Flaky magnetic metal particles of embodiments each have a flat surface and a magnetic metal phase containing iron (Fe), cobalt (Co), and silicon (Si). An amount of Co is from 0.001 at % to 80 at % with respect to the total amount of Fe and Co. An amount of Si is from 0.001 at % to 30 at % with respect to the total amount of the magnetic metal phase. The flaky magnetic metal particles have an average thickness of from 10 nm to 100 μm. An average value of the ratio of the average length in the flat surface with respect to a thickness in each of the flaky magnetic metal particles is from 5 to 10,000. The flaky magnetic metal particles have the difference in coercivity on the basis of direction within the flat surface.

A soft magnetic powder of the invention has a composition represented by Fe.sub.100-a-b-c-d-e-fCu.sub.aSi.sub.bB.sub.cM.sub.dM′.sub.eX.sub.f (at %) [wherein M is Nb, W, Ta, Zr, Hf, Ti, or Mo, M′ is V, Cr, Mn, Al, a platinum group element, Sc, Y, Au, Zn, Sn, or Re, X is C, P, Ge, Ga, Sb, In, Be, or As, and a, b, c, d, e, and f are numbers that satisfy the following formulae: 0.1≤a≤3, 0<b≤30, 0<c≤25, 5≤b+c≤30, 0.1≤d≤30, 0≤e≤10, and 0≤f≤10], wherein a crystalline structure having a particle diameter of 1 nm or more and 30 nm or less is contained in an amount of 40 vol % or more, and the difference in the coercive force of the powder after classification satisfies predetermined conditions.

A soft magnetic powder of the invention has a composition represented by Fe.sub.100-a-b-c-d-e-fCu.sub.aSi.sub.bB.sub.cM.sub.dM′.sub.eX.sub.f (at %) [wherein M is Nb, W, Ta, Zr, Hf, Ti, or Mo, M′ is V, Cr, Mn, Al, a platinum group element, Sc, Y, Au, Zn, Sn, or Re, X is C, P, Ge, Ga, Sb, In, Be, or As, and a, b, c, d, e, and f are numbers that satisfy the following formulae: 0.1≤a≤3, 0<b≤30, 0<c≤25, 5≤b+c≤30, 0.1≤d≤30, 0≤e≤10, and 0≤f≤10], wherein a crystalline structure having a particle diameter of 1 nm or more and 30 nm or less is contained in an amount of 40 vol % or more, and the difference in the coercive force of the powder after classification satisfies predetermined conditions.

A crystalline Fe-based alloy powder composed of Fe-based alloy particles containing, within a structure thereof, nanocrystal grains having an average grain size of 30 nm or less, and in which d50, which is a particle diameter corresponding to a cumulative frequency of 50% by volume, is from 3.5 μm to 35.0 μm in a cumulative distribution curve that is obtained by laser diffractometry and that shows the relationship between the particle diameter and the cumulative frequency from the small particle diameter side, and a ratio of Fe-based alloy particles having a particle diameter of 2 μm or less to the total of the Fe-based alloy particles, which is determined by laser diffractometry, is from 0% by volume to 8% by volume.

A crystalline Fe-based alloy powder composed of Fe-based alloy particles containing, within a structure thereof, nanocrystal grains having an average grain size of 30 nm or less, and in which d50, which is a particle diameter corresponding to a cumulative frequency of 50% by volume, is from 3.5 μm to 35.0 μm in a cumulative distribution curve that is obtained by laser diffractometry and that shows the relationship between the particle diameter and the cumulative frequency from the small particle diameter side, and a ratio of Fe-based alloy particles having a particle diameter of 2 μm or less to the total of the Fe-based alloy particles, which is determined by laser diffractometry, is from 0% by volume to 8% by volume.

An iron-based rare earth boron-based isotropic magnet alloy, which has an alloy composition represented by T.sub.100-x-y-z(B.sub.1-nC.sub.n).sub.xRE.sub.yM.sub.z (where T is a transition metal element containing at least Fe, RE contains at least Nd, and M is one or more metal elements selected from the group consisting of Al, Si, V, Cr, Ti, Mn, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, and Pb), 4.2 atom %≤x≤5.6 atom %, 11.5 atom %≤y≤13.0 atom %, 0.0 atom %≤z≤5.0 atom %, and 0.0≤n≤0.5, and the iron-based rare earth boron-based isotropic magnet alloy has an average crystal grain size of 10 nm to less than 70 nm as a main phase.

A dust core contains a powder of a crystalline magnetic material powder and a powder of an amorphous magnetic material. The sum of the content of the crystalline magnetic material powder and the content of the amorphous magnetic material powder is 83 mass percent or more. The mass ratio of the content of the crystalline magnetic material powder to the sum of the content of the crystalline magnetic material powder and the content of the amorphous magnetic material powder is 20 mass percent or less. The median diameter D50 of the amorphous magnetic material powder is greater than or equal to the median diameter D50 of the crystalline magnetic material powder.

A dust core contains a powder of a crystalline magnetic material powder and a powder of an amorphous magnetic material. The sum of the content of the crystalline magnetic material powder and the content of the amorphous magnetic material powder is 83 mass percent or more. The mass ratio of the content of the crystalline magnetic material powder to the sum of the content of the crystalline magnetic material powder and the content of the amorphous magnetic material powder is 20 mass percent or less. The median diameter D50 of the amorphous magnetic material powder is greater than or equal to the median diameter D50 of the crystalline magnetic material powder.

Provided is a coated body including a base member coated with an iron-based amorphous alloy powder capable of maintaining an amorphous structure even after a coating process, such that the durability, surface hardness, and friction of the base member may be improved. The coated body includes the base member and a coating layer which is formed of an iron-based amorphous alloy and provided on a surface of the base member.

A soft magnetic alloy and the like which simultaneously satisfy a high saturation magnetic flux density Bs and a high corrosion resistance. A soft magnetic alloy includes Mn and a component expressed by a compositional formula of ((Fe.sub.(1−(α+β))Co.sub.αNi.sub.β).sub.1−γX1.sub.γ).sub.(1−(a+b+c+d+e))B.sub.aP.sub.bSi.sub.cC.sub.dCr.sub.e (atomic ratio). X1 is one or more selected from Ti, Zr, Hf, Nb, Ta, Mo, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Sn, As, Sb, Bi, N, O, Au, Cu, rare earth elements, and platinum group elements. Further, a to e and α to γ are within predetermined ranges. Mn amount f (at %) is within a range of 0.002≤f<3.0. The soft magnetic alloy satisfies a corrosion potential of −630 mV or more and −50 mV or less and a corrosion current density of 0.3 μA/cm.sup.2 or more and 45 μA/cm.sup.2 or less.