A dust core including an iron-based magnetic powder containing iron as a main component, including: a first magnetic powder which has a first peak in a particle size distribution of the iron-based magnetic powder; and a second magnetic powder which has a second peak corresponding to a particle size larger than a particle size corresponding to the first peak in the particle size distribution of the iron-based magnetic powder, and of which a crystal structure is nanocrystal or amorphous, in which a particle of the first magnetic powder and a particle of the second magnetic powder are in a state of being bonded to each other.

New types of particle feedstocks and heterogeneous grain structures are provided for rare earth permanent magnets (REPMs) and their production in a manner to significantly enhance toughness of the magnet with little or no sacrifice in the hard magnetic properties. The novel tough REPMs made from the feedstock have heterogeneous grain structures, such as bi-modal, tri-modal, multi-modal, laminated, gridded, gradient fine/coarse grain structures, or other microstructural heterogeneity and configurations, without changing the chemical compositions of magnets.

New types of particle feedstocks and heterogeneous grain structures are provided for rare earth permanent magnets (REPMs) and their production in a manner to significantly enhance toughness of the magnet with little or no sacrifice in the hard magnetic properties. The novel tough REPMs made from the feedstock have heterogeneous grain structures, such as bi-modal, tri-modal, multi-modal, laminated, gridded, gradient fine/coarse grain structures, or other microstructural heterogeneity and configurations, without changing the chemical compositions of magnets.

The present disclosure provides a rare earth ion-doped soft magnetic alloy, a soft magnetic composite material and a preparation method thereof. The rare earth ion-doped soft magnetic alloy is composed of Fe, Si, Al, N and Re, and the Re is a rare earth element; and herein, in the rare earth ion-doped soft magnetic alloy, the content of the Fe is 82-85 wt %, the content of the Si is 8-10 wt %, the content of the Al is 3-5 wt %, the content of the Re is 1-2 wt %, and the content of the N is 0.25-0.65 wt %. Most of the interior of the rare earth ion-doped soft magnetic alloy of the present disclosure is composed of FeSiAl crystal grains, but an appropriate amount of an easy-faced ReFeN compound is dispersed among the FeSiAl crystal grains. Based on such a structure, the rare earth ion-doped soft magnetic alloy of the present disclosure has excellent electromagnetic properties and lower loss under a working condition of MHz.

Provided is a method of manufacturing a soft magnetic dust core. The method includes: preparing coated powder including amorphous powder made of an Fe-B-Si-P-C-Cu-based alloy, an Fe-B-P-C-Cu-based alloy, an Fe-B-Si-P-Cu-based alloy, or an Fe-B-P-Cu-based alloy, with a first initial crystallization temperature T.sub.x1 and a second initial crystallization temperature T.sub.x2; and a coating formed on a surface of particles of the amorphous powder; applying a compacting pressure to the coated powder or a mixture of the coated powder and the amorphous powder at a temperature equal to or lower than T.sub.x1?100 K; and heating to a maximum end-point temperature equal to or higher than T.sub.x1?50 K and lower than T.sub.x2 with the compacting pressure being applied.

Provided is a soft magnetic dust core having high density and favorable properties. A method of manufacturing a soft magnetic dust core includes: preparing coated powder including amorphous powder made of an FeBSiPCCu-based alloy, an FeBPCCu-based alloy, an FeBSiPCu-based alloy, or an FeBPCu-based alloy, with a first initial crystallization temperature T.sub.x1 and a second initial crystallization temperature T.sub.x2; and a coating formed on a surface of particles of the amorphous powder; applying a compacting pressure to the coated powder or a mixture of the coated powder and the amorphous powder at a temperature equal to or lower than T.sub.x1?100 K; and heating to a maximum end-point temperature equal to or higher than T.sub.x1?50 K and lower than T.sub.x2 with the compacting pressure being applied.

Provided is a soft magnetic alloy including a Fe-based nanocrystal and metallic glass. A differential scanning calorimetry curve of the soft magnetic alloy has a glass transition point Tg, a temperature rising rate of the soft magnetic alloy in measurement of the differential scanning calorimetry curve is 40 K/minute, and a temperature Tp of a maximum exothermic peak in the differential scanning calorimetry curve is higher than the Tg.

A soft magnetic alloy comprising a main component having a compositional formula of ((Fe.sub.(1(+))X1.sub.X2.sub.).sub.(1(a+b))M.sub.aB.sub.b).sub.1cC.sub.c, and a sub component including P, S and Ti, wherein X1 is selected from the group Co and Ni, X2 is selected from the group Al, Mn, Ag, Zn, Sn, As, Sb, Bi, and rare earth elements, M is one or more selected from the group Nb, Hf, Zr, Ta, Mo, W, and V, 0.030a0.14, 0.005b0.20, 0c0.040, 0, 0, and 0+0.50 are satisfied, when magnetic alloy is 100 wt %, P is 0.001 to 0.050 wt %, S is 0.001 to 0.050 wt %, and Ti is 0.001 to 0.080 wt %, and when a value obtained by dividing P by S is P/S, then P/S satisfies 0.10P/S10.

A soft magnetic alloy comprising a main component having a compositional formula of ((Fe.sub.(1(+))X1.sub.X2.sub.).sub.(1(a+b+c))M.sub.aB.sub.bCr.sub.c).sub.1dC.sub.d, and a sub component including P, S and Ti, wherein X1 is selected from the group Co and Ni, X2 is selected from the group Al, Mn, Ag, Zn, Sn, As, Sb, Bi and rare earth elements, M is selected from the group Nb, Hf, Zr, Ta, Mo, W and V, 0.030a0.14, 0.005b0.20, 0<c0.040, 0d0.040, 0, 0, and 0+0.50 are satisfied, when soft magnetic alloy is 100 wt %, P is 0.001 to 0.050 wt %, S is 0.001 to 0.050 wt %, and Ti is 0.001 to 0.080 wt %, and when a value obtained by dividing P by S is P/S, then P/S satisfies 0.10P/S10.

A soft magnetic alloy including a compositional formula of ((Fe.sub.(1(+))X1.sub.X2.sub.).sub.(1(a+b+c+e))M.sub.aB.sub.bP.sub.cCu.sub.e).sub.1fC.sub.f, wherein X1 is one or more selected from the group consisting Co and Ni, X2 is one or more selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Bi, N, O, and rare earth elements, M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Ti, Mo, W, and V, 0.030<a0.14, 0.028b0.20, 0c0.030, 0<e0.030, 0<f0.040, 0, 0, and 0+0.50 are satisfied.