Method for manufacturing nanocrystalline alloy strips, and nanocrystalline alloy strips

Abstract

Provided are: a thin nanocrystal alloy band having excellent magnetic characteristics, and isotropy; and a production method for the thin nanocrystal alloy band. A method for producing a thin nanocrystal alloy band, the method comprising: thermally treating an thin alloy band represented by a composition formula (Fe1-xAx)aSibBcCudMe, where A represents at least one of Ni and Co, M represents one or more of Nb, Mo, V, Zr, Hf, and W, 81≤a≤86, 0.15≤b≤5.0, 12.5≤c≤15, 0≤d≤1.0, 0≤e≤1.0, and 0≤x≤0.1 are satisfied, wherein the alloy band, in a state of having a tension of 10-160 MPa applied thereto, is brought into contact with a heating body while being transported, and is subjected to the thermal treatment so that the temperature increase rate is at least 100 K / s, and the temperature Ta of the heating body is in the range of Tx1+85°C to Tx1+140°C when e<0.4 is satisfied in the composition formula and is in the range of Tx1+60°C to Tx1+100°C when e≥0.4 is satisfied in the composition formula, where Tx1 represents the crystallization temperature of the alloy band.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a nanocrystalline alloy ribbon having a nanocrystalline structure and a nanocrystalline alloy ribbon.

Background Art

[0002] Nanocrystalline alloy ribbons having a nanocrystalline structure exhibit excellent magnetic properties and are used in transformers, electronic components, motors, etc. Those transformers, electronic components, motors, etc. are required to be miniaturized and made more efficient. Therefore, further improvement in the properties of the soft magnetic alloy used for the magnetic cores of those components (transformers, electronic components, motors, etc.) is required. The properties required for the soft magnetic alloy include high saturation magnetic flux density and low core loss. Among those components, with the increase in the operating frequency due to the high frequency of semiconductors and the like, miniaturization is being promoted by increasing the operating frequency, and Fe-based amorphous alloys and Fe-based nanocrystalline alloys with low core loss have attracted attention. In order to commercialize them, soft magnetic alloys with excellent price, productivity, and heat treatment properties are required.

[0003] In Patent Document 1, a composition formula Fe c B a Cu b M’ c where M’ is at least one element selected from Nb, Mo, Ta, W, Ni, and Co, having a composition satisfying 10 ≦ a ≦ 16, 0 < b ≦ 2, and 0 ≦ c ≦ 8, and heating an alloy having an amorphous phase at a heating rate of 10 °C / second or more, and holding it for 0 to 80 seconds at a temperature above the crystallization start temperature and below the formation start temperature of the Fe-B compound, a method for manufacturing a soft magnetic material that achieves both high saturation magnetization and low coercive force is described.

[0004] In Patent Document 2, a composition formula ((Fe (1-(α+β)) X1 α X2 β ) (1-(a+b+c+d+e)) B a Si b C c Cu d M eA soft magnetic alloy comprising: X1 is one or more selected from the group consisting of Co and Ni; X2 is one or more selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Bi, N, O and rare earth elements; M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Ti, Mo, W and V; 0.140 < a ≦ 0.240, 0 ≦ b ≦ 0.030, 0 < c < 0.080, 0 < d ≦ 0.020, 0 ≦ e ≦ 0.030, α ≧ 0, β ≧ 0, 0 ≦ α + β ≦ 0.50. A soft magnetic alloy is disclosed which has a high saturation magnetic flux density, a low coercive force and a high magnetic permeability μ´ simultaneously.

[0005] In Patent Document 3, Fe 100-x-y―z A x M y X z is represented by, where A is at least one element selected from Cu and Au, M is at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, X is at least one element selected from B and Si, in atomic%, 0 < x ≦ 5, 0.4 ≦ y < 2.5, 10 ≦ z ≦ 20, and a soft magnetic alloy having a saturation magnetic flux density of 1.7 T or more and a coercive force of 15 A / m or less for the soft magnetic alloy is disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] According to the soft magnetic material described in Patent Document 1, a soft magnetic material having a high saturation magnetization is disclosed. However, since the soft magnetic material described in Patent Document 1 does not contain Si, a SiO₂ film that contributes to the corrosion resistance of the soft magnetic material is not formed on the material surface, making it difficult to prevent rust and the like.

[0008] In the soft magnetic alloy described in Patent Document 2, the saturation magnetic flux density (Bs) is not very high. Generally, as the amount of Fe increases, the saturation magnetic flux density increases. However, in Example 6 where the amount of Fe is 84 at%, the saturation magnetic flux density (Bs) is 1.76 T. Also, due to the relatively large amount of B, it is considered that the heat treatability is insufficient.

[0009] In the soft magnetic alloy described in Patent Document 3, since it contains a large amount of M elements such as expensive Nb, the price becomes high. Also, anisotropy is imparted in the casting direction, and since the ratio of the magnetic flux density when a magnetic field of 80 A / m is applied in the casting direction to the magnetic flux density when a magnetic field of 80 A / m is applied in the direction orthogonal to the casting direction is large, it is not suitable for applications that require isotropy.

[0010] The nanocrystalline alloy ribbon is manufactured by ejecting an alloy melt adjusted to a predetermined alloy composition onto a rotating cooling roll for rapid solidification to produce an alloy ribbon, and then heat-treating the alloy ribbon. The nanocrystalline alloy ribbon is thin in thickness, has a predetermined width, and is manufactured as a long ribbon. According to this manufacturing method, anisotropy is likely to be introduced in the casting direction (longitudinal direction), and even after heat treatment, the magnetic properties tend to be different in the long longitudinal direction and the width direction orthogonal to the longitudinal direction.

[0011] For example, the nanocrystalline alloy ribbon used in a motor or the like is required to have isotropic properties as much as possible. However, as described above, it has been difficult to obtain a nanocrystalline alloy ribbon having excellent magnetic properties (high saturation magnetic flux density, low iron loss) and isotropy.

[0012] This disclosure aims to provide a method for producing nanocrystalline alloy thin strips that possess excellent magnetic properties and isotropy. Furthermore, it aims to provide nanocrystalline alloy thin strips that possess excellent magnetic properties and isotropy. [Means for solving the problem]

[0013] This disclosure comprises the following configuration. <1> Composition formula (Fe 1-x A x ) a Si b B c Cu d M e In a method for producing a nanocrystalline alloy strip having a structure in which crystal grains with an average particle size of 30 nm or less exist in the amorphous phase, the alloy strip is heat-treated such that 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 the atomic percentages are 81 ≤ a ≤ 86, 0.15 ≤ b ≤ 5.0, 12.5 ≤ c ≤ 15, 0 ≤ d ≤ 1.0, 0 ≤ e ≤ 1.0, and 0 ≤ x ≤ 0.1, While applying a tension of 10 MPa to 160 MPa to the alloy strip, the alloy strip is transported and brought into contact with a heating element, and the alloy strip is heat-treated so that the heating rate of the alloy strip is 100 K / second or more. A method for manufacturing a nanocrystalline alloy thin strip, wherein, when the crystallization temperature of the alloy thin strip is Tx1, the temperature Ta of the heating element is in the range of Tx1 + 85°C to Tx1 + 140°C when e < 0.4 in the composition formula, and in the range of Tx1 + 60°C to Tx1 + 100°C when e ≥ 0.4 in the composition formula. <2> The saturation magnetic flux density Bs of the nanocrystalline alloy thin band is 1.6T or higher, and when the remanent magnetic flux density Br in the longitudinal direction of the nanocrystalline alloy thin band (maximum measured magnetic field Hm = 80 A / m) is denoted as LBr, and the remanent magnetic flux density Br in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is denoted as WBr, then LBr / WBr is between 0.2 and 1.8. <1> A method for producing a nanocrystalline alloy thin strip as described above. <3> The maximum permeability μm of the nanocrystalline alloy thin band is 4000 or more, and when the maximum permeability μm in the longitudinal direction of the nanocrystalline alloy thin band (maximum measured magnetic field Hm = 80 A / m) is L μm, and the maximum permeability μm in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is W μm, then L μm / W μm is 0.3 to 1.7. <1> or <2> A method for producing a nanocrystalline alloy thin strip as described above.

[0014] <4> The anisotropic energy E of the aforementioned nanocrystalline alloy thin band (maximum measured magnetic field Hm = 800 A / m) is 400 J / m 3 The following conditions apply: When the anisotropy energy E in the longitudinal direction of the nanocrystalline alloy thin band (maximum measured magnetic field Hm = 800 A / m) is denoted as LE, and the anisotropy energy E in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 800 A / m) is denoted as WE, then LE / WE is between 0.2 and 1.8. <1> from <3> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <5> The magnetic flux density B80 of the nanocrystalline alloy thin strip when a magnetic field of 80 A / m is applied is 0.4 T or more, and when the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin strip is denoted as LB80, and the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction is denoted as WB80, then LB80 / WB80 is 0.3 to 1.7. <1> from <4> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <6> During the heat treatment of the alloy strip, the temperature of the alloy strip is controlled so as not to exceed Ta + 50°C. <1> from <5> A method for producing a nanocrystalline alloy thin strip as described in any one of the items. <7> The heating element is composed of multiple heating sections with different temperatures, and the temperature of the heating section with the highest temperature among the multiple heating sections is the temperature Ta. <1> from <6> A method for producing a nanocrystalline alloy thin strip as described in any one of the items.

[0015] <8> This is a nanocrystalline alloy thin strip having a structure in which crystal grains with an average particle size of 30 nm or less exist in the amorphous phase. The aforementioned nanocrystalline alloy thin strip has the compositional formula (Fe 1-x A x ) a Si b Bc Cu d M e Represented as follows, where 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 in atomic percent the values ​​are 81≦a≦86, 0.15≦b≦5.0, 12.5≦c≦15, 0≦d≦1.0, 0≦e≦1.0, 0≦x≦0.1, and the saturation magnetic flux density Bs is 1.6T or higher. A nanocrystalline alloy thin strip in which the remanent magnetic flux density Br in the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is LBr, and the remanent magnetic flux density Br in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is WBr, wherein LBr / WBr is 0.2 to 1.8. <9> The maximum permeability μm of the nanocrystalline alloy thin band is 4000 or more, and when the maximum permeability μm in the longitudinal direction of the nanocrystalline alloy thin band (maximum measured magnetic field Hm = 80 A / m) is L μm, and the maximum permeability μm in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is W μm, then L μm / W μm is 0.3 to 1.7. <8> The nanocrystalline alloy thin strip described above. <10> The anisotropic energy E of the aforementioned nanocrystalline alloy thin band (maximum measured magnetic field Hm = 800 A / m) is 400 J / m 3 The following conditions apply: When the anisotropy energy E in the longitudinal direction of the nanocrystalline alloy thin band (maximum measured magnetic field Hm = 800 A / m) is denoted as LE, and the anisotropy energy E in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 800 A / m) is denoted as WE, then LE / WE is between 0.2 and 1.8. <8> or <9> The nanocrystalline alloy thin strip described above. <11> The magnetic flux density B80 of the nanocrystalline alloy thin strip when a magnetic field of 80 A / m is applied is 0.4 T or more, and when the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin strip is denoted as LB80, and the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction is denoted as WB80, then LB80 / WB80 is 0.3 to 1.7. <8> from <10> A nanocrystalline alloy thin strip as described in any one of the items. <12> The thickness is 15 μm or more, and the width is 5 mm or more. <8> from <11> A nanocrystalline alloy thin strip as described in any one of the items. <13> The occupancy rate is 86% or higher. <8> from <12> A nanocrystalline alloy thin strip as described in any one of the items. <14> The saturation magnetostriction is 30 ppm or less. <8> from <13> A nanocrystalline alloy thin strip as described in any one of the items. [Effects of the Invention]

[0016] According to this disclosure, it is possible to provide a method for producing nanocrystalline alloy thin strips that have excellent magnetic properties and isotropy. Furthermore, it is possible to provide nanocrystalline alloy thin strips that have excellent magnetic properties and isotropy. [Brief explanation of the drawing]

[0017] [Figure 1] This figure shows an example of an in-line annealing apparatus that can be used for the heat treatment described herein. [Figure 2] This figure plots the examples and comparative examples of the present disclosure with the X-axis representing Ta-Tx1 (°C) and the Y-axis representing tension (MPa). [Modes for carrying out the invention]

[0018] The embodiments of this disclosure will be described in detail below. This disclosure is not limited to the embodiments described below and may be implemented with appropriate modifications within the scope of the purposes of this disclosure.

[0019] In this disclosure, numerical ranges indicated using "~" represent ranges that include the numbers before and after "~" as the lower and upper limits, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples. In this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

[0020] The nanocrystalline alloy thin strip disclosed herein has the compositional formula (Fe 1-x A x ) a Si b B c Cu d M e It is represented as follows: A is at least one of Ni and Co, and M is one or more selected from the group consisting of Nb, Mo, V, Zr, Hf and W, with atomic percent values ​​of 81≦a≦86, 0.15≦b≦5.0, 12.5≦c≦15, 0≦d≦1.0, 0≦e≦1.0, and 0≦x≦0.1.

[0021] The composition of the nanocrystalline alloy strips of this disclosure will be described in detail below. Fe (iron) makes up between 81% and 86% of the atomic percentage. A high saturation magnetic flux density can be obtained by setting the Fe content to 81% or more. Preferably, it is 82% or more, more preferably 82.5% or more, even more preferably 83% or more, even more preferably 83.5% or more, and even more preferably 84% or more. Furthermore, since amorphous formation becomes difficult if the Fe content exceeds 86%, the Fe content should be 86% or less. Preferably, it should be 85.5% or less.

[0022] The amount of silicon (Si) is between 0.15% and 5.0% in atomic percent. By including Si, an oxide film of SiO2 with a thickness of several tens of nanometers can be formed on the alloy surface. This improves the corrosion resistance of the nanocrystalline alloy strip. To obtain this improved corrosion resistance, the Si content should be 0.15% or more, preferably 1.0% or more. If the Si content exceeds 5.0%, it becomes difficult to obtain a high saturation magnetic flux density, and it also becomes difficult to increase the thickness of the alloy strip. For this reason, the Si content should be 5.0% or less. Preferably, it should be 4% or less, more preferably 3% or less, and even more preferably 2% or less.

[0023] The amount of boron (B) is between 12.5% ​​and 15% in atomic percent. Since amorphous formation becomes difficult if the B content is less than 12.5%, the B content should be 12.5% ​​or more. Preferably it is 13.0% or more, and more preferably 13.5% or more. If the B content exceeds 15%, the difference between the bccFe(αFe) crystallization start temperature and the FeB precipitation start temperature decreases, narrowing the temperature range in which heat treatment is possible. As a result, it becomes difficult to obtain a uniform, fine nanocrystalline structure in which iron loss at 1T, 1kHz can be obtained at 25W / kg or less. For this reason, the B content should be 15% or less. Preferably, it is 14.5% or less, more preferably 14.4% or less, and even more preferably 14.0% or less.

[0024] The amount of copper (Cu) is between 0% and 1.0% in atomic percent. The Cu content can be 0%, but including Cu makes it easier to obtain a uniform, fine nanocrystalline structure. In particular, including Cu is preferable to reduce iron loss. For this reason, the Cu content is preferably 0.05% or more. More preferably 0.1% or more, even more preferably 0.2% or more, even more preferably 0.4% or more, and even more preferably 0.5% or more. If the Cu content exceeds 1.0%, the material becomes brittle, making it difficult to increase the thickness of the nanocrystalline alloy strip. For this reason, the Cu content should be 1.0% or less. Preferably, it should be 0.9% or less, more preferably 0.85% or less, even more preferably 0.7% or less, and even more preferably 0.6% or less.

[0025] Element M is one or more elements selected from the group consisting of Nb, Mo, V, Zr, Hf, and W, and its atomic percentage is between 0% and 1.0%. The amount of element M may be 0%, but by including element M, the precipitation start temperature of the FeB compound, which significantly degrades soft magnetism, can be shifted to a higher temperature. This widens the difference between the bccFe(αFe) crystallization start temperature (also called the crystallization temperature) and the FeB precipitation start temperature, which has the effect of expanding the range of optimal heat treatment temperatures and relaxing the heat treatment conditions. Preferably, it is 0.1% or more, and more preferably 0.15% or more. Since element M is expensive, its price increases. Therefore, a lower content is preferable. Accordingly, the content of element M should be 1.0% or less. Preferably, it should be 0.9% or less, more preferably 0.8% or less, even more preferably 0.7% or less, and even more preferably 0.6% or less. Furthermore, the amount of element M is preferably less than 0.4%, more preferably 0.3% or less, and even more preferably 0.25% or less.

[0026] The nanocrystalline alloy strip of this disclosure may have a portion of Fe replaced with at least one element, Ni and Co. (Fe 1-x A x When this is the case, A is at least one of Ni and Co, and x is 0.1 or less.

[0027] The nanocrystalline alloy strips of this disclosure may contain carbon (C). The amount of C is preferably 1% by mass or less.

[0028] Furthermore, the nanocrystalline alloy strips of this disclosure may contain impurities other than the elements mentioned above. Examples of impurities include sulfur (S), oxygen (O), nitrogen (N), Cr, manganese (Mn), phosphorus (P), titanium (Ti), and aluminum (Al). For example, the S content is preferably 200 ppm by mass or less, the O content is preferably 5000 ppm by mass or less, and the N content is preferably 1000 ppm by mass or less. The total content of these impurities is preferably 0.5% by mass or less. Furthermore, elements corresponding to impurities may be added as long as they are within the above range.

[0029] The nanocrystalline alloy strip of this disclosure has a structure in which crystal grains with an average particle size of 30 nm or less are present in the amorphous phase. This structure in which crystal grains with an average particle size of 30 nm or less are present in the amorphous phase is also called a nanocrystalline structure. The average particle size was determined using Scherrer's equation, employing the full width at half maximum (FMAX) of the diffraction peak from the (110) plane in the X-ray diffraction pattern obtained from the X-ray diffraction experiment. The FMAX of the (110) peak was determined by peak decomposition using a pseudo-Voigt function for the diffraction pattern. If the average particle size is D, the FMAX is W, the diffraction angle is θ, Scherrer's constant is K, and the X-ray wavelength is λ, then D can be determined from Scherrer's equation (Equation 1) given below. In this case, we assumed an X-ray wavelength λ = 0.154050 nm and a Scherrer constant K = 0.891.

[0030]

number

[0031] The method for manufacturing the nanocrystalline alloy strip of this disclosure will now be described. The nanocrystalline alloy strip of this disclosure can be obtained by ejecting a molten alloy having the above-described alloy composition onto a rotating cooling roll, rapidly cooling and solidifying it on the cooling roll to obtain an alloy strip, and then heat-treating the alloy strip. The alloy strip obtained by rapidly cooling and solidifying the molten alloy is in an amorphous state and is an amorphous alloy strip. By heat-treating this amorphous alloy strip (amorphous alloy strip), a nanocrystalline alloy strip can be obtained. The amorphous alloy strip may have a crystalline phase consisting of fine crystals.

[0032] A molten alloy can be produced by mixing various elemental sources (pure iron, ferroboron, ferrosilicon, etc.) that make up the desired alloy composition, heating them in an induction furnace, and melting them above their melting point. A thin alloy strip can be obtained by ejecting molten alloy from a slit-shaped nozzle of a predetermined shape onto a rotating cooling roll, and rapidly cooling and solidifying the molten alloy on the cooling roll. In this case, the cooling roll can have an outer diameter of 350 to 1000 mm, a width of 100 to 400 mm, and a rotational speed of 20 to 35 m / sec. This cooling roll is equipped with an internal cooling mechanism (such as water cooling) to suppress the temperature rise of the outer circumference. Furthermore, it is preferable that the outer periphery of the cooling roll is made of a Cu alloy with a thermal conductivity of 120 W / (m·K) or higher. By making the thermal conductivity of the outer periphery 120 W / (m·K) or higher, the cooling rate when the molten alloy is cast into an alloy strip can be increased. This suppresses the embrittlement of the alloy strip, enables the thickness of the alloy strip, and suppresses surface crystallization during casting, thereby suppressing grain coarsening during heat treatment and reducing iron loss.

[0033] Furthermore, the thermal conductivity of the outer periphery is preferably 150 W / (m·K) or higher, and more preferably 180 W / (m·K) or higher. In particular, when the thickness of the nanocrystalline alloy thin band is 30 μm or more, it is preferable that the thermal conductivity of the outer periphery be 150 W / (m·K) or higher. The outer circumference of the cooling roll is the part that comes into contact with the molten alloy, and its thickness should be approximately 5 to 15 mm. The inner part should be made of a structural material that maintains the roll structure.

[0034] A nanocrystalline alloy strip is obtained by heat-treating the alloy strip produced by the rapid cooling method described above. The method for producing a nanocrystalline alloy strip according to this disclosure is characterized by its heat treatment method. The heat treatment method of this disclosure involves applying a tension of 10 MPa to 160 MPa to an alloy strip, transporting the alloy strip, and bringing it into contact with a heating element so that the heating rate of the alloy strip is 100 K / second or more, thereby performing the heat treatment. When the crystallization temperature of the alloy strip is Tx1, the temperature Ta of the heating element is set to the range of Tx1 + 85°C to Tx1 + 140°C when e < 0.4 in the compositional formula, and to the range of Tx1 + 60°C to Tx1 + 100°C when e ≥ 0.4 in the compositional formula. In this disclosure, the crystallization temperature of the alloy strip is the crystallization start temperature of bccFe(αFe).

[0035] The heat treatment method described herein involves applying tension to an alloy strip, transporting it, and heating it in contact with a heating element to heat-treat the alloy strip. The tension, heating element temperature, and heating rate of the alloy strip are important requirements at this stage. By appropriately setting the tension, heating element temperature, and heating rate of the alloy strip, it is possible to obtain a nanocrystalline alloy strip that possesses excellent magnetic properties (high saturation magnetic flux density, low iron loss) and isotropy.

[0036] In this disclosure, it is expected that isotropic magnetic properties can be obtained by applying tension and performing heat treatment at a rapid heating rate. The tension should be between 10 MPa and 160 MPa. Preferably, it should be 30 MPa or higher. More preferably, it should be 34 MPa or higher. Also preferably, it should be 150 MPa or lower. More preferably, it should be 145 MPa or lower.

[0037] In this disclosure, it was found that the preferred temperature range for the heating element's temperature Ta varies depending on the composition. Furthermore, it was found that the heating element's temperature Ta can be set using a relationship with the crystallization temperature of the alloy strip (the crystallization start temperature of bccFe(αFe)) Tx1. When e < 0.4 in the composition formula, the temperature Ta of the heating element is in the range of Tx1 + 85°C to Tx1 + 140°C. Preferably it is Tx1 + 90°C or higher, more preferably Tx1 + 95°C or higher. Preferably it is Tx1 + 120°C or lower, more preferably Tx1 + 115°C or lower. Furthermore, when the composition formula e ≥ 0.4, the temperature Ta of the heating element is set to be in the range of Tx1 + 60°C to Tx1 + 100°C. When selecting a lower temperature within this temperature range, it may be preferable to increase the contact time between the alloy strip and the heated object.

[0038] [Crystallization temperature (crystallization start temperature of bccFe(αFe)) Tx1, FeB precipitation start temperature Tx2] When a nanocrystalline alloy strip is obtained by heat-treating an alloy strip, the FeB deposition initiation temperature Tx2 exists at a temperature higher than the crystallization temperature. If the alloy strip reaches the FeB deposition initiation temperature, the crystals coarseen, and FeB, which degrades magnetic properties, precipitates. Therefore, heat treatment must be performed in a way that prevents the FeB deposition initiation temperature from being reached. The crystallization temperature and FeB precipitation initiation temperature of the alloy strip can be obtained as follows. The crystallization temperature and FeB precipitation initiation temperature vary with the heating rate, but the upper limit of the heating rate of a typical thermal analyzer is about 2°C / second, and it is not possible to measure the heating rate during the heat treatment described in this disclosure. Therefore, the values ​​at a heating rate of 50°C / second were determined by the following method and were used as the crystallization temperature and FeB precipitation initiation temperature. Using a Rigaku differential scanning calorimeter DSC8231, the crystallization temperature and FeB precipitation initiation temperature were measured at three points with heating rates of 5°C / min (0.083°C / sec), 20°C / min (0.333°C / sec), and 50°C / min (0.833°C / sec). These values ​​were plotted on a logarithmic scale of the heating rate on the X-axis and the crystallization temperature or FeB precipitation initiation temperature on the Y-axis. The value for a heating rate of 50°C / sec was then extrapolated from the approximation curve.

[0039] In this disclosure, the heating rate of the alloy strip is set to 100 K / second or more. This heating rate was calculated by determining the slope of the tangent near the heat treatment temperature Ta when heated. Preferably, it is 300 K / second or more, and more preferably 500 K / second or more. The upper limit may be set within the range possible by the equipment and process conditions. For example, it can be 4000 K / second or less. Preferably, it is 3000 K / second or less, and more preferably 2500 K / second or less.

[0040] In this disclosure, the alloy strip is heat-treated while being transported. The alloy strip is formed in a long length, and by heat-treating it while it is being transported, the long length of the alloy strip can be heat-treated efficiently. In this disclosure, the contact time between the alloy strip and the heated body is preferably 0.5 seconds to 60 seconds. In this disclosure, the conveying speed of the alloy strip is preferably 3 m / min to 300 m / min. More preferably, it is 200 m / min or less.

[0041] In this disclosure, the heating element may be composed of multiple heating sections with different temperatures. In this case, the temperature of the heating section with the highest temperature among the multiple heating sections is defined as the temperature Ta described above.

[0042] During heat treatment, alloy strips may generate self-heat due to crystallization. As mentioned above, if the temperature of the alloy strip reaches the FeB deposition initiation temperature, the desired magnetic properties cannot be obtained as a nanocrystalline alloy strip. Furthermore, even if the temperature does not reach the FeB deposition initiation temperature, if it rises too high, the grain size growth will accelerate, and the iron loss will deteriorate. In this disclosure, if there is no temperature rise due to self-heating, the heating temperature of the alloy strip will be such that the temperature Ta of the heating element is the highest temperature. In contrast, when the temperature rise is accompanied by self-heating, the heating temperature of the alloy strip exceeds the temperature Ta of the heating element. In this case, it is preferable to suppress an excessive temperature rise. In this disclosure, it is preferable to control the temperature of the alloy thin band so that it does not exceed Ta + 50°C due to the temperature rise caused by self-heating.

[0043] In a method for heat-treating an alloy strip by applying tension to it, transporting it, and heating it in contact with a heating element, the method for manufacturing amorphous alloy ribbons disclosed in international publication number WO2019 / 009309 can be used as a reference. Figure 1 shows the in-line annealing apparatus described in international publication number WO2019 / 009309.

[0044] The heat treatment of this disclosure can be performed, for example, by using the in-line annealing apparatus shown in Figure 1. The in-line annealing apparatus 100 shown in Figure 1 comprises an unwinding roller 12 (unwinding device) that unwinds the alloy strip 10 from a wound body 11 of alloy strips, a heating element (heating plate) 22 that heats the alloy strip 10 unwinded from the unwinding roller 12, a cooling plate 32 that cools the alloy strip 10 heated by the heating element 22, and a winding roller 14 (winding device) that winds up the alloy strip 10 that has been cooled by the cooling plate 32. In Figure 1, the direction of travel of the alloy strip 10 is indicated by the arrow R.

[0045] As shown in the enlarged circled area in Figure 1, the heating element 22 includes a first plane 22S on which the alloy strip 10 unwound from the unwinding roller 12 travels while in contact with it. The heating element 22 heats the alloy strip 10 as it travels on the first plane 22S while in contact with it, via the first plane 22S. This ensures that the alloy strip 10 is stably and rapidly heated while in motion. The heating element 22 may be a combination of multiple heating sections that can be set to different temperatures, or the first plane 22S portion described above may be integrated, but the heating element may be configured to allow for multiple heating temperature settings. Thus, the heating element can be composed of multiple heating sections.

[0046] The heating element 22 is housed in the heating chamber 20. The heating chamber 20 may be equipped with a heat source for controlling the temperature of the heating chamber, separate from the heat source for the heating element 22. Furthermore, in the inline annealing apparatus shown in Figure 1, as shown in the enlarged circled area, the cooling plate 32 includes a second surface 32S on which the alloy ribbon 10 travels while in contact with it. This cooling plate 32 cools the alloy ribbon 10 as it travels on the second surface 32S while in contact with it, via the second surface 32S. The cooling plate 32 is housed in a cooling chamber 30.

[0047] The winding roller 14 is equipped with a rotation mechanism (e.g., a motor) that rotates axially in the direction of arrow W. The rotation of the winding roller 14 causes the alloy ribbon 10 to be wound up at the desired speed.

[0048] The inline annealing apparatus 100 is equipped with a guide roller 41, a dancer roller 60 (one of the tension adjustment devices), a guide roller 42, and a pair of guide rollers 43A and 43B between the unwinding roller 12 and the heating chamber 20, along the path of the alloy ribbon 10. Tension adjustment is also performed by controlling the operation of the unwinding roller 12 and the winding roller 14. The dancer roller 60 is provided so as to be movable in the vertical direction (in the direction of the double-headed arrows in Figure 1). By adjusting the vertical position of the dancer roller 60 (in the direction of the double-headed arrows), the tension of the alloy strip 10 can be adjusted. The same applies to the dancer roller 62.

[0049] Multiple openings may be provided on the first plane of the heating element 22 to allow suction, thereby improving the adhesion between the alloy strip and the heating element. Suitable materials for the heating element include copper, copper alloys (bronze, brass, etc.), aluminum, iron, and iron alloys (stainless steel, etc.). Of these, copper, copper alloys, or aluminum are preferred due to their high thermoelectric coefficient (heat transfer coefficient). The heating element may be plated with a nickel plating, silver plating, or the like.

[0050] The nanocrystalline alloy strip of this disclosure is obtained by the manufacturing method described above, has the composition described above, possesses excellent magnetic properties, and isotropic. The nanocrystalline alloy strip of this disclosure is a nanocrystalline alloy strip having a structure in which crystal grains with an average particle size of 30 nm or less exist in an amorphous phase, having a saturation magnetic flux density Bs of 1.6 T or higher, where LBr is the remanent magnetic flux density Br in the longitudinal direction of the nanocrystalline alloy strip (maximum measured magnetic field Hm = 80 A / m), and WBr is the remanent magnetic flux density Br in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 80 A / m), and LBr / WBr is 0.2 to 1.8. LBr / WBr is preferably 0.4 to 1.6, more preferably 0.6 to 1.4, and more preferably 0.8 to 1.2.

[0051] Furthermore, the nanocrystalline alloy thin strip of this disclosure preferably has an iron loss of 25 W / kg or less at 1 kHz, 1 T. More preferably, it is 20 W / kg or less, and more preferably, 15 W / kg or less. Furthermore, the saturation magnetic flux density Bs is preferably 1.65T or higher, more preferably 1.7T or higher, and even more preferably 1.75T or higher.

[0052] Furthermore, the nanocrystalline alloy thin strip of this disclosure has a maximum magnetic permeability of 4000 μm or more, and when the maximum magnetic permeability μm in the longitudinal direction of the nanocrystalline alloy thin strip (maximum measured magnetic field Hm = 80 A / m) is Lμm and the maximum magnetic permeability μm in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is Wμm, it is preferable that Lμm / Wμm is 0.3 to 1.7. Lμm / Wμm is more preferably 0.6 to 1.4, and more preferably 0.8 to 1.2.

[0053] Furthermore, the nanocrystalline alloy thin strip of this disclosure has an anisotropic energy E (maximum measured magnetic field Hm = 800 A / m) of 400 J / m 3 The following conditions apply: When the anisotropy energy E in the longitudinal direction of the nanocrystalline alloy thin band (maximum measured magnetic field Hm = 800 A / m) is denoted as LE, and the anisotropy energy E in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 800 A / m) is denoted as WE, it is preferable that LE / WE is 0.2 to 1.8. More preferably, LE / WE is 0.4 to 1.6, more preferably 0.6 to 1.4, and more preferably 0.8 to 1.2.

[0054] Furthermore, the nanocrystalline alloy thin strip of this disclosure has a magnetic flux density B80 of 0.4T or more when a magnetic field of 80 A / m is applied. When the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin strip is denoted as LB80, and the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction is denoted as WB80, it is preferable that LB80 / WB80 is 0.3 to 1.7. More preferably, LB80 / WB80 is 0.6 to 1.4, and more preferably 0.8 to 1.2.

[0055] Furthermore, the nanocrystalline alloy strips of this disclosure preferably have a thickness of 15 μm or more. More preferably, they have a thickness of 30 μm or more. A thickness of 15 μm or more reduces the number of steps and manufacturing costs when laminating nanocrystalline alloy strips to produce a magnetic core. Even more preferably, the thickness is 32 μm or more. Furthermore, for applications requiring lower iron loss in the high-frequency range above 1 kHz, ribbons with a thickness of approximately 15-25 μm are preferable. Furthermore, the width is preferably 5 mm or more. More preferably 10 mm or more, and even more preferably 100 mm or more. Even more preferably 200 mm or more.

[0056] Furthermore, the nanocrystalline alloy strips of this disclosure preferably have a packing density of 86% or more. More preferably, the packing density is 88% or more, and even more preferably 90% or more. Due to the high packing density, when stacking soft magnetic alloy strips, the stacking thickness can be reduced even with the same number of layers compared to alloy strips with a low packing density, contributing to the miniaturization of magnetic cores and components. The space factor can be measured using the following method in accordance with JIS C 2534:2017. Twenty thin strips, each cut to a length of 120 mm, are stacked and placed on a flat sample stage. A flat anvil with a diameter of 16 mm is placed on the stacked strips under a pressure of 50 kPa, and the height is measured at 10 mm intervals in the width direction. The maximum height at that time is defined as hmax (μm), and the packing fraction LF is calculated using the following formula: LF (%) = weight of sample (g) / density (g / cm³). 3 ) / hmax(μm) / sample length (240cm) / thin band width (cm) × 10000 At this time, density (g / cm³) 3 ) is the density of the alloy strip after heat treatment, and is 7.5 g / cm³. 3 Furthermore, it is preferable that the saturation magnetostriction is 30 ppm or less.

[0057] The nanocrystalline alloy thin strips disclosed herein can be used to form magnetic cores for transformers, electronic components, motors, and the like, thereby obtaining magnets with excellent properties. When constructing a magnetic core, it can be done by cutting alloy strips into a predetermined shape and stacking them, winding alloy strips, or stacking and bending alloy strips. Furthermore, by combining the magnetic core and windings of this disclosure to construct components such as transformers, electronic components, and motors, components with excellent properties can be obtained. In this case, the magnetic core of this disclosure may be combined with a magnetic core made of other magnetic materials.

[0058] [Example 1] Elemental sources were mixed to achieve the compositions shown in Table 1, heated to 1300°C to produce molten alloy, and then ejected onto a cooling roll with an outer diameter of 400 mm and a width of 200 mm, rotating at a peripheral speed of 30 m / s. The molten alloy was rapidly cooled and solidified on the cooling roll to produce thin alloy strips. The outer periphery of the cooling roll is made of a Cu alloy with a thermal conductivity of 150 W / (m·K), and it is equipped with a cooling mechanism inside for temperature control of the outer periphery. The produced thin alloy strips were in an amorphous state and were non-crystalline alloy strips. For each material, the crystallization temperature (crystallization start temperature of bccFe(αFe)) Tx1 and the FeB precipitation start temperature Tx2 were measured using the method described above, and the results are shown in Table 1.

[0059] Heat treatment was performed on alloy strips of each material, varying the tension, heating element temperature (Ta), and contact time with the heating element. The conditions and evaluation results are shown in Tables 2, 3, and 4. After heat treatment, the alloy strips were nanocrystalline alloy strips with a structure in which crystal grains with an average particle size of 30 nm or less existed in the amorphous phase.

[0060] For each sample, iron loss, saturation magnetic flux density Bs, remanent magnetic flux density Br, magnetic flux density B80, maximum permeability μm, anisotropic energy, and coercivity Hc were measured. The details of each measurement are as follows.

[0061] [Iron loss] A heat-treated single-plate sample was measured using a Toei Kogyo AC magnetic field measuring device TWM18SR under conditions of magnetic flux density 1T and frequency 1kHz.

[0062] [Saturated magnetic flux density Bs] A magnetic field of 8000 A / m is applied to a heat-treated single-plate sample using a DC magnetization characteristic tester manufactured by Metron Giken, and the maximum magnetic flux density at that time is measured and defined as Bs. Since the nanocrystalline alloy thin strip of this disclosure has a relatively easy-to-saturate property, it is saturated when a magnetic field of 8000 A / m is applied, and B 8000 Since the saturation magnetic flux density Bs is approximately the same value, the saturation magnetic flux density Bs is set to B 8000 It is represented as follows.

[0063] [Residual magnetic flux density Br] Using a DC magnetization characteristic testing device manufactured by Metron Giken, a magnetic field of 80 A / m was applied to a nanocrystalline alloy thin strip, and then the magnetic field was gradually weakened until the applied magnetic field was 0 A / m. The magnetic flux density at this point was defined as the remanent magnetic flux density Br. In addition, a magnetic field of 80 A / m was applied to the longitudinal direction (casting direction) and the width direction perpendicular to the longitudinal direction of the nanocrystalline alloy thin strip, and then the magnetic field was gradually weakened until the applied magnetic field was 0 A / m. The magnetic flux densities at these points were defined as LBr and WBr, respectively, and their ratio LBr / WBr was calculated to evaluate the isotropy.

[0064] [Magnetic flux density B80] A magnetic field of 80 A / m was applied to a nanocrystalline alloy thin strip using a DC magnetization characteristic testing device manufactured by Metron Giken, and the maximum magnetic flux density at that time was defined as B80. In addition, a magnetic field of 80 A / m was applied to the longitudinal direction (casting direction) and the width direction perpendicular to the longitudinal direction of the nanocrystalline alloy thin strip, and the maximum magnetic flux densities at that time were defined as LB80 and WB80, respectively. The ratio LB80 / WB80 was calculated to evaluate the isotropy.

[0065] [Maximum permeability μm] Using a DC magnetization characteristic testing device manufactured by Metron Giken, a magnetic field up to 80 A / m was applied to a nanocrystalline alloy thin strip. The maximum value of the quotient between the magnetic flux density and the magnetic field at that time was defined as the maximum permeability in μm. The maximum permeability measured in the longitudinal direction (casting direction) and the width direction perpendicular to the longitudinal direction were defined as Lμm and Wμm, respectively, and the ratio Lμm / Wμm was calculated to evaluate the isotropy.

[0066] [Anisotropic energy] Using a DC magnetization characteristic testing device manufactured by Metron Giken, a magnetic field up to 800 A / m was applied to a nanocrystalline alloy thin strip. The anisotropy energy E was defined as the product of the maximum magnetic flux density and the maximum measured magnetic field, minus the area of ​​the magnetic flux density-magnetic field curve. The anisotropy energies measured in the longitudinal direction (casting direction) and the width direction perpendicular to the longitudinal direction were defined as LE and WE, respectively, and the ratio LE / WE was calculated to evaluate the isotropy.

[0067] [Coercive force Hc] Using a DC magnetization characteristic testing device manufactured by Metron Giken, a magnetic field of 8000 A / m was applied to the longitudinal direction (casting direction) of a nanocrystalline alloy thin strip. The magnetic field was then gradually weakened, and the magnetic field at which the magnetic flux density became 0 T was defined as the coercivity.

[0068] [Table 1]

[0069] [Table 2]

[0070] [Table 3]

[0071] [Table 4]

[0072] Tables 2 and 3 show materials A, B, D, and G, where the composition formula e < 0.4. Samples with an LBr / WBr ratio in the range of 0.2 to 1.8 are designated as examples, and samples outside this range are designated as comparative examples. Examples are marked with ● and comparative examples with ▲. Figure 2 shows a plot of examples and comparative examples with the X-axis representing Ta-Tx1 (°C) and the Y-axis representing tension (MPa). As shown in Figure 2, it can be seen that when Ta-Tx1 is 81°C or below, it is a comparative example, and when it is above 81°C, it is an example. Therefore, when e < 0.4 in the composition formula, it can be seen that a highly isotropic nanocrystalline alloy thin band can be obtained by setting the tension to 10 MPa to 160 MPa and the temperature Ta of the heating element to the range of Tx1 + 85°C to Tx1 + 140°C.

[0073] In this example, Lμm / Wμm is within the range of 0.3 to 1.7. Also, LE / WE is within the range of 0.2 to 1.8. Furthermore, LB80 / WB80 is within the range of 0.3 to 1.7.

[0074] In Tables 2 and 3, for materials C, E, and F, where the composition formula e ≥ 0.4, good values ​​were obtained for Ta-Tx1 at 77°C, 81°C, and 83°C. When the composition formula e ≥ 0.4, it can be seen that a highly isotropic nanocrystalline alloy thin strip can be obtained by setting the tension to 10 MPa to 160 MPa and the heating element temperature Ta to the range of Tx1 + 60°C to Tx1 + 100°C. In this case, the heating rate was 100 K / second or more. In this example, Lμm / Wμm is within the range of 0.3 to 1.7. Also, LE / WE is within the range of 0.2 to 1.8. Furthermore, LB80 / WB80 is within the range of 0.3 to 1.7.

[0075] Furthermore, as shown in Table 4, the nanocrystalline alloy thin strips of the embodiments of this disclosure have an iron loss of 10 W / kg or less, and low-loss nanocrystalline alloy thin strips with an iron loss of 25 W / kg or less have been obtained. In addition, a saturation magnetostriction of 15 ppm or less has been obtained, and nanocrystalline alloy thin strips with a saturation magnetostriction of 30 ppm or less have been obtained.

[0076] [Saturated magnetostriction] Saturated magnetostriction was measured by applying a 5 kOe magnetic field to a sample with strain gauges manufactured by Kyowa Denki attached using an electromagnet. The electromagnet was rotated 360°, changing the direction of the magnetic field applied to the sample by 360°. The maximum change in the expansion and contraction of the sample was measured from the change in the electrical resistance of the strain gauges. Saturated magnetostriction was defined as 2 / 3 × maximum change.

[0077] Table 4 shows the self-heating. This self-heating is the value (temperature of the alloy strip - Ta) when the temperature of the alloy strip rises above the heating temperature (temperature of the heating element Ta) due to the heat generated by crystallization. According to the examples of this disclosure, it is possible to control the temperature to a range that does not exceed Ta + 50°C.

[0078] [Example 2] Using materials B and G shown in Table 1, nanocrystalline alloy strips were fabricated in the same manner as in Example 1. The tension, heating element temperature Ta, heating rate of the strip, contact time with the heating element, crystal volume fraction, and average grain size are shown in Table 5. Here, the average grain size refers to the average grain size of the nanocrystals. The average grain size of the nanocrystals was calculated from Scherrer's equation (Equation 1) described above. In the embodiments of this disclosure, it can be seen that the average grain size is 30 nm or less. Therefore, the nanocrystalline alloy strip of this disclosure has a structure in which crystal grains with an average grain size of 30 nm or less exist in the amorphous phase.

[0079] Furthermore, in Table 5, the crystal volume fraction represents the volume fraction of crystal grains (nanocrystals) with an average particle size of 30 nm or less. The parts other than the nanocrystals are amorphous. The crystalline volume fraction is the ratio of the integrated intensity of the nanocrystal to the integrated intensity of (crystal + amorphous). The integrated intensities of the peaks shown by the nanocrystal and the halo patterns shown by the amorphous material are obtained by peak decomposition using a pseudo-Voigt function for the X-ray diffraction pattern. If Ic is the sum of the integrated intensities of all the peaks shown by the nanocrystal and Ia is the sum of the integrated intensities of all the halo patterns shown by the amorphous material, then the volume fraction V can be obtained from the following equation (Equation 2).

[0080]

number

[0081] [Table 5]

[0082] The heating rate for each sample was 100 K / second or higher, as shown in Table 5.

[0083] [Example 3] Using material B shown in Table 1, nanocrystalline alloy strips were fabricated in the same manner as in Example 1. In this example, the heating element had a structure with two heating sections. For example, the heating element (heating plate) 22 shown in Figure 1 had a structure that allowed for two temperature settings, with the temperature of the first section set to T1 and the temperature of the second section set to T2. The higher of T1 and T2 was defined as Ta. The tension of each sample, the temperatures of the heating element T1, T2, and Ta, and the transport speed of the alloy strip are shown in Table 6. The characteristics of each sample manufactured under these conditions are shown in Table 7. When a nanocrystalline alloy strip is manufactured as a heating element with a structure having multiple heating sections, a nanocrystalline alloy strip with higher isotropy is obtained.

[0084] [Table 6]

[0085] [Table 7]

[0086] As described above, according to this disclosure, a method for producing nanocrystalline alloy thin strips that have excellent magnetic properties and isotropy can be obtained, and a nanocrystalline alloy thin strip with excellent magnetic properties and isotropy can be obtained.

Claims

1. In a method for producing a nanocrystalline alloy strip having a structure in which crystal grains with an average particle size of 30 nm or less exist in the amorphous phase, the compositional formula is (Fe1-xAx)aSibBcCudMe, where A is at least one of Ni and Co, and M is one or more selected from the group consisting of Nb, Mo, V, Zr, Hf and W, and atomic percent values ​​are 81 ≤ a ≤ 86, 0.15 ≤ b ≤ 5.0, 12.5 ≤ c ≤ 15, 0 ≤ d ≤ 1.0, 0 ≤ e ≤ 1.0, and 0 ≤ x ≤ 0.1, the alloy strip is heat-treated, While applying a tension of 10 MPa to 160 MPa to the alloy strip, the alloy strip is transported and brought into contact with a heating element, and the alloy strip is heat-treated so that the heating rate of the alloy strip is 100 K / second or more. A method for manufacturing a nanocrystalline alloy thin strip, wherein, when the crystallization temperature of the alloy thin strip is Tx1, the temperature Ta of the heating element is in the range of Tx1 + 85°C to Tx1 + 140°C when e < 0.4 in the composition formula, and in the range of Tx1 + 60°C to Tx1 + 100°C when e ≥ 0.4 in the composition formula.

2. A method for manufacturing a nanocrystalline alloy thin band according to claim 1, wherein the saturation magnetic flux density Bs of the nanocrystalline alloy thin band is 1.6 T or more, and when the remanent magnetic flux density Br in the longitudinal direction of the nanocrystalline alloy thin band (maximum measured magnetic field Hm = 80 A / m) is LBr, and the remanent magnetic flux density Br in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is WBr, LBr / WBr is 0.2 to 1.

8.

3. A method for manufacturing a nanocrystalline alloy thin band according to claim 1 or claim 2, wherein the maximum permeability μm of the nanocrystalline alloy thin band is 4000 or more, and when the maximum permeability μm in the longitudinal direction of the nanocrystalline alloy thin band (maximum measurement magnetic field Hm = 80 A / m) is L μm, and the maximum permeability μm in the width direction perpendicular to the longitudinal direction (maximum measurement magnetic field Hm = 80 A / m) is W μm, L μm / W μm is 0.3 to 1.

7.

4. A method for manufacturing a nanocrystalline alloy thin band according to claim 1 or claim 2, wherein the anisotropy energy E (maximum measurement magnetic field Hm = 800 A / m) of the nanocrystalline alloy thin band is 400 J / m³ or less, and when the anisotropy energy E (maximum measurement magnetic field Hm = 800 A / m) in the longitudinal direction of the nanocrystalline alloy thin band is denoted as LE, and the anisotropy energy E (maximum measurement magnetic field Hm = 800 A / m) in the width direction perpendicular to the longitudinal direction is denoted as WE, then LE / WE is 0.2 to 1.

8.

5. A method for manufacturing a nanocrystalline alloy thin strip according to claim 1 or claim 2, wherein the magnetic flux density B80 when a magnetic field of 80 A / m is applied to the nanocrystalline alloy thin strip is 0.4 T or more, and when the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin strip is denoted as LB80, and the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction is denoted as WB80, then LB80 / WB80 is 0.3 to 1.

7.

6. A method for producing a nanocrystalline alloy strip according to claim 1 or claim 2, wherein the temperature of the alloy strip is controlled so as not to exceed Ta + 50°C during heat treatment of the alloy strip.

7. The method for manufacturing a nanocrystalline alloy thin strip according to claim 1 or claim 2, wherein the heating element is composed of a plurality of heating sections with different temperatures, and the temperature of the heating section with the highest temperature among the plurality of heating sections is the temperature Ta.

8. This is a nanocrystalline alloy thin strip having a structure in which crystal grains with an average particle size of 30 nm or less exist in the amorphous phase. The nanocrystalline alloy thin strip is represented by the compositional formula (Fe1-xAx)aSibBcCudMe, where A is at least one of Ni and Co, and M is one or more selected from the group consisting of Nb, Mo, V, Zr, Hf, and W, with atomic percentages of 81≦a≦86, 0.15≦b≦5.0, 12.5≦c≦15, 0≦d≦1.0, 0≦e≦1.0, and 0≦x≦0.1, and the saturation magnetic flux density Bs is 1.6T or higher. A nanocrystalline alloy thin strip in which the remanent magnetic flux density Br in the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is LBr, and the remanent magnetic flux density Br in the width direction perpendicular to the longitudinal direction (maximum measured magnetic field Hm = 80 A / m) is WBr, wherein LBr / WBr is 0.2 to 1.

8.

9. The nanocrystalline alloy thin band according to claim 8, wherein the maximum permeability μm of the nanocrystalline alloy thin band is 4000 or more, and when the maximum permeability μm in the longitudinal direction of the nanocrystalline alloy thin band (maximum measurement magnetic field Hm = 80 A / m) is L μm, and the maximum permeability μm in the width direction perpendicular to the longitudinal direction (maximum measurement magnetic field Hm = 80 A / m) is W μm, L μm / W μm is 0.3 to 1.

7.

10. The nanocrystalline alloy thin band according to claim 8 or claim 9, wherein the anisotropy energy E (maximum measurement magnetic field Hm = 800 A / m) of the nanocrystalline alloy thin band is 400 J / m³ or less, and when the anisotropy energy E (maximum measurement magnetic field Hm = 800 A / m) in the longitudinal direction of the nanocrystalline alloy thin band is denoted as LE, and the anisotropy energy E (maximum measurement magnetic field Hm = 800 A / m) in the width direction perpendicular to the longitudinal direction is denoted as WE, then LE / WE is 0.2 to 1.

8.

11. The nanocrystalline alloy thin strip according to claim 8 or claim 9, wherein the magnetic flux density B80 when a magnetic field of 80 A / m is applied to the nanocrystalline alloy thin strip is 0.4 T or more, and when the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the longitudinal direction of the nanocrystalline alloy thin strip is denoted as LB80, and the magnetic flux density B80 when a magnetic field of 80 A / m is applied in the width direction perpendicular to the longitudinal direction is denoted as WB80, then LB80 / WB80 is 0.3 to 1.

7.

12. A nanocrystalline alloy strip according to claim 8 or claim 9, having a thickness of 15 μm or more and a width of 5 mm or more.

13. A nanocrystalline alloy thin strip according to claim 8 or claim 9, wherein the packing density is 86% or more.

14. The nanocrystalline alloy thin band according to claim 8 or claim 9, wherein the saturation magnetostriction is 30 ppm or less.

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