in which silver powder is used to produce silver fine particles by means of a gas phase method. The silver fine particle production method has a step for supplying an organic acid to the silver fine particles. The gas phase method is, for example, a plasma method or a flame method. The silver fine particles have a surface coating that includes at least a carboxyl group.

The present invention relates to an RFeB-based magnet in which a treatment (grain boundary diffusion treatment) for diffusing atoms of the heavy rare earth element R.sup.H is performed in a base material including an R.sup.LFeB-based sintered magnet obtained by subjecting crystal grains in a raw-material powder including a powder of an R.sup.LFeB-based alloy containing the light rare earth element R.sup.L, Fe and B to orientation in a magnetic field and then sintering the oriented raw-material powder, or an R.sup.LFeB-based hot-deformed magnet obtained by subjecting the same raw-material powder to hot pressing and then to hot deforming to thereby orient the crystal grains in the raw-material powder, and a method for producing the RFeB-based magnet.