A soft magnetic alloy powder includes a particle body and a surface layer. The particle body comprises a soft magnetic alloy including Fe and Co. The surface layer is located on a surface side of the particle body. The surface layer includes one or more local maximum points of Si concentration and one or more local maximum points of Co concentration. The surface layer satisfies D.sub.Si≤D.sub.Co, in which D.sub.Si is a distance from an interface between the particle body and the surface layer to a first Si local maximum point L.sup.Si.sub.max, and D.sub.Co is a distance from the interface to a first Co local maximum point L.sup.Co.sub.max.

Provided is a soft magnetic powder that can produce a dust core having excellent magnetic properties. The soft magnetic powder has a chemical composition, excluding inevitable impurities, represented by a composition formula of Fe.sub.aSi.sub.bB.sub.cP.sub.dCu.sub.eM.sub.f, where the M is at least one element selected from the group consisting of Nb, Mo, Zr, Ta, W, Hf, Ti, V, Cr, Mn, C, Al, S, O, and N, 79 at %≤a≤84.5 at %, 0 at %≤b<6 at %, 0 at %<c≤10 at %, 4 at %<d≤11 at %, 0.2 at %≤e≤0.53 at %, 0 at %≤f≤4 at %, a+b+c+d+e+f=100 at %, a particle size is 1 mm or less, and a median of circularity of particles constituting the soft magnetic powder is 0.4 or more and 1.0 or less.

Provided is a soft magnetic powder that can produce a dust core having excellent magnetic properties. The soft magnetic powder has a chemical composition, excluding inevitable impurities, represented by a composition formula of Fe.sub.aSi.sub.bB.sub.cP.sub.dCu.sub.eM.sub.f, where the M is at least one element selected from the group consisting of Nb, Mo, Zr, Ta, W, Hf, Ti, V, Cr, Mn, C, Al, S, O, and N, 79 at %≤a≤84.5 at %, 0 at %≤b<6 at %, 0 at %<c≤10 at %, 4 at %<d≤11 at %, 0.2 at %≤e≤0.53 at %, 0 at %≤f≤4 at %, a+b+c+d+e+f=100 at %, a particle size is 1 mm or less, and a median of circularity of particles constituting the soft magnetic powder is 0.4 or more and 1.0 or less.

The invention provides an iron-based metallic glass alloy powder including: Fe as the main component; a metalloid element group including Si, B, and C; a small amount of Mo to improve the degree-of-supercooling; and the addition of Cr and Ni to increase corrosion resistance, where the total amount of the metalloid element group, the amount of the degree-of-supercooling improvement element and the total amount of the elements to increase corrosion resistance are set within predetermined ranges.

The invention provides an iron-based metallic glass alloy powder including: Fe as the main component; a metalloid element group including Si, B, and C; a small amount of Mo to improve the degree-of-supercooling; and the addition of Cr and Ni to increase corrosion resistance, where the total amount of the metalloid element group, the amount of the degree-of-supercooling improvement element and the total amount of the elements to increase corrosion resistance are set within predetermined ranges.

A soft magnetic alloy including an internal area having a soft magnetic type alloy composition including Fe and Co, a Co concentrated area existing closer to a surface side than the internal area and having a higher Co concentration than in the internal area, and a SB concentrated area existing closer to the surface side than the Co concentrated area and having a higher concentration of at least one element selected from Si and B than in the internal area.

A soft magnetic alloy including an internal area having a soft magnetic type alloy composition including Fe and Co, a Co concentrated area existing closer to a surface side than the internal area and having a higher Co concentration than in the internal area, and a SB concentrated area existing closer to the surface side than the Co concentrated area and having a higher concentration of at least one element selected from Si and B than in the internal area.

To provide a soft magnetic alloy or the like, from which a magnetic component having a good temperature property of core loss can be obtained. The soft magnetic alloy includes Fe. The soft magnetic alloy includes a crystallite, and an amorphous phase existing around the crystallite. A total area ratio of the crystallite in a cross section of the soft magnetic alloy is 40% or more and less than 60%. An average thickness of the amorphous phase is 3.0 nm or more and 10.0 nm or less. A standard deviation of a thickness of the amorphous phase is 10.0 nm or less.

To provide a soft magnetic alloy or the like, from which a magnetic component having a good temperature property of core loss can be obtained. The soft magnetic alloy includes Fe. The soft magnetic alloy includes a crystallite, and an amorphous phase existing around the crystallite. A total area ratio of the crystallite in a cross section of the soft magnetic alloy is 40% or more and less than 60%. An average thickness of the amorphous phase is 3.0 nm or more and 10.0 nm or less. A standard deviation of a thickness of the amorphous phase is 10.0 nm or less.

An Fe-based nanocrystalline alloy is represented by Composition Formula, (Fe.sub.(1-a)M.sup.1a).sub.100-b-c-d-e-gM.sup.2.sub.bB.sub.cP.sub.dCu.sub.eM.sup.3.sub.g, where M.sup.1 is at least one element selected from the group consisting of Co and Ni, M.sup.2 is at least one element selected from the group consisting of Nb, Mo, Zr, Ta, W, Hf, Ti, V, Cr, and Mn, M.sup.3 is at least two elements selected from the group consisting of C, Si, Al, Ga, and Ge but necessarily includes C, and 0≤a≤0.5, 1.5<b≤3, 10≤c≤13, 0<d≤4, 0<e≤1.5, and 8.5≤g≤12.