A method of producing anisotropic magnetic powders comprising obtaining a precipitate containing an element R, iron and lanthanum from a solution including R, iron and lanthanum, wherein R is at least one selected from the group consisting of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm and Lu; obtaining an oxide containing R, iron and lanthanum from the precipitate; treating the oxide with a reducing gas to obtain a partial oxide; obtaining alloy particles by reduction diffusion of the partial oxide at a temperature in the range of 920° C. to 1200° C.; and nitriding the alloy particles to produce an anisotropic magnetic powder represented by the following general formula: R.sub.v-xFe.sub.(100-v-w-z)N.sub.wLa.sub.xW.sub.z, where 3≤v−x≤30, 5≤w≤15, 0.08≤x≤0.3, and 0≤z≤2.5.

Provided are a new, highly magnetically stable magnetic material which has higher saturation magnetization than ferrite-based magnetic materials, and with which problems of eddy current loss and the like can be solved due to higher electric resistivity than that of existing metal-based magnetic materials, and a method for manufacturing the same. A magnetic material powder is obtained by reducing in hydrogen Ni-ferrite nanoparticies obtained by wet synthesis and causing grain growth, while simultaneously causing nanodispersion of an α-(Fe, Ni) phase and an Ni-enriched phase by means of a phase dissociation phenomenon due to disproportional reaction. The powder is sintered to obtain a solid magnetic material.

Provided are a new, highly magnetically stable magnetic material which has higher saturation magnetization than ferrite-based magnetic materials, and with which problems of eddy current loss and the like can be solved due to higher electric resistivity than that of existing metal-based magnetic materials, and a method for manufacturing the same. A magnetic material powder is obtained by reducing in hydrogen Ni-ferrite nanoparticies obtained by wet synthesis and causing grain growth, while simultaneously causing nanodispersion of an α-(Fe, Ni) phase and an Ni-enriched phase by means of a phase dissociation phenomenon due to disproportional reaction. The powder is sintered to obtain 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.

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.

One object of the present invention is to provide copper fine particles which have sufficient dispersibility when made into a paste and can be sintered at 150° C. or lower, the present invention provides copper fine particles, wherein the copper fine particles have a coating film containing copper carbonate and cuprous oxide on at least a part of the surface thereof, and a ratio between the following Db and the following Dv (Db/Dv) is in a range of 0.50˜0.90, Dv: an average value (nm) of the area equivalent circle diameter of the copper fine particles obtained by acquiring SEM images for 500 or more copper fine particles using a scanning electron microscope, and calculating by image analysis software, Db: a particle size (nm) of the copper fine particles obtained by measuring a specific surface area (SSA (m.sup.2/g)) of the copper fine particles using a specific surface area meter, and calculating by the following formula (1), Db=6/(SSA×ρ)×10.sup.9 . . . (1) in the formula (1), ρ is a density of copper (g/m.sup.3).

One object of the present invention is to provide copper fine particles which have sufficient dispersibility when made into a paste and can be sintered at 150° C. or lower, the present invention provides copper fine particles, wherein the copper fine particles have a coating film containing copper carbonate and cuprous oxide on at least a part of the surface thereof, and a ratio between the following Db and the following Dv (Db/Dv) is in a range of 0.50˜0.90, Dv: an average value (nm) of the area equivalent circle diameter of the copper fine particles obtained by acquiring SEM images for 500 or more copper fine particles using a scanning electron microscope, and calculating by image analysis software, Db: a particle size (nm) of the copper fine particles obtained by measuring a specific surface area (SSA (m.sup.2/g)) of the copper fine particles using a specific surface area meter, and calculating by the following formula (1), Db=6/(SSA×ρ)×10.sup.9 . . . (1) in the formula (1), ρ is a density of copper (g/m.sup.3).

A method for producing fine copper particles includes producing fine copper particles having a coating film containing cuprous oxide on a surface by heating copper or a copper compound in a reducing flame formed by a burner. The fine copper particles are produced by adjusting a mixing ratio between a combustible gas and a combustion supporting gas which form the reducing flame such that a volume ratio of CO/CO.sub.2 is in a range of 1.5 to 2.4.

A preparation method of cemented carbide with FeCoCu medium-entropy alloy as binding phase is provided. The preparation method includes: 1) preparing FeCoCu precursor powders by solution combustion synthesis; 2) preparing FeCoCu medium-entropy alloy powders by mechanical alloying; 3) evenly mixing the FeCoCu medium-entropy alloy powders with ultra-fine WC powders and a binder to obtain mixed powders and pressing the mixed powders into a shaped green body; 4) preparing a WC-FeCoCu cemented carbide by microwave sintering after removing the binder from the shaped green body. The preparation method reduces sintering temperature and time and obtains a new-type cemented carbide with fine grains, high hardness and good toughness while reducing the cost.

A preparation method of cemented carbide with FeCoCu medium-entropy alloy as binding phase is provided. The preparation method includes: 1) preparing FeCoCu precursor powders by solution combustion synthesis; 2) preparing FeCoCu medium-entropy alloy powders by mechanical alloying; 3) evenly mixing the FeCoCu medium-entropy alloy powders with ultra-fine WC powders and a binder to obtain mixed powders and pressing the mixed powders into a shaped green body; 4) preparing a WC-FeCoCu cemented carbide by microwave sintering after removing the binder from the shaped green body. The preparation method reduces sintering temperature and time and obtains a new-type cemented carbide with fine grains, high hardness and good toughness while reducing the cost.