Soft magnetic alloy, soft magnetic alloy strip, manufacturing method thereof, magnetic core and component

Abstract

The present invention provides a soft magnetic alloy with high saturation magnetic flux density and low iron loss, a soft magnetic alloy strip composed of the alloy and a method for manufacturing the same, and a magnetic core and a component using the soft magnetic alloy strip. a Si b B c Cu d M e It means that M is at least one element selected from Nb, Mo, V, Zr, Hf, and W, and in terms of atomic %, 82.5≦a≦86, 0.3≦b≦3, 12.5≦c≦15.0, 0.05≦d≦0.9, and 0≦e<0.4. The soft magnetic alloy has a structure in which grains with a particle size of less than 60 nm exist in the amorphous phase.

Description

Technical Field

[0001] The present disclosure relates to a soft magnetic alloy, a soft magnetic alloy ribbon, a method for manufacturing the same, a magnetic core, and a component. Background Art

[0002] Soft magnetic alloys with nanocrystalline structures can obtain excellent magnetic properties and are used in transformers, electronic components, motors, etc. These transformers, electronic components, motors, etc. need to be miniaturized and highly efficient. Therefore, for the soft magnetic alloys used in these components (transformers, electronic components, motors, etc.), it is necessary to further improve the properties. As the characteristics required for this soft magnetic alloy, there are high saturation flux density and low iron loss. Among these components, with the high frequency of semiconductors, etc., many are promoting miniaturization by increasing the operating frequency. Fe-based amorphous alloys and Fe-based nanocrystalline alloys with low iron loss have attracted much attention. In order to popularize them commercially, soft magnetic alloys with excellent price, productivity and heat treatment properties are required.

[0003] Patent Document 1 describes a method for producing a soft magnetic material having both high saturation magnetization and low coercive force by: 100-a-b-c B a Cu b M' c An alloy having an amorphous phase, in which M' is at least one element selected from Nb, Mo, Ta, W, Ni and Co and satisfies the following conditions: 10≦a≦16, 0<b≦2 and 0≦c≦8, is heated at a heating rate of 10°C / s or higher and maintained at a temperature above the crystallization start temperature and below the formation start temperature of Fe-B compounds for 0 to 80 seconds.

[0004] Patent Document 2 discloses a soft magnetic alloy characterized by having 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 e The soft magnetic alloy is described as having a composition wherein X1 is at least one selected from the group consisting of Co and Ni, X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Bi, N, O, and rare earth elements, M is at least one 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, and 0 ≤ α + β ≤ 0.50. This soft magnetic alloy is described as having a high saturation magnetic flux density, low coercivity, and high permeability μ'.

[0005] Patent Document 3 discloses a soft magnetic alloy composed of Fe 100-x-y-z A x M y X z Indicates that, here, 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, and W, and X is at least one element selected from B and Si. In terms of atomic %, 0<x≦5, 0.4≦y<2.5, 10≦z≦20, and the saturation flux density of the soft magnetic alloy is greater than 1.7 T and the coercive force is less than 15 A / m.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2018 / 025931

[0009] Patent Document 2: Japanese Patent Application Publication No. 2019-94532

[0010] Patent Document 3: International Publication No. 2008 / 133301 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] Patent Document 1 discloses a soft magnetic material having high saturation magnetization. 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.

[0013] The soft magnetic alloy described in Patent Document 2 has a relatively low saturation magnetic flux density (Bs). Generally, increasing the Fe content increases the saturation magnetic flux density, but in Example 6, which has an Fe content of 84 at%, the saturation magnetic flux density (Bs) is 1.76 T. Furthermore, it is believed that the high B content results in insufficient heat treatability.

[0014] The soft magnetic alloy described in Patent Document 3 contains a large amount of expensive M elements such as Nb, which increases its price. Furthermore, it exhibits anisotropy in the casting direction. The ratio of the magnetic flux density when an 80 A / m magnetic field is applied in the casting direction to the magnetic flux density when an 80 A / m magnetic field is applied in a direction perpendicular to the casting direction is large, making it unsuitable for applications requiring isotropy.

[0015] The present disclosure aims to provide a soft magnetic alloy having high saturation magnetic flux density and low iron loss, a soft magnetic alloy ribbon composed of the soft magnetic alloy and a method for producing the same, and a magnetic core and a component using the soft magnetic alloy ribbon.

[0016] Methods for solving problems

[0017] Specific methods for solving the above-mentioned problems include the following aspects.

[0018] <1> A soft magnetic alloy having the composition formula Fe a Si b B c Cu d M e It indicates that M is at least one element selected from Nb, Mo, V, Zr, Hf, and W, and in terms of atomic %: 82.5≦a≦86, 0.3≦b≦3, 12.5≦c≦15.0, 0.05≦d≦0.9, and 0≦e<0.4.

[0019] The soft magnetic alloy has a structure in which crystal grains having a particle size of 60 nm or less exist in an amorphous phase.

[0020] <2> The soft magnetic alloy according to <1>, wherein 83≦a≦86, 0.3≦b≦2, 0.4≦d≦0.9, and 0≦e≦0.3.

[0021] <3> The soft magnetic alloy according to <1> or <2>, wherein 13.0≦c≦14.0.

[0022] <4> The soft magnetic alloy according to any one of <1> to <3>, wherein a portion of Fe is substituted with at least one element of Co and Ni within a range of up to 6 atomic %.

[0023] <5> The soft magnetic alloy according to any one of <1> to <4>, wherein the saturation magnetic flux density is 1.75 T or more.

[0024] <6> The soft magnetic alloy according to any one of <1> to <5>, wherein the density is 7.45 g / cm 3 above.

[0025] <7> A soft magnetic alloy strip, the alloy composition of which is composed of the formula Fe a Si b B c Cu d M e It indicates that M is at least one element selected from Nb, Mo, V, Zr, Hf, and W, and in terms of atomic %: 82.5≦a≦86, 0.3≦b≦3, 12.5≦c≦15.0, 0.05≦d≦0.9, and 0≦e<0.4.

[0026] The soft magnetic alloy ribbon has a structure in which grains with a grain size of 60 nm or less exist in an amorphous phase, a saturation magnetic flux density of 1.75 T or more, and an iron loss of 25 W / kg or less at 1 kHz and 1 T.

[0027] <8> The soft magnetic alloy strip according to <7>, wherein the density is 7.45 g / cm 3 above.

[0028] <9> The soft magnetic alloy strip according to <7> or <8>, wherein the area ratio is 86% or more.

[0029] <10> The soft magnetic alloy strip according to any one of <7> to <9>, wherein the thickness is 25 μm or more.

[0030] <11> The soft magnetic alloy strip according to any one of <7> to <10>, wherein the area ratio is 88% or more.

[0031] <12> A soft magnetic alloy strip according to any one of <7> to <11>, wherein the ratio (L / W) of the magnetic flux density L when a magnetic field of 80 A / m is applied in the casting direction of the soft magnetic alloy strip to the magnetic flux density W when a magnetic field of 80 A / m is applied in a direction orthogonal to the casting direction of the soft magnetic alloy strip is 0.7 to 1.3.

[0032] <13> The soft magnetic alloy strip according to any one of <7> to <12>, wherein the saturation magnetostriction is 20 ppm or less.

[0033] <14> The soft magnetic alloy strip according to any one of <7> to <13>, wherein 83≦a≦86, 0.3≦b≦2, 0.4≦d≦0.9, 0≦e≦0.3, and the saturation magnetic flux density is 1.77 T or more.

[0034] <15> The soft magnetic alloy strip according to any one of <7> to <14>, wherein 13.0≦c≦14.0.

[0035] <16> The soft magnetic alloy strip according to any one of <7> to <15>, wherein a portion of Fe is substituted with at least one element of Co and Ni within a range of up to 6 atomic %.

[0036] <17> A method for manufacturing a soft magnetic alloy strip, which is a method for manufacturing a soft magnetic alloy strip as described in any one of <7> to <16>, comprising a strip manufacturing process of spraying an alloy melt onto a rotating cooling roller and cooling the alloy melt on the cooling roller to obtain an alloy strip, wherein the outer peripheral portion of the cooling roller is composed of a Cu alloy having a thermal conductivity of 120 W / (m·K) or more.

[0037] <18> A method for producing a soft magnetic alloy ribbon, comprising heat-treating the alloy ribbon to produce a soft magnetic alloy ribbon having a structure in which grains having a particle size of 60 nm or less are present in an amorphous phase, wherein, during the heat treatment, temperature T1 is set at a temperature 10 to 140°C lower than the bccFe crystallization start temperature, and temperature T2 is set at a temperature 30 to 120°C lower than the FeB precipitation start temperature.

[0038] Heating from room temperature to temperature T1 at a heating rate of 50°C / s or more,

[0039] Heating from temperature T1 to temperature T2 at a heating rate slower than the heating rate to temperature T1 and less than 400°C / second,

[0040] Cool down after reaching temperature T2, or

[0041] After reaching temperature T2, the temperature is maintained at a temperature between temperature T2-50°C and temperature T2 for 0.5 to 60 seconds, and then cooled.

[0042] <19> According to the method for manufacturing a soft magnetic alloy strip described in <18>, the alloy strip before heat treatment is obtained by spraying the alloy melt onto a rotating cooling roller and cooling the alloy melt on the cooling roller, and the outer periphery of the cooling roller is composed of a Cu alloy with a thermal conductivity of more than 120 W / (m·K).

[0043] <20> The method for producing a soft magnetic alloy strip according to <18> or <19>, wherein the density of the alloy strip before the heat treatment is M1 and the density of the alloy strip after the heat treatment is M2, and M2 / M1 is 1.005 or more.

[0044] <21> The method for producing a soft magnetic alloy strip according to any one of <18> to <20>, wherein the alloy composition of the soft magnetic alloy strip is composed of the composition formula Fe a Si b B c Cu d M eIt indicates that M is at least one element selected from Nb, Mo, V, Zr, Hf, and W, and in terms of atomic %, 82.5≦a≦86, 0.3≦b≦3, 12.5≦c≦15.0, 0.05≦d≦0.9, and 0≦e<0.4.

[0045] <22> A magnetic core formed using the soft magnetic alloy strip according to any one of <7> to <16>.

[0046] <23> A component comprising the magnetic core according to <22> and a winding.

[0047] Effects of the Invention

[0048] According to one embodiment of the present disclosure, a soft magnetic alloy and a soft magnetic alloy ribbon having high saturation magnetic flux density and low iron loss can be obtained. Furthermore, according to one embodiment of the present disclosure, a soft magnetic alloy ribbon having isotropy can be obtained. Furthermore, according to magnetic cores and components using the soft magnetic alloy ribbon according to one embodiment of the present disclosure, magnetic cores and components having high saturation magnetic flux density and low iron loss can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Graphs showing an example of a heat treatment mode according to an embodiment of the present disclosure and a comparative example of the heat treatment mode.

[0050] Figure 2 The holding temperature of the sample subjected to heat treatment in the heat treatment mode of the comparative example and B 8000 , and iron loss correlation diagram.

[0051] Figure 3 The holding temperature and B of the heat-treated sample in the heat treatment mode of one embodiment of the present disclosure are 8000 , and iron loss correlation diagram. DETAILED DESCRIPTION

[0052] The following describes the embodiments of the present disclosure in detail. The present disclosure is not limited to the following embodiments and can be implemented with appropriate modifications within the scope of the purpose of the present disclosure.

[0053] In this disclosure, the numerical range represented by "~" represents a range that includes the numerical values ​​recorded before and after "~" as the lower limit and upper limit, respectively. In the numerical ranges recorded in sections in this disclosure, the upper limit or lower limit recorded in a certain numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical ranges recorded in this disclosure, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the values ​​shown in the examples.

[0054] In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect.

[0055] The soft magnetic alloy disclosed herein is composed of the formula Fe a Si b B c Cu d M e It indicates that M is at least one element selected from Nb, Mo, V, Zr, Hf, and W, and in terms of atomic %: 82.5≦a≦86, 0.3≦b≦3, 12.5≦c≦15.0, 0.05≦d≦0.9, and 0≦e<0.4.

[0056] The soft magnetic alloy has a structure in which crystal grains having a particle size of 60 nm or less exist in an amorphous phase.

[0057] First, the configuration of the present disclosure will be described in detail below.

[0058] The Fe (iron) content is 82.5% to 86% in atomic %.

[0059] By setting the Fe content to 82.5% or more, the saturation magnetic flux density can be set to 1.75 T or more. The Fe content is preferably 83% or more, more preferably 83.5% or more, and even more preferably 84% or more.

[0060] If the Fe content exceeds 86%, amorphization becomes difficult, so the Fe content is set to 86% or less, preferably 85.5% or less.

[0061] The Si (silicon) content is not less than 0.3% and not more than 3% in terms of atomic %.

[0062] The inclusion of Si allows for the formation of a SiO2 oxide film tens of nanometers thick on the alloy surface. This improves the corrosion resistance of the soft magnetic alloy. To achieve this improved corrosion resistance, the Si content should be 0.3% or more, preferably 1.0% or more.

[0063] If the Si content exceeds 3%, it is difficult to achieve a saturation magnetic flux density exceeding 1.75 T, and it is also difficult to increase the thickness of the soft magnetic alloy ribbon. Therefore, the Si content is set to 3% or less. It is preferably 2% or less, and more preferably 1.4% or less.

[0064] The content of B (boron) is not less than 12.5% ​​and not more than 15.0% by atomic %.

[0065] If the B content is less than 12.5%, it becomes difficult to form an amorphous structure, so the B content is set to 12.5% ​​or more, preferably 13.0% or more, and more preferably 13.5% or more.

[0066] If the B content exceeds 15.0%, the difference between the bccFe (αFe) crystallization start temperature and the FeB precipitation start temperature decreases, narrowing the range of the optimal heat treatment temperature. Consequently, it becomes difficult to achieve a uniform and fine nanocrystalline structure that achieves an iron loss of 25 W / kg or less at 1 T and 1 kHz. Therefore, the B content is set to 15.0% or less. It is preferably 14.5% or less, more preferably 14.4% or less, and even more preferably 14.0% or less.

[0067] The Cu (copper) content is 0.05% to 0.9% in atomic %.

[0068] If the Cu content is less than 0.05%, it is difficult to obtain a uniform and fine nanocrystalline structure that can achieve an iron loss of 25 W / kg or less at 1 T and 1 kHz. Therefore, the Cu content is set to 0.05% or more. It is preferably 0.2% or more, more preferably 0.4% or more, and even more preferably 0.5% or more.

[0069] If the Cu content exceeds 0.9%, the alloy tends to become brittle, making it difficult to increase the thickness of the soft magnetic alloy ribbon. Therefore, the Cu content is set to 0.9% or less, preferably 0.7% or less, and more preferably 0.6% or less.

[0070] The element M is at least one element selected from Nb, Mo, V, Zr, Hf, and W, and its content is 0% or more and less than 0.4% in terms of atomic %.

[0071] The M element can be 0%, but its inclusion shifts the precipitation start temperature of the FeB compound, which significantly degrades magnetic properties, toward higher temperatures. This widens the difference between the bccFe (αFe) crystallization start temperature and the FeB precipitation start temperature, expanding the optimal heat treatment temperature range and easing heat treatment conditions. The M element is preferably 0.1% or higher, and more preferably 0.15% or higher.

[0072] Element M is expensive, so its price increases with increasing its content. Therefore, a low content is preferred. Therefore, the content of element M is set to less than 0.4%, preferably 0.3% or less, and more preferably 0.25% or less.

[0073] The soft magnetic alloy disclosed herein may replace a portion of Fe with at least one of Co and Ni within a range of up to 6 atomic %. The soft magnetic alloy disclosed herein may also replace a portion of Fe with at least one of Co and Ni within a range of up to 5 atomic %.

[0074] The soft magnetic alloy disclosed herein may contain C (carbon), and the content of C is preferably 1% by mass or less.

[0075] The soft magnetic alloy disclosed herein contains the following components:a Si b B c Cu d M e In addition to the elements indicated above, impurities other than the above-mentioned Co, Ni, and C may be contained.

[0076] Impurities include elements other than those listed above. Examples include sulfur (sulfur), oxygen (oxygen), nitrogen (nitrogen), chromium, manganese, phosphorus (P), titanium (Ti), and aluminum (Al). For example, the sulfur content is preferably 200 mass ppm or less, the oxygen content is preferably 5000 mass ppm or less, and the nitrogen content is preferably 1000 mass ppm or less. The total impurity content is preferably 0.5 mass % or less. Furthermore, elements equivalent to impurities may be added as long as they are within the above ranges.

[0077] The soft magnetic alloy disclosed herein has a structure in which the crystal grains below the particle diameter 60nm are present in the amorphous phase. The structure in which the crystal grains below the particle diameter 60nm are present in the amorphous phase is also referred to as nanocrystalline structure. In addition, the crystals below the particle diameter 60nm are also referred to as nanocrystals.

[0078] One characteristic of the soft magnetic alloy disclosed herein is that it has a nanocrystalline structure.

[0079] In addition, in the soft magnetic alloy disclosed herein, the proportion of nanocrystals is preferably 50% or more by volume. This volume ratio can be estimated by, for example, observing a cross section of the alloy using a transmission electron microscope (TEM) to observe the nanocrystals and amorphous phase. In other words, whether the nanocrystal ratio is 50% or more can be determined from the observed image.

[0080] Furthermore, when observing a cross section of the alloy, it is preferred that the area ratio of grains having a crystal grain size of 60 nm or less in a specific field of view area is 50% or more (the value when the specific field of view area is set to 100%). The soft magnetic alloy disclosed herein has crystal grains having a crystal grain size of 60 nm or less and an amorphous phase, and the area ratio of crystal grains having a crystal grain size of 60 nm or less is preferably 50% or more. For example, the area ratio can be determined by observing the crystal grains and the amorphous phase by observing the cross section of the alloy using a transmission electron microscope (TEM).

[0081] In the soft magnetic alloy disclosed herein, the saturation magnetic flux density is preferably not less than 1.75 T. In addition, the saturation magnetic flux density of the soft magnetic alloy disclosed herein is preferably not less than 1.77 T.

[0082] The density of the soft magnetic alloy disclosed in the present invention is preferably 7.45 g / cm 3 Above. Through density is 7.45g / cm 3 As a result, the volume ratio of the nanocrystals is increased, and the saturation magnetic flux density is increased.

[0083] In the soft magnetic alloy disclosed herein, the iron loss at 1 kHz and 1 T is preferably 25 W / kg or less. Furthermore, the iron loss is preferably 18 W / kg or less. Furthermore, the iron loss is preferably 15 W / kg or less.

[0084] Furthermore, the saturation magnetostriction of the soft magnetic alloy disclosed herein is preferably 20 ppm or less, thereby making it easier to obtain isotropy.

[0085] According to the soft magnetic alloy disclosed herein, a soft magnetic alloy having high saturation magnetic flux density and low iron loss can be obtained.

[0086] The soft magnetic alloy disclosed herein can be in the form of an alloy ribbon as described below, a pulverized powder obtained by pulverizing an alloy ribbon, or a powder produced by an atomization method or the like.

[0087] The soft magnetic alloy ribbon disclosed herein can be obtained by spraying an alloy melt having the above-mentioned soft magnetic alloy composition onto a rotating cooling roll, rapidly solidifying the alloy ribbon on the cooling roll to obtain the alloy ribbon, and then heat-treating the alloy ribbon.

[0088] The alloy melt can be prepared by combining various element sources (pure iron, ferroboron, ferrosilicon, etc.) to form a target alloy composition, heating them to above their melting point in an induction heating furnace, and melting them to form an alloy melt.

[0089] The alloy melt can be sprayed from a slit-shaped nozzle of a predetermined shape onto a rotating cooling roll, where it is rapidly solidified to produce an alloy ribbon. The cooling roll can have an outer diameter of 350 to 1000 mm, a width of 100 to 400 mm, and a circumferential speed of 20 to 35 m / s. The cooling roll is preferably equipped with a cooling mechanism (e.g., water cooling) to suppress temperature increases in the outer periphery.

[0090] Furthermore, the outer periphery of the cooling roller is preferably composed of a Cu alloy with a thermal conductivity of 120 W / (m·K) or higher. By increasing the thermal conductivity of the outer periphery to 120 W / (m·K) or higher, the cooling rate during casting of the alloy strip from the molten alloy can be increased. This prevents embrittlement of the alloy strip, increasing its thickness. Furthermore, by suppressing surface crystallization during casting, grain coarsening during heat treatment can be suppressed, reducing iron loss.

[0091] Furthermore, the thermal conductivity of the outer periphery of the cooling roller is preferably set to 150 W / (m·K) or higher, and more preferably to 180 W / (m·K) or higher. In particular, when the thickness of the soft magnetic alloy strip is 30 μm or higher, the thermal conductivity of the outer periphery is preferably set to 150 W / (m·K) or higher.

[0092] It should be noted that the outer periphery of the cooling roller is the portion in contact with the alloy melt, and its thickness may be approximately 5 to 15 mm. The inner side may be made of a structural material that maintains the roller structure.

[0093] A soft magnetic alloy ribbon having a nanocrystalline structure can be obtained by rapidly solidifying an alloy melt on a cooling roller to produce an alloy ribbon, and then subjecting the alloy ribbon to a heat treatment. The heat treatment is preferably performed while raising the temperature to a temperature above the bccFe (αFe) crystallization start temperature, while adjusting the temperature so that the alloy ribbon does not reach the FeB precipitation start temperature.

[0094] Conventional heat treatment of alloy strips is generally performed by heating from room temperature to a temperature 30 to 100°C lower than the FeB precipitation starting temperature at a heating rate of 10°C / s or more, and then holding the temperature for several seconds.

[0095] However, in alloy ribbons where the amount of Cu and Nb has been reduced and the amount of Fe has been increased to achieve a high saturation magnetic flux density, the temperature difference between the crystallization start temperature of bccFe (αFe) and the precipitation start temperature of FeB becomes smaller, and the range of the most suitable heat treatment temperature (maximum temperature) becomes very narrow. This creates the problem of having to adjust the heat treatment temperature (maximum temperature) within a very narrow temperature range. In addition, for the wide alloy ribbons manufactured in actual production, cooling in the width direction, uneven thickness, and uneven composition between batches occur, making it even more difficult to adjust the heat treatment temperature within a narrow temperature range, and there is a problem of difficulty in performing uniform heat treatment.

[0096] In the heat treatment of the alloy strip disclosed herein, it is preferred to set a temperature T1 that is 10 to 140°C lower than the bccFe (αFe) crystallization start temperature, and set a temperature T2 that is 30 to 120°C lower than the FeB precipitation start temperature. The strip is heated from room temperature to T1 at a heating rate of 50°C / second or higher, and then heated from T1 to T2 at a heating rate slower than the heating rate to T1 and less than 400°C / second, and then cooled. After reaching T2, the strip may be cooled directly, or after reaching T2, the strip may be held at a temperature between T2 and 50°C and T2 for 0.5 to 60 seconds, and then cooled. T1 may be a temperature 10 to 120°C lower than the bccFe (αFe) crystallization start temperature. T2 may be a temperature 10 to 120°C lower than the FeB precipitation start temperature, or a temperature 10 to 100°C lower than the FeB precipitation start temperature.

[0097] Here, the heating rate is the average heating rate between the temperatures. For example, the heating rate from room temperature to temperature T1 can be calculated using the time (seconds) from room temperature to temperature T1 as the denominator and the temperature obtained by subtracting room temperature (25°C) from temperature T1 as the numerator.

[0098] According to the heat treatment method of the alloy strip disclosed in the present invention, a soft magnetic alloy strip having a high saturation magnetic flux density and low iron loss can be stably produced.

[0099] It should be noted that the heat treatment of the alloy strip disclosed herein may also be performed after the alloy strip is processed into a magnetic core shape. The magnetic core shape refers to a strip processed into a magnetic core shape by pressing or the like, a magnetic core formed by stacking such core-shaped strips, or a wound magnetic core formed by winding a strip.

[0100] Figure 1 An example of a heat treatment mode according to an embodiment of the present disclosure and a comparative example of a heat treatment mode are shown. Figure 2 (Comparative example of heat treatment mode), Figure 3 (One embodiment of the present disclosure) shows the magnetic flux density B when the magnetic field of 8000 A / m is applied, with the holding temperature at this time as the X-axis. 8000 The Y-axis shows the correlation between the iron loss (CL) at 1T and 1kHz. Table 1 (comparative example of heat treatment mode) and Table 2 (an embodiment of the present disclosure) show the heat treatment conditions and B at this time. 8000 The alloy composition of this sample is the same as that of No. 3 in Table 3 described below, with a bccFe (αFe) crystallization start temperature of 460°C and a FeB precipitation start temperature of 580°C.

[0101] like Figure 2 As shown in Table 1, in the heat treatment mode of Comparative Examples C1 to C5, as the holding temperature increases from 470°C to 500°C, B 8000 The iron loss at 500℃ is significantly higher than that at 470℃~490℃. 8000 When the holding temperature exceeds 1.82T, the iron loss increases rapidly, and the temperature range in which both high saturation magnetic flux density and low iron loss can be achieved is very narrow.

[0102] On the other hand, Figure 3 As shown in Table 2, in the heat treatment patterns of Examples E1 to E4 of the present disclosure, T1 for E1, E2, E3, and E4 is 100°C, 90°C, 80°C, and 50°C lower than the bccFe(αFe) crystallization start temperature (460°C), respectively. T2 for E1, E2, E3, and E4 is 90°C, 80°C, 70°C, and 40°C lower than the FeB precipitation start temperature (580°C), respectively. The holding time for T1 in the heat treatment patterns of E1 to E4 is 0 seconds, and the holding time for T2 is 0.5 seconds.

[0103] In the heat treatment mode of one embodiment E1 to E4 of the present disclosure, when the holding temperature of T2 is 490°C to 540°C, B 8000It shows a high and almost stable value of 1.82T to 1.83T, and the iron loss also shows a nearly constant value between 9.8W / kg and 11W / kg. 8000 The temperature range of the holding temperature where the iron loss is below 25W / kg exceeds 1.82T exists above 50°C, and high saturation magnetic flux density and low iron loss can be stably obtained. The sample obtained by the heat treatment mode of one embodiment of the present disclosure has a structure in which grains with a particle size of 60nm or less exist in the amorphous phase. In addition, cross-sectional observations were performed on each sample, and the results showed that the area ratio of grains with a crystal particle size of 60nm or less was 50% or more (the value when the observation field area is set to 100%). It should be noted that, Figure 3 , in Table 2, the temperature is maintained at T2.

[0104] [Table 1]

[0105]

[0106] [Table 2]

[0107]

[0108] From the perspectives of heat treatment productivity, generated nucleus density, and suppression of grain size coarsening, a faster heating rate during heat treatment is preferred. However, if the heating rate is too fast, crystallization occurs in a shorter period of time, the calorific value per unit time increases, and the temperature of the alloy strip rises excessively, reaching the FeB precipitation starting temperature, inducing FeB precipitation. Alternatively, even if the FeB precipitation starting temperature is not reached, the temperature rises, accelerating the growth of grain size and deteriorating the iron loss.

[0109] Therefore, in the heat treatment disclosed herein, the heating rate is controlled from the first temperature T1 to suppress FeB precipitation. Furthermore, controlling the heating rate can also suppress crystal growth and reduce crystal unevenness. This can improve shape defects that occur during heat treatment, such as increased iron loss and wrinkles caused by differential shrinkage.

[0110] It should be noted that the faster the heating rate from room temperature to temperature T1, the better, for example, 50°C / second or higher. This can be selected based on equipment capabilities. It is preferably 200°C / second or higher, more preferably 300°C / second or higher, and even more preferably 400°C / second or higher.

[0111] Furthermore, the heating rate from temperature T1 to temperature T2 is 400°C / second or less, preferably 200°C / second or less, more preferably 150°C / second or less, and even more preferably 100°C / second or less. Furthermore, the heating rate from temperature T1 to temperature T2 is preferably 10°C / second or more, more preferably 30°C / second or more, and even more preferably 50°C / second or more.

[0112] When the heating rate from room temperature to temperature T1 is 200°C / s or more, the heating rate from temperature T1 to temperature T2 is lower than 200°C / s, preferably 150°C / s or less, and more preferably 100°C / s or less.

[0113] When the heating rate from temperature T1 to temperature T2 is 300°C / second or more, the heating rate from temperature T1 to temperature T2 is less than 300°C / second, preferably less than 200°C / second, more preferably less than 150°C / second, and most preferably less than 100°C / second.

[0114] In the soft magnetic alloy thin strip disclosed herein, heat treatment is performed at a fast heating rate as described above. Simultaneously, heat treatment is performed at a fast heating rate until a temperature T1 below the temperature at which the temperature starts to rise due to the crystallization of bccFe (αFe). The heating rate after temperature T1 is set to be slower than the previous heating rate and to be less than 400°C / second, thereby controlling the heat generated by crystallization and suppressing the precipitation of FeB compounds and the grain growth of αFe.

[0115] Therefore, in the soft magnetic alloy thin strip disclosed herein, the heat treatment method disclosed herein can expand the heat treatment temperature range in which high saturation magnetic flux density and low iron loss can be obtained, the controlled temperature range is widened, and a soft magnetic alloy thin strip with excellent heat treatability can be obtained.

[0116] In the soft magnetic alloy strip disclosed herein, where the density of the alloy strip before heat treatment is defined as M1 and the density of the alloy strip after heat treatment is defined as M2, M2 / M1 is preferably greater than 1.005. The heat treatment method disclosed herein can increase the density of the alloy strip, thereby achieving a high saturation magnetic flux density.

[0117] The soft magnetic alloy ribbon disclosed herein has a high saturation magnetic flux density and low iron loss. The saturation magnetic flux density can reach a value of 1.75 T or higher, while the iron loss can reach a value of 25 W / kg or lower at 1 T at 1 kHz. Furthermore, the iron loss is preferably 18 W / kg or lower.

[0118] In addition, the density of the soft magnetic alloy strip disclosed in the present invention is preferably 7.45 g / cm 3 Above. Through density is 7.45g / cm 3 As a result, the volume ratio of the nanocrystals is increased, and the saturation magnetic flux density is increased.

[0119] Furthermore, the saturation magnetic flux density of the soft magnetic alloy ribbon disclosed herein is preferably 1.77 T or higher.

[0120] Furthermore, the soft magnetic alloy strip disclosed herein preferably has an iron loss of 15 W / kg or less at 1 kHz and 1 T.

[0121] Furthermore, the saturation magnetostriction of the soft magnetic alloy ribbon disclosed herein is preferably 20 ppm or less, thereby making it easier to obtain isotropy.

[0122] The soft magnetic alloy ribbon disclosed herein has the configuration and characteristics of the soft magnetic alloy described above, and the descriptions thereof are redundant, and thus the above descriptions apply.

[0123] The thickness of the soft magnetic alloy strip disclosed herein is preferably 15 μm or greater, more preferably 20 μm or greater, more preferably 25 μm or greater, and even more preferably 30 μm or greater. For example, a thickness of 25 μm or greater can reduce the time and cost of manufacturing a magnetic core by stacking soft magnetic alloy strips. A thickness of 32 μm or greater is more preferred. Furthermore, increasing the thickness of the soft magnetic alloy strip makes manufacturing the strip more difficult. Therefore, a thickness of 50 μm or less is preferred. A thickness of 35 μm or less is even more preferred.

[0124] Furthermore, in applications where it is necessary to further reduce the iron loss in a high frequency band exceeding 1 kHz, a soft magnetic alloy thin strip having a thickness of approximately 15 to 25 μm is preferred.

[0125] Furthermore, the soft magnetic alloy strip disclosed herein can achieve a high fill factor. In the soft magnetic alloy strip disclosed herein, the fill factor can be set to 86% or greater. Furthermore, the fill factor of the soft magnetic alloy strip disclosed herein is preferably 88% or greater, and more preferably 90% or greater. This high fill factor allows the stacking thickness to be reduced when stacking the soft magnetic alloy strips, even with the same number of layers, compared to alloy strips with a lower fill factor. This contributes to the miniaturization of the magnetic core and components.

[0126] In addition, the occupation ratio can be measured by the following method based on JIS C 2534:2017.

[0127] Twenty ribbons cut to 120 mm lengths were stacked and placed on a flat sample stand. A flat anvil with a diameter of 16 mm was placed on the stacked ribbons at a pressure of 50 kPa. The height was measured at 10 mm intervals across the width. The maximum height at this point was designated as hmax (μm). The occupancy factor (LF) was calculated using the following formula.

[0128] LF (%) = weight of sample (g) / density (g / cm 3 ) / hmax(μm) / sample length(240cm) / strip width(cm)×10000

[0129] At this time, the density (g / cm 3 ) is the density of the alloy ribbon after heat treatment.

[0130] Furthermore, for the soft magnetic alloy strip disclosed herein, the ratio (L / W) of the magnetic flux density L when a magnetic field of 80 A / m is applied in the casting direction of the soft magnetic alloy strip to the magnetic flux density W when a magnetic field of 80 A / m is applied in a direction perpendicular to the casting direction of the soft magnetic alloy strip is preferably 0.7 to 1.3. A ratio (L / W) of 0.7 to 1.3 allows for a highly isotropic soft magnetic alloy strip to be obtained.

[0131] Generally speaking, alloy strips produced by spraying a molten alloy onto a rotating chill roll and rapidly solidifying it as described above will have anisotropy introduced in the casting direction. It should be noted that the casting direction is the direction along the rotation of the chill roll and is the longitudinal direction of the continuously cast alloy strip.

[0132] As described above, in soft magnetic alloy ribbons that have anisotropy in the casting direction introduced during casting, this introduced anisotropy also affects the properties after heat treatment (after heat treatment to form a nanocrystalline structure). In particular, if the volume fraction of the amorphous phase is high, the magnetic flux density in the casting direction of the alloy ribbon (the longitudinal direction of the alloy ribbon) and the direction orthogonal to the casting direction (the direction orthogonal to the longitudinal direction, equivalent to the width direction of the alloy ribbon) will differ, and the anisotropy will remain after heat treatment.

[0133] However, there are also applications where isotropic soft magnetic alloy ribbons are required, such as motor applications. Therefore, it is preferable to perform heat treatment to increase the crystal volume fraction in order to control the difference in magnetic flux density between the casting direction and the direction perpendicular to the casting direction within a certain range.

[0134] On the other hand, if the high temperature or heat treatment time is extended to increase the volume fraction of nanocrystals, FeB compounds may precipitate under certain conditions, degrading the magnetic properties. In particular, in soft magnetic alloy ribbons containing a high amount of Fe, the temperature range for achieving isotropy during heat treatment is narrow, making it difficult to obtain soft magnetic alloy ribbons with a nanocrystalline structure that combines high saturation magnetic flux density, low iron loss, and isotropy.

[0135] According to the present disclosure, the above-mentioned problems can be solved, and a soft magnetic alloy ribbon having both high saturation magnetic flux density and low iron loss can be obtained while suppressing the precipitation of FeB compounds, and a soft magnetic alloy ribbon having further isotropy can be obtained.

[0136] The soft magnetic alloy ribbon disclosed herein has a wide permissible temperature range during heat treatment to achieve desired properties, resulting in high mass production even when considering variations in mass production. This wide permissible temperature range is particularly effective in wide alloy ribbons used in motor cores and other applications, as temperature variations are more likely to occur during heat treatment.

[0137] Generally speaking, if the heating rate and temperature are uneven within the alloy ribbon, the heat generated by crystallization cannot be controlled locally, shrinkage during crystallization becomes uneven, and wrinkles appear in the alloy ribbon, which can easily lead to problems such as reduced space utilization when made into a magnetic core.

[0138] However, the soft magnetic alloy ribbon of the present disclosure has a wide tolerance range for temperature variations during heat treatment as described above, wrinkles are suppressed, and a soft magnetic alloy ribbon having a high fill factor and high smoothness can be obtained.

[0139] The smoothness can be defined by the maximum value hmax and minimum value hmin of the thickness in the width direction measured when measuring the occupancy ratio, and by (hmax-hmin) / 20. The smoothness is preferably 4 μm or less, and more preferably 3 μm or less.

[0140] By using the soft magnetic alloy ribbon disclosed herein to constitute a magnetic core used in a transformer, an electronic component, a motor, etc., a magnetic core having excellent characteristics can be obtained.

[0141] When forming the magnetic core, the alloy thin strips may be cut into a predetermined shape and stacked, the alloy thin strips may be wound, the alloy thin strips may be stacked and bent, or the like.

[0142] Alternatively, the soft magnetic alloy ribbon of the present disclosure may be crushed into powder, and the powder may be used to form a magnetic core. Alternatively, the soft magnetic alloy powder of the present disclosure may be prepared by atomization, and the powder may be used to form a magnetic core.

[0143] Furthermore, by combining the magnetic core of the present disclosure with windings to form components such as transformers, electronic components, and motors, components with excellent characteristics can be obtained. In this case, the magnetic core of the present disclosure can also be combined with magnetic cores made of other magnetic materials.

[0144] Example

[0145] [Example 1]

[0146] The element sources are mixed in such a manner as to form the compositions shown in Table 3, and heated to 1300°C to produce an alloy melt. The alloy melt is sprayed onto a cooling roller with an outer diameter of 400 mm and a width of 200 mm, which rotates at a peripheral speed of 30 m / s, and is rapidly solidified on the cooling roller to produce an alloy strip. Each alloy strip is heat treated under the heat treatment conditions shown in Table 4 to produce a soft magnetic alloy strip with a nanocrystalline structure. The width and thickness of the produced alloy strips are shown in Table 4. It should be noted that the outer periphery of the cooling roller is composed of a Cu alloy with a thermal conductivity of 150 W / (m·K), and has a cooling mechanism inside for controlling the temperature of the outer periphery.

[0147] In Tables 3 and 4, No. 1 to 6 and No. 10 to 23 correspond to the soft magnetic alloy strips disclosed in the present invention, and No. 51 to 53 correspond to comparative examples. 8000 Table 4 shows the core loss at 1T / 1kHz, density, bccFe (αFe) crystallization start temperature, FeB precipitation start temperature, temperature T1, temperature T2, the heating rate from room temperature to temperature T1, and the heating rate between T1 and T2. The heating rate from room temperature to temperature T1 was set at 400 to 500°C / second. Density refers to the density after heat treatment.

[0148] Note that each of Samples No. 1 to 6 and No. 10 to 23 had a structure in which grains with a grain size of 60 nm or less existed in the amorphous phase. Furthermore, cross-sectional observation of each sample revealed that the area ratio of grains with a grain size of 60 nm or less was 50% or more (value when the observation field area was set to 100%).

[0149] bccFe(αFe) crystallization starting temperature, FeB precipitation starting temperature

[0150] The bccFe (αFe) crystallization start temperature and the FeB precipitation start temperature vary depending on the heating rate. Generally, the upper limit of the heating rate of a thermal analyzer is about 2°C / second, which cannot measure the heating rate during the heat treatment of the present disclosure. Therefore, the values ​​at a heating rate of 50°C / second are determined by the method described below and used as the bccFe (αFe) crystallization start temperature and the FeB precipitation start temperature.

[0151] Using a DSC8231 manufactured by Rigaku Corporation, the bccFe(αFe) crystallization start temperature and the FeB precipitation start temperature were measured at three points: a heating rate of 5°C / min (0.083°C / sec), 20°C / min (0.333°C / sec), and 50°C / min (0.833°C / sec). The values ​​were plotted with the X-axis as the logarithm of the heating rate and the Y-axis as the bccFe(αFe) crystallization start temperature or the FeB precipitation start temperature. The value at a heating rate of 50°C / sec was obtained by extrapolation from the approximate curve.

[0152] The saturation magnetic flux density (B 8000 ), iron loss, and density.

[0153] 〔Saturation magnetic flux density (B 8000 )〕

[0154] The DC magnetization characteristic test device developed by METRON technology was used to apply a magnetic field of 8000A / m to the soft magnetic alloy thin strip (single plate sample) after heat treatment, and the maximum magnetic flux density at this time was measured as B 8000The soft magnetic alloy strip disclosed in the present invention has the characteristic of being easy to saturate, so it is already saturated when the magnetic field of 8000A / m is applied. 8000 It is almost the same value as the saturation magnetic flux density, so the saturation magnetic flux density is expressed as B 8000 To express.

[0155] Iron loss

[0156] The core loss was measured using a TWM18SR AC magnetic measuring apparatus manufactured by Toei Industries, Ltd. using a heat-treated soft magnetic alloy strip (single plate sample) under the conditions of a magnetic flux density of 1 T and a frequency of 1 kHz.

[0157] 〔density〕

[0158] A dry density meter AccuPyc 1330 manufactured by Shimadzu Corporation was used to prepare a core sample having a size that could be inserted into a cylindrical sample chamber with a diameter of 17 mm and a height of 33 mm by the constant volume expansion method. The volume of the core sample was measured, and the density was calculated as the value obtained by dividing the weight of the core by its volume.

[0159] The density obtained using the alloy ribbon before heat treatment is density M1, and the density obtained using the alloy ribbon after heat treatment is density M2.

[0160] [Table 3]

[0161]

[0162] [Table 4]

[0163]

[0164] In the examples (No. 1 to 6, 10 to 23) of the present disclosure, high saturation magnetic flux density and low iron loss were obtained. In addition, the density was also 7.45 g / cm 3 above.

[0165] Comparative Examples No. 51 and 52 have low saturation magnetic flux density.

[0166] Comparative Example No. 53 had slightly higher iron loss, but generally had the same characteristics as the examples of the present disclosure. However, due to the low Si content, it rusted after being stored in the air for several days, causing operational problems.

[0167] Table 5 shows the ratio (L / W) of the magnetic flux density L when a magnetic field of 80 A / m is applied in the casting direction of the soft magnetic alloy strips No. 1 to 6, No. 20 to 22, and No. 51 to 53 (single plate samples) to the magnetic flux density W when a magnetic field of 80 A / m is applied in a direction perpendicular to the casting direction, as well as M2 / M1 when the density of the alloy strip before heat treatment is set to M1 and the density of the alloy strip after heat treatment is set to M2.

[0168] 〔Magnetic flux density L, W〕

[0169] A DC magnetization characteristics test device was developed using METRON technology. A magnetic field of 80 A / m was applied to the casting direction and the direction perpendicular to the casting direction of the heat-treated soft magnetic alloy thin strip (single plate sample). The magnetic flux density at this time was set to L and W, respectively, and the isotropy was evaluated using the ratio of L to W (L / W).

[0170] In the examples (No. 1 to 6, 20 to 22) of the present disclosure, the ratio (L / W) was in the range of 0.7 to 1.3, and highly isotropic soft magnetic alloy ribbons were obtained. The density ratio (M2 / M1) was also 1.005 or more.

[0171] In Comparative Examples No. 51 and 53, the ratio (L / W) exceeded 1.3.

[0172] [Table 5]

[0173]

[0174] Table 6 shows the saturation magnetostriction values ​​of Nos. 1 to 4, 12, 15, and 20 to 23.

[0175] 〔Saturation magnetostriction〕

[0176] A 5 kOe magnetic field was applied to a sample with a Kyowa Electric strain gauge attached using an electromagnet. The electromagnet was rotated 360°. The maximum change in sample expansion and contraction caused by changing the direction of the magnetic field applied to the sample 360° was measured based on the change in the strain gauge's resistance. The saturation magnetostriction was calculated as 2 / 3 × maximum change.

[0177] The saturation magnetostriction of Examples (Nos. 1 to 4, 12, 15, and 20 to 23) of the present disclosure was 20 ppm or less.

[0178] [Table 6]

[0179]

[0180] [Example 2]

[0181] To form Fe 82.93 Si 2.30 B 13.70 Nb 0.38 Cu 0.69The composition is composed of a composition in which the element source is matched, and the alloy melt obtained by heating at 1300°C is sprayed onto a cooling roller with an outer diameter of 400mm and a width of 300mm rotating at a peripheral speed of 30m / s, and is rapidly solidified on the cooling roller to produce an alloy strip. Each alloy strip is heat treated under the heat treatment conditions shown in Table 8 to produce a soft magnetic alloy strip with a nanocrystalline structure. The width and thickness of the produced alloy strips are shown in Table 7. It should be noted that the outer periphery of the cooling roller is composed of a Cu alloy with a thermal conductivity of 150W / (m·K), and a cooling mechanism is provided inside for controlling the temperature of the outer periphery. It should be noted that the heating rate from room temperature to temperature T1 is set to 400-500°C / second. In addition, the density is the density after heat treatment.

[0182] Note that each of Samples No. 7 to 9 had a structure in which grains with a grain size of 60 nm or less existed in the amorphous phase. Furthermore, cross-sectional observation of each sample revealed that the area ratio of grains with a grain size of 60 nm or less was 50% or more (value when the observation field area was set to 100%).

[0183] The heat treatment conditions of each sample were measured, and the sample occupancy rate, smoothness, B 8000 The results of iron loss and density are shown in Tables 7 and 8. Sample No. 54 is a sample with heat treatment conditions where T2 is 140°C lower than the FeB precipitation start temperature and T1 is 160°C lower than the bccFe crystallization start temperature. Sample No. 55 is a sample with heat treatment conditions where T2 is 20°C lower than the FeB precipitation start temperature. The values ​​of the results are also shown in Tables 7 and 8. The B of sample No. 54 is 140°C lower than the FeB precipitation start temperature and T1 is 160°C lower than the bccFe crystallization start temperature. 8000 The heat treatment was insufficient, as low as 1.74T. Sample No. 55 exhibited a significant increase in iron loss, making it impossible to measure at 1T and 1kHz. This suggests that the characteristics of Sample No. 55 were degraded due to FeB precipitation. Furthermore, Sample No. 55 exhibited wrinkles during heat treatment, resulting in an occupancy rate of 80% and a significantly degraded smoothness of 6.3μm.

[0184] The examples (Nos. 7 to 9) of the present disclosure have high saturation magnetic flux density, low iron loss, and an occupation ratio of 86% or more. Furthermore, they have high density and good smoothness.

[0185] [Table 7]

[0186]

[0187] [Table 8]

[0188]

[0189] 〔Plot ratio〕

[0190] The measurement was performed by the following method based on JIS C 2534:2017.

[0191] Twenty ribbons cut to 120 mm lengths were stacked and placed on a flat sample stand. A flat anvil with a diameter of 16 mm was placed on the stacked ribbons at a pressure of 50 kPa. The height was measured at 10 mm intervals across the width. The maximum height at this point was designated as hmax (μm). The occupancy factor (LF) was calculated using the following formula.

[0192] LF (%) = weight of sample (g) / density (g / cm 3 ) / hmax(μm) / sample length(240cm) / strip width(cm)×10000

[0193] As described above, according to the present disclosure, a soft magnetic alloy ribbon with high saturation flux density and low iron loss is obtained. Furthermore, according to the present disclosure, an isotropic soft magnetic alloy ribbon with suppressed anisotropy is obtained. Furthermore, according to the present disclosure, a soft magnetic alloy ribbon with high density, high fill factor, and excellent smoothness is obtained.

[0194] When the soft magnetic alloy strip of the present disclosure is used to form a magnetic core, the core can be formed using a known method. Moreover, the magnetic core formed using the soft magnetic alloy strip of the present disclosure can be formed to have the high saturation magnetic flux density, low iron loss, and isotropy of the soft magnetic alloy strip of the present disclosure, thereby obtaining a magnetic core with excellent characteristics.

[0195] Furthermore, by constructing a component having a magnetic core and winding made of the soft magnetic alloy thin strip disclosed in the present invention, a component having high saturation magnetic flux density, low iron loss, and further isotropy possessed by the soft magnetic alloy thin strip disclosed in the present invention can be constructed, thereby obtaining a component having excellent characteristics.

Claims

1. A soft magnetic alloy strip, the alloy composition of which is composed of the formula Fe a Si b B c Cu d M e It indicates that M is at least one element selected from Nb, Mo, V, Zr, Hf, and W, and in terms of atomic %: 82.5≦a≦86, 0.3≦b≦3, 12.5≦c≦15.0, 0.05≦d≦0.9, and 0≦e<0.

4. The soft magnetic alloy ribbon has a structure in which grains with a particle size of 60 nm or less exist in an amorphous phase, a saturation magnetic flux density of 1.75 T or more, and an iron loss of 25 W / kg or less at 1 kHz and 1 T. The volume ratio of the crystal grains with a particle size of less than 60 nm is greater than 50%, and the area ratio is greater than 86%.

2. The soft magnetic alloy strip according to claim 1, wherein Density is 7.45g / cm 3 above.

3. The soft magnetic alloy strip according to claim 1 or 2, wherein: The thickness is 25 μm or more.

4. The soft magnetic alloy strip according to claim 1 or 2, wherein The plot ratio is over 88%.

5. The soft magnetic alloy strip according to claim 1 or 2, wherein The ratio of the magnetic flux density L when a magnetic field of 80 A / m is applied in the casting direction of the soft magnetic alloy strip to the magnetic flux density W when a magnetic field of 80 A / m is applied in a direction perpendicular to the casting direction of the soft magnetic alloy strip, i.e. L / W, is 0.7 to 1.

3.

6. The soft magnetic alloy strip according to claim 1 or 2, wherein The saturation magnetostriction is 20 ppm or less.

7. The soft magnetic alloy strip according to claim 1 or 2, wherein: 83≦a≦86, 0.3≦b≦2, 0.4≦d≦0.9, 0≦e≦0.3, saturation magnetic flux density is above 1.77T.

8. The soft magnetic alloy strip according to claim 1 or 2, wherein 13.0≦c≦14.0。 9. The soft magnetic alloy strip according to claim 1 or 2, wherein: A portion of Fe is substituted with at least one element of Co and Ni within a range of up to 6 atomic %.

10. A method for manufacturing a soft magnetic alloy strip, which is a method for manufacturing a soft magnetic alloy strip according to any one of claims 1 to 9, comprising a strip manufacturing process of spraying an alloy melt onto a rotating cooling roller, cooling the alloy melt on the cooling roller to obtain an alloy strip, wherein the outer periphery of the cooling roller is composed of a Cu alloy having a thermal conductivity of 120 W / (m·K) or more.

11. A method for producing a soft magnetic alloy ribbon, comprising heat-treating the alloy ribbon to produce a soft magnetic alloy ribbon having a structure in which grains having a particle size of 60 nm or less exist in an amorphous phase, wherein: In the heat treatment, a temperature 10 to 140°C lower than the bccFe crystallization start temperature is set as temperature T1, and a temperature 30 to 120°C lower than the FeB precipitation start temperature is set as temperature T2. Heating from room temperature to temperature T1 at a heating rate of 50°C / s or more, Heating from temperature T1 to temperature T2 at a heating rate slower than the heating rate to temperature T1 and less than 400°C / second, Cool down after reaching temperature T2, or After reaching temperature T2, keep the temperature between temperature T2-50℃ and temperature T2 for 0.5 to 60 seconds, then cool down. The alloy composition of the soft magnetic alloy strip is composed of the composition formula Fe a Si b B c Cu d M e It indicates that M is at least one element selected from Nb, Mo, V, Zr, Hf, and W, and in terms of atomic %, 82.5≦a≦86, 0.3≦b≦3, 12.5≦c≦15.0, 0.05≦d≦0.9, and 0≦e<0.

4.

12. The method for manufacturing a soft magnetic alloy strip according to claim 11, wherein the alloy strip before heat treatment is obtained by spraying the alloy melt onto a rotating cooling roller and cooling the alloy melt on the cooling roller, and the outer periphery of the cooling roller is composed of a Cu alloy with a thermal conductivity of 120 W / (m·K) or more. 13 . The method for producing a soft magnetic alloy strip according to claim 11 , wherein, when the density of the alloy strip before the heat treatment is defined as M1 and the density of the alloy strip after the heat treatment is defined as M2, M2 / M1 is equal to or greater than 1.

005. 14 . A magnetic core comprising the soft magnetic alloy strip according to claim 1 . A component comprising the magnetic core according to claim 14 and a winding wire.

Images