JP2022058246A - AMORPHOUS Fe-BASED ALLOY PLATE AND MANUFACTURING METHOD THEREOF - Google Patents

Abstract

To provide an amorphous Fe-based alloy plate which enables manufacture of an iron core having little iron loss with respect to high frequency AC current, and a manufacturing method thereof.SOLUTION: An amorphous Fe-based alloy plate 1 is comprised of an amorphous Fe-based alloy including 77 to 83 atom% of Fe, 4 to 15 atom% of Si, 8 to 15 atom% of B, and 0 to 3 atom% of C, and has a thickness of 35 μm or more. When a stripe domain of a freely solidified surface 11 is observed using a Kerr effect microscope, the amorphous Fe-based alloy plate 1 includes a stripe domain in which a first domain M1 and a second domain M2 are alternately arranged in a casting direction, and a region S1 in which an angle to the casting direction of the first domain M1 is 60 degrees or more and 120 degrees or less, a width is 30 μm or more and a region S2 in which the angle to the casting direction of the second domain M2 is 60 degrees or more and 120 degrees or less, and the width is 30 μm or less occupy 2.0% or more of an area of the freely solidified surface 11 can be observed.SELECTED DRAWING: Figure 8

Description

The present invention relates to an amorphous Fe-based alloy plate and a method for producing the same.

Electrical steel sheets are often used for the iron cores of coils in motors and the like mounted on reactors and electric vehicles. When a coil with an iron core is energized, an energy loss called iron loss due to the physical characteristics of the iron core occurs.

The iron loss is mainly composed of a hysteresis loss generated when the magnetic domain of the iron core changes the direction of the magnetic field and an eddy current loss caused by the eddy current flowing in the iron core. Since the magnitude of eddy current loss is theoretically proportional to the square of the thickness of the iron core, a technique for forming an iron core by laminating relatively thin electromagnetic steel sheets has been conventionally known (for example,). Patent Document 1).

On the other hand, the magnitude of the hysteresis loss changes according to the physical properties of the materials constituting the iron core. In recent years, an iron core made of an amorphous Fe-based alloy strip having smaller hysteresis loss and eddy current loss than an electromagnetic steel sheet has been studied. For example, Patent Document 2 contains Fe _{100-x-y-z Si x} By P _z (atomic%) as a main component, and x, y and z are 0.5 ≦ x ≦ 15 and 5 ≦ y ≦ 25, respectively. , Z ≦ 15, 18 ≦ x + y + z ≦ 30, Mn is 0.01% by mass or more and 0.3% by mass or less, Al is 0.0001% by mass or more and 0.01% by mass or less, Ti. Is contained in an amount of 0.001% by mass or more and 0.03% by mass or less, Cu is contained in an amount of 0.005% by mass or more and 0.2% by mass or less, and S is contained in an amount of 0.001% by mass or more and 0.05% by mass or less. The amorphous soft magnetic alloy to be described is described. Further, Patent Document 2 describes that the thickness of the thin band made of an amorphous soft magnetic alloy is in the range of 40 μm to 350 μm.

Japanese Unexamined Patent Publication No. 61-190017 Japanese Unexamined Patent Publication No. 2009-174034

In recent years, in order to make the reactor, motor, and the like smaller, it is required to increase the frequency of the alternating current flowing through the coil. Since the eddy current loss is also proportional to the square of the frequency of the alternating magnetic field, the higher the frequency of the alternating current, the larger the eddy current loss. Therefore, an iron core capable of reducing eddy current loss even with high-frequency alternating current is strongly desired.

However, the Fe-based amorphous alloy strip of Patent Document 2 has a problem that iron loss worsens as the thickness increases.

The present invention has been made in view of this background, and an object of the present invention is to provide an amorphous Fe-based alloy plate capable of producing an iron core having a small iron loss even with a high frequency alternating current, and a method for producing the same. be.

One aspect of the present invention is an amorphous Fe-based alloy plate produced by a single-roll quenching solidification method and having a free solidification surface and a roll contact surface.
Fe (iron): 77 atomic% or more and 83 atomic% or less, Si (silicon): 4 atomic% or more and 15 atomic% or less, B (boron): 8 atomic% or more and 15 atomic% or less, and C (carbon): 0 atomic% or less. It is made of an amorphous Fe-based alloy having a chemical component containing the above 3 atomic%.
It has a thickness of 35 μm or more and has a thickness of 35 μm or more.
When observing the magnetic domain structure of the free solidification surface using a Kerr effect microscope,
The first magnetic domain having a magnetization in a direction different from the casting orthogonal direction and the second magnetic domain having a magnetization in a different direction with respect to both the casting orthogonal direction and the magnetization direction of the first magnetic domain are alternately arranged in the casting direction. Includes striped magnetic domains and
The region of the first magnetic domain where the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less and the width is 30 μm or less, and the region of the second magnetic domain where the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less and the width is 30 μm. The following regions are in the amorphous Fe-based alloy plate from which the magnetic domain structure occupying 2.0% or more of the area of the free solidification surface can be observed.

Another aspect of the present invention is the method for producing an amorphous Fe-based alloy plate according to the above aspect.
Fe: Fe-based alloy molten metal containing 77 atomic% or more and 83 atomic% or less, Si: 4 atomic% or more and 15 atomic% or less, B: 8 atomic% or more and 15 atomic% or less, and C: 0 atomic% or more and 3 atomic% or less. Prepare and
An amorphous Fe-based alloy plate for casting the amorphous Fe-based alloy plate by discharging the Fe-based alloy molten metal from a casting nozzle to a cooling roll and quenching the Fe-based alloy molten metal on the surface of the cooling roll. It is in the manufacturing method of.

The amorphous Fe-based alloy plate is made of an amorphous Fe-based alloy having the specific chemical composition and has a thickness of 35 μm or more. As a result, the amorphous Fe-based alloy plate can realize magnetic properties such that a specific magnetic domain structure appears on the free solidification surface. The amorphous Fe-based alloy plate having the magnetic properties represented by the specific magnetic domain structure can reduce iron loss even with respect to a high-frequency alternating current.

Further, the amorphous Fe-based alloy plate can be made thicker than the conventional Fe-based amorphous alloy ribbon while suppressing an increase in iron loss due to a high-frequency alternating current. Therefore, by laminating or winding a plurality of the amorphous Fe-based alloy plates to produce an iron core, the number of laminated amorphous Fe-based alloy plates on the iron core can be reduced as compared with the conventional case. .. As a result, the productivity of the iron core can be improved.

Further, in this case, the number of gaps formed between the amorphous Fe-based alloy plates in the iron core is reduced, and the space factor of the iron core, that is, the ratio of the volume of the amorphous Fe-based alloy plate to the volume of the iron core. Can be made higher. Therefore, according to the amorphous Fe-based alloy plate, the iron core can be made smaller more easily.

Further, in the method for manufacturing the amorphous Fe-based alloy plate, the Fe-based alloy molten metal having the specific chemical component is discharged from the casting nozzle to the cooling roll, and the Fe-based alloy molten metal is rapidly cooled on the surface of the cooling roll. do. Since the molten Fe-based alloy in contact with the cooling roll solidifies while being compressed by quenching, the amorphous Fe-based alloy plate after casting has components in both the casting direction and the casting orthogonal direction in the vicinity of the roll contact surface. It is considered that compressive stress is generated. On the other hand, the surface of the molten Fe-based alloy, that is, the surface not in contact with the cooling roll, solidifies after the surface in contact with the cooling roll solidifies. As a result, it is considered that tension having components in both the casting direction and the casting perpendicular direction is generated in the vicinity of the free solidification surface in the amorphous Fe-based alloy plate.

At this time, by casting so that the thickness of the amorphous Fe-based alloy plate is within the above-mentioned specific range, the tension generated in the vicinity of the free solidification surface of the amorphous Fe-based alloy plate can be sufficiently increased. can. Then, by annealing the amorphous Fe-based alloy plate after casting, the components in the direction perpendicular to the casting are alleviated while avoiding the excessive relaxation of the components in the direction perpendicular to the casting in the vicinity of the free solidification surface. Can be done. As a result, it is possible to impart the magnetic properties represented by the specific magnetic domain structure to the free solidified surface of the amorphous Fe-based alloy plate.

As described above, according to the above aspect, it is possible to provide an amorphous Fe-based alloy plate capable of producing an iron core having a small iron loss even with a high frequency alternating current and a method for producing the same.

FIG. 1 is an explanatory diagram schematically showing the magnetic domain structure of the free solidification surface of the amorphous Fe-based alloy plate in a state where the strength of the magnetic field is relatively weak. FIG. 2 is an explanatory diagram schematically showing the magnetic domain structure of the free solidification surface of the amorphous Fe-based alloy plate when the strength of the magnetic field increases from the state of FIG. 1. FIG. 3 is an explanatory diagram schematically showing the magnetic domain structure of the free solidification surface of the amorphous Fe-based alloy plate when the strength of the magnetic field increases from the state of FIG. 2. FIG. 4 is an explanatory diagram schematically showing the magnetic domain structure of the free solidification surface of the amorphous Fe-based alloy plate when the strength of the magnetic field increases from the state of FIG. FIG. 5 is an explanatory diagram schematically showing the magnetic domain structure of the free solidification surface of the amorphous Fe-based alloy plate when the strength of the magnetic field increases from the state of FIG. FIG. 6 is a microscope image showing the magnetic domain structure of the free solidification surface in a state where a magnetic field of 30.4 Oe is applied to the test material 7 of Example 1. FIG. 7 is a microscope image showing the magnetic domain structure of the free solidification surface in a state where a magnetic field of 45.4 Oe is applied to the test material 7 of Example 1. FIG. 8 is a microscope image showing the magnetic domain structure of the free solidification surface in a state where a magnetic field of 50.5 Oe is applied to the test material 7 of Example 1. FIG. 9 is a microscope image showing the magnetic domain structure of the free solidification surface in a state where a magnetic field of 55.5 Oe is applied to the test material 7 of Example 1. FIG. 10 is a microscope image showing the magnetic domain structure of the free solidification surface in a state where a magnetic field of 100.7 Oe is applied to the test material 7 of Example 1. FIG. 11 is an explanatory diagram showing a main part of the casting apparatus used in the first embodiment. FIG. 12 is an explanatory diagram showing iron loss of the test materials 5 to 9 when an alternating magnetic field having a frequency of 400 Hz is applied in the first embodiment. FIG. 13 is an explanatory diagram showing iron loss of the test materials 5 to 9 when an alternating magnetic field having a frequency of 1 kHz is applied in the first embodiment. FIG. 14 is an explanatory diagram showing iron loss of the test materials 5 to 9 when an alternating magnetic field having a frequency of 10 kHz is applied in the first embodiment. FIG. 15 is an explanatory diagram showing iron loss of the test materials 5 to 9 when an alternating magnetic field having a frequency of 20 kHz is applied in the first embodiment. FIG. 16 is an explanatory diagram showing iron loss of the test materials 1 to 4 when an alternating magnetic field having a frequency of 400 Hz is applied in the first embodiment. FIG. 17 is an explanatory diagram showing iron loss of the test materials 1 to 4 when an alternating magnetic field having a frequency of 1 kHz is applied in the first embodiment. FIG. 18 is an explanatory diagram showing iron loss of the test materials 1 to 4 when an alternating magnetic field having a frequency of 10 kHz is applied in the first embodiment. FIG. 19 is an explanatory diagram showing iron loss of the test materials 1 to 4 when an alternating magnetic field having a frequency of 20 kHz is applied in the first embodiment. FIG. 20 is an explanatory diagram showing a torque curve obtained by magnetic anisotropy torque measurement in Example 2.

(Amorphous Fe-based alloy plate)
The amorphous Fe-based alloy plate is manufactured by a single-roll quenching solidification method, and has a free solidification surface and a roll contact surface. The above-mentioned "roll contact surface" refers to the surface of the amorphous Fe-based alloy plate that was in contact with the cooling roll during the manufacturing process, and the "free solidification surface" refers to the back surface of the roll contact surface. .. The roll contact surface has fine streaky irregularities formed by transferring the surface shape of the cooling roll. On the other hand, the free solidified surface is smoother than the roll contact surface because it is not in contact with the cooling roll during the manufacturing process. Therefore, in order to discriminate between the free solidification surface and the roll contact surface of the amorphous Fe-based alloy plate, the plate surface of the amorphous Fe-based alloy plate may be visually observed.

Further, the casting direction and the casting orthogonal direction of the amorphous Fe-based alloy plate are air pockets existing on the roll contact surface, that is, the Fe-based alloy molten metal and the cooling roll in the manufacturing process of the amorphous Fe-based alloy plate. It can be judged based on the direction of the trace of the bubble bitten between and. In the single-roll quenching solidification method, when the Fe-based alloy molten metal is discharged onto the cooling roll, gas is caught between the Fe-based alloy molten metal and the cooling roll. Since the cooling roll rotates at high speed, bubbles between the molten Fe-based alloy and the cooling roll are stretched along the rotation direction of the cooling roll, that is, the casting direction. As a result, an air pocket extending in a direction parallel to the casting direction is formed on the roll contact surface. Therefore, the direction parallel to the longitudinal direction of the air pocket may be determined to be the casting direction of the amorphous Fe-based alloy plate, and the direction perpendicular to the longitudinal direction of the air pocket may be determined to be the casting orthogonal direction.

The amorphous Fe-based alloy plate has Fe: 77 atomic% or more and 83 atomic% or less, Si: 4 atomic% or more and 15 atomic% or less, B: 8 atomic% or more and 15 atomic% or less, and C: 0 atomic% or more 3 It is composed of an amorphous Fe-based alloy having a chemical component containing atomic% or less. That is, the amorphous Fe-based alloy plate may be composed of a ternary amorphous Fe-based alloy composed of Fe, Si, and B, and may be composed of a quaternary system composed of Fe, Si, B, and C. It may be composed of an amorphous Fe-based alloy.

By setting the content of Fe atoms, the content of Si atoms, the content of B atoms and the content of C atoms in the amorphous Fe-based alloy within the above-mentioned specific ranges, the amorphous Fe-based alloy plate can be obtained. Performance can be improved. When the content of Fe atoms in the amorphous Fe-based alloy is higher than the specific range, the iron loss of the amorphous Fe-based alloy plate may increase. When the content of Fe atoms in the amorphous Fe-based alloy plate is lower than the above-mentioned specific range, the saturation magnetic flux density of the amorphous Fe-based alloy plate may decrease.

The Si atoms in the amorphous Fe-based alloy plate have the effect of reducing the coercive force of the amorphous Fe-based alloy plate and promoting the formation of the amorphous phase. When the content of Si atoms is higher than the above-mentioned specific range, the saturation magnetic flux density of the amorphous Fe-based alloy plate may decrease. When the content of Si atoms is lower than the above-mentioned specific range, a crystal phase may be easily formed in the amorphous Fe-based alloy plate.

The B atom in the amorphous Fe-based alloy plate has an action of promoting the formation of an amorphous phase. When the content of B atoms is higher than the above-mentioned specific range, the content of Fe atoms becomes relatively low, which may lead to a decrease in the saturation magnetic flux density of the amorphous Fe-based alloy plate. When the content of B atoms is lower than the above-mentioned specific range, a crystal phase may be easily formed in the amorphous Fe-based alloy plate.

The C atom in the amorphous Fe-based alloy plate has an action of enhancing the wettability of the Fe-based alloy molten metal with respect to the cooling roll. By setting the C atom content to the above-mentioned specific range, the Fe-based alloy molten metal can be cooled more quickly by the cooling roll. Thereby, the amorphous Fe-based alloy plate can be manufactured more easily. If the content of C atoms is excessively high, the performance of the amorphous Fe-based alloy plate may easily fluctuate when the amorphous Fe-based alloy plate is used for a long period of time. Further, in this case, the content of Fe atoms becomes relatively low, which may lead to a decrease in the saturation magnetic flux density of the amorphous Fe-based alloy plate.

Whether or not the alloy constituting the Fe-based alloy plate is amorphous can be determined based on the X-ray diffraction chart of the Fe-based alloy plate. That is, when a halo pattern indicating the presence of amorphous appears on the X-ray diffraction chart of the Fe-based alloy plate, it may be determined that the alloy constituting the Fe-based alloy plate is amorphous.

The amorphous Fe-based alloy plate is used at any stage when the magnetic domain structure of the free solidification surface is observed while gradually increasing the strength of the magnetic field applied to the observation target using a car effect microscope. , The first magnetic domain having a magnetization different from the casting orthogonal direction and the second magnetic domain having different directions with respect to both the casting orthogonal direction and the magnetization direction of the first magnetic domain are alternately arranged in the casting direction. The region including the striped magnetic domain and the angle of the first magnetic domain with respect to the casting direction is 60 degrees or more and 120 degrees or less and the width is 30 μm or less, and the angle of the second magnetic domain with respect to the casting direction is 60. The region having a temperature of 120 degrees or more and a width of 30 μm or less is configured so that a magnetic domain structure occupying 2.0% or more of the area of the free solidification surface appears.

The width of the first magnetic domain and the second magnetic domain described above is the shortest distance from one domain wall in the casting direction to the other domain wall in each magnetic domain. The first magnetic domain and the second magnetic domain may include a region where the angle with respect to the casting direction is less than 60 degrees, a region larger than 120 degrees, and a region having a width larger than 30 μm. Further, magnetic domains other than the first magnetic domain and the second magnetic domain may exist on the free solidification surface.

In each first magnetic domain, a region in which the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less and the width is 30 μm or less is specifically specified as follows. First, the angle formed by the domain wall surrounding each first magnetic domain and the casting direction is determined at all positions of the domain wall existing in the microscope image. If the domain wall does not include a portion where the angle with respect to the casting direction is less than 60 degrees or exceeds 120 degrees, the entire first magnetic domain surrounded by the domain wall is covered in the range where the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less. Judge as a certain area.

On the other hand, when the domain wall includes a portion where the angle with respect to the casting direction is less than 60 degrees or exceeds 120 degrees, the end point of the portion of the domain wall whose angle with respect to the casting direction is 60 degrees or more and 120 degrees or less is determined. Then, the portion of the domain wall surrounded by the portion where the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less and the straight line connecting the end points described above is in the range where the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less. It is judged that the area is.

The width of the magnetic domain in the region determined in this way is measured at various positions, and the region having a width of 30 μm or less is determined. From the above, it is possible to specify a region in which the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less and the width is 30 μm or less in each first magnetic domain.

The method for specifying the region where the angle with respect to the casting direction in each second magnetic domain is in the range of 60 degrees or more and 120 degrees or less and the width is 30 μm or less is the same as the above-mentioned method.

Since the amorphous Fe-based alloy plate has the magnetic properties specified by the above-mentioned magnetic domain structure, it is possible to reduce the eddy current loss even with respect to a high-frequency alternating current. In the present specification, the "high frequency alternating current" means an alternating current having a frequency of 400 Hz or higher.

Further, in the above-mentioned magnetic domain structure, the region of the first magnetic domain having a width of 30 μm or less and the region of the second magnetic domain having a width of 30 μm or less occupy 5.0% or more of the area of the free solidification surface. It is preferable to occupy. In this case, the eddy current loss with respect to the high frequency alternating current can be further reduced.

The magnetic domain structure described above is a structure that appears at any stage when the free solidification surface is observed while gradually increasing the strength of the magnetic field applied to the observation target using a Kerr effect microscope. In a state where the amorphous Fe-based alloy plate is used as an iron core or the like, a magnetic domain structure different from the specific magnetic domain structure can be formed depending on the frequency and amplitude of an alternating current.

Further, the specific observation conditions when the above-mentioned magnetic domain structure appears may change depending on the size of the amorphous Fe-based alloy plate to be observed, the size of the coil to which the magnetic field is applied, and the like. For example, when using "BH-4753-NML-ASM" manufactured by NeoArc Co., Ltd. as a Kerr effect microscope and observing an amorphous Fe-based alloy plate having a square shape with a side of about 10 mm, the observation target is 50 Oe. By applying a magnetic field, the above-mentioned magnetic domain structure can be observed.

The amorphous Fe-based alloy plate can easily realize the magnetic properties specified by the above-mentioned magnetic domain structure by sufficiently increasing the component of the tension in the vicinity of the free solidification surface in the direction perpendicular to the casting. .. The amorphous Fe-based alloy plate having such magnetic properties can reduce iron loss even with respect to a high-frequency alternating current.

The reason why the eddy current loss can be reduced by the amorphous Fe-based alloy plate in which the specific magnetic domain structure described above appears is not always clear at this time, but for example, the eddy current loss can be reduced for the following reasons. Is presumed to be possible. Eddy current loss is composed of two components: classical eddy current loss, that is, loss assuming that the magnetization changes uniformly, and abnormal eddy current loss, that is, loss due to the movement of the domain wall. There is. Of these, the factor that greatly affects the eddy current loss with respect to high-frequency alternating current is the abnormal eddy current loss.

Since the amorphous Fe-based alloy plate is a soft magnetic material, there are many magnetic domains having magnetizations in various directions on the free solidification surface in a state where a magnetic field is not applied, and as a whole, there are many magnetic domains. The magnetization is in a state where it does not face a specific direction. When an alternating magnetic field is applied to the amorphous Fe-based alloy plate, magnetic domains corresponding to the direction and strength of the magnetic field are formed on the free solidified surface. For example, when an alternating magnetic field H in a direction parallel to the casting direction is applied to the amorphous Fe-based alloy plate 1, as shown in FIG. 1, the first magnetic domain M1 and the second magnetic domain M2 are applied to the free solidification surface 11. A magnetic domain structure appears that includes striped magnetic domains in which and are alternately arranged.

At this time, the direction of magnetization of the first magnetic domain M1 is different from the casting direction and the casting perpendicular direction. The magnetization of the first magnetic domain M1 is directed to, for example, a direction in which the angle formed by the casting perpendicular direction and the magnetization direction is smaller than the angle formed by the casting direction and the magnetization direction. On the other hand, the magnetization of the second magnetic domain M2 faces, for example, a direction substantially opposite to the direction of the magnetization of the first magnetic domain M1. In the following description, for convenience, the magnetic domain in which the angle between the direction of the magnetic field applied to the test piece and the direction of magnetization is smaller is defined as the first magnetic domain M1.

The approximate magnetization direction of the first magnetic domain M1 and the second magnetic domain M2 can be determined by the following method. First, a microscope image when a magnetic field is applied in the casting direction and a microscope image when a magnetic field is applied in the direction perpendicular to the casting are acquired. In the microscope image observed by the Kerr effect microscope, the smaller the magnetic domain where the angle between the direction of the magnetic field applied to the observation target and the direction of magnetization is smaller, the brighter it is displayed, and the angle between the direction of the magnetic field and the direction of magnetization is displayed. The larger the magnetic domain, the darker it is displayed.

Therefore, the difference in brightness between the first magnetic domain M1 and the second magnetic domain M2 in the microscope image when the magnetic field is applied in the casting perpendicular direction is the first magnetic domain M1 and the second magnetic domain in the microscope image when the magnetic field is applied in the casting direction. When it is larger than the difference in brightness from M2, it can be determined that the magnetizations of the first magnetic domain M1 and the second magnetic domain M2 are oriented in a direction close to the casting orthogonal direction. On the contrary, the difference in brightness between the first magnetic domain M1 and the second magnetic domain M2 in the microscope image when the magnetic field is applied in the casting direction is the first magnetic domain M1 and the second magnetic domain M1 in the microscope image when the magnetic field is applied in the casting perpendicular direction. When it is larger than the difference in brightness from the magnetic domain M2, it can be determined that the magnetizations of the first magnetic domain M1 and the second magnetic domain M2 are oriented in a direction close to the casting direction.

When the strength of the magnetic field increases from the state shown in FIG. 1, the directions of magnetization of the first magnetic domain M1 and the second magnetic domain M2 gradually change according to the direction of the magnetic field. Further, in order to minimize the static magnetic energy, as shown in FIG. 2, the first magnetic domain M1 has a different magnetization direction from the first magnetic domain M1 in the region where the magnetic field strength is weak. The two magnetic domains M2 are newly formed by magnetization rotation starting from the surface or the inside of the amorphous Fe base alloy plate. Similarly, in the region that was the second magnetic domain M2 in the state where the strength of the magnetic field is weak, the first magnetic domain M1 having a different magnetization direction from the second magnetic domain M2 is newly formed by the magnetization rotation. That is, when the strength of the magnetic field applied to the amorphous Fe-based alloy plate becomes stronger, the magnetic domain of the free solidified surface is subdivided. Further, when the strength of the magnetic field becomes stronger from the state shown in FIG. 2, the magnetic domain of the free solidification surface is further subdivided as shown in FIG.

When the strength of the magnetic field becomes stronger from the state shown in FIG. 3, the amount of increase in the static energy when the magnetic domains are merged by the magnetization rotation is larger than the amount of increase in the static energy when the magnetic domains are subdivided. Becomes smaller. Therefore, in a state where the strength of the magnetic field is increased to some extent, as shown in FIG. 4, the second magnetic domain M2 having a larger angle between the direction of the magnetic field and the direction of magnetization disappears due to the rotation of the magnetization, and the adjacent second magnetic domain M2 disappears. 1 Merged into magnetic domain M1. Finally, when the magnetic flux density of the amorphous Fe-based alloy plate is saturated, the second magnetic domain M2 completely disappears as shown in FIG.

As described above, in the amorphous Fe-based alloy plate, when the strength of the magnetic field fluctuates, the magnetic domains are likely to be subdivided or merged. Then, in the process of subdividing or merging the magnetic domains, the movement of the domain wall W, which causes an abnormal eddy current loss, is suppressed. Therefore, it is considered that the amorphous Fe-based alloy plate can reduce the eddy current loss with respect to the high-frequency alternating current by suppressing the movement of the domain wall W when the external magnetic field fluctuates.

The thickness of the amorphous Fe-based alloy plate is 35 μm or more. By setting the thickness of the amorphous Fe-based alloy plate to 35 μm or more, the component of the tension in the vicinity of the free solidification surface of the amorphous Fe-based alloy plate in the direction perpendicular to the casting can be sufficiently increased. As a result, the amorphous Fe-based alloy plate is imparted with the magnetic properties specified by the above-mentioned magnetic domain structure, and iron loss can be reduced even with respect to a high-frequency alternating current.

From the viewpoint of further enhancing the above-mentioned effects, the thickness of the amorphous Fe-based alloy plate is preferably 40 μm or more.

If the thickness of the amorphous Fe-based alloy plate is less than 35 μm, the stress generated inside in the manufacturing process of the amorphous Fe-based alloy plate may be insufficient. Therefore, in this case, it becomes difficult to impart the magnetic properties represented by the specific magnetic domain structure to the amorphous Fe-based alloy plate, and the eddy current of the amorphous Fe-based alloy plate with respect to the high-frequency alternating current. It may be difficult to reduce the loss.

On the other hand, when the thickness of the amorphous Fe-based alloy plate becomes excessively thick, the effect of increasing the eddy current loss due to the thickness becomes higher than the effect of reducing the abnormal eddy current loss described above, and the amorphous Fe-based alloy plate becomes larger. May lead to an increase in eddy current loss. From the viewpoint of avoiding such a problem, the thickness of the amorphous Fe-based alloy plate is preferably 110 μm or less.

The thickness of the amorphous Fe-based alloy plate is a value calculated by dividing the mass of the amorphous Fe-based alloy plate by the density of the Fe-based alloy plate and the area of the plate surface.

The saturation magnetic flux density of the amorphous Fe-based alloy plate is preferably 1.5 T or more. By producing an iron core using such an amorphous Fe-based alloy plate, the iron core can be made smaller more easily.

The amorphous Fe-based alloy plate has a torque curve per unit volume obtained by applying a magnetic field in a direction parallel to the free solidification surface and measuring the magnetic anisotropy torque per unit volume. The angle at which the value of the magnetic anisotropy torque is 0 μN ・ m / mm ³ is −10 ° or more and 10 ° or less, 35 ° or more and 55 ° or less, 80 ° or more and 100 ° or less, and 125 ° or more with respect to the casting direction. It is preferable to have the characteristic that one place is present in each of the range of 145 ° or less.

In the magnetic anisotropy torque measurement, the angle at which the value of the magnetic anisotropy torque is 0 μN · m / mm ³ corresponds to the direction of the easy-to-magnetize axis or the difficult-to-magnetize axis. Therefore, in the torque curve, the amorphous Fe-based alloy plate having an angle at which the value of the magnetic anisotropy torque is 0 μN ・ m / mm ³ in each of the above-mentioned four ranges is relative to the free solidified surface. It has two easy-to-magnetize axes and two difficult-to-magnetize axes in parallel directions. Such magnetic properties are called biaxial magnetic anisotropy. It is considered that the magnetic domain of the amorphous Fe-based alloy plate having biaxial magnetic anisotropy is subdivided in order to reduce the static magnetic energy generated by the magnetic poles generated on the surface when the magnetization rotates in the magnetic field direction. As a result, the amorphous Fe-based alloy plate having biaxial magnetic anisotropy is more effective in iron loss against high-frequency alternating current than the amorphous Fe-based alloy plate having uniaxial magnetic anisotropy. Can be reduced to.

From the same viewpoint, the root mean square of the magnetic anisotropy torque per unit volume of the torque curve in the range of 0 ° to 180 ° with respect to the casting direction is 1.4 × 10 ^-3 μN · m /. It is more preferably mm ³ or more.

The above-mentioned magnetic anisotropy torque can be measured using a magnetic anisotropy torque meter (for example, "TM-TR2750-HGC type" manufactured by Tamagawa Seisakusho Co., Ltd.). The magnetic anisotropy torque is measured at room temperature, and the strength of the magnetic field applied to the sample is 500 Oe. The unprocessed torque curve obtained by the magnetic anisotropy torque measurement may contain noise. In order to mitigate the influence of noise, the unprocessed torque curve is smoothed, and the presence or absence of biaxial magnetic anisotropy is determined based on the smoothed torque curve, and the squared average square root of the magnetic anisotropy torque. Will be calculated. The smoothing process is, for example, a simple moving average in which the values of the magnetic anisotropy torque at the measurement points included in the range of -10 ° or more and + 10 ° or less are arithmetically averaged with respect to the measurement point to be the smoothing process. The law can be adopted.

The value of the root mean square of the magnetic anisotropy torque per unit volume is specifically calculated as follows. First, in the torque curve, the value of the magnetic anisotropy torque per unit volume of the measurement points whose angle with respect to the casting direction is included in the range of 0 ° to 180 ° is squared, and then the arithmetic mean of these values is calculated. .. The square root of this arithmetic mean value is defined as the root mean square of the magnetic anisotropy torque per unit volume.

From another point of view, the amorphous Fe-based alloy plate according to the present invention can be grasped as the following invention. That is, the amorphous Fe-based alloy plate is manufactured by a single-roll quenching solidification method, and has a free solidification surface and a roll contact surface.
Fe: 77 atomic% or more and 83 atomic% or less, Si: 4 atomic% or more and 15 atomic% or less, B: 8 atomic% or more and 15 atomic% or less, and C: 0 atomic% or more and 3 atomic% or less. Consisting of crystalline Fe-based alloy
It has a thickness of 35 μm or more and has a thickness of 35 μm or more.
In the torque curve obtained by applying a magnetic field in a direction parallel to the free solidification surface and measuring the magnetic anisotropy torque per unit volume, the value of the magnetic anisotropy torque is 0 μN · m / mm. There is one angle of ³ in the range of -10 ° or more and 10 ° or less, 35 ° or more and 55 ° or less, 80 ° or more and 100 ° or less, and 125 ° or more and 145 ° or less with respect to the casting direction. ing.

The amorphous Fe-based alloy plate is made of an amorphous Fe-based alloy having the specific chemical composition, has a thickness of 35 μm or more, and has biaxial magnetic anisotropy. As a result, the amorphous Fe-based alloy plate can reduce iron loss even with respect to high-frequency alternating current.

Further, the amorphous Fe-based alloy plate can be thicker than the conventional Fe-based amorphous alloy ribbon while suppressing an increase in iron loss due to a high-frequency alternating current. Therefore, by laminating or winding a plurality of the amorphous Fe-based alloy plates to produce an iron core, the number of laminated amorphous Fe-based alloy plates on the iron core can be reduced as compared with the conventional case. .. As a result, the productivity of the iron core can be improved.

Further, in this case, the number of gaps formed between the amorphous Fe-based alloy plates in the iron core is reduced, and the space factor of the iron core, that is, the ratio of the volume of the amorphous Fe-based alloy plate to the volume of the iron core. Can be made higher. Therefore, according to the amorphous Fe-based alloy plate, the iron core can be made smaller more easily.

From the viewpoint of obtaining these effects more reliably, the root mean square of the magnetic anisotropy torque per unit volume of the torque curve in the range of 0 ° to 180 ° with respect to the casting direction is 1.4 ×. It is more preferably 10 ^-3 μN · m / mm ³ or more.

(Manufacturing method of amorphous Fe-based alloy plate)
The amorphous Fe-based alloy plate can be produced by a so-called single-roll quenching solidification method. Specifically, in manufacturing an amorphous Fe-based alloy plate, Fe: 77 atomic% or more and 83 atomic% or less, Si: 4 atomic% or more and 15 atomic% or less, B: 8 atomic% or more and 15 atomic% or less. And C: Prepare a molten Fe-based alloy containing 0 atomic% or more and 3 atomic% or less.
The amorphous Fe-based alloy plate is cast by discharging the Fe-based alloy molten metal from a casting nozzle to a cooling roll and quenching the Fe-based alloy molten metal on the surface of the cooling roll.
The amorphous Fe-based alloy plate may be annealed without applying a magnetic field.

As the molten Fe-based alloy used in the production method, one prepared by a conventional method can be used. The temperature of the molten Fe-based alloy is preferably, for example, about 50 ° C. to 300 ° C. higher than the melting point of the Fe-based alloy.

Next, the Fe-based alloy molten metal is rapidly cooled on the surface of the cooling roll by discharging the Fe-based alloy molten metal from the casting nozzle to the cooling roll. The molten Fe-based alloy discharged to the surface of the cooling roll is rapidly cooled by the cooling roll and solidified on the cooling roll.

When the molten Fe-based alloy comes into contact with the cooling roll, the molten Fe-based alloy in the vicinity of the cooling roll shrinks due to cooling. As a result, compressive stress can be generated in the vicinity of the roll contact surface in the amorphous Fe-based alloy plate.

On the other hand, the molten Fe-based alloy at a position away from the cooling roll is cooled more slowly than the molten Fe-based alloy near the cooling roll. As a result, a surface tension having components in both the casting direction and the casting perpendicular direction is generated in the vicinity of the free solidification surface in the amorphous Fe-based alloy plate. In the amorphous Fe-based alloy plate, the casting direction component of tension is more likely to be relaxed by annealing than the casting perpendicular direction component of tension. Therefore, by heating the amorphous Fe-based alloy plate to an appropriate temperature and annealing it, casting is performed while avoiding excessive relaxation of the components in the direction perpendicular to the casting of the tension inside the amorphous Fe-based alloy plate. The directional component can be relaxed.

Therefore, by annealing the amorphous Fe-based alloy plate after casting, a tension having a large size of the component in the direction perpendicular to the casting can remain in the vicinity of the free solidification surface of the amorphous Fe-based alloy plate. can. Since the easy axis of magnetization in an amorphous material tends to be oriented in the main axis direction of surface tension, the easy axis of magnetization is oriented perpendicular to the casting direction in the vicinity of the free solidification surface of the amorphous Fe-based alloy plate. Cheap. That is, the amorphous Fe-based alloy plate has an induced magnetic anisotropy having an axis that is easy to magnetize in the direction perpendicular to the casting.

As described above, the stress inside the amorphous Fe-based alloy plate differs depending on the position in the thickness direction. By setting the thickness of the amorphous Fe-based alloy plate within the specific range, the influence of the compressive stress in the vicinity of the roll contact surface and the influence of the tension in the vicinity of the free solidification surface are balanced, and the free solidification surface is affected. The direction of the easy axis of magnetization can be the direction inclined with respect to the direction perpendicular to the casting. As a result, it is possible to obtain an amorphous Fe-based alloy plate capable of forming the above-mentioned specific magnetic domain structure.

The thickness and magnetic properties of the finally obtained amorphous Fe-based alloy plate are the discharge speed of the Fe-based alloy molten metal discharged from the casting nozzle, the rotation speed of the cooling roll, and the cooling of the Fe-based alloy molten metal on the cooling roll. It can be controlled by speed or the like. For example, in order to increase the thickness of the amorphous Fe-based alloy plate, it has a plurality of discharge slits arranged in the casting direction to increase the discharge speed of the Fe-based alloy molten metal or to slow down the rotation speed of the cooling roll. The thickness of the molten Fe-based alloy discharged onto the cooling roll may be increased by a method such as simultaneously discharging the molten Fe-based alloy from a plurality of discharge slits using a casting nozzle. From the viewpoint of increasing the thickness of the amorphous Fe-based alloy plate more easily, it is possible to use a casting nozzle having a plurality of discharge slits arranged in the casting direction and simultaneously discharge the Fe-based alloy molten metal from the plurality of discharge slits. preferable.

Further, in order to impart the magnetic properties specified by the above-mentioned magnetic domain structure to the amorphous Fe-based alloy plate, the cooling rate of the Fe-based alloy molten metal on the cooling roll may be set to 1 million ° C./sec or more. preferable. If the cooling rate of the molten Fe-based alloy is slowed down, the Fe-based alloy tends to crystallize on the cooling roll, and an amorphous Fe-based alloy plate may not be obtained. Further, if the cooling rate of the molten Fe-based alloy is slowed down, the specific magnetic domain structure may not be formed.

In the above-mentioned manufacturing method, the amorphous Fe-based alloy plate peeled off from the cooling roll is annealed without applying a magnetic field. As described above, by annealing the amorphous Fe-based alloy plate at an appropriate temperature, excessive relaxation of the components in the direction perpendicular to the casting of the tension existing inside the amorphous Fe-based alloy plate after casting is avoided. At the same time, the components in the casting direction can be relaxed. This makes it possible to obtain an amorphous Fe-based alloy plate capable of forming the specific magnetic domain structure.

The holding temperature and holding time when annealing the amorphous Fe-based alloy plate may be appropriately set according to the chemical composition of the amorphous Fe-based alloy plate. The holding temperature at the time of annealing can be appropriately set from, for example, in the range of 330 ° C. or higher and 390 ° C. or lower. Further, the holding time at the time of annealing can be appropriately set from the range of, for example, 30 minutes or more and 2 hours or less. Further, the atmosphere at the time of annealing is preferably an inert gas atmosphere from the viewpoint of suppressing unnecessary oxidation of the amorphous Fe-based alloy plate.

Further, in the above-mentioned manufacturing method, by casting an amorphous Fe-based alloy plate by a single-roll quenching solidification method, the above-mentioned compressive stress and tension are generated inside the amorphous Fe-based alloy plate to free solidify. The direction of the easy-to-magnetize axis on the surface can be the direction inclined with respect to the direction perpendicular to the casting. As a result, the above-mentioned magnetic properties can be easily imparted without applying a magnetic field during annealing. The above-mentioned "annealing without applying a magnetic field" means that the strength of the magnetic field at the time of annealing is equal to or less than the strength of a naturally occurring magnetic field such as geomagnetism. More specifically, the concept of "annealing without applying a magnetic field" includes the case of annealing without positively applying a magnetic field from the outside to the amorphous Fe-based alloy plate, or the inside of a heating device. This includes the case where annealing is performed in a state where the magnetic field of the above is demagnetized and the strength of the magnetic field naturally exists or less.

(Example 1)
Examples of the amorphous Fe-based alloy plate and the method for producing the same will be described with reference to FIGS. 6 to 19. The amorphous Fe-based alloy plate of this example is manufactured by a single-roll quenching solidification method, and has a free solidification surface and a roll contact surface. The amorphous Fe-based alloy plate has Fe: 77 atomic% or more and 83 atomic% or less, Si: 4 atomic% or more and 15 atomic% or less, B: 8 atomic% or more and 15 atomic% or less, and C: 0 atomic% or more and 3 atoms. It is made of an amorphous Fe-based alloy having a chemical component containing% or less, and has a thickness of 35 μm or more.

Further, the amorphous Fe-based alloy plate 1 has a magnetization in a direction different from the direction perpendicular to the casting direction as shown in FIG. 8 when the magnetic domain structure of the free solidification surface 11 is observed using a car effect microscope. A striped magnetic domain in which one magnetic domain M1 and a second magnetic domain M2 having magnetizations in different directions with respect to both the direction perpendicular to the casting and the direction of magnetization of the first magnetic domain M1 are alternately arranged in the casting direction is included, and A magnetic domain structure in which a region S1 having a width of 30 μm or less in the first magnetic domain M1 and a region S2 having a width of 30 μm or less in the second magnetic domain M2 occupy 2.0% or more of the area of the free solidification surface 11. It is configured to be observable.

In this example, an amorphous Fe-based alloy plate was prepared by a single-roll quenching solidification method, and their magnetic properties and iron loss were evaluated. The method for producing the amorphous Fe-based alloy plate of this example will be described in more detail below.

The casting apparatus 2 shown in FIG. 11 was used for producing the amorphous Fe-based alloy plate. The casting apparatus 2 of this example has a casting nozzle 21 configured to be able to discharge the Fe-based alloy molten metal 10 and a cooling roll 22 arranged to face the casting nozzle 21 and configured to be able to cool the Fe-based alloy molten metal 10. And have. The casting nozzle 21 is configured so that the molten Fe-based alloy 10 stored in the crucible 211 can be pressurized with argon gas and discharged toward the cooling roll 22. Further, around the crucible 211, a high frequency heating device 212 for maintaining the temperature of the Fe-based alloy molten metal in the crucible 211 is provided.

As the cooling roll 22 in the casting apparatus 2, a roll made of copper having a diameter of about 200 to 250 mm was used.

In this example, first, the Fe-based alloy molten metal 10 having a chemical component represented by any of the component symbols C1 to the component symbol C12 shown in Table 1 is placed in the crucible 211 to form the Fe-based alloy molten metal 10. The temperature was set to 1200 ° C. Next, the position of the casting nozzle 21 was adjusted so that the distance from the casting nozzle 21 to the cooling roll 22 was 0.20 to 0.30 mm.

With the cooling roll 22 rotated at a speed of 10.47 to 32.72 m / s, the Fe-based alloy molten metal 10 in the crucible 211 is pressurized with argon gas of 0.03 to 0.05 MPa from the casting nozzle 21. The Fe-based alloy molten metal 10 was discharged onto the rotating cooling roll 22. Then, the molten Fe-based alloy 10 was solidified on the cooling roll 22 to form an amorphous Fe-based alloy plate 1. The amorphous Fe-based alloy plate 1 was peeled off from the cooling roll 22 by spraying argon gas onto the solidified amorphous Fe-based alloy plate 1 on the cooling roll 22.

Then, the obtained amorphous Fe-based alloy plate was annealed in a nitrogen atmosphere without applying a magnetic field. The holding temperature in annealing was the temperature shown in Tables 2 and 3, and the holding time was 60 minutes. From the above, the test materials 1 to 65 shown in Tables 2 and 3 were obtained.

Among the test materials 1 to 65, the test materials having a thickness of less than 35 μm and the test materials having a value of 0 in the “area ratio (%) of regions S1 and S2” column in Tables 2 and 3 are It was prepared for comparison with other test materials. The method for producing the test material in which the value in the “Area ratio (%) of regions S1 and S2” column is 0 is the same as the method for producing the test material other than these, except that the holding temperature at the time of annealing is different.

When the X-ray diffraction charts of the test materials 1 to 65 were obtained by using the X-ray diffractometer, the X-ray diffraction charts of the test materials 1 to 65 all showed the presence of amorphous halo. A pattern was appearing. From these results, it can be confirmed that the alloys constituting the test materials 1 to 65 are all amorphous.

Next, the magnetic domain structure and iron loss of the test materials 1 to 65 were evaluated by the following methods.

[Magnetic domain structure]
A square-shaped test piece having a side of about 10 mm was collected from each test material. A test piece was attached to the sample stage of the Kerr effect microscope via an adhesive gel sheet. A magnetic field whose direction of the magnetic field was parallel to the casting direction was applied to the test piece, and a microscope image of the test piece was obtained while increasing the strength of the magnetic field. As the Kerr effect microscope, "BH-4753-NML-ASM" manufactured by NeoArc Co., Ltd. was used, and the magnetic domain structure was observed using the vertical Kerr effect.

As an example, FIGS. 6 to 10 show when the strength of the magnetic field is 30.4 Oe, 45.4 Oe, 50.5 Oe, 55.5 Oe, and 100.7 Oe. The microscope image of the test material 7 is shown. The casting direction of the test material 7 is the left-right direction of FIGS. 6 to 10, and the casting perpendicular direction is the vertical direction of FIGS. 6 to 10. The direction of the magnetic field applied to the test piece is from left to right in FIGS. 6 to 10. In FIGS. 6 to 10, a magnetic domain having a smaller angle between the direction of the magnetic field applied to the test piece and the direction of magnetization is displayed brighter, and the angle between the direction of the magnetic field applied to the test piece and the direction of magnetization is displayed. The larger the magnetic domain, the darker it is displayed. In this example, for convenience, the magnetic domain in which the angle between the direction of the magnetic field applied to the test piece and the direction of magnetization is smaller is defined as the first magnetic domain M1.

Although not shown in the figure, when a magnetic field is not applied to the test piece, there are many magnetic domains having magnetizations in various directions on the free solidification surface, and the magnetizations as a whole point in a specific direction. It is in a state of nothingness. Further, a magnetic domain larger than the field of view of the microscope may be formed on the free solidifying surface in a state where no magnetic field is applied. When a magnetic field is applied to the test piece from this state, first, a magnetic domain including a striped magnetic domain in which the first magnetic domain M1 and the second magnetic domain M2 whose magnetization direction is different from that of the first magnetic domain M1 are alternately arranged in the casting direction. The structure appears. As shown in FIG. 6, when the magnetic field applied to the test piece is relatively weak, the widths of the first magnetic domain M1 and the second magnetic domain M2 are relatively wide. Specifically, the magnetization of the first magnetic domain M1 in this example is oriented so that the angle formed by the direction perpendicular to the casting and the direction of magnetization is smaller than the angle formed by the direction of casting and the direction of magnetization. Further, in a state where the strength of the magnetic field is relatively weak, the magnetization of the second magnetic domain M2 faces in a direction substantially opposite to that of the first magnetic domain M1.

When the strength of the magnetic field is increased from this state, new first magnetic domains M1 and second magnetic domains M2 are formed inside the first magnetic domain M1 and the second magnetic domain M2, and as shown in FIGS. 7 and 8, the individual magnetic domains M1 and the second magnetic domain M2 are formed. The widths of the first magnetic domain M1 and the second magnetic domain M2 are narrowed.

When the strength of the magnetic field is further increased, as shown in FIG. 9, the second magnetic domain M2 having a larger angle between the direction of the magnetic field and the direction of the magnetization is merged with the first magnetic domain M1 by the magnetization rotation, and the first magnetic domain M1 Grow up. Finally, the magnetic flux density of the test piece is saturated, and the second magnetic domain M2 completely disappears as shown in FIG. Although not shown in the figure, the test material in which the value in the "area ratio (%) of regions S1 and S2" column in Tables 2 and 3 is a value other than 0 also has the same change in magnetic domain structure as the test material 7. Observed.

In this example, in the magnetic domain structure of each test material appearing in the microscope image of the test piece in the state where the magnetization of 50 Oe is applied, among the regions S1 and the second magnetic domain M2 in which the width is 30 μm or less in the first magnetic domain M1. The area of the region S2 having a width of 30 μm or less was calculated. The occupied area ratios of the regions S1 and S2 with respect to the free solidification surface 11 in each test material are as shown in Tables 2 and 3. An image processing program attached to the high-speed microscope "VW9000" manufactured by KEYENCE CORPORATION was used to calculate the area ratios of the regions S1 and S2.

[Iron loss]
A single-plate magnetic measuring device (“SY-956” manufactured by Iwatsu Electric Co., Ltd.) was attached to a BH analyzer (“SY-8218” manufactured by Iwatsu Electric Co., Ltd.), and the iron loss of each test material was measured. The measurement frequency was 50 Hz, 400 Hz, 1 kHz, 10 kHz, or 20 kHz. The maximum magnetic flux density B _m when the measurement frequency is 50 Hz, 400 Hz or 1 kHz is 1.3 T, and the maximum magnetic flux density B _m when the measurement frequency is 10 kHz or 20 kHz is 0.1 T. The iron loss of each test material was as shown in Tables 2 and 3.

The value of iron loss is greatly affected by the thickness of the test material. Therefore, as an example, FIGS. 12 to 15 show iron losses of test materials 5 to 9 having a thickness of 43 μm to 47 μm for each measurement frequency, and FIGS. 16 to 19 show test materials 1 having a thickness of less than 35 μm. The iron loss of the test material 4 is shown for each measurement frequency. The vertical axis of FIGS. 12 to 19 is the iron loss (unit: W / kg), and the horizontal axis is the occupied area ratio (unit:%) of the regions S1 and S2 with respect to the free solidification surface 11.

Among the test materials shown in Table 2, when the test materials 5 to 9 having a thickness of 43 to 47 μm and having the same chemical composition are compared, the test materials 5 to the test material in which the specific magnetic domain structure was observed are observed. In No. 8, iron loss could be reduced as compared with the test material 9 in which the specific magnetic domain structure did not appear when a high-frequency alternating magnetic field was applied (see FIGS. 12 to 15).

Further, among the test materials 5 to 9, the test materials 6 to 8 in which the occupied area ratios of the regions S1 and S2 are 5% or more are compared with the test materials 5 in which the occupied area ratio is less than 5%. It was possible to reduce iron loss at any frequency.

Further, according to Tables 2 and 3, when comparing the test materials 10 to 65 having the same thickness and having the same chemical composition, the same as those of the test materials 5 to 9. It can be understood that the test material in which the specific magnetic domain structure is observed can reduce iron loss when a high frequency alternating magnetic field is applied, as compared with the test material in which the specific magnetic domain structure does not appear.

On the other hand, among the test materials shown in Table 2, the test materials 1 to 4 having a thickness of less than 35 μm did not form a magnetic domain structure in which the area ratios of the regions S1 and S2 were 2% or more. Further, among these test materials, the test material 2 and the test material 3 in which the region S1 and the region S2 are formed are the test materials in which the region S1 and the region S2 are not formed even when an alternating magnetic field of any frequency is applied. The iron loss equivalent to that of No. 1 and the test material 4 was shown (see FIGS. 16 to 19).

From these results, by setting the chemical composition and thickness of the amorphous Fe-based alloy plate within the specific range, the amorphous Fe-based alloy plate is imparted with the magnetic properties represented by the specific magnetic domain structure. be able to. The amorphous Fe-based alloy plate having such magnetic properties can reduce iron loss due to high-frequency alternating current.

(Example 2)
In this example, the magnetic anisotropy was evaluated using the test material 2, the test material 4, and the test material 8 in Example 1. Specifically, an amorphous Fe-based alloy plate having a chemical component represented by the component symbol C1 (see Table 1) was produced by a single-roll quenching solidification method. The production conditions in the single-roll quenching solidification method were the same as those adopted in Example 1. The obtained amorphous Fe-based alloy plate was etched to prepare a test piece having a circle with a diameter of about 6 mm. This test piece was held at one of the holding temperatures of the test material 2, the test material 4, and the test material 8 shown in Table 2 for 60 minutes for annealing. From the above, a test piece used for evaluation of magnetic anisotropy was obtained.

The evaluation of magnetic anisotropy was performed in a room temperature environment using a magnetic anisotropy torque meter (“TM-TR2750-HGC” manufactured by Tamagawa Seisakusho Co., Ltd.). Specifically, the test material was attached to the magnetic anisotropy torque meter so that a magnetic field was applied in a direction parallel to the free solidification surface of the test material. Then, the electromagnet of the magnetic anisotropy torque meter was swirled around the test material, and the magnitude of the magnetic anisotropy torque generated in the test piece was measured while changing the direction of the magnetic field with respect to the casting direction of the test material. Then, a torque curve was created by plotting the angle of the direction of the magnetic field with respect to the casting direction of the test material on the horizontal axis and plotting the magnitude of the magnetic anisotropy torque per unit volume corresponding to the angle on the vertical axis. .. The magnitude of the magnetic field applied to the test material was set to 500 Oe. The magnitude of the magnetic anisotropy torque per unit volume (unit: μN ・ m / mm ³ ) is the unit of the magnitude of the magnetic anisotropy torque (unit: dyne ・ cm) obtained by the above-mentioned measurement. It is a value divided by the volume of the test piece (unit: mm ³ ) after being converted to μN · m.

In FIG. 20, the unprocessed torque curve obtained by the above-mentioned measurement is subjected to a smoothing process by arithmetically averaging the magnetic anisotropy torque contained in the range of −10 ° or more and + 10 ° or less with respect to the measurement point. The torque curve obtained by this is shown. The vertical axis of FIG. 20 is the magnitude of the magnetic anisotropy torque per unit volume (unit: μN ・ m / mm ³ ), and the horizontal axis is the angle of the direction of the magnetic field with respect to the casting direction of the test material (unit: °). Is.

As shown in FIG. 20, the test material 8 is per unit volume when the angles of direction of the magnetic field with respect to the casting direction are −0.1 °, 53.6 °, 89.6 ° and 130.7 °. The value of the magnetic anisotropy torque is 0 μN · m / mm ³ . Further, the value of the root mean square of the magnetic anisotropy torque per unit volume in the range where the angle of the direction of the magnetic field with respect to the casting direction is from 0 ° to 180 °, which is calculated based on the torque curve of the test material 8, is 2. It is 0.0 × 10 ^-3 μN ・ m / mm ³ . According to these results, the test material 8 has two easy-to-magnetize axes and two difficult-to-magnetize axes in the direction parallel to the free solidification surface, and has biaxial magnetic anisotropy. I can judge.

On the other hand, the test material 2 has magnetic anisotropy per unit volume when the angles of the direction of the magnetic field with respect to the casting direction are 4.9 °, 25.0 °, 66.5 ° and 144.5 °. The torque value is 0 μN ・ m / mm ³ . However, in the test material 2, the value of the magnetic anisotropy torque per unit volume is 0 μN. There is no angle of m / mm ³ . Further, the value of the root mean square of the magnetic anisotropy torque per unit volume in the range where the angle of the direction of the magnetic field with respect to the casting direction is from 0 ° to 180 °, which is calculated based on the torque curve of the test material 2, is 1. It is 0.0 × 10 ^-3 μN ・ m / mm ³ . Based on these results, it is determined that the test material 2 does not have biaxial magnetic anisotropy.

Further, in the test material 4, the value of the magnetic anisotropy torque per unit volume is 0 μN · m / mm ³ when the angles of the direction of the magnetic field with respect to the casting direction are 0.8 ° and 78.5 °. .. However, in the test material 4, the angle of the direction of the magnetic field with respect to the casting direction is in the range of 35 ° or more and 55 ° or less, in the range of 80 ° or more and 100 ° or less, and in the range of 125 ° or more and 155 ° or less, the magnetism per unit volume. There is no angle at which the anisotropic torque value is 0 μN · m / mm ³ . Based on these results, it is determined that the test material 4 does not have biaxial magnetic anisotropy. The value of the squared average square root of the magnetic anisotropy torque per unit volume in the range where the angle of the direction of the magnetic field with respect to the casting direction is from 0 ° to 180 °, which is calculated based on the torque curve of the test material 4, is 3. Since it is .5 × 10 ^-3 μN ・ m / mm ³ , it is presumed that the test material 4 has uniaxial magnetic anisotropy.

As shown in Example 1, the test material 8 can reduce iron loss with respect to high-frequency alternating current. On the other hand, the test material 2 and the test material 4 have a higher iron loss with respect to a high-frequency alternating current than the test material 8. Therefore, from the results shown in this example, it can be easily understood that the amorphous Fe-based alloy plate having biaxial magnetic anisotropy can reduce the iron loss with respect to the high-frequency alternating current. ..

1 Amorphous Fe-based alloy plate 11 Free solidification surface 12 Roll contact surface M1 1st magnetic domain M2 2nd magnetic domain

Claims (8)

An amorphous Fe-based alloy plate manufactured by a single-roll quenching solidification method and having a free solidification surface and a roll contact surface.
Fe: 77 atomic% or more and 83 atomic% or less, Si: 4 atomic% or more and 15 atomic% or less, B: 8 atomic% or more and 15 atomic% or less, and C: 0 atomic% or more and 3 atomic% or less. Consisting of crystalline Fe-based alloy
It has a thickness of 35 μm or more and has a thickness of 35 μm or more.
When observing the magnetic domain structure of the free solidification surface using a Kerr effect microscope,
The first magnetic domain having a magnetization in a direction different from the casting orthogonal direction and the second magnetic domain having a magnetization in a different direction with respect to both the casting orthogonal direction and the magnetization direction of the first magnetic domain are alternately arranged in the casting direction. Includes striped magnetic domains and
The region of the first magnetic domain where the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less and the width is 30 μm or less, and the region of the second magnetic domain where the angle with respect to the casting direction is 60 degrees or more and 120 degrees or less and the width is 30 μm. An amorphous Fe-based alloy plate in which a magnetic domain structure in which the following regions occupy 2.0% or more of the area of the free solidified surface can be observed. The amorphous Fe-based alloy plate according to claim 1, which has a thickness of 110 μm or less. Claim 1 or claim 1, wherein a region having a width of 30 μm or less in the first magnetic domain and a region having a width of 30 μm or less in the second magnetic domain occupy 5.0% or more of the area of the free solidifying surface. 2. The amorphous Fe-based alloy plate according to 2. In the torque curve obtained by applying a magnetic field in a direction parallel to the free solidification surface and measuring the magnetic anisotropy torque per unit volume, the value of the magnetic anisotropy torque per unit volume is 0 μN. The angle of m / mm ³ is -10 ° or more and 10 ° or less, 35 ° or more and 55 ° or less, 80 ° or more and 100 ° or less, and 125 ° or more and 145 ° or less with respect to the casting direction. The amorphous Fe-based alloy plate according to any one of claims 1 to 3, which exists one by one. The root mean square of the magnetic anisotropy torque per unit volume of the torque curve in the range of the angle from 0 ° to 180 ° with respect to the casting direction is 1.4 × 10 ^-3 μN · m / mm ³ or more. The amorphous Fe-based alloy plate according to claim 4. The method for manufacturing an amorphous Fe-based alloy plate according to any one of claims 1 to 5.
Fe: Fe-based alloy molten metal containing 77 atomic% or more and 83 atomic% or less, Si: 4 atomic% or more and 15 atomic% or less, B: 8 atomic% or more and 15 atomic% or less, and C: 0 atomic% or more and 3 atomic% or less. Prepare and
The amorphous Fe-based alloy plate is cast by discharging the Fe-based alloy molten metal from a casting nozzle to a cooling roll and quenching the Fe-based alloy molten metal on the surface of the cooling roll.
A method for manufacturing an amorphous Fe-based alloy plate, wherein the amorphous Fe-based alloy plate is annealed without applying a magnetic field. An amorphous Fe-based alloy plate manufactured by a single-roll quenching solidification method and having a free solidification surface and a roll contact surface.
Fe: 77 atomic% or more and 83 atomic% or less, Si: 4 atomic% or more and 15 atomic% or less, B: 8 atomic% or more and 15 atomic% or less, and C: 0 atomic% or more and 3 atomic% or less. Consisting of crystalline Fe-based alloy
It has a thickness of 35 μm or more and has a thickness of 35 μm or more.
In the torque curve obtained by applying a magnetic field in a direction parallel to the free solidification surface and measuring the magnetic anisotropy torque per unit volume, the value of the magnetic anisotropy torque is 0 μN · m / mm. There is one angle of ³ in the range of -10 ° or more and 10 ° or less, 35 ° or more and 55 ° or less, 80 ° or more and 100 ° or less, and 125 ° or more and 145 ° or less with respect to the casting direction. An amorphous Fe-based alloy plate. The root mean square of the magnetic anisotropy torque per unit volume of the torque curve in the range of the angle from 0 ° to 180 ° with respect to the casting direction is 1.4 × 10 ^-3 μN · m / mm ³ or more. The amorphous Fe-based alloy plate according to claim 7.

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