Soft magnetic fe-co-si-based alloy plate

Abstract

The present invention provides a soft magnetic material plate capable of reducing iron loss in high-rotational-speed regions / high-frequency regions to a greater extent than in the past without significantly impairing the magnetization characteristics of the soft magnetic material. A soft magnetic Fe-Co-Si-based alloy plate according to the present invention comprises an alloy composition containing 1 at% to less than 48 at% of Co and 0.5 to 8 at% of Si, the total of the Co and the Si being 1.5 at% to less than 48 at%, and the balance being composed of Fe and impurities. In the soft magnetic Fe-Co-Si-based alloy plate, the average grain size d (m) of the surface has a relationship of "0.25δ ≤ d ≤ δ" to the skin depth δ (m), which is a function of the maximum magnetic permeability μm (H / m), the conductivity σ (S / m), and the operating frequency (Hz) of the soft magnetic Fe-Co-Si-based alloy plate.

Description

Soft Magnetic Fe-Co-Si Based Alloy Sheet

[0001] The present invention relates to the technology of soft magnetic materials, and in particular to a soft magnetic sheet made of Fe-Co-Si (iron-cobalt-silicon) based alloy material.

[0002] In electromechanical devices (such as rotating electrical machines and transformers), laminated iron cores formed by laminating a plurality of soft magnetic material sheets (for example, having a thickness of 0.01 to 3 mm) are widely used. From the perspective of global environmental protection, the application fields of electromechanical devices using soft magnetic materials have been expanding in recent years, and accordingly, the demands for higher output and higher efficiency of such electromechanical devices have been increasing.

[0003] When a rotating electrical machine is assumed as the electromechanical device, its output is proportional to the product of the torque during operation and the rotational speed (the number of rotations per unit time), so higher output can be achieved by increasing either the torque or the rotational speed. Torque is proportional to the product of magnetic flux density and current value during operation. In order to increase torque, it is necessary for the iron core to have high magnetization characteristics (for example, high saturation magnetic flux density B s or high saturation magnetization M s ), it is desirable to use a soft magnetic material that achieves these properties.

[0004] When increasing the rotational speed during operation, the conversion efficiency between electrical energy and magnetic energy is important, and reduction of the loss (total iron loss P i ) in the soft magnetic material sheet becomes a problem. Reduction of total iron loss P i also leads to suppression of heat generation during operation. Total iron loss P i is hysteresis loss P h and eddy current loss P e , which is the sum of hysteresis loss P h , it is desirable that coercive force H c is small for reducing hysteresis loss, and for eddy current loss P e , increasing electrical resistance (e.g., by alloying) and reducing eddy current area (e.g., by thinning the sheet) are effective for reduction.

[0005] Electromagnetic pure iron material has high magnetization characteristics (B s ≒2.2 T, M s ≒220 emu / g), but the coercive force H c is relatively large, so the total iron loss Pi It has the weakness that the magnitude tends to increase. Fe-Si (iron-silicon) alloy materials have relatively high magnetization properties (B s ≈1.8 T, M s (approximately 180 emu / g) and relatively low total iron loss P i As a material with a well-balanced composition, it is currently widely used.

[0006] Furthermore, among currently commercially available soft magnetic bulk materials, permendur (49Fe-49Co-2V mass% = 50Fe-48Co-2V atomic%, B) is considered to have the highest magnetization properties. s ≈2.4 T, M s A well-known value is approximately 240 emu / g. However, the material cost of Co is significantly higher than that of Fe, although this fluctuates depending on market conditions, making permendur a high-cost material. In other words, in Fe-Co alloy materials, the material cost can be reduced by lowering the Co content.

[0007] Magnetization properties and total iron loss P in soft magnetic materials i Considering the balance with these factors, various methods are being used to control the composition and microstructure of soft magnetic materials. For example, Patent Document 1 (JP 2022-113111) describes an alloy composition with the composition formula (Fe 1-x A x ) a Si b B c Cu d M e A soft magnetic alloy thin strip is provided, 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 atomic percent values ​​of 82.4≦a≦86, 0.2≦b≦2.4, 12.5≦c≦15.0, 0.05≦d≦0.8, 0.4≦e≦1.0, and 0≦x≦0.1, wherein the soft magnetic alloy thin strip has a structure in which crystal grains with a particle size of 60 nm or less exist in the amorphous phase, a saturation magnetic flux density of 1.74 T or higher, and an iron loss of 25 W / kg or less at 1 kHz and 1 T.

[0008] Japanese Patent Publication No. 2022-113111

[0009] The demand for achieving both high power output and lightweight design in electromechanical equipment (the demand for increasing the power-to-weight ratio W / kg) is becoming increasingly strong. As a means of increasing output while suppressing mass increase, recent advances have focused on increasing rotational speed and / or frequency during operation. However, increasing power output through high rotational speed / high frequency presents challenges to the total iron loss P of soft magnetic materials. i Energy loss and reduced efficiency resulting from this pose a major problem. In other words, in order to improve the power-to-weight ratio and efficiency of the electromechanical device, high magnetization characteristics and low total iron loss P in the high rotational speed / high frequency range are required for the soft magnetic material. i It is desirable to achieve both. On the other hand, naturally, reducing the cost of the iron core is one of the most important issues for an industrial product.

[0010] This invention was made to achieve the above objectives. The primary objective of this invention is to reduce total iron loss P in the high rotational speed / high frequency range without significantly impairing the magnetization properties of the soft magnetic material. i The objective is to provide a soft magnetic material plate that can reduce [unclear / unclear].

[0011] (I) One aspect of the present invention is a soft magnetic material plate comprising 1 atomic% or more and less than 48 atomic% of Co and 0.5 atomic% or more and 8 atomic% of Si, wherein the total of Co and Si is 1.5 atomic% or more and less than 48 atomic%, and the remainder is Fe and impurities, and the soft magnetic material plate has a maximum permeability μ m The present invention provides a soft magnetic Fe-Co-Si alloy sheet characterized in that the average grain size d (m) of the surface has the relationship "0.25δ≦d≦δ" with respect to the skin depth δ (m), which is a function of the conductivity σ (S / m) and the usable frequency f (Hz).

[0012] The present invention allows for the following improvements and modifications to be freely combined in the soft magnetic Fe-Co-Si alloy plate (I) according to the present invention: (i) The conductivity σ is 4.3 × 10 8(ii) The thickness of the soft magnetic material plate is greater than twice the skin depth δ and is between 0.1 mm and 1 mm. (iii) The total iron loss in the AC magnetic property evaluation under the conditions of a maximum magnetic flux density of 1 T and an AC frequency of 5 kHz is 650 W / kg or less. (iv) The magnetic flux density B in the DC magnetic property evaluation under the condition of an external magnetic field of 5000 A / m 50 It is 1.9 T or higher.

[0013] According to the present invention, total iron loss P in the high rotational speed / high frequency range can be achieved without significantly impairing the magnetization properties of the soft magnetic material compared to conventional methods. i This provides a soft magnetic Fe-Co-Si alloy sheet that can reduce [unclear / unclear].

[0014] This is a process diagram showing an example of a method for manufacturing a soft magnetic Fe-Co-Si alloy sheet according to the present invention. These are optical microscope images of the surfaces of soft magnetic material sheets SMP-3a to 3c.

[0015] [Basic Concept of the Invention] When a rotating electric machine using a laminated iron core is operated, each soft magnetic material plate constituting the laminated iron core is exposed to an alternating magnetic field / AC magnetic field from the windings. As the rotational speed / AC frequency increases, the induced electromotive force on each soft magnetic material plate increases, and the eddy currents increase (Faraday's Law). Furthermore, in high-frequency AC magnetic fields, it is necessary to consider the skin effect, in which the penetration of the magnetic field and the induced current concentrate in the skin region of each soft magnetic material plate.

[0016] As mentioned above, total iron loss P i P is the hysteresis loss. h and eddy current loss P e The sum of these is the eddy current loss P in the high rotation speed / high frequency region. e The influence of becomes relatively larger. The inventors have found that the total iron loss P of a soft magnetic material plate in the high rotation speed region / high frequency region is relatively large. i (Especially eddy current loss P) e We have been conducting various studies on technologies to reduce ) compared to conventional methods.

[0017] In their research, the inventors have found that by using an Fe-Co alloy material as a base, they can secure higher magnetization properties than conventional Fe-Si alloy materials, and by adding a Si component while reducing the amount of Co component compared to Permendur, they can suppress material costs while reducing eddy current loss P e It was found to be effective in reducing the eddy current loss P in the high rotation speed region / high frequency region by controlling the relationship between the average grain size on the surface of the soft magnetic material plate and the skin depth that is subject to the skin effect to a predetermined range. e We found that it is possible to suppress the increase of [the substance]. This invention was completed based on this finding.

[0018] Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the present invention is not limited to the specific embodiments described, and it is possible to combine it with or improve upon prior art without departing from the technical spirit of the invention.

[0019] [Soft Magnetic Fe-Co-Si Alloy Sheet] Figure 1 is a process diagram showing an example of a method for manufacturing a soft magnetic Fe-Co-Si alloy sheet according to the present invention. As shown in Figure 1, the method for manufacturing a soft magnetic Fe-Co-Si alloy sheet according to the present invention generally comprises a starting material preparation step S1, a soft magnetic material sheet precursor forming step S2, and a magnetic annealing step S3. In the present invention, in order to obtain a soft magnetic Fe-Co-Si alloy sheet that achieves the objective, steps S2 and S3 are controlled to control the average grain size of the surface of the alloy sheet.

[0020] The following explains each step in more detail.

[0021] The starting material preparation step S1 is a step of preparing starting materials (e.g., ingots) having a desired alloy composition. There are no particular limitations on the method of preparing the starting materials, as long as the desired alloy composition can be controlled, and conventional alloy preparation methods (e.g., casting) can be used as appropriate. The starting materials may also be prepared by purchasing them to have the desired alloy composition.

[0022] The alloy composition preferably contains 1 atomic% to less than 48 atomic% of Co and 0.5 atomic% to 8 atomic% of Si, with the total of Co and Si being 1.5 atomic% to less than 48 atomic%, and the remainder consisting of Fe and impurities.

[0023] From the viewpoint of balancing the securing of magnetization properties and the suppression of material costs, 2 atomic percent to 30 atomic percent of Co is more preferable, and 5 atomic percent to 25 atomic percent of Co is even more preferable. Total iron loss P i From the viewpoint of balancing the reduction of silicon content with ensuring magnetization properties, Si content of 0.8 atomic% to 6 atomic% is more preferable, and Si content of 1 atomic% to 4 atomic% is even more preferable.

[0024] The total content of impurities is preferably 2 atomic percent or less, and more preferably 1 atomic percent or less. In other words, the total amount of components intentionally included is preferably at least 98 atomic percent or more. Typical impurities in the soft magnetic material plate of the present invention include C (carbon), N (nitrogen), O (oxygen), Mg (magnesium), Al (aluminum), P (phosphorus), S (sulfur), Ca (calcium), Ti (titanium), V (vanadium), Mn (manganese), Ni (nickel), Zn (zinc), Sr (strontium), Zr (zirconium), Nb (niobium), Mo (molybdenum), Cd (cadmium), Ba (barium), La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), and W (tungsten).

[0025] Note that eddy current loss P e From the perspective of reducing the conductivity, the conductivity σ of the final soft magnetic material plate is 4.3 × 10⁻⁶. 8 S / m or less (electrical resistivity ρ is 2.3 × 10) -7 Preferably, it is Ω·m or greater, and 4.0 × 10 8 S / m or less (electrical resistivity ρ is 2.5 × 10) -7 It is more preferable that the value be Ω·m or greater, and 3.7 × 10 8 S / m or less (electrical resistivity ρ is 2.7 × 10⁻⁶) -7 It is even more preferable that the conductivity is Ω·m or greater. In other words, it is also important to select the alloy composition considering the conductivity σ and electrical resistivity ρ of the soft magnetic material plate.

[0026] The soft magnetic material sheet precursor forming step S2 is a step in which the starting material prepared in step S1 is subjected to metalworking to form a soft magnetic material sheet precursor of a desired shape. There are no particular limitations on the method of metalworking, and conventional methods (e.g., rolling, pressing, cutting, punching, etc.) can be used as appropriate. Annealing / intermediate annealing may be combined during the metalworking process as needed. The soft magnetic material sheet precursor is preferably metalworked to have a thickness of 0.1 mm or more and 1 mm or less, more preferably 0.1 mm or more and 0.5 mm or less, and even more preferably 0.1 mm or more and 0.3 mm or less.

[0027] Due to processing strain in step S2, magnetized regions often occur in the soft magnetic material plate precursor. Magnetic annealing step S3 is a process of performing heat treatment (magnetic annealing) to restore the magnetized regions that have occurred in the soft magnetic material plate precursor to a soft magnetic material plate. Magnetic annealing is preferably performed in a non-oxidizing atmosphere (a substantially oxygen-free atmosphere, such as a high-purity argon gas atmosphere, a high-purity nitrogen gas atmosphere, a hydrogen gas atmosphere, or a vacuum) to a temperature of 700°C to 950°C and then cooling relatively slowly (for example, with a cooling rate of 100°C / h to 200°C / h) in order to suppress oxidation of the soft magnetic material plate precursor, which is the material to be heat-treated. A heating temperature of 750°C to 900°C is more preferable.

[0028] Here, when the magnetized region generated in the soft magnetic material plate precursor in step S2 is restored to its original state by step S3, recrystallization occurs and the average grain size of the soft magnetic material plate changes. At this time, it is preferable to control the average grain size of the soft magnetic material plate so that it falls within an appropriate range. The desirable average grain size will be described later.

[0029] Generally, the driving force for recrystallization of metallic materials is proportional to the internal energy accumulated within the material (for example, the sum of the residual strain energy introduced by the metal processing in step S2), and the heat treatment temperature is related to the kinetics of recrystallization (for example, the nucleation frequency of recrystallization, the diffusion coefficient of atomic rearrangement). In other words, in order to control the average grain size of the soft magnetic material plate to be within an appropriate range, it is preferable to control it by combining the residual strain energy of the soft magnetic material plate precursor introduced in step S2 and the heat treatment temperature in step S3.

[0030] (Regarding the desirable average grain size of soft magnetic material plates) As mentioned above, the iron core used in rotating electric machines is exposed to an alternating magnetic field (AC magnetic field) from the windings, so as the rotation speed / AC frequency increases, the induced electromotive force on each soft magnetic material plate increases and the AC eddy currents increase. Also, when an AC current flows through a conductor, as the frequency increases, the current concentrates in the surface region of the conductor due to the skin effect (the current in the central region of the conductor becomes smaller).

[0031] The depth to which the current becomes 1 / e (approximately 0.37) of the surface current is called the skin depth δ, and is expressed by the following equation: δ = 1 / (π × f × μ) m ×σ) 1 / 2 ...(Formula 1) f: frequency, μ m σ represents the maximum magnetic permeability of the soft magnetic material plate, and σ represents the electrical conductivity of the soft magnetic material plate.

[0032] As can be seen from Equation 1, the skin depth δ decreases as the frequency f increases, and the skin depth δ decreases as the conductivity σ of the soft magnetic material plate decreases (as the electrical resistivity ρ increases). When the thickness t of the soft magnetic material plate is less than or equal to twice the skin depth δ, the entire soft magnetic material plate can be considered as a substantially uniform conductor. However, when the thickness t of the soft magnetic material plate is greater than twice the skin depth δ, a region where current does not easily flow is created in the central region in the thickness direction of the soft magnetic material plate, and the entire soft magnetic material plate can no longer be considered as a uniform conductor.

[0033] On the other hand, the hysteresis loss P of the soft magnetic material plate... h and eddy current loss P e It is said that this can be expressed by Steinmetz's empirical formula as follows: Ph = k h × f × B m 1.6 ...(Formula 2), P e = 1 / 6 × k e × t 2 × f 2 × B m 2 × σ...(Formula 3), k h : The proportionality constant for hysteresis loss, k e : proportionality constant for eddy current loss, t: thickness of soft magnetic material plate, B m This is the maximum magnetic flux density generated in a soft magnetic material plate.

[0034] As shown in Equations 2 and 3, the hysteresis loss P h While the frequency f is proportional to the first power of the eddy current loss P e Since P is proportional to the square of the frequency f, the eddy current loss P increases as the frequency f increases. e It can be seen that the effect of P becomes relatively larger. Also, eddy current loss P e Since the eddy current loss P is proportional to the square of the thickness t of the soft magnetic material plate and proportional to the conductivity σ (reciprocal of the electrical resistivity ρ) of the soft magnetic material plate, reducing the thickness or decreasing the conductivity will reduce the eddy current loss P. e It can be seen that it has a reduction effect.

[0035] However, Steinmetz's empirical formula is said to represent the case where the entire conductor is uniform (uniform conductor), and it is known that a discrepancy occurs between the measured value and Steinmetz's empirical formula in the high-frequency region where the skin effect occurs. In experiments conducted by the inventors, this discrepancy has been confirmed in the high-frequency region above 3 kHz.

[0036] Eddy current loss P in the case of a uniform conductor e (See Equation 3) is called the classical eddy current loss, whereas the loss that underlies the deviation is the abnormal eddy current loss P. a This is called eddy current loss (P) and is considered to be a loss caused by eddy currents generated when magnetic domain walls move due to an alternating magnetic field. a This is the measured total iron loss P iThe hysteresis loss P is calculated from Equation 2. h The eddy current loss P calculated by equation 3 e (Here, classical eddy current loss) is defined as the amount obtained by subtracting this. Since the soft magnetic material plate of the present invention is intended for use in high rotational speed ranges / high frequency ranges (e.g., 3 kHz or higher), the total iron loss P i Abnormal eddy current loss P a This needs to be taken into consideration. In the research of the present inventors, total iron loss P i The result of polynomial analysis using the least squares method was that the abnormal eddy current loss P of the Fe-Co alloy plate was found to be a It was found that this is approximately proportional to the frequency f raised to the power of 1.5.

[0037] Abnormal eddy current loss P a Since this is a loss caused by the movement of magnetic domain walls due to an alternating magnetic field, the inventors believe that if the distance of movement of the magnetic domain walls is reduced (in other words, if the magnetic domains become finer), the abnormal eddy current loss P a We considered whether it might be possible to suppress the effects of [the magnetic domain]. As a way to reduce the distance traveled by the magnetic domain walls and make the magnetic domains finer, we considered reducing the average grain size d of the soft magnetic material plate. Then, we investigated the relationship between the average grain size d and the skin depth δ due to the skin effect.

[0038] As a result, by controlling the relationship to "0.25δ≦d≦δ", the distance of the magnetic domain wall movement can be reduced, and the magnetic field in the region requiring magnetic domain wall movement can be made nearly uniform, thus reducing the abnormal eddy current loss P a It was found that the effects of [the specified factor] can be suppressed. As a result, total iron loss P in the high rotational speed / high frequency range can be suppressed. i This can be reduced compared to conventional methods. The relationship between the average crystal grain size d and the skin depth δ is more preferably "0.3δ≦d≦0.9δ" and even more preferably "0.35δ≦d≦0.85δ".

[0039] Furthermore, if "d < 0.25δ", recrystallization by magnetic annealing tends to be insufficient, and magnetized regions due to processing strain may remain. If "δ < d", the displacement distance of the domain wall tends to be large, and the magnetic field in the region requiring domain wall movement becomes non-uniform, which is thought to create a situation where domain wall movement is difficult.

[0040] The present invention will be described in more detail below through various experiments. However, the present invention is not limited to the configurations and structures described in these experiments.

[0041] [Experiment 1] (Preparation of starting materials SM-1 to SM-3) As the starting material preparation step S1, three types of starting materials SM-1 to SM-3 were prepared. For SM-1, an ingot of Fe-Co alloy (80 atomic % Fe - 20 atomic % Co) was prepared. For SM-2, an ingot of Fe-Co-Si alloy (79.9 atomic % Fe - 20 atomic % Co - 0.1 atomic % Si) was prepared. For SM-3, an ingot of Fe-Co-Si alloy with a different composition from SM-2 (79 atomic % Fe - 20 atomic % Co - 1 atomic % Si) was prepared.

[0042] (Preparation of soft magnetic material plate precursors PSMP-1 to PSMP-3) As the soft magnetic material plate precursor forming process S2, metal processing was performed on the starting materials SM-1 to PSMP-3 prepared in process S1 to prepare soft magnetic material plate precursors PSMP-1 to PSMP-3 (each with a thickness of 0.2 mm). During the metal processing, the degree of processing and intermediate annealing were controlled so that the average crystal grain size d of PSMP-1 to PSMP-3 was 15 to 20 μm.

[0043] The average grain size was measured by mirror-polishing the surface of a plate-shaped sample, etching the sample surface with Nital, and then performing the cutting procedure according to JIS G 0551:2020.

[0044] (Fabrication of soft magnetic material plates SMP-1a to 1c, SMP-2a to 2c, and SMP-3a to 3c) Soft magnetic material plates SMP-1a to 1c were fabricated by performing a magnetic annealing process S3 on PSMP-1, a soft magnetic material plate precursor prepared in process S2, which involved heating it to (a) 750°C, (b) 900°C, and (c) 1000°C in a hydrogen gas atmosphere and cooling it at a rate of 150°C / h. Similarly, soft magnetic material plates SMP-2a to 2c and SMP-3a to 3c were fabricated by performing a magnetic annealing process S3 on PSMP-2 and PSMP-3, soft magnetic material plate precursors, which involved heating them to (a) 750°C, (b) 900°C, and (c) 1000°C in a hydrogen gas atmosphere and cooling them at a rate of 150°C / h.

[0045] The soft magnetic material plates SMP-1a to 1c (SMP-1 series) are samples made of Fe-Co alloy (SM-1) containing no Si component. The soft magnetic material plates SMP-2a to 2c (SMP-2 series) are samples made of Fe-Co-Si alloy (SM-2) whose Si component content deviates from the alloy composition specification of the present invention. The soft magnetic material plates SMP-3a to 3c (SMP-3 series) are samples made of Fe-Co-Si alloy (SM-3) that conforms to the alloy composition specification of the present invention.

[0046] [Experiment 2] (Investigation on properties of soft magnetic material plates SMP-1a to 1c, SMP-2a to 2c, SMP-3a to 3c) For each sample of the soft magnetic material plates SMP-1a to 1c, SMP-2a to 2c, and SMP-3a to 3c produced in Experiment 1, the average crystal grain size d was measured in the same manner as in Experiment 1. Additionally, the electrical resistivity ρ of each sample was measured by the direct current four-probe method in an environment at a temperature of 20°C, and converted to electrical conductivity σ. The results are shown in Table 1 described later.

[0047] Furthermore, the magnetic properties of the samples were measured by the H coil method (conforming to JIS C 2556:2015) using a BH loop analyzer (manufactured by IFG Co., Ltd., model IF-BH550) and a vertical yoke single-plate testing machine. In the DC magnetic property evaluation, the magnetic flux density B of the sample under the conditions of a temperature of 20°C and an external magnetic field of 5000 A / m 50 (unit: T) and maximum magnetic permeability μ m were measured. In the AC magnetic property evaluation, the total iron loss P of the sample under the conditions of a temperature of 20°C, a maximum magnetic flux density of 1.0 T, and an AC frequency of 5 kHz i-10 / 5k (unit: W / kg) was measured.

[0048] The skin depth δ at an AC frequency of 5 kHz was calculated from the measured maximum magnetic permeability μ m and electrical conductivity σ. Additionally, based on the measured total iron loss P i-10 / 5k , hysteresis loss P h (see formula 2), classical eddy current loss P e (see formula 3), and anomalous eddy current loss P calculated therefrom a were obtained. The results are shown in Table 2 described later.

[0049]

[0050] Fig. 2 is optical micrographs of the surfaces of soft magnetic material plates SMP-3a to 3c. As shown in Fig. 2, it can be confirmed that the average crystal grain size d due to recrystallization increases as the magnetic annealing temperature is raised. In addition, as shown in Table 1, the same tendency regarding the average crystal grain size d is also confirmed in the soft magnetic material plates SMP-1a to 1c and SMP-2a to 2c. On the other hand, regarding electrical resistivity ρ and electrical conductivity σ, the magnetic annealing temperature has almost no influence, and it is considered that the influence of the alloy composition is greater.

[0051]

[0052] As described above, the present invention aims to reduce total iron loss P in higher rotational speed regions / higher frequency regions (for example, 3 kHz or higher) than before without significantly impairing the magnetic properties of soft magnetic materials i and provides a soft magnetic material plate capable of achieving this object.

[0053] Regarding magnetic flux density B 50 , the SMP-3 series conforming to the alloy composition specification of the present invention has higher magnetization properties than conventional Fe-Si based electrical steel sheets, and as shown in Table 2, exhibits values comparable to those of the SMP-1 series composed of Fe-Co alloy containing no Si component, and it is confirmed that the soft magnetic magnetization properties are not significantly impaired.

[0054] Next, the total iron loss P i-10 / 5k will be discussed with reference to Tables 1 to 2.

[0055] First, looking at the SMP-1 series, the total iron loss P of soft magnetic material plate SMP-1b (magnetic annealing temperature: 900°C, average crystal grain size d = 29.8 µm) i-10 / 5k is lower than that of soft magnetic material plate SMP-1a (magnetic annealing temperature: 750°C, average crystal grain size d = 21.5 µm), and the total iron loss P of soft magnetic material plate SMP-1c (magnetic annealing temperature: 1000°C, average crystal grain size d = 238 µm) i-10 / 5k is higher than those of soft magnetic material plates SMP-1a and SMP-1b. The total iron loss P of soft magnetic material plate SMP-1a i-10 / 5kAlthough the mechanism by which it is larger than that of SMP-1b has not been fully elucidated, one possible factor is that the magnetic annealing of the magnetization region caused by processing strain was partially incomplete.

[0056] All Japan Iron and Steel Loss i-10 / 5k Contents (Hysteresis loss P) h , classical eddy current loss P e , abnormal eddy current loss P a Looking at each of these, as the magnetic annealing temperature increases and the average grain size d increases, the hysteresis loss P h It clearly decreases, and the classical eddy current loss P e While the overall trend is slightly decreasing, the abnormal eddy current loss P a The anomalous eddy current loss P is clearly increasing. In particular, in soft magnetic material plates SMP-1c where the average grain size d is greater than the skin depth δ, the anomalous eddy current loss P is increasing. a The total iron loss P is increasing rapidly. i-10 / 5k It accounts for the majority.

[0057] Similar trends are observed in the SMP-2 and SMP-3 series. From these observations, the abnormal eddy current loss P a To suppress the increase in grain size, it is desirable that the average grain size d is smaller than the skin depth δ.

[0058] On the other hand, from the perspective of the power-to-weight ratio and efficiency of electromechanical equipment, the total iron loss is ideally zero, but in reality, it is never zero. And current design requirements are for the total iron loss P i-10 / 5k It is said to be 650 W / kg or less. Looking at the SMP-1 to SMP-3 series from this perspective, it can be confirmed that SMP-3a and SMP-3b can meet this requirement.

[0059] The embodiments and experiments described above are explained to aid in understanding the present invention, and the present invention is not limited to the specific configurations described. For example, it is possible to replace some of the configurations of the embodiments with configurations that are common knowledge to those skilled in the art, and it is also possible to add configurations that are common knowledge to those skilled in the art to the configurations of the embodiments. In other words, the present invention allows for the deletion, substitution, and addition of some of the configurations of the embodiments and experiments specified herein, as long as it does not depart from the technical spirit of the invention.

Claims

1. A soft magnetic material plate comprising 1 atomic% to less than 48 atomic% of Co and 0.5 atomic% to 8 atomic% of Si, wherein the total amount of Co and Si is 1.5 atomic% to less than 48 atomic%, and the remainder is Fe and impurities, and the soft magnetic material plate has a maximum magnetic permeability μ m A soft magnetic Fe-Co-Si alloy sheet characterized in that the average grain size d (m) of the surface has the relationship "0.25δ≦d≦δ" with respect to the skin depth δ (m), which is a function of (H / m), conductivity σ (S / m), and usable frequency f (Hz).

2. In the soft magnetic Fe-Co-Si alloy plate according to claim 1, the conductivity σ is 4.3 × 10 8 A soft magnetic Fe-Co-Si alloy sheet characterized by having a density of S / m or less.

3. A soft magnetic Fe-Co-Si alloy sheet according to claim 1, characterized in that the thickness of the soft magnetic material sheet is more than twice the surface depth δ and is 0.1 mm or more and 1 mm or less.

4. A soft magnetic Fe-Co-Si alloy sheet according to claim 2, characterized in that the thickness of the soft magnetic material sheet is more than twice the surface depth δ and is 0.1 mm or more and 1 mm or less.

5. A soft magnetic Fe-Co-Si alloy sheet according to any one of claims 1 to 4, characterized in that the total iron loss in the AC magnetic property evaluation under the conditions of a maximum magnetic flux density of 1 T and an AC frequency of 5 kHz is 650 W / kg or less.

6. In the soft magnetic Fe-Co-Si alloy sheet according to any one of claims 1 to 4, the magnetic flux density B in the DC magnetic property evaluation under the condition of an external magnetic field of 5000 A / m 50 A soft magnetic Fe-Co-Si alloy sheet characterized by having a T of 1.9 or higher.

7. In the soft magnetic Fe-Co-Si alloy plate according to claim 5, the magnetic flux density B in the DC magnetic property evaluation under the condition of an external magnetic field of 5000 A / m 50 A soft magnetic Fe-Co-Si alloy sheet characterized by having a T of 1.9 or higher.

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