Magnetostrictive member and method for manufacturing magnetostrictive member

Abstract

The magnetostrictive member is composed of a crystal of an iron-based alloy having a magnetostrictive property, is a plate-like body having a long side direction and a short side direction, and at least one of a front surface and a back surface of the plate-like body has a plurality of grooves extending in the long side direction.

Description

Technical Field

[0001] This invention relates to magnetostrictive components and methods for manufacturing magnetostrictive components. Background Technology

[0002] Magnetostrictive materials have attracted attention as functional materials. For example, Fe-Ga alloys, as iron-based alloys, exhibit both magnetostrictive and antimagnetostrictive effects, displaying a relatively large magnetostriction of approximately 100–350 ppm. Therefore, in recent years, they have garnered attention as materials for vibration-driven power generation in the field of energy harvesting, with anticipated applications in wearable devices, sensors, and the like. As a method for manufacturing single crystals of Fe-Ga alloys, a single crystal cultivation method based on the Czochralski method (hereinafter referred to as the "Cz method") is known (e.g., Patent Document 1). In addition, as manufacturing methods other than the Cz method, the vertical Bridgman method (VB method) and the vertical temperature gradient solidification method (VGF method) are known (e.g., Patent Documents 2 and 3).

[0003] Fe-Ga alloys in crystals <100> The orientation has an easy magnetization axis, which can exhibit a large magnetic strain in that orientation. Previously, magnetostrictive components of Fe-Ga alloys were produced by cutting Fe-Ga polycrystalline materials to the desired dimensions. <100> It can be manufactured by oriented single-crystal portions (e.g., non-patent literature 1), but since the crystal orientation has a significant impact on the magnetostrictive properties, it is believed that the direction of magnetostriction of the required magnetostrictive component should be aligned with the direction of magnetic strain of the crystal to maximize its magnetic properties. <100> Single crystals with consistent orientation are the best material for magnetostrictive components.

[0004] Fe-Ga alloy single crystals relative to single crystals <100> When a magnetic field is applied parallel to the orientation, it exhibits positive magnetostriction (hereinafter referred to as "parallel magnetostriction"). On the other hand, relative to... <100> When a magnetic field is applied perpendicularly, negative magnetostriction is exhibited (hereinafter referred to as "perpendicular magnetostriction"). If the strength of the applied magnetic field is gradually increased, either the parallel magnetostriction or the perpendicular magnetostriction will saturate. The magnetostriction constant (3 / 2λ) 100 It is determined by the difference between the saturated parallel magnetostriction and the saturated perpendicular magnetostriction, and is obtained by the following equation (1) (for example, Patent Document 4, Non-Patent Document 2).

[0005] 3 / 2λ 100 =ε( / / )―ε(⊥)…Formula (1)

[0006] 3 / 2λ 100 Magnetostriction constant

[0007] ε( / / ): relative to <100> Parallel magnetostriction when a magnetic field is applied in a parallel direction and the magnetostriction saturates

[0008] ε(⊥): relative to <100> Vertical magnetostriction when a magnetic field is applied perpendicularly and the magnetostriction saturates

[0009] The magnetostrictive properties of Fe-Ga alloys are believed to influence the magnetostrictive / inverse magnetostrictive effects and the characteristics of magnetostrictive vibration power generation devices, making them an important parameter in device design (e.g., Non-Patent Literature 4). In particular, it is known that the magnetostrictive constant depends on the Ga composition of the Fe-Ga alloy single crystal, becoming extremely large when the Ga composition is 18–19 at% and 27–28 at% (e.g., Non-Patent Literature 2), and it is desirable to use Fe-Ga alloys with such Ga concentrations in devices. Furthermore, in recent years, it has been reported that, in addition to a larger magnetostrictive constant, a greater parallel magnetostriction also tends to result in higher device characteristics such as output voltage (e.g., Non-Patent Literature 3).

[0010] Magnetostrictive vibration power generation devices, for example, consist of an Fe-Ga magnetostrictive member wound around a coil, a magnetic yoke, and a permanent magnet for excitation (e.g., Patent Document 5, Non-Patent Document 4). In this magnetostrictive vibration power generation device, the structure is such that when the magnetic yoke of the movable part of the device vibrates, the Fe-Ga magnetostrictive member fixed to the center of the magnetic yoke vibrates in conjunction. Through the inverse magnetostrictive effect, the magnetic flux density of the coil wound around the Fe-Ga magnetostrictive member changes, generating an electromagnetic induced electromotive force and thus producing electricity. In the magnetostrictive vibration power generation device, since vibration is caused by applying force in the long side direction of the magnetic yoke, the Fe-Ga magnetostrictive member used in the device is preferably positioned such that it serves as an easy magnetization axis. <100> Processing is carried out in a way that makes the long side the same.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent Application Publication No. 2016-28831

[0014] Patent Document 2: Japanese Patent Application Publication No. 2016-138028

[0015] Patent Document 3: Japanese Patent Application Publication No. 4-108699

[0016] Patent Document 4: Japanese Patent Publication No. 2015-517024

[0017] Patent Document 5: International Publication No. 2011-158473

[0018] Non-patent literature

[0019] Non-patent literature 1: Etrema Corporation, State of the Art of Galfenol Processing.

[0020] Non-patent literature 2: AEClark et al., Appl. Phys. 93 (2003) 8621.

[0021] Non-patent literature 3: Jung Jin Park, Suok-Min Na, Ganesh Raghunath, and Alison B. Flatau., AIP ADVANCES 6,056221 (2016).

[0022] Non-patent literature 4: Toshiyuki Ueno, Journal of the Institute of Precision Engineering, Vol.79, No.4, (2013) 305-308. Summary of the Invention

[0023] The problem that the invention aims to solve

[0024] The characteristics of magnetostrictive vibration power generation devices are influenced by the magnetostrictive properties of the magnetostrictive component. Therefore, the magnetostrictive component is required to have high magnetostrictive properties and small deviations in these properties. It is believed that if the crystal orientation of a single crystal of Fe-Ga alloy is... <100> If the Ga concentration is uniform, a magnetostrictive component with a uniform magnetostriction constant can be obtained. However, as described in Non-Patent Document 3, the device characteristics are disclosed to be affected not only by the magnetostriction constant but also by the amount of parallel magnetostriction. The inventors of this invention have determined that even if the magnetostriction constant is uniform in a magnetostrictive component manufactured as described above, there is still a deviation in the amount of parallel magnetostriction (or perpendicular magnetostriction), and the magnetostriction constant itself also has a deviation.

[0025] Therefore, the purpose of this invention is to provide a magnetostrictive component with high magnetostriction constant and parallel magnetostriction, and small deviations in magnetostriction constant and parallel magnetostriction between components, as well as a method for manufacturing the magnetostrictive component.

[0026] means for solving problems

[0027] According to the present invention, a magnetostrictive member is provided, wherein the magnetostrictive member is composed of a crystal of an iron-based alloy having magnetostrictive properties, the magnetostrictive member is a plate having a long side direction and a short side direction, and at least one of the front and back sides of the plate has a plurality of grooves extending along the long side direction.

[0028] Alternatively, the surface roughness Ra along the long side of the face with multiple grooves can be smaller than the surface roughness Ra along the short side. Alternatively, the surface roughness Ra along the long side can be 0.3 μm or more and 1.5 μm or less, and the surface roughness Ra along the short side can be 0.6 μm or more and 4.5 μm or less. Alternatively, the magnetostrictive constant of the magnetostrictive member can be 200 ppm or more, and the magnetostriction amount when the magnetostriction amount along the long side is saturated by applying a magnetic field parallel to the long side direction (i.e., the parallel magnetostriction amount) can be 200 ppm or more. Alternatively, the plate-like body can have multiple grooves on its front and back sides. Alternatively, the direction of the multiple grooves extending along the long side direction of the magnetostrictive member can be within 30° relative to the long side direction. Alternatively, the thickness of the magnetostrictive member can be 0.3 mm or more and 2 mm or less. Alternatively, the crystal can be a single crystal. Alternatively, the iron-based alloy can be an Fe-Ga alloy. Alternatively, the multiple grooves can be formed by surface grinding. Alternatively, the magnetostrictive member can be multiple magnetostrictive members manufactured from a single crystal, wherein the deviation of the magnetostriction amount (i.e., the parallel magnetostriction amount) when the magnetostriction amount in the long side direction is saturated by applying a magnetic field parallel to the long side direction is within 10%.

[0029] In addition, according to the present invention, a method for manufacturing a magnetostrictive member is provided, wherein the method comprises forming a plurality of grooves extending along the long side direction on at least one of the front and back sides of a plate-shaped body having a long side direction and a short side direction, which is composed of a crystal of an iron-based alloy having magnetostrictive properties.

[0030] Alternatively, the manufacturing method of the magnetostrictive member may include forming multiple grooves by surface grinding. Alternatively, the surface grinding may include using a grinding stone of #40 or higher and #500 or lower. Alternatively, the manufacturing method of the magnetostrictive member may include forming multiple grooves such that the magnetostriction constant is 200 ppm or higher, and the magnetostriction amount in the long-side direction saturates when a magnetic field parallel to the long-side direction is applied, i.e., the parallel magnetostriction amount, is 200 ppm or higher. Alternatively, the manufacturing method of the magnetostrictive member may include: manufacturing multiple magnetostrictive members from a single crystal; and forming multiple grooves in multiple plate-like bodies manufactured from a single crystal such that the deviation of the magnetostriction amount in the long-side direction saturates when a magnetic field parallel to the long-side direction is applied, i.e., the parallel magnetostriction amount, is within 10%.

[0031] Invention Effects

[0032] The magnetostrictive component of the present invention has the characteristics of high magnetostriction constant and high parallel magnetostriction, and small deviations in magnetostriction constant and parallel magnetostriction between components. The manufacturing method of the magnetostrictive component of the present invention can easily manufacture magnetostrictive components with high magnetostriction constant and high parallel magnetostriction, and small deviations in magnetostriction constant and parallel magnetostriction between components. Attached Figure Description

[0033] Figure 1 (A) and Figure 1 (B) in the figure is a photographic representation of an example of the magnetostrictive member according to the embodiment. Figure 1 (A) in the image is the overall image. Figure 1 (B) in the middle is to Figure 1 A magnified portion of (A) in the image.

[0034] Figure 2 This is a flowchart illustrating an example of a method for manufacturing a magnetostrictive member according to an embodiment.

[0035] Figure 3 This is a diagram showing the first example of a single crystal, thin-plate component, and magnetostrictive component.

[0036] Figure 4 This is a diagram representing the second example of a single crystal, a thin-plate component, and a magnetostrictive component.

[0037] Figure 5 This is a diagram representing the third example of a single crystal, a thin-plate component, and a magnetostrictive component.

[0038] Figure 6 This is a diagram illustrating the strain gauge method used in the embodiments.

[0039] Figure 7 This is a diagram showing the magnetostrictive component of Comparative Example 1. Detailed Implementation

[0040] The following description refers to the accompanying drawings. Furthermore, in each of the accompanying drawings, some or all portions are depicted schematically as appropriate, and the scale is altered for clarity.

[0041] [Implementation Method]

[0042] The magnetostrictive member of this embodiment and the method for manufacturing the magnetostrictive member will be described below.

[0043] First, the magnetostrictive member of this embodiment will be described. Figure 1 (A) and Figure 1 (B) in the figure is a photographic representation of an example of the magnetostrictive member according to the embodiment. Figure 1 (A) in the image is the overall image. Figure 1 (B) in the middle is to Figure 1 A magnified portion of (A) in the image.

[0044] like Figure 1 As shown in (A), the magnetostrictive member 1 is a plate-shaped body having a long side direction D1 and a short side direction D2. The plate-shaped body is rectangular when viewed from above. The plate-shaped body has a front side 3 and a back side 4. Preferably, the front side 3 and the back side 4 are parallel to each other, but they may not be parallel to each other.

[0045] Magnetostrictive component 1 is composed of crystalline iron-based alloys. The iron-based alloys are not particularly limited as long as they possess magnetostrictive properties. Magnetostrictive properties refer to the characteristic of changing shape when a magnetic field is applied. Examples of iron-based alloys include Fe-Ga, Fe-Ni, Fe-Al, Fe-Co, Tb-Fe, Tb-Dy-Fe, Sm-Fe, and Pd-Fe alloys. Additionally, alloys containing a third component can also be used. For example, alloys containing Ba, Cu, etc., can be used in Fe-Ga alloys. Among these iron-based alloys, Fe-Ga alloys exhibit greater magnetostrictive properties and are easier to process compared to other alloys, thus finding applications in vibration-powered energy harvesting materials, wearable devices, and sensors. In the following description, an example of a magnetostrictive component 1 composed of a single crystal of an Fe-Ga alloy will be illustrated.

[0046] Single crystals of Fe-Ga alloys possess a body-centered cubic lattice structure, with orientation indices from the first to the third in the Miller indices. <100> Axis (reference) Figures 3 to 5 Equivalent to the first to third {100} surfaces in the Miller index (refer to) Figures 3 to 5 The basic principle is that (100), (010), and (001) are equivalent. Furthermore, Fe-Ga alloys exhibit a large magnetic strain at specific orientations of the crystal. When utilizing this characteristic in a magnetostrictive vibration-generating device, it is preferable to align the direction of magnetostriction of the magnetostrictive member 1 within the device with the orientation (direction) of the crystal where the magnetic strain is greatest. Specifically, as described above, it is preferable to align the easily magnetized direction of the single crystal with the direction of maximum magnetic strain. <100> The direction is set to the long side direction D1 of the magnetostrictive component 1. The easily magnetized direction in the single crystal is... <100> The direction is set to the long side direction D1 of the magnetostrictive member 1. For example, it can be implemented by calculating the crystal orientation of the single crystal through known crystal orientation analysis, and cutting the single crystal based on the calculated crystal orientation.

[0047] Furthermore, the crystal used in the magnetostrictive member 1 of this embodiment can be a single crystal or a polycrystalline crystal. To improve... <100> The directional concentration of monocrystalline materials improves their properties as magnetostrictive materials, making them more advantageous than polycrystalline materials. Furthermore, while polycrystalline materials exhibit lower magnetostrictive properties compared to monocrystalline materials, they can be produced at lower costs, hence their occasional use.

[0048] The magnetostrictive member 1 is used, for example, as a material (component) for vibration-generating devices in the field of energy harvesting, as well as for wearable terminals, sensors, and the like. For example, the magnetostrictive vibration-generating device shown in Patent Document 5 consists of a coil, a magnetostrictive member of an Fe-Ga alloy wound around the coil, a magnetic yoke, and a permanent magnet for excitation. This magnetostrictive vibration-generating device is structured such that when the magnetic yoke, which is the movable part of the device, vibrates, the magnetostrictive member fixed to the center of the magnetic yoke vibrates in conjunction. Through the inverse magnetostrictive effect, the magnetic flux density of the coil wound around the magnetostrictive member changes, generating an electromagnetic induction electromotive force, thereby generating electricity. When used with such a structure, the shape of the magnetostrictive member 1 is preferably set to a thin plate shape, appearing as a slender rectangle when viewed from above. The thickness of the magnetostrictive member 1 is not particularly limited. The lower limit of the thickness is preferably 0.3 mm or more, more preferably 0.4 mm or more, and even more preferably 0.5 mm or more. Furthermore, the upper limit of the thickness of the magnetostrictive member 1 is preferably 2 mm or less, more preferably 1.8 mm or less, and even more preferably 1.5 mm or less. The thickness of the magnetostrictive member 1 is preferably 0.3 mm or more and 2 mm or less, more preferably 0.4 mm or more and 1.8 mm or less, and even more preferably 0.5 mm or more and 1.5 mm or less. As explained above, the structure for generating electricity based on the magnetostrictive member 1 is a structure that generates electricity through the inverse magnetostrictive effect by applying stress (vibration) to the magnetostrictive member. When the thickness of the magnetostrictive member 1 is less than 0.3 mm, it is easily damaged during vibration. Conversely, when the thickness of the magnetostrictive member 1 exceeds 2 mm, the stress caused by vibration needs to be increased, and the efficiency deteriorates. The shape and size of the magnetostrictive member 1 are appropriately set according to the size of the device intended for use. For example, the size of the magnetostrictive member 1 is as follows: the length (dimension) L1 in the long side direction D1 is 16 mm, the width (dimension) L2 in the short side direction D2 is 4 mm, and the thickness is 1 mm.

[0049] Furthermore, the shape and size of the magnetostrictive member 1 are not particularly limited. For example, the magnetostrictive member 1 may not be rectangular when viewed from above. For example, the shape of the magnetostrictive member 1 may be elliptical, racetrack-shaped, or irregular when viewed from above. In addition, when the shape of the magnetostrictive member 1 is other than rectangular when viewed from above, the long side direction D1 is the major axis direction, the major diameter direction, etc., and the short side direction D2 is the direction orthogonal to the long side direction D1.

[0050] The inventors of this invention fabricated multiple plate-shaped magnetostrictive components as described above. These components are made of single crystals of Fe-Ga alloy, with the main face being the {100} plane, which serves as the easy magnetization direction. <100> The magnetostrictive member, when viewed from its long side, has a rectangular shape. The magnetostrictive properties of several magnetostrictive members fabricated from single crystals of Fe-Ga alloys with uniform Ga concentration were confirmed. The results showed that the magnetostrictive constants of the fabricated magnetostrictive members were high, but the parallel magnetostriction amount exhibited a significant deviation. Furthermore, it was found that the magnetostrictive constants themselves also deviated, varying depending on the position from which the magnetostrictive member was cut from the single crystal. Further investigation revealed that the magnetostrictive constant and the parallel magnetostriction amount were correlated with the grinding direction of the magnetostrictive member. This invention was made based on the above insights.

[0051] Magnetostrictive components are manufactured, for example, by cutting a grown iron-based alloy crystal along a certain direction to form a thin plate-like component, and then cutting the thin plate-like component into a specified size. Conventional magnetostrictive components involve grinding or other finishing processes on both sides of the magnetostrictive component to achieve a smooth surface.

[0052] like Figure 1 (A) and Figure 1 As shown in (B) of this embodiment, the magnetostrictive member 1 is characterized in that at least one of the front side 3 and the back side 4 (sometimes collectively referred to as "front and back sides") has a plurality of grooves 2 extending along the long side direction D1. A detailed description follows.

[0053] As described above, the results of confirming the magnetostrictive properties of multiple magnetostrictive members cut from Fe-Ga single crystals with uniform Ga concentration show that the magnetostrictive constant is high, but the parallel magnetostriction amount has a deviation. According to this embodiment, even in magnetostrictive members with such a deviation in the parallel magnetostriction amount, by forming multiple grooves 2 extending along the long side direction D1 on at least one of the front and back surfaces of the magnetostrictive member, it is possible to modify both the magnetostrictive constant and the parallel magnetostriction amount to be high and the deviation between members to be small (also referred to as "modification of the magnetostrictive constant and the parallel magnetostriction amount"), especially the parallel magnetostriction amount. It is speculated that this modification phenomenon is caused by applying stress such as residual strain within the crystal by forming multiple grooves 2, which causes the magnetic moments to be uniformly rearranged and the magnetostrictive properties to be homogenized.

[0054] The modification of the magnetostriction constant and the parallel magnetostriction amount described above will be explained below. In this embodiment, as shown in the examples described later, before forming the plurality of grooves 2, in a sample of a magnetostrictive member with a low parallel magnetostriction amount, a plurality of grooves 2 with different extending directions were formed on both sides of the front and back of the magnetostrictive member, and the changes in the magnetostriction constant and the parallel magnetostriction amount caused by the formation of the plurality of grooves 2 were investigated. In this embodiment, when the magnetostrictive member has a plurality of grooves 2 extending in the same direction as the long side direction D1 (Examples 3, 13, 16, 17, 19, etc.) and a plurality of grooves 2 extending in the same direction as the short side direction D2 (Comparative Examples 2, 3, etc.), the magnetostriction constant and the parallel magnetostriction amount were measured. The results are shown in Table 1.

[0055] In samples of magnetostrictive components with low parallel magnetostriction before the formation of multiple grooves 2, when multiple grooves 2 extending in the same direction as the long side direction D1 are formed in the magnetostrictive component (Examples 3, 13, 16, 17, 19, etc.), the magnetostriction constant and parallel magnetostriction change from a low level to a high level and stabilize at the high level by forming multiple grooves 2. In particular, the parallel magnetostriction increases significantly due to the formation of multiple grooves 2. In addition, the values ​​of magnetostriction constant and parallel magnetostriction show small deviations between components (samples).

[0056] In contrast, in the samples of magnetostrictive members with low parallel magnetostriction before the formation of multiple grooves 2, when multiple grooves 2 extending in the same direction as the short side direction D2 are formed in the magnetostrictive member (Comparative Examples 2 and 3), the parallel magnetostriction is stable at a low level, similar to that before the formation of multiple grooves 2. In addition, the value of parallel magnetostriction has a small deviation between members (between samples).

[0057] Furthermore, in this embodiment, in a sample of a magnetostrictive member with a high parallel magnetostriction before the formation of the multiple grooves 2, multiple grooves 2 with different extending directions were formed on both sides of the front and back of the magnetostrictive member, and the changes in the magnetostriction constant and the parallel magnetostriction caused by the formation of the multiple grooves 2 were investigated. In this embodiment, when the magnetostrictive member has multiple grooves 2 extending in the same direction as the long side direction D1 (Examples 2, 5, 6 to 11, etc.) and multiple grooves 2 extending in the same direction as the short side direction D2 (Comparative Examples 1 and 4), the magnetostriction constant and the parallel magnetostriction were measured.

[0058] In samples of magnetostrictive members with high parallel magnetostriction before the formation of multiple grooves 2, when multiple grooves 2 extending in the same direction as the long side direction D1 are formed in the magnetostrictive member (Examples 2, 5, 6-11, etc.), the magnetostriction constant and the parallel magnetostriction are stable at a high level, similar to before the formation of multiple grooves 2. Furthermore, the values ​​of the magnetostriction constant and the parallel magnetostriction show small deviations between members (samples).

[0059] In contrast, in samples of magnetostrictive members with high parallel magnetostriction before the formation of multiple grooves 2, when multiple grooves 2 extending in the same direction as the short side direction D2 are formed in the magnetostrictive member (Comparative Examples 1 and 4), the value changes from a high level before the formation of multiple grooves 2 to a low level and stabilizes at the low level. In addition, the value of parallel magnetostriction has a smaller deviation between members (between samples).

[0060] Based on the above results, it can be seen that the magnetostriction constant and the parallel magnetostriction amount are affected by the surface state of the magnetostrictive member. Moreover, it can be seen that by forming a plurality of grooves 2 extending along the long side direction D1 on at least one of the front side 3 and the back side 4 of the magnetostrictive member, both the magnetostriction constant and the parallel magnetostriction amount can be modified (corrected) to a higher level with smaller deviations between members.

[0061] In addition, in this embodiment, in Examples 34-37 and Comparative Examples 7-9, when multiple grooves 2 extending in a direction of 0° to 60° relative to the long side direction D1 were formed, the magnetostriction constant and the amount of parallel magnetostriction were measured. The results are shown in Table 6. In the sample of the magnetostrictive member with a low amount of parallel magnetostriction before the formation of multiple grooves 2, when multiple grooves 2 extending in a direction of 0° to 60° relative to the long side direction D1 were formed, the amount of parallel magnetostriction increased due to the formation of multiple grooves 2. However, the closer the angle between the extension direction of the multiple grooves 2 and the long side direction D1 is to 0°, the more it becomes a value at the same level as the case where multiple grooves 2 extending in the same direction as the long side direction D1 are formed. As the angle increases, there is a tendency for the value to be close to the case where multiple grooves 2 extending in the same direction as the short side direction D2 are formed. The value of parallel magnetostriction is approximately the middle value between the value at 0° and the value at 60° relative to the long side direction D1 at around 45°. The angle (the angle formed by the extension direction of the plurality of slots 2 and the long side direction D1) is preferably less than 40°, more preferably less than 35°, and even more preferably within 30°. When the angle is within the above-mentioned preferred range, the effect of modifying the magnetostriction constant and the amount of parallel magnetostriction is more reliably exhibited. When the angle is within 30°, the amount of parallel magnetostriction can be more reliably managed at a high level of 200 ppm or more.

[0062] Furthermore, based on the above results, it is known that by forming a plurality of grooves 2 extending along the long side direction D1 on at least one of the front side 3 and the back side 4 of the magnetostrictive member, deviations in the magnetostrictive constant and the amount of parallel magnetostriction caused by differences in relative positions within the single crystal can be suppressed. The magnetostrictive constant and the amount of parallel magnetostriction are stable at high levels, and this tendency is significant in the amount of parallel magnetostriction. Furthermore, based on the above results, it is known that the amount of parallel magnetostriction is determined by the angle formed by the long side direction D1 and the extension direction of the plurality of grooves 2. The amount of parallel magnetostriction is higher when the long side direction D1 is parallel to the extension direction of the plurality of grooves 2, and is presumably at its maximum in this case. As described above, the plurality of grooves 2 extending along the long side direction D1 of the magnetostrictive member 1 of this embodiment can modify both the magnetostrictive constant and the amount of parallel magnetostriction (at least the amount of parallel magnetostriction). In the magnetostrictive member 1 of this embodiment, the plurality of grooves 2 extending along the long side direction D1 can be modified to significantly increase the parallel magnetostriction (e.g., 200 ppm or more, preferably 250 ppm or more) in a magnetostrictive member that is manufactured under the conditions shown in Example 2 and has a low parallel magnetostriction amount when it is smoothed by polishing.

[0063] Furthermore, the parallel magnetostriction is the magnetostriction when a magnetic field parallel to the long side direction D1 of the magnetostrictive member 1 is applied, causing the magnetostriction in the long side direction D1 to saturate. The perpendicular magnetostriction is the magnetostriction when a magnetic field parallel to the short side direction D2 of the magnetostrictive member 1 is applied, causing the magnetostriction in the short side direction D2 to saturate. In this embodiment, the magnetostriction constant, parallel magnetostriction, and perpendicular magnetostriction in the magnetostrictive member 1 are values ​​obtained as described in the embodiments below. The magnetostriction is obtained by correcting the actual strain detection value with the strain coefficient according to equation (3). The magnetostriction when the magnetic field direction is parallel to the long side direction of the strain gauge is defined as the parallel magnetostriction, and the magnetostriction when the magnetic field direction is perpendicular to the long side direction of the strain gauge is defined as the perpendicular magnetostriction. The magnetostriction constant is obtained according to equation (1) as the difference between the parallel and perpendicular magnetostriction. In addition, the angle between the extension direction of the multiple slots 2 and the long side direction D1 is the value obtained by averaging the values ​​in the multiple slots.

[0064] Next, the plurality of grooves 2 will be described. The plurality of grooves 2 are formed on at least one of the front side 3 and the back side 4. Figure 1 (A) and Figure 1 In the example shown in (B), multiple slots 2 are formed on both the front side 3 and the back side 4. When multiple slots 2 are formed on only one of the front side 3 and the back side 4, compared with the case where multiple slots 2 are formed on both the front side 3 and the back side 4, there is a tendency for the modification effect of the magnetostriction constant and the amount of parallel magnetostriction to be smaller, and the deviation of the magnetostriction characteristics to be larger. Therefore, it is preferable for multiple slots 2 to be formed on both the front side 3 and the back side 4.

[0065] Multiple grooves 2 are formed extending along the long side direction D1. Each groove 2 is linear (striped). From the viewpoint of effectively exhibiting the effects of modifying the magnetostriction constant and the amount of parallel magnetostriction described above, each groove 2 is preferably linear. Alternatively, each groove 2 may also be curved. The length of the long side direction D1 of each groove 2 is not particularly limited. From the viewpoint of effectively exhibiting the effects of modifying the magnetostriction constant and the amount of parallel magnetostriction described above, the multiple grooves 2 are preferably formed in the plane without omission at predetermined intervals in the short side direction D2, and preferably formed entirely in the plane. Furthermore, in this embodiment, the magnetostrictive member 1 may also include grooves extending in directions other than the long side direction to a extent that does not impair the effects of the present invention. Although such magnetostrictive members are not excluded, it is desirable that there are no grooves extending in directions other than the long side direction.

[0066] Furthermore, in this embodiment, the extension of the plurality of slots 2 along the long side direction D1 includes the extension of the plurality of slots 2 along a direction parallel to the long side direction D1, and the extension of the plurality of slots 2 along a direction intersecting the long side direction D1 at an angle of less than 40°. As described above, if the direction in which the plurality of slots 2 extend deviates from the direction parallel to the long side direction D1, the parallel magnetostriction becomes lower. Therefore, the direction in which the plurality of slots 2 extend is preferably the direction parallel to the long side direction D1.

[0067] Figure 1 The multiple grooves 2 shown in (B) can be formed, for example, by performing surface grinding on at least one side of the front side 3 and the back side 4 of a thin plate component obtained by cutting a single crystal. In this case, the multiple grooves 2 are grinding marks (grinding streaks) formed on the machined surface after surface grinding. Grinding marks are marks formed by a grinding stone during surface grinding. These grinding marks are formed as stripes (lines) along the grinding direction (the direction of movement of the grinding stone or the direction of movement of the processing table) by surface grinding. The direction of the grinding marks (the direction in which the multiple grooves 2 extend) can be controlled by controlling the grinding direction. The grinding marks can be controlled by the grit size (grit number) of the grinding stone. The state of the multiple grooves 2 formed by surface grinding can be confirmed by a microscope or the like. Furthermore, the method of forming the multiple grooves 2 is not limited to the surface grinding described later. In addition, the multiple grooves 2 can include grooves extending in different directions, or grooves of different shapes with different lengths or depths.

[0068] Regarding the surface roughness Ra of the surface with multiple grooves 2, the surface roughness Ra in the long side direction D1 is generally smaller than the surface roughness Ra in the short side direction D2. The multiple grooves 2 are formed in a linear (striped) shape extending along the long side direction D1. Therefore, the short side direction D2 of the magnetostrictive member 1 becomes uneven, and thus the surface roughness Ra is larger than that in the long side direction D1. Furthermore, the long side direction D1 of the magnetostrictive member 1 mimics the linear (striped) grooves 2 extending along the long side direction D1, and therefore the surface roughness Ra is smaller than that in the short side direction D2. In this embodiment, the surface roughness Ra is the value obtained by averaging values ​​measured from multiple different portions of a magnetostrictive member 1.

[0069] In the surface with multiple grooves 2, the surface roughness Ra in the long side direction D1 is smaller than the surface roughness Ra in the short side direction D2. The lower limit of the surface roughness Ra in the long side direction D1 of the surface with multiple grooves 2 is preferably 0.3 μm or more, the upper limit is preferably 1.5 μm or less, and more preferably 0.3 μm or more and 1.5 μm or less. Furthermore, the lower limit of the surface roughness Ra in the short side direction D2 of the surface with multiple grooves 2 is preferably 0.6 μm or more, more preferably 0.7 μm or more, the upper limit is preferably 4.5 μm or less, and the range is preferably 0.6 μm or more and 4.5 μm or less, more preferably 0.7 μm or more and 4.5 μm or less. When the surface roughness Ra in the long side direction D1 or the short side direction D2 of the surface with multiple grooves 2 is within the above range, the modification effects of the magnetostriction constant and the parallel magnetostriction amount described above can be effectively exhibited.

[0070] The characteristics of the magnetostrictive member 1 according to this embodiment will be described. With the structure described above, the magnetostrictive member 1 of this embodiment can achieve a magnetostrictive constant of 200 ppm or more, preferably 250 ppm or more. Furthermore, with the structure described above, the magnetostrictive member 1 can achieve a parallel magnetostriction amount of 200 ppm or more, preferably 250 ppm or more. When the magnetostrictive constant and parallel magnetostriction amount of the magnetostrictive member 1 are set within the above-described ranges, it is preferable to form the magnetostrictive member 1 from a single crystal of an Fe-Ga alloy.

[0071] Furthermore, in this embodiment, the magnetostrictive member 1 modifies (corrects) both the magnetostrictive constant and the parallel magnetostriction amount to a high level and reduces the deviation between members by forming a plurality of grooves 2 extending along the long side direction D1 on at least one of the front side 3 and the back side 4 of the magnetostrictive member. Therefore, when the magnetostrictive member 1 of this embodiment is a plurality of magnetostrictive members 1 manufactured from a single crystal, the deviation of the magnetostrictive constant among the plurality of magnetostrictive members 1 can be within 15%, and the deviation of the parallel magnetostriction amount can be within 10%. In addition, when the magnetostrictive member 1 of this embodiment is a plurality of magnetostrictive members 1 manufactured from a single crystal, the variation coefficient of the magnetostrictive constant among the plurality of magnetostrictive members 1 is preferably 0.1 or less, more preferably 0.06 or less, and the variation coefficient of the parallel magnetostriction amount is preferably 0.1 or less, more preferably 0.05 or less. Furthermore, in this embodiment, the deviation of the magnetostrictive constant and the parallel magnetostriction amount among the plurality of magnetostrictive members 1 is a value calculated by the following formula (2).

[0072] Deviation (%) = |Difference between the average and the maximum deviation| / average... Equation (2)

[0073] Furthermore, the term "a cultivated crystal" refers to the effective crystal (the portion actually used as a component) within the cultivated crystals that serves as a magnetostrictive component. For example, for crystals cultivated by the BV method, it refers to the portion with a curing rate ranging from 10% to 85%, while for crystals cultivated by the CZ method, it refers to the range with a uniform diameter (excluding the cultivated shoulder and other portions).

[0074] As described above, the magnetostrictive member 1 of this embodiment is composed of a crystal of an iron-based alloy with magnetostrictive properties, and is a plate-shaped body having a long side direction and a short side direction. At least one of the front and back sides of the plate-shaped body has a plurality of grooves extending along the long side direction. Furthermore, in the magnetostrictive member 1 of this embodiment, the structure other than the above-described is arbitrary. The magnetostrictive member 1 of this embodiment has the characteristics of high magnetostriction constant and parallel magnetostriction, and small deviations in magnetostriction constant and parallel magnetostriction between components. In addition, the magnetostrictive member 1 of this embodiment has undergone the aforementioned modification of the magnetostriction constant and parallel magnetostriction, correcting the deviations in the magnetostriction constant and parallel magnetostriction in conventional magnetostrictive members manufactured from the same single crystal, thus resulting in a high yield and stable production. Because the magnetostrictive member 1 of this embodiment has high magnetostriction constant and parallel magnetostriction, it is suitable as a final product of a component (material) exhibiting excellent magnetostrictive and contramagnetic-strictive effects.

[0075] Next, the manufacturing method of the magnetostrictive member according to this embodiment will be described. The manufacturing method of the magnetostrictive member according to this embodiment is the manufacturing method of the magnetostrictive member 1 of this embodiment described above. The manufacturing method of the magnetostrictive member according to this embodiment includes forming a plurality of grooves 2 extending along the long side direction D1 on at least one of the front side 3 and the back side 4 of a plate-shaped body made of a crystal of an iron-based alloy having magnetostrictive properties and having a long side direction D1 and a short side direction D2. In addition, in the following description, the method of manufacturing the magnetostrictive member 1 from a single crystal ingot of Fe-Ga alloy is described as an example, but the manufacturing method of the magnetostrictive member according to this embodiment is not limited to the following description. Furthermore, the content described in this specification that can be applied to the manufacturing method of the magnetostrictive member according to this embodiment can also be applied to the manufacturing method of the magnetostrictive member according to this embodiment.

[0076] Figure 2 This is a flowchart illustrating an example of a method for manufacturing a magnetostrictive member according to this embodiment. Figures 3 to 5These figures illustrate the first to third examples of single-crystal, thin-plate, and magnetostrictive components. The manufacturing method of the magnetostrictive component in this embodiment includes a crystal preparation step (step S1), a crystal cutting step (step S2), a groove forming step (step S3), and a cutting step (step S4).

[0077] In the manufacturing method of the magnetostrictive component according to this embodiment, firstly, in the crystal preparation step (step S1), a crystal of an iron-based alloy having magnetostrictive properties is prepared. The prepared crystal can be a single crystal or a polycrystalline crystal. Furthermore, the prepared crystal can be a cultivated crystal or a commercially available product. For example, in the crystal preparation step, a single crystal of an Fe-Ga alloy is prepared. The cultivation method for the Fe-Ga alloy single crystal is not particularly limited. The cultivation method for the Fe-Ga alloy single crystal can be, for example, the Czochralski method, unidirectional solidification method, etc. For example, the Cz method can be used in the Czochralski method, and the VB method, VGF method, and micro-pull-down method can be used in the unidirectional solidification method.

[0078] The magnetostriction constant of Fe-Ga alloy single crystals is maximized by setting the gallium content to 18.5 at% or 27.5 at%. Therefore, in Fe-Ga single crystals, the gallium content is preferably 16.0–20.0 at% or 25.0–29.0 at%, more preferably 17.0–19 at% or 26.0–28.0 at%. The shape of the grown single crystal is not particularly limited; for example, it can be cylindrical or prismatic. Furthermore, the grown single crystal can be cut as needed using a cutting device to remove the seed crystal, the diameter-enlarging portion, or the shoulder (the portion increasing from the seed crystal to the predetermined diameter of the single crystal), thereby producing a cylindrical single crystal. The size of the grown single crystal is not particularly limited, as long as it ensures the size of the magnetostrictive member in the predetermined direction. In the case of growing Fe-Ga single crystals, a method is used to ensure that the growth axis direction is... <100> The method involves machining the upper or lower surface of a seed crystal into a {100} facet for cultivation. The cultivated Fe-Ga alloy single crystal is grown in a direction perpendicular to the upper or lower surface of the seed crystal and inherits the orientation of the seed crystal.

[0079] After the crystal preparation process (step S1), a crystal cutting process (step S2) is performed. The crystal cutting process is the process of cutting the crystal to produce a thin-plate component. The thin-plate component is a component made of the material that forms the magnetostrictive component 1 of this embodiment. The crystal cutting process, for example, is the process of using a cutting device to cut a single crystal of an Fe-Ga alloy with magnetostrictive properties to produce a thin-plate component with the {100} plane as its main surface. The cutting device can be a wire electrical discharge machine, an internal cutting device, a wire saw, or the like. Among these, a multi-wire saw is particularly preferred because it can cut multiple thin-plate components simultaneously. In the case of a Fe-Ga single crystal, the cutting direction of the single crystal is... <100> Cutting is performed with the main surface of the thin-plate component as the {100} plane. The cutting direction of single crystals is not particularly limited. For example, the cutting direction of single crystals is as follows: Figures 3 to 5 As shown, the direction relative to the growth of the single crystal (the direction in which the crystal is grown) can be either perpendicular or parallel.

[0080] After the crystal cutting process (step S2), a groove forming process (step S3) is performed. In the groove forming process, a plurality of grooves 2 are formed on at least one of the front side 3 and the back side 4 of the obtained thin plate member. In the groove forming process, when the thin plate member is finally cut to form a magnetostrictive member 1, a plurality of grooves 2 are formed on the thin plate member in such a way that a plurality of grooves 2 extending along the long side direction D1 of the magnetostrictive member 1 are formed. As described above, a plurality of grooves 2 can be formed by performing surface grinding on at least one of the front and back sides of the thin plate member obtained by the crystal cutting process. Hereinafter, an example of performing the groove forming process by surface grinding of the thin plate member will be described. When a plurality of grooves 2 are formed by surface grinding, the effects of modification of the magnetostrictive constant and the parallel magnetostriction amount described above can be effectively exhibited.

[0081] Surface grinding is performed using a surface grinder. In surface grinding, from the viewpoint of effectively exhibiting the modified effects of the aforementioned magnetostriction constant and parallel magnetostriction, it is preferable that the direction of the grinding marks formed on the thin sheet member is parallel to the long side direction D1 of the magnetostrictive member 1. For this reason, the grinding marks are preferably straight. When the grinding marks are straight, the surface grinder is preferably configured such that the movement direction of the grinding stone or the worktable is linear; a surface grinder using a flat grinding stone and a reciprocating motion of the worktable is preferred. Alternatively, a surface grinder using a cup-shaped grinding stone and a rotary motion of the worktable can be used, but when using such a surface grinder, since the grinding marks are curved, it is preferable to set the curvature of the grinding marks to be small (the degree of curvature to be small).

[0082] Furthermore, the aforementioned grinding marks need to be formed on the surface of the magnetostrictive member 1. Therefore, when processing is performed by adjusting the thickness of the thin plate member, etc., surface grinding can be performed after the predetermined processing has been completed using a processing machine other than a surface grinder, such as a double-sided polishing device or a surface grinder using a cup-shaped grinding stone. Alternatively, surface grinding can be performed after the surface of the thin plate member (magnetostrictive member) has been polished to a mirror finish using the same grinding process as before. From the viewpoint of effectively demonstrating the effects of the aforementioned modification of the magnetostriction constant and the amount of parallel magnetostriction, it is preferable to perform surface grinding on both the front and back sides of the thin plate member.

[0083] Regarding the grinding stones used in surface grinding, the lower limit of the roughness (grit size) of the grinding stone is preferably #40 or higher, more preferably #100 or higher, and the upper limit is preferably #500 or lower, more preferably #400 or lower. The range is preferably #40 or higher and #500 or lower, more preferably #40 or higher and #400 or lower, and even more preferably #100 or higher and #400 or lower. When the roughness (grit size) of the grinding stone is within the above range, the effects of modifying the magnetostrictive constant and parallel magnetostriction amount described above can be more reliably achieved. Furthermore, if a grinding stone with a roughness (grit size) smaller than #40 is used, the size of the grinding marks may sometimes be unstable. If a grinding stone with a roughness greater than #500 is used, the surface of the magnetostrictive component becomes smooth, and there is a risk that the effects of modifying the magnetostrictive constant and parallel magnetostriction amount described above cannot be effectively manifested.

[0084] In the groove forming process, as described above, the plurality of grooves 2 are preferably formed such that the surface roughness Ra of the long side direction D1 of the surface on which the plurality of grooves 2 are formed in the magnetostrictive member 1 is within the aforementioned preferred range. For example, the plurality of grooves 2 are preferably formed such that the lower limit is 0.3 μm or more, the upper limit is preferably 1.5 μm or less, and the range is 0.3 μm or more and 1.5 μm or less. Furthermore, the plurality of grooves 2 are preferably formed such that the lower limit of the surface roughness Ra of the short side direction D2 of the surface on which the plurality of grooves 2 are formed in the magnetostrictive member 1 is preferably 0.6 μm or more, more preferably 0.7 μm or more, the lower limit is preferably 4.5 μm or less, and the range is preferably 0.6 μm or more and 4.5 μm or less. Additionally, the plurality of grooves 2 are preferably formed such that the magnetostriction constant and the parallel magnetostriction amount in the magnetostrictive member 1 are within the aforementioned range. For example, the plurality of grooves 2 are preferably formed such that the magnetostriction constant is 200 ppm or more and the parallel magnetostriction amount is 200 ppm or more in the magnetostrictive member 1. Multiple grooves 2, forming the preferred ranges of surface roughness Ra, magnetostriction constant, and parallel magnetostriction amount described above, can be formed by the aforementioned surface grinding process. Furthermore, the groove forming process only needs to form multiple grooves 2 on at least one of the front side 3 and back side 4 of the resulting sheet metal component, and can also be performed by methods other than surface grinding. For example, sheet metal components can also be manufactured using a wire saw with a fixed abrasive grain. That is, the grooves formed when slicing crystals with a wire saw with a fixed abrasive grain can also be used as multiple grooves 2. In wire saw cutting, there are free abrasive grain and fixed abrasive grain methods. In the free abrasive grain method, the workpiece is pressed against multiple parallel rows of extremely fine wires at a certain spacing, and the wires are fed along the wire direction while a processing fluid containing abrasive grains (also called abrasive fluid) is supplied between the workpiece and the wires, thereby performing cutting. In the fixed abrasive grain method, the workpiece is cut while a wire with abrasive grains such as diamond fixed by electrodeposition or an adhesive is fed along the wire direction. The cutting surface formed by free abrasive grains is a pear-skin-like shape without directionality, which does not achieve the effects of the present invention. However, when cutting with a wire saw using a fixed abrasive grain method, grinding marks are generated in the feed direction of the wire, and multiple grooves 2, similar to those in the above-described planar grinding process, can be formed. Furthermore, when cutting with a wire saw using a fixed abrasive grain method, both the crystal cutting process (step S2) and the groove forming process (step S3) can be combined, enabling efficient production of thin sheet components. Alternatively, multiple grooves 2 can also be formed by applying pressure using sandpaper or the like.

[0085] After the groove forming process (step S3), a cutting process (step S4) is performed. The cutting process is a process of cutting the thin plate member with multiple grooves 2 formed by the groove forming process to obtain the magnetostrictive member 1 of this embodiment.

[0086] In the cutting process, when a thin plate component with multiple grooves 2 is cut to form a magnetostrictive member 1, the thin plate component is cut to form multiple grooves 2 extending along the long side direction D1 of the magnetostrictive member 1. In the cutting process, the thin plate component is cut to a predetermined size. In the cutting process, the thin plate component is cut into the magnetostrictive member 1 so that the magnetostrictive member 1 is a rectangular plate-like body when viewed from above. In the cutting process, a cutting device is used to cut the thin plate component. The cutting device used in the cutting process is not particularly limited; for example, a peripheral cutting device, a wire EDM machine, a wire saw, etc., can be used. The direction in which the magnetostrictive member is cut from the thin plate component is not particularly limited; for example, it can be set to a direction that allows for more efficient acquisition of the size of the magnetostrictive member, etc.

[0087] As described above, the manufacturing method of the magnetostrictive member of this embodiment includes forming a plurality of grooves 2 extending along the long side direction D1 on at least one of the front side 3 and back side 4 of a plate-shaped body composed of a crystal of an iron-based alloy having magnetostrictive properties and having a long side direction D1 and a short side direction D2. Furthermore, in the manufacturing method of the magnetostrictive member of this embodiment, the structure other than the above-described is arbitrary. The manufacturing method of the magnetostrictive member of this embodiment can manufacture magnetostrictive members with high magnetostriction constants and parallel magnetostriction amounts, and small deviations in magnetostriction constants and parallel magnetostriction amounts between components. The manufacturing method of the magnetostrictive member of this embodiment only requires forming a plurality of grooves 2 on a material having magnetostrictive properties, and therefore can be easily implemented.

[0088] Conventionally, among magnetostrictive components cut from the same single crystal, a magnetostrictive component with a high parallel magnetostriction quantity was selected based on the cutting position from the single crystal. However, in the manufacturing method of the magnetostrictive component in this embodiment, since the aforementioned modification of the magnetostriction constant and parallel magnetostriction quantity is performed, the deviation of the magnetostriction constant and parallel magnetostriction quantity in the conventional magnetostrictive components manufactured from the same single crystal is corrected. Therefore, it is possible to produce magnetostrictive components with high yield and stable production, which have high magnetostriction constant and parallel magnetostriction quantity and small deviation of magnetostriction constant and parallel magnetostriction quantity between components.

[0089] Example

[0090] The following description uses embodiments of the present invention, but the present invention is not limited to these embodiments in any way.

[0091] [Example 1]

[0092] The raw materials were adjusted to an iron-gallium ratio of 81:19 (stoichiometric ratio) to prepare cylindrical Fe-Ga alloy single crystals for cultivation via the vertical Bridgman (VB) method. The growth axis of the single crystal was oriented as follows: <100> The orientation of the {100} plane on the upper or lower surface of the single crystal, perpendicular to the crystal growth axis, was confirmed by X-ray diffraction. Furthermore, measurements of the upper and lower surface samples of the crystal using a Shimadzu sequential plasmaluminescence analyzer (ICPS-8100) showed that the gallium content in the single crystal was 17.5–19.0 ​​at%.

[0093] As described below, magnetostrictive components are fabricated from the grown single crystals. First, a free abrasive wire saw is used, along a direction parallel to the single crystal growth direction (relative to...). <100> The single crystal is cut (parallel orientation) to create a thin plate component with a cut surface (main surface) of {100}. Next, using a #200 flat grinding stone, the thin plate component is surface ground on a surface grinder to adjust its thickness and create multiple grooves (grinding marks) on both sides. Then, the cutting position is set so that the long side of the magnetostrictive component is in the same direction as the surface grinding direction (grinding mark direction). Using an external cutting device, a magnetostrictive component with dimensions of 16mm (long side) × 4mm (short side) × 1mm (thickness) is cut out.

[0094] Next, the magnetostrictive properties of the cut-out magnetostrictive component were measured. The magnetostrictive properties were measured using the strain gauge method. For example... Figure 6 As shown, a strain gauge (manufactured by Kyowa Electric Co., Ltd.) is bonded to the main surface ({100}) of the manufactured magnetostrictive member using an adhesive. Furthermore, since the long side direction of the strain gauge is the detection direction of the magnetostriction, the long side direction of the strain gauge is aligned with the long side direction of the magnetostrictive member. <100> Adhesive bonding is performed using a parallel orientation method.

[0095] The magnetostriction measuring instrument (manufactured by Kyowa Electric Co., Ltd.) consists of neodymium-based permanent magnets, a bridge box, a compact recording system, a strain unit, and dynamic data acquisition software.

[0096] Magnetostriction is determined by correcting the actual strain measurement value using the strain coefficient.

[0097] Furthermore, the strain coefficient is given by equation (3) below.

[0098] ε=2.00 / Ks×εi…Equation (3)

[0099] (ε: strain coefficient, εi: measured strain value, Ks: strain coefficient of the strain gauge used)

[0100] Furthermore, the magnetostriction when the magnetic field direction is parallel to the long side direction of the strain gauge is defined as the parallel magnetostriction. On the other hand, the magnetostriction when the magnetic field direction is perpendicular to the long side direction of the strain gauge is defined as the perpendicular magnetostriction. The magnetostriction constant is determined by the difference between the parallel magnetostriction and the perpendicular magnetostriction, according to equation (1). When machining with the long side direction parallel to the grinding mark direction, the parallel magnetostriction of this magnetostrictive component is 280 ppm, and the magnetostriction constant is 285 ppm.

[0101] Furthermore, for the surface of the magnetostrictive component, the surface roughness Ra was measured at five locations each in both the long and short sides of the component using a surface roughness meter (manufactured by KEYENCE Co., Ltd., VK-X1050) at a magnification of 20x. The average value of these measurements was taken as the surface roughness Ra. The surface roughness Ra in the long side direction was 0.56 μm, and the surface roughness Ra in the short side direction was 0.82 μm. The manufacturing conditions and evaluation results are shown in Table 1.

[0102] [Examples 2-3]

[0103] In Examples 2 and 3, to confirm the change in parallel magnetostriction before and after surface grinding, after grinding with a cup-shaped grinding stone (a conventional method) without leaving grinding marks, the surface of the magnetostrictive member was polished smooth and cut to a predetermined size, and the parallel magnetostriction and magnetostriction constant were measured. Then, the long side direction of the magnetostrictive member was set to the same direction as the grinding direction during surface grinding, and surface grinding with a flat grinding stone was performed. Except as described above, it was the same as in Example 1. The manufacturing conditions and evaluation results are shown in Table 1.

[0104] [Comparative Examples 1-2]

[0105] In Comparative Examples 1 and 2, the surface grinding process in Examples 2 and 3 was performed with the short side of the magnetostrictive member aligned with the grinding direction during surface grinding. Except as described above, it was the same as in Examples 2 and 3. The manufacturing conditions and evaluation results are shown in Table 1. The magnetostrictive member of Comparative Example 1 is shown in... Figure 7 .

[0106] [Examples 4-5, Comparative Examples 3-4]

[0107] Examples 4 and 5, and Comparative Examples 3 and 4, were implemented by replacing the direction of cutting the thin plate component from the single crystal in Examples 2 and 3, and Comparative Examples 1 and 2 with a direction perpendicular to the crystal growth direction. Except as described above, they were the same as Examples 4 and 5, and Comparative Examples 3 and 4. Furthermore, the measurement of surface roughness was omitted. The manufacturing conditions and evaluation results are shown in Table 1.

[0108] [Examples 6-15, Examples 16-23]

[0109] In Examples 6-15 and Examples 16-23, multiple thin-plate components were fabricated from the same single crystal, and random magnetostrictive components were cut from them. Everything else was the same as in Example 4. That is, Examples 6-15 and Examples 16-23 were magnetostrictive components fabricated from the same single crystal. The manufacturing conditions and evaluation results are shown in Table 1. The results of the deviations in parallel magnetostriction and magnetostriction constant are recorded in Tables 2 and 3. Furthermore, the measurement of surface roughness was omitted.

[0110] [Examples 24-29, Comparative Examples 5-6]

[0111] Examples 24-29 and Comparative Examples 5-6 are examples of comparing various changes to the cutting direction of the single crystal and the grit size (grit number) of the grinding stone used in surface grinding. Example 25 was performed in the same manner as Example 2. Examples 24 and 26 were the same as Example 2 except for changing the grit size (grit number) of the grinding stone used in surface grinding. Example 28 was performed in the same manner as Example 4. Examples 27 and 29 were the same as Example 4 except for changing the grit size (grit number) of the grinding stone used in surface grinding. Comparative Example 5 was the same as Comparative Example 1. Comparative Example 6 was the same as Comparative Example 3. The surface roughness in each example was measured in the same manner as in Example 1. The manufacturing conditions and evaluation results are shown in Table 4.

[0112] [Examples 30-33]

[0113] Examples 30 to 33 are examples of various modifications to the plate thickness conditions of the magnetostrictive member and comparisons thereof. Example 31 was performed in the same manner as Example 2. Examples 30, 32, and 33 were identical to Example 2 except for changes to the plate thickness conditions adjusted during surface grinding and the grit size (grit number) of the grinding stone used. Furthermore, the surface roughness in each example was assessed in the same manner as in Example 1. The manufacturing conditions and evaluation results are shown in Table 5.

[0114] [Examples 34-37, Comparative Examples 7-9]

[0115] Examples 34-37 and Comparative Examples 7-9 are examples where the angles formed by the extension directions of multiple grooves 2 and the long side direction D1 are set to 0°, 10°, 20°, 30°, 40°, 50°, and 60° respectively, and comparisons are made. Furthermore, the plate thickness is set to 0.5 mm. Example 34 was performed in the same manner as Example 2. Examples 35, 36, and Comparative Examples 8 and 9 are the same as Example 2, except that the grinding direction in the surface grinding process is changed to 10°, 20°, 40°, and 60° respectively. Examples 37 and Comparative Example 8 are the same as Example 4, except that the grinding direction in the surface grinding process is changed to 30° and 50° respectively. Furthermore, the surface roughness in each example is performed in the same manner as in Example 1. The manufacturing conditions and evaluation results are shown in Table 6.

[0116] [Examples 38 to 42]

[0117] Examples 38 to 42 used polycrystalline materials as the crystal material. Examples 38 to 42 were identical to Example 2, except that the prepared single crystal was replaced with a polycrystalline material. For the prepared polycrystalline material, the raw materials were adjusted to an iron-gallium ratio of 81:19 in stoichiometry to prepare cylindrical Fe-Ga alloy polycrystalline materials grown using the vertical Bridgman (VB) method. The growth axis direction of the polycrystalline material was set as... <100> The orientation of the {100} planes on the upper or lower surface of the polycrystalline material perpendicular to the crystal growth axis was confirmed by X-ray diffraction. Furthermore, measurements of the upper surface sample of the crystal using a Shimadzu sequential plasmaluminescence analyzer (ICPS-8100) showed that the gallium content in the polycrystalline material was 17.5–19.0 ​​at%. The manufacturing conditions and evaluation results are shown in Table 7.

[0118] Table 1

[0119]

[0120] Table 2

[0121] Parallel magnetostriction

[0122]

[0123] Magnetostriction constant

[0124]

[0125] Table 4

[0126]

[0127] Table 5

[0128]

[0129] Table 6

[0130]

[0131] Table 7

[0132]

[0133] [Summarize]

[0134] Based on the results of the embodiments, the modification of the magnetostrictive constant and parallel magnetostriction amount described above can be confirmed. Furthermore, based on the results of the embodiments, it can be confirmed that the magnetostrictive member 1 of this embodiment has the characteristics of high magnetostrictive constant and parallel magnetostriction amount, and small deviations in the magnetostrictive constant and parallel magnetostriction amount between members. Additionally, based on the results of the embodiments, it can be confirmed that the manufacturing method of the magnetostrictive member according to the present invention can easily manufacture magnetostrictive members with high magnetostrictive constant and parallel magnetostriction amount, and small deviations in the magnetostrictive constant and parallel magnetostriction amount between members.

[0135] Furthermore, the technical scope of the present invention is not limited to the methods described in the above-described embodiments, etc. One or more of the elements described in the above-described embodiments, etc., are sometimes omitted. Additionally, the elements described in the above-described embodiments, etc., can be appropriately combined. Furthermore, wherever permitted by law, all disclosures of Japanese Patent Applications No. 2019-207723 and No. 2020-144760, and all documents cited in the above-described embodiments, etc., are incorporated into this document.

[0136] Explanation of reference numerals in the attached figures

[0137] 1: Magnetostrictive components;

[0138] 2: slot;

[0139] 3: Front;

[0140] 4: Back side;

[0141] D1: Long side direction;

[0142] D2: Short side direction;

[0143] S1: Crystal preparation process;

[0144] S2: Crystal cutting process;

[0145] S3: Groove forming process;

[0146] S4: Cutting process.

Claims

1. A magnetostrictive component, wherein, The magnetostrictive component is composed of crystals of an iron-based alloy that possesses magnetostrictive properties. The magnetostrictive member is a plate-shaped body having a long side and a short side. At least one of the front and back surfaces of the plate-like body has a plurality of grooves extending along a direction at an angle of less than 40° to the direction of the long side.

2. The magnetostrictive member according to claim 1, wherein, The surface roughness Ra of the surface having the plurality of grooves in the long side direction is smaller than the surface roughness Ra in the short side direction.

3. The magnetostrictive member according to claim 2, wherein, The surface roughness Ra along the long side is 0.3 μm or more and 1.5 μm or less, and the surface roughness Ra along the short side is 0.6 μm or more and 4.5 μm or less.

4. The magnetostrictive member according to any one of claims 1 to 3, wherein, The magnetostrictive constant of the magnetostrictive component is above 200 ppm. The magnetostrictive amount, i.e., the parallel magnetostrictive amount, when the magnetostrictive amount in the long side direction is saturated by applying a magnetic field parallel to the long side direction, is 200 ppm or more.

5. The magnetostrictive member according to any one of claims 1 to 3, wherein, The plate-like body has the plurality of grooves on its front and back sides.

6. The magnetostrictive member according to any one of claims 1 to 3, wherein, The orientation of the plurality of slots is within 30° relative to the direction of the long side.

7. The magnetostrictive member according to any one of claims 1 to 3, wherein, The thickness of the plate-like body is 0.3 mm or more and 2 mm or less.

8. The magnetostrictive member according to any one of claims 1 to 3, wherein, The crystal is a single crystal.

9. The magnetostrictive member according to any one of claims 1 to 3, wherein, The iron-based alloy is an Fe-Ga alloy.

10. The magnetostrictive member according to any one of claims 1 to 3, wherein, The multiple grooves are formed by surface grinding.

11. The magnetostrictive member according to any one of claims 1 to 3, wherein, The magnetostrictive component is a plurality of magnetostrictive components manufactured from one of the crystals. The deviation of the magnetostriction amount, i.e. the parallel magnetostriction amount, when the magnetostriction amount in the long side direction is saturated by applying a magnetic field parallel to the long side direction of the plurality of magnetostrictive components is within 10%.

12. A method for manufacturing a magnetostrictive component, wherein, The method for manufacturing the magnetostrictive member comprises: forming a plurality of grooves extending in a direction at an angle of less than 40° to the long side direction on at least one of the front and back sides of a plate-shaped body composed of a crystal of an iron-based alloy having magnetostrictive properties.

13. The method for manufacturing a magnetostrictive component according to claim 12, wherein, The method for manufacturing the magnetostrictive member includes forming the plurality of grooves by surface grinding.

14. The method for manufacturing a magnetostrictive component according to claim 13, wherein, The surface grinding process involves using grinding stones of #40 or higher and #500 or lower.

15. A method for manufacturing a magnetostrictive member according to any one of claims 12 to 14, wherein, The method for manufacturing the magnetostrictive member includes forming the plurality of grooves such that the magnetostriction constant is 200 ppm or more, and the magnetostriction amount, i.e., the parallel magnetostriction amount, is 200 ppm or more when a magnetic field parallel to the long side direction is applied to saturate the magnetostriction amount in the long side direction.

16. A method for manufacturing a magnetostrictive member according to any one of claims 12 to 14, wherein, The method for manufacturing the magnetostrictive component includes: A plurality of magnetostrictive components are fabricated from one of the crystals; and In the plurality of magnetostrictive members made of one of the crystals, the plurality of grooves are formed such that the deviation of the magnetostriction amount, i.e. the parallel magnetostriction amount, when the magnetostriction amount in the long side direction is saturated by applying a magnetic field parallel to the long side direction is less than 10%.

Images