Manufacturing method for SmCo magnets

Abstract

To provide a magnet having a high surface magnetic flux density, a small device, a microactuator and a sensor.SOLUTION: A method for manufacturing an SmCo-based magnet has a Co base material, an Sm2Co17 film on the Co base material, and an SmCo5 film on the Sm2Co17 film. The method for manufacturing the SmCo-based magnet includes a reaction diffusion step for acquiring a laminate having the Co base material and an SmCo2 film formed on the Co base material by immersing the Co base material containing an Sm source to perform reaction diffusion, and a heating step for reacting the Co base material and the SmCo2 film by heating the laminate to form the Sm2Co17 film and the SmCo5 film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to magnets and miniature devices, microactuators and sensors using the same. [Background technology]

[0002] As miniaturization of various electronic devices is required, development of miniature devices such as micromotors and microactuators to be incorporated into these devices is progressing. The size and performance of these devices are greatly influenced by the magnetic properties of the permanent magnets used in the devices.

[0003] Films of rare earth intermetallic compounds with high energy products are attracting attention as permanent magnets. Among them, SmCo-based magnetic films are in high demand for applications requiring thermal stability of magnetic properties due to their high Curie point, and for applications requiring reliability due to their high weather resistance.

[0004] For example, Patent Document 1 discloses a Sm-Co alloy-based perpendicular magnetic anisotropy thin film, which has perpendicular magnetic anisotropy in which the axis of easy magnetization is oriented perpendicular to the film surface, and is formed on a base made of Cu or a Cu alloy, and is made of an alloy containing Sm and Co. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4614046 Summary of the Invention [Problem to be solved by the invention]

[0006] Permanent magnet films used in small devices are required to have a high surface magnetic flux density, but the Sm—Co alloy-based perpendicular magnetic anisotropy thin film disclosed in Patent Document 1 leaves room for improvement in terms of surface magnetic flux density.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a SmCo-based magnet film with a high surface magnetic flux density, a magnet with a high surface magnetic flux density, and small devices, microactuators, and sensors that use the same. [Means for solving the problem]

[0008] A magnet according to one aspect of the present invention comprises a yoke portion including a soft magnetic material and a magnet portion including a hard magnetic material formed on a main surface of the yoke portion, and the interface between the magnet portion and the yoke portion has an uneven shape.

[0009] A magnet according to one aspect of the present invention includes a yoke portion and a magnet portion, and the interface therebetween is uneven, which allows the magnetic flux density of the protruding portions to be greater than that of the recessed portions. As a result, such a magnet has a high surface magnetic flux density.

[0010] Here, the degree of irregularity of the uneven shape of the interface may be 1.0<degree of irregularity<2.0. If the degree of irregularity exceeds 1.0, the magnetic flux density of the convex portions can be made higher than that of the concave portions. If the degree of irregularity is less than 2.0, the heat treatment temperature and time tend to be lower and shorter, respectively, in the heat treatment step for manufacturing the magnet. This makes it possible to suppress decomposition of the magnet portion and further improve the magnetic flux density.

[0011] The yoke is made of soft magnetic material Sm2Co 17 The magnet part contains SmCo5 as a hard magnetic material, and Sm2Co 17 However, the SmCo5 may be formed on the main surface of the SmCo5, and the crystal orientation [00L] of the SmCo5 may be oriented in the thickness direction of the SmCo5. Since SmCo5 has a high Curie point of 700°C or higher, it has excellent thermal stability of magnetic properties. The crystal orientation [00L] of SmCo5 is oriented perpendicular to the film surface, resulting in high surface magnetic flux. Furthermore, SmCo5 has a higher saturation magnetization than SmCo5 and is soft magnetic. 17 However, by being present as a base, they act as a back yoke, and as a result, the magnet according to one aspect of the present invention has an even greater surface magnetic flux density.

[0012] The thickness of the magnet portion may be 1 to 200 μm. When the thickness of the hard magnetic material SmCo5 is 1 μm or more, the surface magnetic flux density tends to be further improved. When the thickness of the magnet portion is 200 μm or less, the magnet according to one aspect of the present invention can be suitably used in small devices.

[0013] Another aspect of the present invention may be a small device using the magnet. Another aspect of the present invention may be a microactuator using the magnet. Another aspect of the present invention may be a sensor using the magnet.

[0014] The SmCo-based magnet film according to another aspect of the present invention is SmCo 17 membrane and Sm2Co 17 and a SmCo5 film formed on the film, the crystal orientation [00L] of the SmCo5 film being oriented in the thickness direction of the SmCo5 film, where L is any natural number.

[0015] According to another aspect of the present invention, the SmCo-based magnet film is SmCo 17 The crystal orientation [00L] of the SmCo5 film is oriented in the thickness direction of the SmCo5 film, so that a SmCo-based magnet film with high surface magnetic flux density can be provided.

[0016] Here, the thickness of the SmCo5 film may be 1 to 20 μm. [Effects of the Invention]

[0017] According to one aspect of the present invention, there are provided magnets with high surface magnetic flux density, as well as small devices, microactuators, and sensors using the same.

[0018] Another aspect of the present invention provides an SmCo-based magnet film with high surface magnetic flux density. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic cross-sectional view of a magnet according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram of a portion cut out from an SEM photograph of a cross section of a magnet according to one embodiment of the present invention. [Figure 3] 1 is a schematic cross-sectional view of a SmCo-based magnet film according to one embodiment of the present invention. [Figure 4] FIG. 1 is a schematic cross-sectional view of an SmCo-based magnet according to one embodiment of the present invention. [Figure 5] FIG. 1 is a schematic diagram of measurement points for confirming the presence or absence of radial alignment. [Figure 6] 1A to 1C are schematic cross-sectional views of a method for manufacturing an SmCo-based magnet film according to one embodiment of the present invention. [Figure 7] 1A to 1C are schematic cross-sectional views of a method for manufacturing an SmCo-based magnet film according to one embodiment of the present invention. [Figure 8] 1 is a schematic cross-sectional view of a method for manufacturing an SmCo magnet according to one embodiment of the present invention. [Figure 9] 1 shows an X-ray diffraction profile obtained by irradiating an SmCo5 film, which is an SmCo-based magnet film obtained in Example 2, with X-rays. [Figure 10] FIG. 10 is a pole figure obtained by performing EBSD on the SmCo-based magnet obtained in Example 10. DETAILED DESCRIPTION OF THE INVENTION

[0020] <Magnet> A magnet according to one embodiment will be described with reference to the drawings.

[0021] As shown in FIG. 1, the magnet 200 according to this embodiment includes a yoke portion 15 made of a soft magnetic material, and a magnet portion 17 formed on a main surface of the yoke portion 15 and made of a hard magnetic material.

[0022] The yoke portion 15 includes a soft magnetic material. Examples of the soft magnetic material include metal Co, metal Fe, and metal Ni, as well as alloys and compounds containing these metals. Examples of such alloys include SmCo. 17 and silicon steel. Such compounds include, for example, ferrite.

[0023] The proportion of the soft magnetic material contained in the yoke portion 15 may be, for example, 80 mass % or more, 85 mass % or more, 90 mass % or more, or 95 mass % or more.

[0024] The thickness of the yoke portion 15 is not particularly limited and can be appropriately selected depending on the application, but can be, for example, 0.0010 to 1 mm.

[0025] The magnet portion 17 includes a hard magnetic material, such as SmCo5 or Sm5Fe. 17 (NdFe 17 SmFe7 (Sm and Fe alloy with TbCu7 type crystal structure), SmFe 17 N3(Pr2Mn 17 C 1.77 SmFe (an alloy of Sm, Fe and N with a crystalline structure of the SmFe type) 12 (ThMn 12 NdFe (an alloy of Sm and Fe with a crystalline structure of the NdFe type) 14 B(NdFe 14 Examples of alloys include alloys of Nd, Fe, and B that have a B-type crystal structure. The atomic ratio of the atoms contained in these alloys may deviate from the stoichiometric ratio.

[0026] The proportion of hard magnetic material contained in the magnet portion 17 may be, for example, 80 mass % or more, 85 mass % or more, 90 mass % or more, or 95 mass % or more.

[0027] The thickness of magnet portion 17 is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, as this tends to further improve the surface magnetic flux density of magnet 200. The thickness of magnet portion 17 is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 20 μm or less, as magnet 200 can be suitably used in small devices. The thickness of magnet portion 17 can be measured by embedding magnet 200 in resin, polishing the resulting sample to expose the cross section of magnet 200 from the resin, and observing the exposed cross section of magnet 200 with a scanning electron microscope (SEM).

[0028] The interface between magnet portion 17 and yoke portion 15 has an uneven shape. The shape of the interface can be measured by embedding magnet 200 in resin, polishing the obtained sample to expose the cross section of magnet 200 from the resin, and observing the exposed cross section of magnet 200 with a scanning electron microscope (SEM).

[0029] The degree of unevenness at the interface between the magnet portion 17 and the yoke portion 15 is preferably 1.0 < degree of unevenness < 2.0, more preferably 1.15 < degree of unevenness < 1.6, and even more preferably 1.2 < degree of unevenness < 1.5. When the degree of unevenness exceeds 1.0, the magnetic flux density of the convex portions can be increased relative to the concave portions. When the degree of unevenness is less than 2.0, the heat treatment temperature and time tend to be lower and shorter, respectively, in the heat treatment process for manufacturing the magnet 200. This makes it possible to suppress decomposition of the magnet portion 17, further improving the magnetic flux density.

[0030] The degree of unevenness of the interface between the magnet portion 17 and the yoke portion 15 can be measured by observing the interface with a scanning electron microscope (SEM). Specifically, the magnet 200 is embedded in resin, and the obtained sample is polished to expose the cross-section of the magnet 200 from the resin. The cross-section is observed by SEM to obtain a backscattered electron image. The acceleration voltage when obtaining the backscattered electron image is 10 to 15 kV, and the WD (working distance) is 10 to 15 mm. A portion (quadrilateral) to be subjected to analysis is cut out from the obtained backscattered electron image, and the degree of unevenness is calculated by analyzing the cut-out image. FIG. 2 is a schematic diagram of a portion cut out from a SEM photograph (backscattered electron image) of the cross-section of the magnet 200. As shown in FIG. 2, the backscattered electron image is cut out such that one side of the cut-out image and the side opposite thereto intersect with the interface B1 between the magnet portion 17 and the yoke portion 15 (b1 and b2), and the interface B1 is accommodated between the remaining two sides. Further, the backscattered electron image is cut out such that the length of the straight line connecting b1 and b2 described later is 100 μm or more. The cut-out image is subjected to image quality adjustment, binarization processing, and edge (contour) extraction processing. Then, the length from one end b1 to the other end b2 of the interface B1 in the cut-out image is measured. Also, the length of the straight line connecting b1 and b2 is measured. The length indicated by the scale bar is used as the length standard. The degree of unevenness can be calculated by dividing the length of the interface B1 by the length of the straight line connecting b1 and b2. The measurement magnification is 1000 times. The location observed by SEM is two or more locations so as not to be an analysis of only a part thereof. The degree of unevenness is the average value of the degrees of unevenness obtained from each of two or more images.

[0031] The use of the magnet 200 is not particularly limited, but since the magnet 200 has a high surface magnetic flux density, it is suitable for, for example, small devices. As small devices, a micromotor, a microactuator, and a sensor are suitable.

[0032] <SmCo-based magnet film> As an example of the magnet according to the above embodiment, a SmCo-based magnet film according to an embodiment will be described. The SmCo-based magnet film according to an embodiment will be described with reference to the drawings.

[0033] As shown in FIG. 3, the SmCo-based magnet film 100 according to this embodiment (hereinafter also referred to as the "magnet film 100") is composed of a Mo substrate 10 and a SmCo layer formed on the Mo substrate 10. 17 Film 20 and Sm2Co 17 and a SmCo5 film 30 formed on the film 20. In the magnet film 100, Sm2Co 17 The film 20 is the yoke portion, and the SmCo5 film 30 is the magnet portion.

[0034] The Mo substrate 10 is a metal Mo plate. The Mo purity of the Mo substrate may be 99% by mass or more, or may be 99.998% by mass or more. The Mo substrate 10 may have another substrate underneath.

[0035] The thickness of the Mo substrate 10 is not particularly limited and can be appropriately selected depending on the application, but can be, for example, 0.0010 to 0.5 mm.

[0036] Sm2Co 17 The film 20 is Sm2Co 17 Contains Sm2Co as the main phase. 17 is Th2Zn 17 It is an alloy of Sm and Co that has a crystal structure of the type Sm2Co. 17 The ratio of Sm atoms to Co atoms in SmCo may deviate from the stoichiometric ratio. 17 The ratio of Sm atoms to Co atoms in SmCo may not necessarily be stoichiometric, for example, if various elements are added to improve magnetic properties. 17 is Th2Zn 17 As long as the crystal structure is of this type, the ratio of Sm atoms to Co atoms may deviate from the stoichiometric ratio.

[0037] In this specification, "as the main phase" means that it has the largest mass ratio in the film. 17 The film 20 is Sm2Co 17 It may have different phases, for example, other crystalline phases and grain boundary phases. 17 Sm2Co in film 20 17The proportion of may be, for example, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more.

[0038] Sm2Co 17 The thickness of the film 20 is not particularly limited and can be appropriately selected depending on the application, but can be, for example, 1 to 100 μm. 17 The thickness of the film 20 can be measured by embedding the magnet film 100 in resin, polishing the resulting sample to expose the cross section of the magnet film 100 from the resin, and observing the exposed cross section of the magnet film 100 using a scanning electron microscope (SEM).

[0039] The SmCo5 film 30 contains SmCo5 as a main phase. SmCo5 is an alloy of Sm and Co that has a CaCu5-type crystal structure. The ratio of Sm atoms to Co atoms in SmCo5 may deviate from the stoichiometric ratio. For example, when various elements are added to improve magnetic properties, the ratio of Sm atoms to Co atoms in SmCo5 may not necessarily be the stoichiometric ratio. Therefore, as long as SmCo5 has a CaCu5-type crystal structure, the ratio of Sm atoms to Co atoms may deviate from the stoichiometric ratio.

[0040] The SmCo5 film 30 may have a phase different from SmCo5, such as another crystalline phase and a grain boundary phase. The proportion of SmCo5 in the SmCo5 film 30 may be, for example, 70 mass % or more, 80 mass % or more, 90 mass % or more, or 95 mass % or more. An example of a different phase is an Sm-rich phase having a higher Sm content than SmCo5.

[0041] The crystal orientation [00L] of the SmCo5 film 30 is oriented in the thickness direction of the SmCo5 film, i.e., in the direction perpendicular to the film surface A1. L is an arbitrary natural number. L indicates the same direction in all cases. L is, for example, 2.

[0042] The crystal orientation [00L] of the SmCo5 film is oriented in the thickness direction of the SmCo5 film when the degree of orientation defined by formula (1) is 50% or more. This degree of orientation is based on the vector-corrected Lotgering method and indicates the ratio of the sum of the diffraction peaks based on the crystal orientation [00L] component to the sum of the diffraction peaks based on the crystal planes (hkl) of the SmCo5 film. The degree of orientation is preferably 60% or more, more preferably 70% or more, and even more preferably 75% or more, because this further improves the surface magnetic flux density of the magnet film 100.

[0043] In equation (1), I is the intensity of the diffraction peak based on the crystal plane (hkl) when the SmCo5 film 30 is irradiated with X-rays. Each diffraction peak is assigned to one of the crystal planes represented by Miller indices. Examples of the crystal planes of the SmCo5 film when 2θ is 30 to 60° are the (002) plane, the (111) plane which is a plane oblique to the (002) plane, and the (110) plane which is a plane perpendicular to the (002) plane. In the following formula (1), the numerator of the fraction on the right side is the sum of the products of the intensity I of each peak and the vector correction coefficient β given to the crystal plane of each peak for each diffraction peak of the SmCo5 film observed in the range of 2θ = 30 to 60°. The vector correction coefficient β is the cosine (cos θ) of the angle θ between the (00L) plane, which is the reference plane, and each crystal plane (hkl), and is a different value for each crystal plane (hkl) as will be described later.

[0044] On the other hand, the denominator of the fraction on the right side is the sum of the intensities I of the diffraction peaks of the SmCo5 film in the range of 2θ=30 to 60°.

[0045]

number

[0046] The thickness of the SmCo5 film 30 is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, since this further improves the surface magnetic flux density of the magnet film 100. There is no particular upper limit to the thickness of the SmCo5 film 30, but it may be, for example, 200 μm or less, 100 μm or less, or 20 μm or less. The thickness of the SmCo5 film 30 can be measured by embedding the magnet film 100 in resin, polishing the resulting sample to expose the cross section of the magnet film 100 from the resin, and observing the exposed cross section of the magnet film 100 with a scanning electron microscope (SEM).

[0047] Sm2Co in SmCo5 film 30 17 The film surface A1 opposite to the surface in contact with the film 20 may be partially or entirely covered with Sm2O3, or may not be covered.

[0048] Sm2Co 17 The total thickness of the film 20 and the SmCo5 film 30 is not particularly limited and can be changed appropriately depending on the application, but may be, for example, 0.002 to 0.2 mm.

[0049] The magnet film 100 does not necessarily have to have the Mo substrate 10. For example, after manufacturing, the Mo substrate can be removed by etching or the like.

[0050] The magnet film 100 may have a Co substrate instead of the Mo substrate 10. The purity of Co in the Co substrate may be the same as the purity of Mo in the Mo substrate. The thickness of the Co substrate may be the same as that of the Mo substrate.

[0051] The planar shape of the magnet film 100 is not particularly limited and can be set appropriately depending on the application. The shape of the magnet film 100 as viewed in the Z-axis direction may be, for example, a square, a rectangle, or a circle. When the shape of the magnet film 100 as viewed in the Z-axis direction is square, the length of one side may be, for example, 0.1 to 100 mm. When the shape of the magnet film 100 as viewed in the Z-axis direction is rectangular, the length of its long side may be, for example, 1 to 100 mm, and the length of its short side may be, for example, 0.1 to 50 mm. When the shape of the magnet film 100 as viewed in the Z-axis direction is circular, its diameter may be, for example, 0.1 to 50 mm.

[0052] The surface magnetic flux density of the magnet film 100 is preferably 5 mT or more, more preferably 7 mT or more, and even more preferably 10 mT or more. The surface magnetic flux density of the magnet film 100 can be measured by contacting a Hall element probe with the film surface A1 of the SmCo5 film of the magnet film 100, tracing the film surface A1, and converting the output voltage into magnetic flux density.

[0053] The use of the magnet film 100 is not particularly limited, but since the surface magnetic flux density of the magnet film 100 is high, sensors, micromotors, and microactuators are suitable. The use of the magnet film 100 is not particularly limited, but since the surface magnetic flux density of the magnet film 100 is high, small devices are suitable.

[0054] (Action and effect) The magnet film 100 is made of Sm2Co, which has a higher saturation magnetization than SmCo5 and is soft magnetic. 17 The film 20 is provided with Sm2Co 17 The film 20 acts as a back yoke that collects magnetic flux. Furthermore, the crystal orientation [00L] of the SmCo5 film 30 is oriented in the thickness direction of the SmCo5 film 30. In other words, the crystal orientation [00L], which is the easy axis of magnetization of SmCo5, coincides with the thickness direction of the SmCo5 film 30 (the direction perpendicular to the film surface A1 (Z-axis direction)), thereby increasing the surface magnetic flux density of the magnet film 100. Furthermore, the Curie point of SmCo5 is high at 700°C or higher, so it has excellent thermal stability.

[0055] <Cylindrical SmCo magnet> As an example of the magnet according to the above embodiment, a cylindrical SmCo-based magnet according to one embodiment will be described with reference to the drawings.

[0056] 4 is a schematic diagram of a cross section perpendicular to the axial direction of a cylindrical SmCo-based magnet 300 (hereinafter also referred to as "magnet 300") according to this embodiment. Magnet 300 is made of a Co base material 12 and an SmCo layer formed on the Co base material 12. 17 Film 20 and Sm2Co 17 and a SmCo5 film 30 formed on the film 20. In the magnet 300, a Co substrate 12 and a Sm2Co 17 The film 20 is the yoke portion, and the SmCo5 film 30 is the magnet portion.

[0057] The diameter of the Co base material 12 is not particularly limited and can be appropriately selected depending on the application, but can be, for example, 0.1 to 2.0 mm. The purity of Co in the Co base material 12 may be the same as the purity of Mo in the Mo substrate of the magnet film 100 according to the above embodiment.

[0058] Sm2Co according to this embodiment 17 The film 20 and the SmCo5 film 30 are the same as those in the magnet film 100 according to the above embodiment. 17 The film 20 and the SmCo5 film 30 may be similar.

[0059] The crystal orientation [00L] of the SmCo5 film 30 is preferably radially oriented in the magnet 300 because the surface magnetic flux density of the magnet 300 is further improved. The presence or absence of radial orientation can be confirmed as follows. That is, the magnet 300 is embedded in resin. By polishing a part of the resin, a cross section perpendicular to the axial direction of the cylindrical magnet 300 is exposed from the resin. In the exposed SmCo5 of the cross section, the orientation of the crystal orientation of SmCo5 is measured by the EBSD (Electron Back Scatter Diffraction Patterns) method. As shown in FIG. 5, the measurement locations are four locations in total: a location Y1 away from the normal direction at the center of the cross section in the Y direction perpendicular to the Y direction in the exposed substantially circular cross section of SmCo5, a location Y2 away from the -Y direction opposite to the Y direction, a location X1 away from the X direction perpendicular to the Y direction, and a location X2 away from the -X direction opposite to the X direction. At Y1, a pole figure of the crystal orientation [00L] of SmCo5 is obtained when observing Y1 in the -Y direction with the XZ plane as the front. At Y2, a pole figure of the crystal orientation [00L] of SmCo5 is obtained when observing Y2 in the Y direction with the XZ plane as the front. At X1, a pole figure of the crystal orientation [00L] of SmCo5 is obtained when observing X1 in the -X direction with the YZ plane as the front. At X2, a pole figure of the crystal orientation [00L] of SmCo5 is obtained when observing X2 in the X direction with the YZ plane as the front. The pole figure is a figure showing the crystal orientation by the stereographic projection method. In each pole figure, when a point is marked in the center, it is determined that the crystal orientation [00L] of SmCo5 is radially oriented in the cylindrical magnet 300.

[0060] The height of the magnet 300 may be, for example, 5 to 30 mm. The diameter of the magnet 300 may be, for example, 0.5 to 3 mm. The surface magnetic flux density of the magnet 300 may be the same as that of the magnet film 100. The use of the magnet 300 may be the same as that of the magnet film 100.

[0061] <Method for manufacturing SmCo-based magnet film> {First Embodiment} Next, a method for manufacturing an SmCo-based magnetic film according to one embodiment will be described in detail. The method for manufacturing an SmCo-based magnetic film according to this embodiment involves, for example, immersing the Mo substrate 10 in a first plating bath containing an Sm source and a Co source, and depositing SmCo on at least one of the main surfaces of the Mo substrate 10 by electroplating. 17 a step of forming a film (hereinafter also referred to as the "first electroplating step"), and a step of immersing the obtained laminated film 50 in a second plating bath containing an Sm source and a Co source to form at least SmCo by an electroplating method. 17 The method may include a step of forming an unoriented SmCo5 film on a main surface of the film opposite to the main surface in contact with the Mo substrate 10 (hereinafter also referred to as the "second electrolytic plating step"), and a step of heating the obtained alloy film, wherein the molar ratio of the Co source to the Sm source in the second plating bath is smaller than the molar ratio of the Co source to the Sm source in the first plating bath.

[0062] (First and second electrolytic plating steps) 6A and 6B are schematic cross-sectional views of a method for manufacturing an SmCo-based magnetic film according to one embodiment. In the first electrolytic plating step, SmCo is deposited on the main surface of the Mo substrate 10 shown in FIG. 6A by electrolytic plating. 17 The Mo substrate 10 and the Sm2Co film 20 are formed as shown in FIG. 17 In FIG. 6(b), a laminated film 50 having a film 20 is obtained. 17 Although the film is shown on only one major surface of the Mo substrate 10, the Sm2Co 17 The film may be formed on the other main surface of the Mo substrate 10 and on the side surface of the Mo substrate 10.

[0063] In the second electrolytic plating step, at least Sm2Co 17 A non-oriented SmCo film is formed on the main surface of the film opposite to the main surface in contact with the Mo substrate 10. As a result, the Mo substrate 10 and the SmCo film are 17 The alloy film 70 is obtained by sequentially forming the SmCo5 film 20 and the unoriented SmCo5 film 40. In FIG. 6(c), the unoriented SmCo5 film is 17Although the film is shown only on the principal surface opposite to the principal surface in contact with the Mo substrate 10, the unoriented SmCo5 film may also be formed on the other principal surface of the Mo substrate 10 and on the side surface of the Mo substrate 10.

[0064] In the first electrolytic plating step, the Mo substrate 10 is immersed in a plating bath containing a Sm source and a Co source, and the Mo substrate 10 is used as a cathode. A current is passed between the cathode and the anode, whereby Sm ions and Co ions are reduced and precipitated on the main surface of the Mo substrate 10, forming SmCo on the main surface of the Mo substrate 10. 17 A membrane 20 is formed.

[0065] In the second electrolytic plating step, the laminated film 50 is immersed in a plating bath containing a Sm source and a Co source, and the laminated film 50 is used as a cathode. A current is passed between the cathode and the anode to form SmCo. 17 Sm ions and Co ions are reduced and precipitated on the main surface of the film 20, forming SmCo 17 An unoriented SmCo5 film 40 is formed on a major surface of the film 20 .

[0066] The plating bath in the first and second electrolytic plating steps may be a molten salt of an Sm source, a Co source, and an inorganic salt other than the Sm source.

[0067] Examples of Sm sources include SmCl3 and SmF3. Examples of Co sources include CoCl2 and CoF2. The Sm sources and Co sources can be used alone or in combination of two or more.

[0068] Examples of inorganic salts other than the Sm source and the Co source include KCl, LiCl, and NaCl. These inorganic salts can be used alone or in combination of two or more.

[0069] The molar ratio of the Co source to the Sm source in the first electrolytic plating step may be 1.3 or more, and SmCo 17 It is preferably 1.4 or more from the viewpoint of efficiently forming the film 20. The molar ratio of the Co source to the Sm source in the first electrolytic plating step may be 1.5 or less.

[0070] The molar ratio of the Co source to the Sm source in the second electrolytic plating step may be 1.1 or less, and is preferably 1.0 or less from the viewpoint of efficiently forming the SmCo5 film 40. The molar ratio of the Co source to the Sm source in the second electrolytic plating step may be 0.9 or more.

[0071] The proportion of the Sm source in the Sm source, Co source, and inorganic salt other than the Sm source and Co source may be, for example, 0.05 to 2 mol % based on the total number of moles of the Sm source and Co source and the inorganic salt other than the Sm source and Co source contained in the plating bath.The proportion of the Co source in the Sm source, Co source, and inorganic salt other than the Sm source and Co source may be, for example, 0.025 to 1 mol % based on the total number of moles of the Sm source and Co source and the inorganic salt other than the Sm source and Co source contained in the plating bath.

[0072] The plating bath may be prepared, for example, by drying the inorganic salt to dehydrate it, then heating it to a plating temperature described below to melt the inorganic salt, and then adding the Sm source and the Co source to the molten inorganic salt.

[0073] The material of the anode used in the first and second electrolytic plating steps is not particularly limited as long as it is one that is used as an anode in electrolytic plating, and examples thereof include graphite, glassy carbon, and Mo. The shape of the anode is not particularly limited, and may be, for example, a rectangular parallelepiped. When the anode is a rectangular parallelepiped, the thickness of the anode may be, for example, 0.1 to 10 mm, the length in the long side direction may be, for example, 10 to 100 mm, and the length in the short side direction may be, for example, 1 to 50 mm.

[0074] The plating temperature in the first and second electrolytic plating steps is not particularly limited as long as it is equal to or higher than the temperature at which the inorganic salt melts. 17From the viewpoint of efficiently forming the film 20 and the unoriented SmCo5 film 40, the plating temperature is preferably 400° C. or higher, more preferably 500° C. or higher, and even more preferably 600° C. or higher. Here, the plating temperature refers to the temperature of the plating bath during plating.

[0075] The electrolytic method of the first and second electrolytic plating steps may be constant current. 17 From the viewpoint of efficiently forming the film 20 and the unoriented SmCo5 film 40, the magnetic field is preferably 0.05 A or more, more preferably 0.1 A or more, and even more preferably 0.2 A or more.

[0076] The plating time for the first and second electrolytic plating steps is determined by the required thickness of Sm2Co 17 As long as the film 20 and the unoriented SmCo5 film 40 can be formed, the time can be changed appropriately depending on the current value, and from the viewpoint of efficiency, it is not necessary to set it longer than necessary, but it may be, for example, 1 to 60 minutes.

[0077] Sm2Co 17 The film 20 is Sm2Co 17 It is preferable that the main phase contains Sm2Co. 17 The film 20 may have a crystal phase (heterogeneous phase) different from the main phase or a grain boundary. The ratio of the main phase may be, for example, 50 mass % or more, 70 mass % or more, or 90 mass % or more. The heterogeneous phase may be, for example, Sm2Co 17 An example is an Sm-rich phase, which has a higher Sm content than the Sm-rich phase.

[0078] The unoriented SmCo5 film 40 preferably contains SmCo5 as a main phase. The unoriented SmCo5 film 40 may have a crystal phase (heterogeneous phase) different from the main phase or a grain boundary. The proportion of the main phase may be, for example, 50 mass % or more, 70 mass % or more, or 90 mass % or more. An example of the heterogeneous phase is an Sm-rich phase having a higher Sm content than SmCo5.

[0079] The obtained alloy film 70 may be washed before the heating step described below. The washing method is not particularly limited, but examples thereof include an organic solvent such as ethanol and water.

[0080] (Heating process) In the heating step, the alloy film 70 is heated to a holding temperature, heated to the holding temperature while applying a magnetic field perpendicular to the main surface of the alloy film 70, and cooled while applying a magnetic field perpendicular to the main surface of the alloy film 70. This changes the orientation of the [00L] crystal orientation of the unoriented SmCo5 film 40, and the unoriented SmCo5 film 40 is transformed into an SmCo5 film 30 in which the [00L] crystal orientation is oriented in the thickness direction of the SmCo5 film.

[0081] The temperature increase rate in the heating step is not particularly limited, but may be, for example, 0.1 to 100°C / second. The holding temperature is preferably 800°C or higher, more preferably 850°C or higher, and even more preferably 900°C or higher, since this further improves the surface magnetic flux density of the magnet film 100. The temperature decrease rate is preferably 5°C / second or higher, more preferably 10°C / second or higher, and even more preferably 20°C / second or higher, since this further improves the surface magnetic flux density of the magnet film 100. The magnetic field applied during the temperature holding process and cooling process is not particularly limited, but may be, for example, 2 to 3 T.

[0082] The holding time in the heating step is preferably 60 seconds or less, more preferably 30 seconds or less, and even more preferably 15 seconds or less, since this further suppresses the decrease in the surface magnetic flux density of the SmCo5 film 30.

[0083] The atmosphere in the heating step is not particularly limited, but from the viewpoint of suppressing oxidation, an inert gas atmosphere is preferable, and examples of the inert gas include Ar and N2.

[0084] {Second embodiment} A method for manufacturing an SmCo-based magnetic film according to another embodiment will now be described in detail. The method for manufacturing an SmCo-based magnetic film according to this embodiment may include, for example, an electroplating step of immersing a Co substrate 12 in a plating bath containing an Sm source and forming an SmCo film 25 on at least one main surface of the Co substrate 12 by electroplating, and a step of heating the resulting laminated film 51.

[0085] 7A and 7B are schematic cross-sectional views of a method for manufacturing an SmCo-based magnetic film according to one embodiment. In the electrolytic plating step, an SmCo film 25 is formed on the main surface of a Co substrate 12 shown in FIG. 7A by electrolytic plating, and a laminated film 51 having the Co substrate 12 and the SmCo film 25 is obtained as shown in FIG. 7B.

[0086] The SmCo2 film 25 preferably contains SmCo2 as a main phase. SmCo2 is an alloy of Sm and Co that has an MgCu2-type crystal structure. The ratio of Sm atoms to Co atoms in SmCo2 may deviate from the stoichiometric ratio. For example, when various elements are added to improve magnetic properties, the ratio of Sm atoms to Co atoms in SmCo2 may not necessarily be the stoichiometric ratio. Therefore, as long as SmCo2 has an MgCu2-type crystal structure, the ratio of Sm atoms to Co atoms may deviate from the stoichiometric ratio.

[0087] The SmCo2 film 25 may have a crystal phase (heterogeneous phase) different from the main phase or a grain boundary. The ratio of the main phase may be, for example, 50 mass % or more, 70 mass % or more, or 90 mass % or more. An example of the heterogeneous phase is an Sm-rich phase having a higher Sm content than SmCo2.

[0088] In FIG. 7(b), the SmCo2 film 25 is shown only on one main surface of the Co substrate 12, but the SmCo2 film 25 may also be formed on the other main surface of the Co substrate 12 and on the side surfaces of the Co substrate 12.

[0089] In the electrolytic plating process, the Co substrate 12 is immersed in a plating bath containing an Sm source, and the Co substrate 12 is used as a cathode. A current is passed between the cathode and the anode, whereby Sm ions are reduced and precipitated on the main surface of the Co substrate 12, forming an SmCo2 film 25 on the main surface of the Co substrate 12.

[0090] The plating bath in the electrolytic plating step may be a molten salt of an Sm source and an inorganic salt other than the Sm source.

[0091] As the Sm source and inorganic salt other than the Sm source, the same Sm source and inorganic salt other than the Sm source as those used in the manufacturing method of the SmCo-based magnet film according to the first embodiment can be used.

[0092] The proportion of the Sm source in the Sm source and the inorganic salts other than the Sm source may be, for example, 0.05 to 2 mol % based on the total number of moles of the Sm source and the inorganic salts other than the Sm source contained in the plating bath.

[0093] The plating bath may be prepared, for example, by drying the inorganic salt to dehydrate it, then heating it to a plating temperature described below to melt the inorganic salt, and then adding an Sm source to the molten inorganic salt.

[0094] The material and shape of the anode used in the electrolytic plating step may be the same as those in the method for producing the SmCo-based magnetic film according to the first embodiment.

[0095] The plating temperature in the electrolytic plating step is not particularly limited as long as it is equal to or higher than the temperature at which the inorganic salt melts, but from the viewpoint of efficiently forming the SmCo2 film 25, it is preferably equal to or higher than 400° C., more preferably equal to or higher than 500° C., and even more preferably equal to or higher than 600° C. Here, the plating temperature refers to the temperature of the plating bath during plating.

[0096] The electrolytic plating method may be a constant current method, and the current value in the electrolytic plating process may be the same as that in the electrolytic plating process in the method for producing an SmCo-based magnetic film according to the first embodiment.

[0097] The plating time in the electrolytic plating process can be changed appropriately depending on the current value as long as it is possible to form an SmCo2 film 25 of the required thickness. From the viewpoint of efficiency, it is not necessary to set the plating time longer than necessary, but it may be, for example, 1 to 120 minutes.

[0098] The obtained laminated film 51 may be washed before the heating step described later. The washing method is not particularly limited, but examples thereof include an organic solvent such as ethanol and water.

[0099] (Heating process) In the heating step, the laminated film 51 is heated to a holding temperature and then cooled. As a result, SmCo2 reacts with Co, and SmCo is formed from the Co substrate 12 and the SmCo2 film 25. 17 A film 20 and an SmCo5 film 30 in which the crystal orientation [00L] is oriented in the thickness direction of the SmCo5 film are formed.

[0100] The temperature rising rate, holding temperature, and temperature dropping rate in the heating step may be the same as those in the heating step in the method for producing an SmCo based magnetic film according to the first embodiment.

[0101] The holding time in the heating step may be 1 hour or more and may be 36 hours or less.

[0102] The atmosphere in the heating step may be the same as that in the method for producing the SmCo-based magnetic film according to the first embodiment.

[0103] Such magnetic films can be used in MEMS devices such as lens drive actuators in smartphones.

[0104] <Manufacturing method for cylindrical SmCo magnets> A method for manufacturing a cylindrical SmCo magnet according to one embodiment will now be described in detail. The method for manufacturing an SmCo magnet according to this embodiment may include, for example, a reaction-diffusion step of forming an SmCo film 25 on the Co base material 12 by reaction-diffusion by immersing the Co base material 12 in a bath containing an Sm source, and a step of heating the resulting laminate 52.

[0105] 8A and 8B are schematic cross-sectional views of a method for manufacturing a cylindrical SmCo magnet according to one embodiment. In the reaction-diffusion step, a SmCo film 25 is formed on a Co base material 12 by reaction-diffusion, as shown in FIG. 8A, to obtain a laminate 52 having the Co base material 12 and the SmCo film 25, as shown in FIG. 8B.

[0106] The SmCo2 film 25 preferably contains SmCo2 as a main phase. SmCo2 is an alloy of Sm and Co that has an MgCu2-type crystal structure. The ratio of Sm atoms to Co atoms in SmCo2 may deviate from the stoichiometric ratio. For example, when various elements are added to improve magnetic properties, the ratio of Sm atoms to Co atoms in SmCo2 may not necessarily be the stoichiometric ratio. Therefore, as long as SmCo2 has an MgCu2-type crystal structure, the ratio of Sm atoms to Co atoms may deviate from the stoichiometric ratio.

[0107] The SmCo2 film 25 may have a crystal phase (heterogeneous phase) different from the main phase or a grain boundary. The ratio of the main phase may be, for example, 50 mass % or more, 70 mass % or more, or 90 mass % or more. An example of the heterogeneous phase is an Sm-rich phase having a higher Sm content than SmCo2.

[0108] In the reaction diffusion process, the Co base material 12 is immersed in a bath containing an Sm source, whereby reaction diffusion occurs on the main surface of the Co base material 12 between the Sm source dispersed in the bath and the Co base material 12, forming an SmCo2 film 25 on the Co base material 12.

[0109] The bath in the reaction diffusion step may be a molten salt of an Sm source and an inorganic salt other than the Sm source.

[0110] Examples of Sm sources include metallic Sm and Sm alloys. The Sm sources can be used alone or in combination of two or more.

[0111] Examples of inorganic salts other than the Sm source include KCl, LiCl, and NaCl. These inorganic salts can be used alone or in combination of two or more.

[0112] The proportion of the Sm source in the Sm source and the inorganic salt other than the Sm source may be, for example, 1 to 6 mol % based on the total number of moles of the Sm source and the inorganic salt other than the Sm source contained in the bath.

[0113] The bath may be adjusted, for example, by drying the inorganic salt to dehydrate it, then heating it to a reaction diffusion temperature described below to melt the inorganic salt, and then adding an Sm source to the molten inorganic salt.

[0114] The reaction diffusion temperature in the reaction diffusion step is not particularly limited as long as it is equal to or higher than the temperature at which the inorganic salt melts, but from the viewpoint of efficiently forming the SmCo2 film 25, it is preferably equal to or higher than 400° C., more preferably equal to or higher than 500° C., and even more preferably equal to or higher than 600° C. Here, the reaction diffusion temperature refers to the temperature of the bath during reaction diffusion.

[0115] The reaction diffusion time in the reaction diffusion step can be appropriately changed depending on the reaction diffusion temperature and the molar concentration of the Sm source in the bath, as long as a SmCo film 25 of the required thickness can be formed. In addition, from the viewpoint of efficiency, it is not necessary to set the reaction diffusion time longer than necessary, but it may be, for example, 1 hour to 48 hours.

[0116] The obtained laminate 52 may be washed before the heating step described below. The washing method is not particularly limited, but examples thereof include an organic solvent such as ethanol and water.

[0117] (Heating process) In the heating process, the laminate 52 is heated until it reaches the holding temperature and then cooled. As a result, SmCo2 and Co react with each other, and from the Co substrate 12 and the SmCo2 film 25, 17 a Sm2Co

[0118] The heating rate in the heating process is not particularly limited, but for example, it may be 0.1 to 100 °C / second. The holding temperature is preferably 800 °C or higher, more preferably 850 °C or higher, and still more preferably 900 °C or higher because the surface magnetic flux density of the magnet 300 is further improved. The cooling rate is preferably 5 °C / second or higher, more preferably 10 °C / second or higher, and still more preferably 20 °C / second or higher because the surface magnetic flux density of the magnet 300 is further improved.

[0119] The holding time in the heating process may be 6 hours or more and may be 36 hours or less.

[0120] The atmosphere in the heating process is not particularly limited, but from the viewpoint of suppressing oxidation, an inert gas atmosphere is preferable, and examples of the inert gas include Ar and N2.

Examples

[0121] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0122] <Manufacture of SmCo-based magnet film> [Example 1] (First electrolytic plating process) KCl and LiCl were mixed in a molar ratio of KCl:LiCl = 41.5:58.5 to obtain a mixture. The resulting mixture was dried to dehydrate it. The dehydrated mixture was heated to 650 °C in a ceramic container using an external heater to melt it. SmCl3 and CoCl2 were added to the molten mixture as Sm and Co sources. The Sm and Co sources were added so that the molar ratio of KCl and LiCl to SmCl3 and CoCl2 was 100.0:0.5:0.7. Next, a 0.5 mm thick Mo substrate was prepared as the cathode, and a 1 mm thick graphite plate was prepared as the anode. The Mo substrate was previously cleaned with acetone. The Mo substrate and graphite plate were immersed in the molten mixture, and a first electrolytic plating was performed on the Mo substrate using an electroplating method. The plating was performed under the conditions of constant current electrolysis, plating temperature 650°C, current 0.5A, and plating time 5 minutes. 17 A laminated film was obtained on which a film was formed.

[0123] (Second electrolytic plating process) Similar to the first electrolytic plating process, a mixture of KCl and LiCl was melted. SmCl3 and CoCl2 were added to the molten mixture as Sm and Co sources. The Sm and Co sources were added so that the molar ratio of KCl and LiCl to SmCl3 and CoCl2 was KCl and LiCl:SmCl3:CoCl2 = 100.0:0.5:0.4. Next, a 1 mm thick graphite plate was prepared as the anode. The laminated film obtained in the first electrolytic plating process served as the cathode. The laminated film and graphite plate were immersed in the molten mixture, and a second electrolytic plating was performed on the laminated film by electrolytic plating. Plating was performed under the conditions of constant current electrolysis, plating temperature 650°C, current 0.5 A, and plating time 5 minutes. Sm2Co was obtained by electrolytic plating. 17 An alloy film was obtained in which a non-oriented SmCo5 film was formed on the main surface of the film opposite to the main surface in contact with the Mo substrate 10.

[0124] (Heating process) The obtained alloy film was heated to 900°C. Next, while applying a 3 T magnetic field perpendicular to the alloy film, the alloy film was heated at a holding temperature of 900°C for 5 seconds. After that, the alloy film was cooled while applying a 3 T magnetic field perpendicular to the alloy film, thereby obtaining a SmCo-based magnet film. The heating rate was 100°C / sec, and the cooling rate was 20°C / sec. The atmosphere during the heating process was Ar. Using an X-ray diffraction measurement device and an energy dispersive X-ray analysis device, the structure of the obtained SmCo-based magnet film was confirmed to be Sm2Co on a Mo substrate. 17 It was confirmed that the SmCo5 film and the SmCo5 film were formed in this order.

[0125] [Example 2] The plating time in the first electrolytic plating step is set to 3 minutes. 17 An SmCo-based magnetic film was obtained in the same manner as in Example 1, except that a non-oriented SmCo film was formed on the Mo substrate and the plating time in the second electrolytic plating step was set to 15 minutes. The structure of the obtained SmCo-based magnetic film was confirmed by an X-ray diffraction measurement device and an energy dispersive X-ray analysis device. 17 It was confirmed that the SmCo5 film and the SmCo5 film were formed in this order.

[0126] [Example 3] (Electrolytic plating process) KCl and LiCl were mixed in a molar ratio of KCl:LiCl = 41.5:58.5 to obtain a mixture. The resulting mixture was dried to dehydrate it. The dehydrated mixture was heated to 700 °C in a ceramic container using an external heater to melt the mixture. SmCl3 was added to the molten mixture as an Sm source. The Sm source was added so that the molar ratio of KCl, LiCl, and SmCl3 was KCl, LiCl, and SmCl3 = 100.0:0.5. Next, a 0.5 mm thick Co substrate was prepared as the cathode, and a 1 mm thick graphite plate was prepared as the anode. The Co substrate was pre-cleaned with acetone. The Co substrate and graphite plate were immersed in the molten mixture, and electroplating was performed on the Co substrate using electroplating. Plating was performed under constant current electrolysis conditions of 700 °C, 0.5 A, and 10 minutes. A laminated film was obtained in which a SmCo2 film was formed on a Co substrate by an electrolytic plating process.

[0127] (Heating process) The obtained laminated film was heated to 900°C. Next, without applying a magnetic field to the laminated film, the laminated film was heated at a holding temperature of 900°C for 21,600 seconds. Thereafter, without applying a magnetic field to the laminated film, the laminated film was cooled to obtain a SmCo-based magnet film. The heating rate was 0.15°C / sec and the cooling rate was 20°C / sec. The atmosphere during the heating process was Ar. Using an X-ray diffraction measurement device and an energy dispersive X-ray analysis device, the structure of the obtained SmCo-based magnet film was confirmed to be SmCo on a Co substrate. 17 It was confirmed that the SmCo5 film and the SmCo5 film were formed in this order.

[0128] [Examples 4, 6, 7 and 9] A laminated film was obtained in the same manner as in Example 3, except that the amount of SmCl3 added relative to 100 molar parts of KCl and LiCl in the electrolytic plating step, the temperature at which KCl and LiCl were melted, the plating temperature, the current, and the plating time were set to the values ​​shown in Table 1. A SmCo-based magnet film was obtained in the same manner as in Example 3, except that the temperature rise rate, holding temperature, holding time, and temperature drop rate in the heating step were set to the values ​​shown in Table 3. The structure of the obtained SmCo-based magnet film was confirmed by an X-ray diffraction measurement device and an energy dispersive X-ray analysis device to be Sm2Co on a Co substrate. 17 It was confirmed that the SmCo5 film and the SmCo5 film were formed in this order.

[0129] [Examples 5 and 8] The same procedure as in Example 1 was repeated except that the plating time in the first electrolytic plating step was set to the values ​​shown in Table 1. 17 The same procedure as in Example 1 was repeated except that the amounts of SmCl3 and CoCl2 added relative to 100 molar parts of KCl and LiCl in the second electrolytic plating step, the temperature at which KCl and LiCl were melted, the plating temperature, the current, and the plating time were set to the values ​​shown in Table 2. 17 An alloy film was obtained in which a non-oriented SmCo5 film was formed on the main surface opposite to the main surface in contact with the Mo substrate. A SmCo-based magnetic film was obtained in the same manner as in Example 1, except that the holding time in the heating step was set to the values ​​shown in Table 3. An X-ray diffraction measurement device and an energy dispersive X-ray analysis device were used to confirm the structure of the obtained SmCo-based magnetic film, which consisted of Sm2Co on a Mo substrate. 17 It was confirmed that the SmCo5 film and the SmCo5 film were formed in this order.

[0130] [Comparative Example 1] (Electrolytic plating process) KCl and LiCl were mixed in a molar ratio of KCl:LiCl = 41.5:58.5 to obtain a mixture. The resulting mixture was dried to dehydrate it. The dehydrated mixture was heated to 650 °C in a ceramic container using an external heater to melt the mixture. SmCl3 and CoCl2 were added to the molten mixture as Sm and Co sources. The Sm and Co sources were added so that the molar ratio of KCl and LiCl to SmCl3 and CoCl2 was 100.0:0.5:0.4. Next, a 0.5 mm thick Mo substrate was prepared as the cathode, and a 1 mm thick graphite plate was prepared as the anode. The Mo substrate was previously cleaned with acetone. The Mo substrate and graphite plate were immersed in the molten mixture, and electroplating was performed on the Mo substrate using electroplating. Plating was performed under the conditions of constant current electrolysis, plating temperature 650°C, current 0.5 A, and plating time 5 minutes. A laminated film was obtained by the electrolytic plating process in which a non-oriented SmCo5 film was formed on a Mo substrate.

[0131] (Heating process) The resulting laminated film was heated to 700°C. Next, without applying a magnetic field to the laminated film, the laminated film was heated at a holding temperature of 700°C for 5 seconds. The laminated film was then cooled without applying a magnetic field to the laminated film, yielding a SmCo-based magnetic film. The heating rate was 0.1°C / sec, and the cooling rate was 0.5°C / sec. The heating process was performed in an Ar atmosphere. Using an X-ray diffraction measurement device and an energy dispersive X-ray analysis device, it was confirmed that the structure of the resulting SmCo-based magnetic film was a non-oriented SmCo5 film formed on a Mo substrate.

[0132] Comparative Example 2 Except for changing the plating time in the electrolytic plating step to 15 minutes, an SmCo-based magnetic film was obtained in the same manner as in Comparative Example 1. Using an X-ray diffraction measurement device and an energy dispersive X-ray analysis device, it was confirmed that the structure of the obtained SmCo-based magnetic film was a non-oriented SmCo5 film formed on a Mo substrate.

[0133] Comparative Example 3 A laminated film was obtained in the same manner as in Example 1, except that the plating time in the first electrolytic plating step was set to the value shown in Table 1. The obtained laminated film was heated to 700°C. Next, without applying a magnetic field to the alloy film, the alloy film was heated at a holding temperature of 700°C for 5 seconds. Thereafter, without applying a magnetic field to the alloy film, the alloy film was cooled to obtain a SmCo-based magnetic film. The heating rate was 0.1°C / sec and the cooling rate was 0.5°C / sec. The atmosphere during the heating step was Ar. Using an X-ray diffraction measurement device and an energy dispersive X-ray analysis device, the structure of the obtained SmCo-based magnetic film was determined to be SmCo on a Mo substrate. 17 It was confirmed that the was formed.

[0134] Comparative Example 4 An SmCo-based magnetic film was obtained in the same manner as in Comparative Example 1, except that the plating time in the electrolytic plating step was set to the values ​​shown in Table 2. Using an X-ray diffraction measurement device and an energy dispersive X-ray analysis device, it was confirmed that the structure of the obtained SmCo-based magnetic film was a non-oriented SmCo5 film formed on a Mo substrate.

[0135] [Table 1]

[0136] [Table 2]

[0137] [Table 3]

[0138] <Manufacturing cylindrical SmCo magnets> [Example 10] (Reaction-diffusion process) LiCl was prepared and dehydrated by drying. The dehydrated LiCl was heated to 700°C in a metal Mo container using an external heater and melted. Sm metal powder was added to the molten LiCl as an Sm source. The Sm source was added so that the molar ratio of LiCl to Sm was LiCl:Sm = 100.0:2.5. Next, a cylindrical Co substrate (diameter: 0.5 mm) was immersed in the molten LiCl. The Co substrate had been washed with acetone in advance. The reaction diffusion temperature was 700°C, and the reaction diffusion time was 9 hours. A laminate in which an SmCo2 film was formed on the Co substrate was obtained by the reaction diffusion process.

[0139] (Heating process) The obtained laminate was heated to 1050°C. Next, without applying a magnetic field to the laminate, the laminate was heated at a holding temperature of 1050°C for 24 hours. Thereafter, the laminate was cooled without applying a magnetic field to the laminate, to obtain a cylindrical SmCo-based magnet. The heating rate was 0.15°C / sec, and the cooling rate was 20°C / sec. The heating atmosphere was Ar. Using an X-ray diffraction measurement device and an energy dispersive X-ray analysis device, the structure of the obtained SmCo-based magnet was confirmed to be SmCo on a Co substrate. 17 It was confirmed that the SmCo5 film and the SmCo5 film were formed in this order.

[0140] [Example 11] A cylindrical SmCo-based magnet was obtained in the same manner as in Example 10, except that the molar ratio of LiCl to Sm in the reaction-diffusion step was set to the value shown in Table 4. The structure of the obtained SmCo-based magnet was confirmed by an X-ray diffraction measurement device and an energy dispersive X-ray analysis device to be SmCo on a Co substrate. 17 It was confirmed that the SmCo5 film and the SmCo5 film were formed in this order.

[0141] [Examples 12 and 13] A laminate was obtained in the same manner as in Example 10, except that the reaction diffusion time and the diameter of the Co substrate in the reaction diffusion process were the values shown in Table 4. A columnar SmCo-based magnet was obtained in the same manner as in Example 10, except that the holding time in the heating process was 25 hours. Using an X-ray diffraction measurement apparatus and an energy dispersive X-ray analyzer, it was confirmed that the structure of the obtained SmCo-based magnet was such that a Sm2Co 17 film and a SmCo5 film were formed in this order on the Co substrate.

[0142]

Table 4

[0143] <Evaluation of SmCo-based Magnet Film> [Examples 1 - 9, Comparative Examples 1 - 4][[ID=,17]] The following evaluations were performed on the SmCo-based magnet films obtained in each example.

[0144] (Sm2Co 17 Film and Film Thickness Measurement of SmCo5 Film) The obtained SmCo-based magnet film was embedded in resin. By polishing a part of the resin, the cross-section of the SmCo-based magnet film was exposed from the resin. The exposed cross-section was observed with a scanning electron microscope (manufactured by Hitachi High-Tech Corporation, product name SU5000), and the film thicknesses of the Sm2Co 17 film and the SmCo5 film were measured. At this time, the observation magnification was adjusted so that the entire film to be measured was within the field of view. The results are shown in Table 5.

[0145] (Measurement of Degree of Orientation of Crystal Orientation of SmCo5) X-ray diffraction measurements were performed on the SmCo5 film in the obtained SmCo-based magnet film using an X-ray diffractometer (Rigaku, product name: RINT-2000). Measurements were performed at room temperature using CuKα radiation. The degree of orientation of the SmCo5 crystal orientation

[0002] was calculated using the above formula (1) from the peaks in the 2θ range of 30 to 60° in the obtained X-ray diffraction profile. Note that peaks derived from the (101), (110), (200), (111), (002), (201), and (112) planes were measured in the 2θ range of 30 to 60°. The angle θ between the (002) plane and each crystal plane, and the vector correction coefficient β, were set to the values ​​shown in Table 6. The calculated degrees of orientation are shown in Table 5. The X-ray diffraction profile obtained from the SmCo-based magnet film of Example 2 is shown in Figure 9.

[0146] (Measurement of surface magnetic flux density of SmCo-based magnet film) The surface magnetic flux density of the SmCo-based magnet film was measured by contacting the probe of a Hall element (manufactured by Asahi Kasei Electronics Corporation, product name: HG0712) to the surface of the SmCo-based magnet film and tracing the film surface, and converting the output voltage into magnetic flux density. The results are shown in Table 5.

[0147] (Measurement of the roughness of SmCo-based magnet films) The obtained SmCo-based magnet film was embedded in resin. A portion of the resin was polished to expose the cross section of the SmCo-based magnet film from the resin. The exposed cross section was observed using a scanning electron microscope (Hitachi High-Tech Corporation, product name SU5000) to obtain a backscattered electron image. The accelerating voltage for obtaining the backscattered electron image was 10-15 kV, and the WD (working distance) was 10-15 mm. A portion (rectangle) to be analyzed was cut out from the obtained backscattered electron image. The backscattered electron image was cut out by dividing one side of the cutout image and the opposite side of the SmCo 17 The backscattered electron image was cut out so that the interface of the Sm2Co film and the SmCo5 film intersected with each other, and the interface was contained between the remaining two sides. 17The length of the straight line connecting both ends of the interface between the Sm2Co film and the SmCo5 film was 100 μm or more. The cut-out image was subjected to image quality adjustment, binarization, and edge (contour) extraction. 17 The length of the interface between the Sm2Co film and the SmCo5 film was measured. 17 The length of the line connecting both ends of the interface between the Sm2Co film and the SmCo5 film was measured. The length indicated on the scale bar was used as the standard for length. 17 The roughness was calculated by dividing the length of the interface between the SmCo5 film and the SmCo5 film by the length of the straight line connecting both ends of the interface between the SmCo5 film and the SmCo5 film in the cut-out image. The measurement magnification was 1000x. Two or more locations were observed using the SEM to avoid analyzing only a portion. The roughness was calculated as the average of the roughness values ​​obtained from the images of two or more locations. The results are shown in Table 5.

[0148] [Table 5]

[0149] [Table 6]

[0150] The SmCo-based magnet films obtained in each example were Sm2Co 17 The film has an orientation degree of SmCo5 of 70% or more, resulting in a surface magnetic flux density of 7.6 mT or more.

[0151] <Evaluation of cylindrical SmCo magnets> [Examples 10 to 13] The cylindrical SmCo magnets obtained in each example were evaluated as follows.

[0152] (Sm2Co 17 (film thickness measurement of SmCo5 film and SmCo5 film) The obtained cylindrical SmCo magnet was embedded in resin. Part of the resin was polished to expose a cross section perpendicular to the axial direction of the cylindrical SmCo magnet from the resin. The exposed cross section was observed using a scanning electron microscope (manufactured by Hitachi High-Tech Corporation, product name SU5000) to determine the SmCo 17 The thicknesses of the SmCo5 film and the SmCo5 film were measured. The observation magnification was adjusted so that the entire film to be measured was within the field of view. The results are shown in Table 7.

[0153] (Measurement of crystal orientation of SmCo5) The resulting cylindrical SmCo magnet was embedded in resin. A portion of the resin was polished to expose a cross section of the cylindrical SmCo magnet perpendicular to its axial direction. The crystal orientation of the SmCo5 in the exposed cross section was measured using EBSD (Electron Backscatter Diffraction Patterns). The EBSD measurement device used was a Versa3D (trade name, manufactured by EFI). As shown in Figure 5, four measurement locations were measured in the exposed, approximately circular cross section of the SmCo5: location Y1 in the Y direction perpendicular to the normal direction at the center of gravity of the cross section; location Y2 in the -Y direction opposite the Y direction; location X1 in the X direction perpendicular to the Y direction; and location X2 in the -X direction opposite the X direction. The measurement results for Example 10 are shown in Figures 10(a) to 10(d). Figure 10(a) is a pole figure of the [00L] crystal orientation of SmCo5 when viewed from the XZ plane toward the -Y direction (Y1). Figure 10(b) is a pole figure of the [00L] crystal orientation of SmCo5 when viewed from the XZ plane toward the Y direction (Y2). Figure 10(c) is a pole figure of the [00L] crystal orientation of SmCo5 when viewed from the YZ plane toward the -X direction (X1). Figure 10(d) is a pole figure of the [00L] crystal orientation of SmCo5 when viewed from the YZ plane toward the X direction (X2). Pole figures are diagrams that display crystal orientations using stereographic projection. In each pole figure in Figure 10, the center is the [00L] crystal orientation. In other words, when the [00L] crystal orientation is facing forward, a dot is placed in the center of the pole figure. 10(a) to (d), a dot is placed in the center of the pole figure, confirming that the [00L] crystal orientation of SmCo5 is radially oriented in the cylindrical SmCo-based magnet. Similar measurement results to those of Example 10 were obtained for Examples 11 to 13, confirming that the [00L] crystal orientation of SmCo5 is radially oriented in the cylindrical SmCo-based magnet.

[0154] (Measurement of surface magnetic flux density of SmCo magnet) The surface magnetic flux density of the cylindrical SmCo magnet was measured in the same manner as in the measurement of the surface magnetic flux density of the SmCo magnet film. The results are shown in Table 7.

[0155] (Measurement of the roughness of SmCo-based magnet films) The obtained cylindrical SmCo magnet was embedded in resin. Part of the resin was polished to expose a cross section perpendicular to the axis of the SmCo magnet. The exposed cross section was observed using a scanning electron microscope (Hitachi High-Tech Corporation, product name SU5000) to obtain a backscattered electron image. The accelerating voltage for obtaining the backscattered electron image was 10-15 kV, and the WD (working distance) was 10-15 mm. A rectangular portion to be analyzed was cut out from the obtained backscattered electron image. The backscattered electron image was cut out by dividing one side of the cutout image and the opposite side of the SmCo magnet, as shown in Figure 2. 17 The backscattered electron image was cut out so that the interface of the Sm2Co film and the SmCo5 film intersected with each other, and the interface was contained between the remaining two sides. 17 The length of the straight line connecting both ends of the interface between the Sm2Co film and the SmCo5 film was 100 μm or more. The cut-out image was subjected to image quality adjustment, binarization, and edge (contour) extraction. 17 The length of the straight line connecting both ends of the interface between the Sm2Co film and the SmCo5 film was measured. 17 The length of the line connecting both ends of the interface between the Sm2Co film and the SmCo5 film was measured. The length indicated on the scale bar was used as the standard for length. 17 The length of the interface between the Sm2Co film and the SmCo5 film was measured in the cutout image. 17 The roughness was calculated by dividing the measured value by the length of the straight line connecting both ends of the interface between the SmCo5 film and the SmCo5 film. The measurement magnification was 1000x. Two or more locations were observed using the SEM to avoid analyzing only a portion of the image. The roughness was calculated as the average value of the roughness obtained from the images of two or more locations. The results are shown in Table 7.

[0156] [Table 7] [Explanation of symbols]

[0157] 10...Mo substrate, 12...Co substrate (Co base material), 15...ヨーク part, 17...Magnet part, 20...Sm2Co 17 Membrane, 25…SmCo2 membrane, 30…SmCo5 membrane, 40…unaligned SmCo5 membrane, 50, 51…stacked membrane, 52…stacked body, 70…alloy membrane, 100…SmCo-based magnet membrane, 200…magnet, 300…SmCo-based magnet.

Claims

[Claim 1] Co substrate, Sm on the Co substrate ２ Co １７ The film and the Sm ２ Co １７ SmCo on the membrane ５ A method for producing a SmCo-based magnet having a film, comprising the steps of: The Co substrate is immersed in a bath containing an Sm source and reacts and diffuses to form a Co substrate and an SmCo layer formed on the Co substrate. ２ a reaction-diffusion process for obtaining a laminate having a film; The laminate is heated to form the Co substrate and the SmCo ２ The film is reacted with the Sm ２ Co １７ The membrane and the SmCo ５ a heating step to form a film; A method for manufacturing a SmCo-based magnet, comprising:

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