The iron loss of a dust core is reduced. A dust core (1) includes soft magnetic metal particles (3) having an average particle size of 5 μm or more and 30 μm or less, and a particle boundary phase (6). The particle boundary phase (6) includes a polycrystalline compound containing Al (aluminum). When a sectional structure of the dust core (1) is observed, an area percentage of α-Al.sub.2O.sub.3 in the particle boundary phase (6) is 75% or less. An average thickness Ta of the particle boundary phase (6) is 10 nm or more and 300 nm or less. According to the present invention, the iron loss is reduced.

The iron loss of a dust core is reduced. A dust core (1) includes soft magnetic metal particles (3) having an average particle size of 5 μm or more and 30 μm or less, and a particle boundary phase (6). The particle boundary phase (6) includes a polycrystalline compound containing Al (aluminum). When a sectional structure of the dust core (1) is observed, an area percentage of α-Al.sub.2O.sub.3 in the particle boundary phase (6) is 75% or less. An average thickness Ta of the particle boundary phase (6) is 10 nm or more and 300 nm or less. According to the present invention, the iron loss is reduced.

A method for producing a thermoelectric material, comprising: mixing an Sn powder and a powder containing a first dopant element to obtain a first mixed raw material, heating the first mixed raw material at a temperature allowing for mutual diffusion of Sn and the first dopant element to obtain a first aggregate, pulverizing the first aggregate to obtain a first powder, mixing an Mg powder, an Si powder, and the first powder to obtain a second mixed raw material, heating the second mixed raw material at a temperature allowing for mutual diffusion of Mg, Si, Sn and the first dopant element to obtain a second aggregate, pulverizing the second aggregate to obtain a second powder, and pressure-sintering the second powder, and wherein the first dopant element is one or more elements selected from Al, Ag, As, Bi, Cu, Sb, Zn, P, and B.

A method for producing a thermoelectric material, comprising: mixing an Sn powder and a powder containing a first dopant element to obtain a first mixed raw material, heating the first mixed raw material at a temperature allowing for mutual diffusion of Sn and the first dopant element to obtain a first aggregate, pulverizing the first aggregate to obtain a first powder, mixing an Mg powder, an Si powder, and the first powder to obtain a second mixed raw material, heating the second mixed raw material at a temperature allowing for mutual diffusion of Mg, Si, Sn and the first dopant element to obtain a second aggregate, pulverizing the second aggregate to obtain a second powder, and pressure-sintering the second powder, and wherein the first dopant element is one or more elements selected from Al, Ag, As, Bi, Cu, Sb, Zn, P, and B.

A method for processing a powder material includes cleaning surfaces of a powder material that has spherical metal particles, coating the cleaned surfaces with an organic bonding agent, mixing the coated particles with a dispersion that contains ceramic nanoparticles, drying the mixture to remove a carrier of the dispersion and deposit the ceramic nanoparticles with a spaced-apart distribution onto the organic bonding agent on the surfaces of the particles, and thermally removing the organic bonding agent to attach the ceramic nanoparticles to the surface of the particles.

A method for processing a powder material includes cleaning surfaces of a powder material that has spherical metal particles, coating the cleaned surfaces with an organic bonding agent, mixing the coated particles with a dispersion that contains ceramic nanoparticles, drying the mixture to remove a carrier of the dispersion and deposit the ceramic nanoparticles with a spaced-apart distribution onto the organic bonding agent on the surfaces of the particles, and thermally removing the organic bonding agent to attach the ceramic nanoparticles to the surface of the particles.

In accordance with the present invention, there are provided: a soft magnetic flattened powder having an average particle diameter, excellent sheet moldability, and a high magnetic permeability; and a method for producing the soft magnetic flattened powder. The soft magnetic flattened powder according to the present invention includes an Fe—Si—Al-based alloy, an average particle diameter D.sub.50 being 30 to less than 50 μm; a coercive force Hc measured by applying a magnetic field in the longitudinal direction of the flattened powder being 176 A/m or less; the ratio of a tap density to a true density being 0.18 or less; a specific surface area BET value being 0.6 m.sup.2/g or more; the amount of contained oxygen being 0.6 mass % or less; and the BET value and oxygen value of the soft magnetic powder satisfying expression (1): [oxygen value/BET value 0.50 (excluding zero)].

In accordance with the present invention, there are provided: a soft magnetic flattened powder having an average particle diameter, excellent sheet moldability, and a high magnetic permeability; and a method for producing the soft magnetic flattened powder. The soft magnetic flattened powder according to the present invention includes an Fe—Si—Al-based alloy, an average particle diameter D.sub.50 being 30 to less than 50 μm; a coercive force Hc measured by applying a magnetic field in the longitudinal direction of the flattened powder being 176 A/m or less; the ratio of a tap density to a true density being 0.18 or less; a specific surface area BET value being 0.6 m.sup.2/g or more; the amount of contained oxygen being 0.6 mass % or less; and the BET value and oxygen value of the soft magnetic powder satisfying expression (1): [oxygen value/BET value 0.50 (excluding zero)].

A method of coating metallic powder particles includes disposing an amount of metallic powder particles in a fluidizing reactor and removing moisture adhered to the powder particles within the reactor with a working gas at an elevated temperature for a predetermined time. The method further includes coating the powder particles in the reactor with silicon present within the precursor gas at an elevated temperature for a predetermined time and purging the precursor gas from the reactor using the working gas.

A method of coating metallic powder particles includes disposing an amount of metallic powder particles in a fluidizing reactor and removing moisture adhered to the powder particles within the reactor with a working gas at an elevated temperature for a predetermined time. The method further includes coating the powder particles in the reactor with silicon present within the precursor gas at an elevated temperature for a predetermined time and purging the precursor gas from the reactor using the working gas.