An Fe-based nanocrystalline soft magnetic alloy including an amorphous phase and crystal grains, wherein clusters are dispersed in the amorphous phase and the alloy has a composition represented by (Fe.sub.1-x-ySi.sub.xAl.sub.y).sub.100-a-b-cM.sub.aM′.sub.bCu.sub.c (M represents one or more elements selected from the group consisting of Nb, W, Zr, Hf, Ti and Mo; M′ represents one or more elements selected from the group consisting of B, C and P; a, b and c represent 2.0≤a≤5.0, 3.0<b<10.0 and 0<c<3.0, each in atomic %; and x and y represent 0.150≤x≤0.250 and 0.012≤y≤0.100 and satisfy 0.190≤x+y≤0.290).

Provided is an iron-based powder for dust core with which a dust core with low iron loss and high insulation properties can be obtained. In the iron-based powder for dust core of the present disclosure, a median particle size calculated based on cumulative volume frequency of particles of the iron-based powder for dust core is 150 μm or less, and cumulative volume frequency of the particles with an aspect ratio of 0.70 or less is 70% or less, and a median aspect ratio calculated based on cumulative volume frequency is 0.60 or more.

Provided is a method for preparing an amorphous strip master alloy. The method includes: providing an amorphous alloy and cementite Fe.sub.3C; and placing the amorphous alloy and the cementite Fe.sub.3C in a smelting furnace for smelting treatment to obtain the amorphous strip master alloy, wherein elements constituting the amorphous alloy include Fe element, Si element and B element. An amorphous strip master alloy prepared by the preparation method is also provided.

Provided is a method for preparing an amorphous strip master alloy. The method includes: providing an amorphous alloy and cementite Fe.sub.3C; and placing the amorphous alloy and the cementite Fe.sub.3C in a smelting furnace for smelting treatment to obtain the amorphous strip master alloy, wherein elements constituting the amorphous alloy include Fe element, Si element and B element. An amorphous strip master alloy prepared by the preparation method is also provided.

A device for the production of a metallic strip using a rapid solidification technology is provided. The device includes a movable heat sink with an external surface onto which a melt is poured and on which the melt solidifies to produce the strip, and which device includes a rolling device which can be pressed against the external surface of the movable heat sink while the heat sink is in motion.

A device for the production of a metallic strip using a rapid solidification technology is provided. The device includes a movable heat sink with an external surface onto which a melt is poured and on which the melt solidifies to produce the strip, and which device includes a rolling device which can be pressed against the external surface of the movable heat sink while the heat sink is in motion.

An amorphous alloy particle is an amorphous alloy particle formed of an iron-based alloy, and the particle contains a grain boundary layer.

An amorphous alloy particle is an amorphous alloy particle formed of an iron-based alloy, and the particle contains a grain boundary layer.

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 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.