A method for producing an Fe-based nanocrystalline alloy ribbon, the method including a step of supplying a molten Fe-based alloy onto a rotating chill roll, and rapidly solidifying the molten Fe-based alloy that has been supplied onto the chill roll, thereby obtaining an Fe-based amorphous alloy ribbon having a free solidified surface and a roll contact surface, and a step of heat-treating the Fe-based amorphous alloy ribbon, thereby obtaining an Fe-based nanocrystalline alloy ribbon; wherein an outer peripheral part of the chill roll is composed of a Cu alloy, and a thermal conductivity of the outer peripheral part is from 70 W/(m.Math.K) to 225 W/(m.Math.K).

A soft magnetic nanoparticle comprising an iron aluminide nanoalloy of the DO.sub.3 phase as a core encapsulated in an inert shell made of alumina.

A soft magnetic alloy is represented by a composition formula (Fe.sub.1-xA.sub.x).sub.aSi.sub.bB.sub.cCu.sub.dM.sub.e, wherein A is at least one of Ni and Co, M is one or more selected from the group consisting of Nb, Mo, V, Zr, Hf, and W, and 82.4≤a≤86, 0.2≤b≤2.4, 12.5≤c≤15.0, 0.05≤d≤0.8, 0.4≤e≤1.0, and 0≤x≤0.1 in at %, and has a structure in which crystal grains having a grain size of 60 nm or less are present in an amorphous phase.

A production method for water-atomized metal powder includes: in a region in which the average temperature of a molten metal stream is higher than the melting point by 100° C. or more, spraying primary cooling water from a plurality of directions at a convergence angle of 10° to 25°, where the convergence angle is an angle between an impact direction on the molten metal stream of the primary cooling water from one direction and an impact direction on the molten metal stream of the primary cooling water from any other direction; and in a region in which 0.0004 seconds or more have passed after an impact of the primary cooling water and the average temperature of metal powder is the melting point or higher and (the melting point+50° C.) or lower, spraying secondary cooling water on the metal powder under conditions of an impact pressure of 10 MPa or more.

A production method for water-atomized metal powder includes: in a region in which the average temperature of a molten metal stream having an Fe concentration of 76.0 at % or more and less than 82.9 at % is 100° C. or more higher than the melting point, spraying primary cooling water at a convergence angle of 10° to 25°, where the convergence angle is an angle between an impact direction on the molten metal stream from one direction and an impact direction on the molten metal stream from any other direction; and in a region in which 0.0004 seconds or more have passed after an impact of the primary cooling water and the average temperature of metal powder is the melting point or higher and (the melting point+100° C.) or lower, spraying secondary cooling water on the metal powder under conditions of an impact pressure of 10 MPa or more.

A Fe-based amorphous alloy containing subnanometer-scale ordered clusters, and a preparation method and a nanocrystalline alloy derivative thereof. The composition expression of the Fe-based amorphous alloy is Fe.sub.aSi.sub.bB.sub.c(Cu.sub.dX.sub.e)M.sub.fM′.sub.g, and X is at least one of Ti, Zr and Hf, M is at least one of V, Ta and Nb, and M′ at least one of Co, Ni, C, P, Ge, Cr, Mn, W, Zn, Sn, Sb and Mo; a, b, c, d, e, f and g respectively represent the atomic percent (percentage of the number of atoms) of the corresponding element, and satisfy: 74≤a≤82, 8≤b≤15, 4≤c≤10, 0.5≤d≤1.2, 0.4≤e≤1.8, 1≤f≤3.5, 0≤g≤1, 0.8≤e/d≤1.5 and a+b+c+d+e+f+g=100; the Fe-based amorphous alloy is a composite material composed of an amorphous alloy matrix with atoms arranged in complete disorder and ordered atomic clusters having the size ranging from 0.5 nm to 2 nm uniformly dispersed and distributed in the matrix. The Fe-based amorphous alloy has ultrahigh permeability: the permeability at the frequency of 100 kHz is more than 35000, and the saturation flux density more than 1.3 T.

A high-frequency acceleration cavity core is a toroidal core obtained by winding an Fe-based magnetic ribbon having crystals with an average crystal grain size of 1 μm or less, in which a space factor of the Fe-based magnetic ribbon is 40% or more and 59% or less, and a μQf value at 1 MHz is 3×10.sup.9 Hz or more. The average crystal grain size is preferably 0.1 μm or less. The toroidal core preferably has a portion having a gap portion from an inner diameter to an outer diameter.

A method of producing a laminated amorphous alloy ribbon holding spool. The method includes providing amorphous alloy ribbon holding spools, each of which is wound with a single layer amorphous alloy ribbon, unwinding the single layer amorphous alloy ribbon from each of the amorphous alloy ribbon holding spools, making the single layer amorphous alloy ribbon travel with a laser being radiated thereto, to thereby simultaneously prepare single layer amorphous alloy ribbons having laser irradiation mark formed thereon, laminating the single layer amorphous alloy ribbons having the laser irradiation mark formed thereon to, thereby prepare a laminated amorphous alloy ribbon, and winding up the laminated amorphous alloy ribbon on a spool.

A soft magnetic metal powder that has low coercivity Hcj and high saturation magnetic flux density Bs, and has high powder resistivity and high insulating performance is obtained. The soft magnetic metal powder is soft magnetic metal powder containing Fe. The soft magnetic metal powder has particles each including a soft magnetic metal portion and a coating portion coating the soft magnetic metal portion. The coating portion includes a first coating portion and a second coating portion. The first coating portion is closer to the soft magnetic metal portion than the second coating portion. The first coating portion and the second coating portion have oxides containing at least one element selected from Si, Fe, and B as a main component. The first coating portion includes amorphous material, the second coating portion includes crystals, and the second coating portion has a higher crystal content ratio than the first coating portion.

The invention discloses a method and its device for preparing a magnetic core with amorphous ribbon. The magnetic core is prepared with amorphous ribbon, the size of the amorphous ribbon is controlled according to the target requirements, and the magnetic core with required size and shape is prepared according to the target requirements; the single-roller rapid quenching technology with online automatic segmentation and automatic storage capability is used for preparation, which can control the length, width and thickness of the amorphous ribbon according to the target requirements; the amorphous ribbon segmented by single-roller rapid quenching technology is used to spray and cool down one by one, and then air-dry, transfer, spray adhesive and online store it one by one; the stored amorphous ribbon is reshaped, compressed and heat-treated successively, and then demoulded to prepare a magnetic core.