To obtain a magnetic core having an improved withstand voltage property while maintaining a high relative magnetic permeability, and the like. The magnetic core contains large particles observed as soft magnetic particles having a Heywood diameter of 5 μm or more and 25 μm or less and small particles observed as soft magnetic particles having a Heywood diameter of 0.5 μm or more and less than 5 μm in a cross section. C1<C2 is satisfied in which an average circularity of the small particles close to the large particles is C1 and an average circularity of all small particles observed in the cross section including small particles not close to the large particles is C2. The small particles close to the large particles are defined as small particles whose distance from centroids of the small particles to a surface of the large particles is 3 μm or less.

A Fe—Ni alloy powder has a small particle diameter, can achieve high μ′ in a high frequency band, and has high heat resistance. The Fe—Ni alloy powder can be obtained in such a manner that an acidic aqueous solution containing a trivalent Fe ion and a Ni ion is neutralized with an alkali aqueous solution in the presence of a phosphorus-containing ion. This provides a slurry of a precipitate of a hydrated oxide. Then, a silane compound is added to the slurry to coat the precipitate of the hydrated oxide with a hydrolyzate of the silane compound. The precipitate of the hydrated oxide after coating is recovered through solid-liquid separation. The recovered precipitate is heated to provide iron particles coated with a silicon oxide, and then the silicon oxide coating is removed through dissolution.

Disclosed herein is a composite magnetic sealing material includes a resin material and a filler blended in the resin material in a blended ratio of 30 vol. % or more to 85 vol. % or less. The filler includes a magnetic filler containing Fe and 32 wt. % or more and 39 wt. % or less of a metal material contained mainly of Ni, thereby a thermal expansion coefficient of the composite magnetic sealing material is 15 ppm/ C. or less.

A soft magnetic alloy powder comprises a component having a compositional formula ((Fe.sub.(1?(?+?))Co.sub.?Ni.sub.?).sub.(1??)X1.sub.?).sub.(1?(a+b+c+d+e))B.sub.aP.sub.bSi.sub.cC.sub.dCr.sub.e in atomic ratio. X1 comprises at least one selected from specific elements. Values of a, b, c, d, e, ?, ?, and ? of the compositional formula satisfy specific ranges. The soft magnetic alloy powder comprises soft magnetic alloy particles including soft magnetic alloy particles having a particle size of (0.95?D90) or more and (1.05?D90) or less. An average Wadell's circularity of the soft magnetic alloy particles having the particle size of (0.95?D90) or more and (1.05?D90) or less is 0.75 or more. A variance of Wadell's circularity of the soft magnetic alloy particles having the particle size of (0.95?D90) or more and (1.05?D90) or less is 0.035 or less.

The present application provides a soft magnetic alloy sheet, a preparation method therefor and a use thereof. The preparation method comprises the following steps: (1) mixing thermosetting resin, thermoplastic resin, a solvent, a curing agent, and soft magnetic alloy powder having insulating coating to obtain casting slurry; and (2) carrying out degassing and casting-drying treatment on the casting slurry in step (1) in sequence to obtain the soft magnetic alloy sheet.

In order to provide a magnetic flaky powder that has a high real part magnetic permeability () and a high saturation magnetic flux density in addition to a high FR, and a magnetic sheet containing the same, the present invention provides a magnetic flaky powder, containing a plurality of magnetic flaky particles, wherein: each of the plurality of magnetic flaky particles contains, by mass %, C: 0.1% or more and 3.0% or less, Cr: 1.0% or more and less than 10%, Si: 0% or more and 1.5% or less, Mn: 0% or more and 1.5% or less, Ni: 0% or more and 1.5% or less, Co: 0% or more and 10% or less, and the remainder being Fe and unavoidable impurities; the magnetic flaky powder has a saturation magnetic flux density of more than 1.2 T; and the magnetic flaky powder has an average particle diameter D50 of 10 m or more and 65 m or less.

An optimal condition is disclosed in which a composition of a soft magnetic molding solution includes 94 to 98 wt % of a soft magnetic powder and 2 to 6 wt % of an organic vehicle, in order to manufacture a coil-embedded inductor having various advantages such as high inductance, a low core loss, and high reliability. An exemplary manufacturing method is provided of a coil-embedded inductor having a structure in which a part of a coil is embedded in a magnetic core, which includes preparing an organic vehicle, preparing a soft magnetic molding solution having the density of 5.5 to 6.5 g/cc by mix-milling a soft magnetic powder with the organic vehicle, positioning and fixing a part of the coil in the case, and forming the magnetic core by injecting and curing the soft magnetic molding solution into the case.

A powder core includes a compact including a soft magnetic powder, and an outer coating of the compact. The outer coating contains polyethersulfone. An electric or electronic component including the powder core, and an electric or electronic device having the electric or electronic component mounted therein are also provided.

A coil component including a coil formed by winding an insulation-coated wire and a composite magnetic body embed with the coil, wherein the composite magnetic body contains: a metallic magnetic powder made by powderizing a metallic magnetic material and a binder resin; and wherein the average particle size D.sub.50[m] of the metallic magnetic powder satisfies the following formula (1):

D.sub.502.192(Fmax).sup.0.518.sup.0.577(1)

wherein (Fmax) is an upper limit operation-frequency [MHz] at which Q-value starts decreasing beyond the maximum value in a case of increasing the frequency applied to the coil component, and is electrical-resistivity [.Math.cm] of the metallic magnetic material.

Disclosed herein is an electronic circuit package includes a substrate having a power supply pattern, an electronic component mounted on a surface of the substrate, and a composite molding member having conductivity that covers the surface of the substrate so as to embed the electronic component and that is connected to the power supply pattern. The composite molding member includes a resin material and a first filler blended in the resin material and containing 32 to 39 wt. % of a metal material composed mainly of Ni in Fe.