Multilayer block core, multilayer block, and method for producing multilayer block

1. A multilayer block core, comprising a multilayer block in which nanocrystalline alloy ribbon pieces of a nanocrystalline alloy ribbon are layered, the nanocrystalline alloy ribbon pieces having a composition represented by the following Composition Formula (A):

Fe 100-a-b-c-d B a Si b Cu c M d   [Composition Formula (A)]

wherein, in Composition Formula (A), each of a, b, c, and d is an atomic percent; the expressions 13.3≤a≤17.0, 3.5≤b≤5.0, 0.6≤c≤1.1, and 0≤d≤0.5 are satisfied; and M represents at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W,

wherein the nanocrystalline alloy ribbon pieces have been heat treated, whereby the temperature of the amorphous alloy ribbon is raised to an achievable temperature of 450° C. or higher, at a temperature increase rate in which an average temperature increase rate in a temperature range of from 350° C. to 450° C. is 10° C./sec or higher, to obtain a nanocrystalline alloy ribbon, and whereby the nanocrystalline alloy ribbon pieces have a high saturated magnetic flow density Bs of 1.70 T or higher,

wherein the multilayer block is a rectangular parallelopiped block having a structure in which long, flat plate-shaped nanocrystalline alloy ribbon pieces are layered,

wherein, due to cured resin, the plural nanocrystalline alloy ribbon pieces are fixed to one another and the rectangular parallelopiped shape of the multilayer block is maintained,

wherein the nanocrystalline alloy ribbon consists of only nanocrystals or of nanocrystals dispersed in an amorphous phase,

wherein each of the nanocrystalline alloy ribbon pieces contains nanocrystal grains having a grain size of from 1 nm to 30 nm in an amount of from 30% by volume to 60% by volume,

wherein each of the nanocrystalline alloy ribbon pieces has a thickness of from 10 μm to 30 μm, a width of from 5 mm to 100 mm, and a ratio of length to width of from 1 to 10, and

wherein a space factor of the multilayer block is from 85% to 92%.

2. The multilayer block core according to claim 1 , wherein:

each of the nanocrystalline alloy ribbon pieces has a rectangular shape,

the multilayer block has a rectangular parallelopiped shape,

the multilayer block core is provided with at least four of the multilayer blocks,

the at least four multilayer blocks are arranged in the shape of a rectangular ring, and

a layering direction of the nanocrystalline alloy ribbon pieces in the multilayer blocks arranged in the shape of a rectangular ring is the same direction as a normal line direction of an arrangement face of the multilayer blocks arranged in the shape of a rectangular ring.

3. The multilayer block core according to claim 2 , wherein:

each of the nanocrystalline alloy ribbon pieces contains nanocrystal grains having a grain size of from 1 nm to 30 nm in an amount of from 30% by volume to 60% by volume, and has a thickness of from 10 μm to 30 μm, a width of from 5 mm to 100 mm, and a ratio of length to width of from 1 to 10; and

a space factor of the multilayer block core is from 85% to 92%.

4. A multilayer block in which nanocrystalline alloy ribbon pieces of a nanocrystalline alloy ribbon are layered, the nanocrystalline alloy ribbon pieces having a composition represented by the following Composition Formula (A):

Fe 100-a-b-c-d B a Si b Cu c M d   [Composition Formula (A)]

wherein, in Composition Formula (A), each of a, b, c, and d is an atomic percent; the expressions 13.3≤a≤17.0, 3.5≤b≤5.0, 0.6≤c≤1.1, and 0≤d≤0.5 are satisfied; and M represents at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W,

wherein the nanocrystalline alloy ribbon pieces have been heat treated, whereby the temperature of the amorphous alloy ribbon is raised to an achievable temperature of 450° C. or higher, at a temperature increase rate in which an average temperature increase rate in a temperature range of from 350° C. to 450° C. is 10° C./sec or higher, to obtain a nanocrystalline alloy ribbon, and whereby the nanocrystalline alloy ribbon pieces have a high saturated magnetic flow density Bs of 1.70 T or higher,

wherein the multilayer block is a rectangular parallelopiped block having a structure in which long, flat plate-shaped nanocrystalline alloy ribbon pieces are layered,

wherein, due to cured resin, the plural nanocrystalline alloy ribbon pieces are fixed to one another and the rectangular parallelopiped shape of the multilayer block is maintained,

wherein the nanocrystalline alloy ribbon consists of only nanocrystals or of nanocrystals dispersed in an amorphous phase,

wherein each of the nanocrystalline alloy ribbon pieces contains nanocrystal grains having a grain size of from 1 nm to 30 nm in an amount of from 30% by volume to 60% by volume,

wherein each of the nanocrystalline alloy ribbon pieces has a thickness of from 10 μm to 30 μm, a width of from 5 mm to 100 mm, and a ratio of length to width of from 1 to 10, and

wherein a space factor of the multilayer block is from 85% to 92%.

5. A method for producing the multilayer block according to claim 4 , the method comprising:

preparing an amorphous alloy ribbon having a composition represented by Composition Formula (A);

causing the amorphous alloy ribbon to travel continuously with tension F applied thereto, and bringing a partial region of the amorphous alloy ribbon, which is traveling continuously with tension F applied thereto, into contact with a heat transfer medium, whose temperature is maintained at 450° C. or higher, under conditions that satisfy the following Formula (1), whereby the temperature of the amorphous alloy ribbon is raised to an achievable temperature of 450° C. or higher at a temperature increase rate in which an average temperature increase rate in a temperature range of from 350° C. to 450° C. is 10° C./sec or higher, to obtain a nanocrystalline alloy ribbon;

cutting out nanocrystalline alloy ribbon pieces from the nanocrystalline alloy ribbon; and

layering the nanocrystalline alloy ribbon pieces, to obtain the multilayer block:

t c >4/   [Formula (1)]

wherein, in Formula (1), t c represents a time (sec) from a moment at which an arbitrary point of the amorphous alloy ribbon touches the heat transfer medium until a moment at which the arbitrary point separates from the heat transfer medium; and is defined by the following Formula (X), and represents a contact pressure (kPa) between the amorphous alloy ribbon and the heat transfer medium:

=(( F ×(sin θ+sin α))/ a )×1000  Formula (X)

wherein, in Formula (X), F represents a tension (N) applied to the amorphous alloy ribbon; a represents a contact area (mm 2 ) between the amorphous alloy ribbon and the heat transfer medium; θ is an angle formed by a travel direction of the amorphous alloy ribbon just before touching the heat transfer medium and a travel direction of the amorphous alloy ribbon at a time of being in contact with the heat transfer medium, and represents an angle of from 3° to 60°; and α is an angle formed by the travel direction of the amorphous alloy ribbon at the time of being in contact with the heat transfer medium and a travel direction of the nanocrystalline alloy ribbon just after separating from the heat transfer medium, and represents an angle of greater than 0° but no greater than 15°.