A magnetic core powder including granular powder A of Fe-based, magnetic, crystalline metal material and granular powder B of Fe-based, magnetic, amorphous metal material; the particle size d50A of granular powder A at a cumulative frequency of 50 volume % being 0.5 μm or more and 7.0 μm or less, and the particle size d50B of granular powder B at a cumulative frequency of 50 volume % being more than 15.0 μm, in a cumulative distribution curve showing the relation between particle size and cumulative frequency from the smaller particle size side, determined by a laser diffraction method; the magnetic core powder meeting (d90M−d10M)/d50M of 1.6 or more and 6.0 or less, d10M being a particle size at a cumulative frequency of 10 volume %, d50M being a particle size at a cumulative frequency of 50 volume %, and d90M being a particle size at a cumulative frequency of 90 volume %.

A method of forming a component from a part in the green state, including selecting at least one first portion of the part to undergo a different local volume reduction from at least one second portion to obtain the component. The green part is provided with the first portion(s) having a first solid loading and the second portion(s) having a second solid loading different from the first solid loading, then debound and sintered to obtain the component. The different first and second solid loadings produce the different local volume reduction in the first portion(s). The first portion(s) can be selected by determining a resulting final shape obtained from debinding and sintering a green part having a uniform first volumetric proportion of binder, and selecting the first portion(s) requiring a different local deformation than that producing the resulting final shape to obtain a desired final shape.

A method of forming a component from a part in the green state, including selecting at least one first portion of the part to undergo a different local volume reduction from at least one second portion to obtain the component. The green part is provided with the first portion(s) having a first solid loading and the second portion(s) having a second solid loading different from the first solid loading, then debound and sintered to obtain the component. The different first and second solid loadings produce the different local volume reduction in the first portion(s). The first portion(s) can be selected by determining a resulting final shape obtained from debinding and sintering a green part having a uniform first volumetric proportion of binder, and selecting the first portion(s) requiring a different local deformation than that producing the resulting final shape to obtain a desired final shape.

A compact is provided. When the compact is used for a magnetic core, a magnetic path cross section has a cross-sectional perimeter of more than 20 mm, and at least part of a surface of the compact is covered with an iron-based oxide film having an average thickness of 0.5 μm or more and 10.0 μm or less. Letting the proportion of the surface area of the compact to the volume of the compact be surface area/volume, the content of Fe.sub.3O.sub.4 present in the iron-based oxide film with respect to 100% by volume of the compact satisfies any one of (1) to (3): (1) less than 0.085% by volume when the (surface area/volume) is 0.40 mm.sup.−1 or less, (2) 0.12% or less by volume when the (surface area/volume) is more than 0.40 mm.sup.−1 and 0.60 mm.sup.−1 or less, and (3) 0.15% or less by volume when the (surface area/volume) is more than 0.60 mm.sup.−1.

A compact is provided. When the compact is used for a magnetic core, a magnetic path cross section has a cross-sectional perimeter of more than 20 mm, and at least part of a surface of the compact is covered with an iron-based oxide film having an average thickness of 0.5 μm or more and 10.0 μm or less. Letting the proportion of the surface area of the compact to the volume of the compact be surface area/volume, the content of Fe.sub.3O.sub.4 present in the iron-based oxide film with respect to 100% by volume of the compact satisfies any one of (1) to (3): (1) less than 0.085% by volume when the (surface area/volume) is 0.40 mm.sup.−1 or less, (2) 0.12% or less by volume when the (surface area/volume) is more than 0.40 mm.sup.−1 and 0.60 mm.sup.−1 or less, and (3) 0.15% or less by volume when the (surface area/volume) is more than 0.60 mm.sup.−1.

A method for manufacturing a powder magnetic core, including a step of compacting a raw material powder to form a compact, a step of performing a first heat treatment on the compact to obtain a first heat-treated body, and a step of performing a second heat treatment on the first heat-treated body to obtain a second heat-treated body, wherein the raw material powder contains a soft magnetic powder and a lubricant that has a melting point Tm, the first heat treatment is performed in a temperature range from Tm to Tm+50° C. inclusive for a time longer than 10 minutes, and the second heat treatment is performed in a temperature range from 400° C. to 900° C. inclusive for a time of 3 minutes to 90 minutes inclusive, the temperature range of the second heat treatment being higher than the temperature range of the first heat treatment.

A method for manufacturing a powder magnetic core, including a step of compacting a raw material powder to form a compact, a step of performing a first heat treatment on the compact to obtain a first heat-treated body, and a step of performing a second heat treatment on the first heat-treated body to obtain a second heat-treated body, wherein the raw material powder contains a soft magnetic powder and a lubricant that has a melting point Tm, the first heat treatment is performed in a temperature range from Tm to Tm+50° C. inclusive for a time longer than 10 minutes, and the second heat treatment is performed in a temperature range from 400° C. to 900° C. inclusive for a time of 3 minutes to 90 minutes inclusive, the temperature range of the second heat treatment being higher than the temperature range of the first heat treatment.

Provided is alloyed steel powder having excellent fluidity, formability, and compressibility without containing Ni, Cr, or Si. The alloyed steel powder includes iron-based alloy containing Mo, in which Mo content is 0.4 mass % to 1.8 mass %, a weight-based median size D50 is 40 μm or more, and among particles contained in the alloyed steel powder, those particles having an equivalent circular diameter of 50 μm to 200 μm have a number average of solidity of 0.70 to 0.86, the solidity being defined as (particle cross-sectional area/envelope-inside area).

Provided is alloyed steel powder having excellent fluidity, formability, and compressibility without containing Ni, Cr, or Si. The alloyed steel powder includes iron-based alloy containing Mo, in which Mo content is 0.4 mass % to 1.8 mass %, a weight-based median size D50 is 40 μm or more, and among particles contained in the alloyed steel powder, those particles having an equivalent circular diameter of 50 μm to 200 μm have a number average of solidity of 0.70 to 0.86, the solidity being defined as (particle cross-sectional area/envelope-inside area).

The invention relates to a production method for an electrical resistance element (for example a shunt) with the following steps: -providing a resistance alloy in powder form, and -forming the resistance element from the powdered resistance material. The invention also relates to a correspondingly produced resistance element.