A preparation method for a metal soft magnetic composite material inductor includes: smelting Fe, Si and Cr and then employing a water atomization or gas atomization means to fabricate an alloy powder; after sifting by particle size, mixing powders of different particle size levels and performing coating insulation, and performing post-granulation to obtain a metal soft composite material granulation powder; adopting the granulation powder to press a material cake, and transferring and molding same; adopting a hollow coil in a liquid-phase coating mold cavity, curing and demolding to obtain a semi-finished product, then continuously heating and curing the semi-finished product, and preparing an end electrode to obtain a finished inductor.

A preparation method for a metal soft magnetic composite material inductor includes: smelting Fe, Si and Cr and then employing a water atomization or gas atomization means to fabricate an alloy powder; after sifting by particle size, mixing powders of different particle size levels and performing coating insulation, and performing post-granulation to obtain a metal soft composite material granulation powder; adopting the granulation powder to press a material cake, and transferring and molding same; adopting a hollow coil in a liquid-phase coating mold cavity, curing and demolding to obtain a semi-finished product, then continuously heating and curing the semi-finished product, and preparing an end electrode to obtain a finished inductor.

A combined transformer/inductor device includes a core having a central core leg and an outer core leg spaced apart from the central core leg, an inner bobbin disposed around the central core leg, an outer bobbin disposed around the inner bobbin and the central core leg and having an upper portion having a first oblong portion disposed around the outer core leg, a lower portion having a second oblong portion disposed around the outer core leg, and a central portion disposed around the inner bobbin and the central core leg, a first winding wound around the inner bobbin, and a second winding wound around the outer bobbin, the second winding having a first portion wound around the first oblong portion, a second portion wound around the central portion, and a third portion wound around the second oblong portion.

A combined transformer/inductor device includes a core having a central core leg and an outer core leg spaced apart from the central core leg, an inner bobbin disposed around the central core leg, an outer bobbin disposed around the inner bobbin and the central core leg and having an upper portion having a first oblong portion disposed around the outer core leg, a lower portion having a second oblong portion disposed around the outer core leg, and a central portion disposed around the inner bobbin and the central core leg, a first winding wound around the inner bobbin, and a second winding wound around the outer bobbin, the second winding having a first portion wound around the first oblong portion, a second portion wound around the central portion, and a third portion wound around the second oblong portion.

A compound for dust core includes a metal powder including iron, a resin composition, and a metal salt, in which the metal salt is represented by R.sub.2M, R represents a saturated fatty acid group having 6 or more and 12 or less carbon atoms, and M represents at least one metal element between Ca and Ba.

A dust core that can significantly reduce the iron loss is provided. The dust core of the present invention includes soft magnetic particles comprising pure iron or an iron alloy and a grain boundary layer existing between adjacent soft magnetic particles. The grain boundary layer has a compound layer comprising M.sub.xFe.sub.2-xSiO.sub.4 (0≤x≤1, M: one or more types of metal elements that serve as divalent cations). Such a dust core is obtained by annealing a compact. The compact is obtained by compression-molding a powder for magnetic cores. In the powder for magnetic cores, coating layers that coat the surfaces of soft magnetic particles are each composed of a composite phase in which spinel-type ferrite represented by M.sub.yFe.sub.3-yO.sub.4 (0≤y≤1, M: one or more types of metal elements that serve as divalent cations) is dispersed on a surface of a silicone resin or inside the silicone resin. The dust core after annealing exhibits a high specific resistance due to the grain boundary layer having the compound layer and can reduce both the eddy-current loss and the hysteresis loss.

A dust core that can significantly reduce the iron loss is provided. The dust core of the present invention includes soft magnetic particles comprising pure iron or an iron alloy and a grain boundary layer existing between adjacent soft magnetic particles. The grain boundary layer has a compound layer comprising M.sub.xFe.sub.2-xSiO.sub.4 (0≤x≤1, M: one or more types of metal elements that serve as divalent cations). Such a dust core is obtained by annealing a compact. The compact is obtained by compression-molding a powder for magnetic cores. In the powder for magnetic cores, coating layers that coat the surfaces of soft magnetic particles are each composed of a composite phase in which spinel-type ferrite represented by M.sub.yFe.sub.3-yO.sub.4 (0≤y≤1, M: one or more types of metal elements that serve as divalent cations) is dispersed on a surface of a silicone resin or inside the silicone resin. The dust core after annealing exhibits a high specific resistance due to the grain boundary layer having the compound layer and can reduce both the eddy-current loss and the hysteresis loss.

A composite magnetic material includes a powder and a resin. The powder has a main component containing Fe or Fe and Co. An average minor axis length in primary particles of the powder is 100 nm or less. A point satisfying (X, Y)=(σ/A.sub.v (%), (A.sub.v-σ)) on an XY coordinate plane is present within a region (including a boundary) surrounded by three points α(24.5, 6.7), β(72.0, 1.2), and γ(24.5, 1.2), in which an average of aspect ratios in the primary particles of the powder is set to A.sub.v, and a standard deviation of the aspect ratios in the primary particles of the powder is set to σ.

A composite magnetic material includes a powder and a resin. The powder has a main component containing Fe or Fe and Co. An average minor axis length in primary particles of the powder is 100 nm or less. A point satisfying (X, Y)=(σ/A.sub.v (%), (A.sub.v-σ)) on an XY coordinate plane is present within a region (including a boundary) surrounded by three points α(24.5, 6.7), β(72.0, 1.2), and γ(24.5, 1.2), in which an average of aspect ratios in the primary particles of the powder is set to A.sub.v, and a standard deviation of the aspect ratios in the primary particles of the powder is set to σ.

Disclosed herein is a composite magnetic powder that includes an iron-containing magnetic powder and an insulating layer comprising a silicon oxide formed on a surface of the iron-containing magnetic powder. The insulating layer contains pores, and an area ratio of the pores in a cross section of the insulating layer is 5% or less.