Magnetic wire, composite magnetic wire, and method for producing magnetic wire

Abstract

A magnetic wire comprising an alloy containing iron and cobalt as main components, wherein the magnetic wire has a structure in which the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more.

Description

Magnetic wire, composite magnetic wire, and method for manufacturing magnetic wire

[0001] This disclosure relates to magnetic wires, composite magnetic wires, and methods for manufacturing magnetic wires.

[0002] Patent Document 1 discloses a magnetic wire made of an alloy mainly composed of iron and cobalt. This magnetic wire contains at least an α phase and has a structure in which the area ratio of the α phase, the average grain size of the α phase, and the ratio of the length of the high-angle grain boundaries satisfy a specific range. This magnetic wire is manufactured by twisting a wire having a specific structure in which the α phase and γ phase coexist.

[0003] International Publication No. 2023 / 074693

[0004] The magnetic wire of this disclosure is a magnetic wire made of an alloy mainly composed of iron and cobalt, and has a structure in which the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more.

[0005] Figure 1 is a schematic perspective view of the magnetic wire of the embodiment. Figure 2 is a schematic diagram showing the twist marks of the magnetic wire of the embodiment. Figure 3 is a schematic diagram illustrating the manufacturing method of the magnetic wire of the embodiment. Figure 4 is a schematic perspective view of the composite magnetic wire of the embodiment.

[0006] [Problems this disclosure aims to solve] There is a need for further increases in the power output of magnetic wires that generate the large Barkhausen jump phenomenon. Magnetic wires are used in magnetic sensors. A magnetic sensor comprises a core made of magnetic wire and a coil wound around the outer circumference of this core. The performance of a magnetic sensor largely depends on the characteristics of the magnetic wire used in the core. In order to miniaturize and increase the power output of magnetic sensors, magnetic wires that can produce high output are desired.

[0007] One of the objectives of this disclosure is to provide a magnetic wire with excellent output characteristics. Another objective of this disclosure is to provide a composite magnetic wire with excellent output characteristics. Another objective of this disclosure is to provide a method for manufacturing a magnetic wire that can produce a magnetic wire with excellent output characteristics.

[0008] [Effects of this disclosure] The magnetic wire of this disclosure has excellent output characteristics.

[0009] [Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be listed and described.

[0010] (1) The magnetic wire according to the embodiment of the present disclosure is a magnetic wire made of an alloy mainly composed of iron and cobalt, and has a structure in which the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more.

[0011] Magnetic wires having a structure in which the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more have high output characteristics, as shown in the test examples described later. The above ratio is correlated with the proportion of the specific B2 ordered phase. The B2 ordered phase is a phase in which iron atoms and cobalt atoms are regularly arranged with a body-centered cubic lattice (bcc) as the unit cell. The specific B2 ordered phase is a B2 ordered phase in which iron atoms are placed at each vertex of the unit cell and cobalt atoms are placed at the body-center position. When the proportion of the specific B2 ordered phase is high, the above diffraction intensity ratio becomes 1.0% or more, and the output characteristics become high.

[0012] Magnetic wires having a structure in which the above-mentioned diffraction intensity ratio is 1.0% or more have high output characteristics, and if these magnetic wires are used as the core of the magnetic sensor described above, the output of the magnetic sensor can be increased. Magnetic wires having a structure in which the above-mentioned ratio is 1.0% or more have high output characteristics and also have low output variation. With magnetic wires that have low output variation, stable output can be easily obtained even when miniaturizing by reducing the diameter or length of the magnetic wire. Therefore, if these magnetic wires are used as the core of the magnetic sensor described above, the magnetic sensor can be miniaturized.

[0013] (2) In the magnetic wire of (1) above, the alloy may contain 6.0% by mass or more and 8.0% by mass or less of vanadium.

[0014] Magnetic wires made from alloys containing vanadium within the above range tend to have high output characteristics.

[0015] (3) In the magnetic wire described in (1) or (2) above, the alloy may contain 0.2% by mass or more and 0.4% by mass or less silicon, and 0.5% by mass or more and 0.7% by mass or less manganese.

[0016] Magnetic wires made from alloys containing silicon and manganese within the above ranges tend to have high output characteristics.

[0017] (4) In any of the magnetic wires described in (1) to (3) above, the Vickers hardness may be 470 HV or more and 530 HV or less.

[0018] As described later, magnetic wires are manufactured by heat-treating the wire material that will become the magnetic wire, and then heating it with electricity while twisting it. If the Vickers hardness of the magnetic wire is within the above range, tensile residual stress is easily introduced into the magnetic wire through the twisting process during the manufacturing process, which tends to improve the output characteristics.

[0019] (5) Any of the magnetic wires described in (1) to (4) above may have a twist mark on its outer surface, and the angle of the twist mark with respect to the axis of the magnetic wire may be 2° or more and 60° or less.

[0020] Magnetic wires with twist marks tend to retain the tensile residual stress introduced into the magnetic wire by the twisting process. When the angle of the twist mark is within the above range, the tensile residual stress is easily introduced uniformly along the longitudinal direction of the magnetic wire along its entire length. As a result, the output characteristics of the magnetic wire tend to be higher. The longitudinal direction of the magnetic wire is the direction from the first end to the second end of the magnetic wire along its axis.

[0021] (6) In any of the magnetic wires described in (1) to (5) above, the diameter of the magnetic wire may be 0.1 mm or more and 1.0 mm or less, and the length of the magnetic wire may be 25 mm or less.

[0022] Generally, if the diameter of a magnetic wire is small or the length of the magnetic wire is short, the volume of the magnetic wire decreases, which tends to lower the output of the magnetic wire. Also, if the length of the magnetic wire is short, the effect of the demagnetizing field becomes larger, so the output of the magnetic wire tends to fluctuate. Magnetic wires with a structure in which the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more, as described above, can obtain high output and have low output fluctuation. Therefore, even if the diameter of the magnetic wire is small or the length is short, it is easy to obtain a stable output. Magnetic wires with a structure in which the above ratio is 1.0% or more have sufficient output characteristics even if the diameter is small or the length is short. When magnetic wires with diameters and lengths within the above ranges are used as the core of a magnetic sensor, the magnetic sensor can be miniaturized.

[0023] (7) A composite magnetic wire according to an embodiment of the present disclosure comprises any of the magnetic wires described in (1) to (6) above, and a metallic coating material disposed on the outer surface of the magnetic wire.

[0024] Composite magnetic wires are manufactured, for example, by heat-treating a coated wire in which a metal coating material is placed on the outer surface of the wire material that will become the magnetic wire, and then heating it with electricity while twisting it. When a metal coating material is placed on the outer surface of the magnetic wire, tensile residual stress is easily introduced into the magnetic wire by the twisting process during the manufacturing of composite magnetic wires, which tends to improve the output characteristics of the magnetic wire.

[0025] (8) In the composite magnetic wire described in (7) above, the ratio of the diameter of the magnetic wire to the diameter of the composite magnetic wire may be 45% or more and 95% or less.

[0026] If the ratio of the diameter of the magnetic wire to the diameter of the composite magnetic wire is 45% or more, the ratio of the cross-sectional area of ​​the magnetic wire to the cross-sectional area of ​​the composite magnetic wire will not become too small, and the output characteristics of the composite magnetic wire are likely to be high. If the ratio of the diameter of the magnetic wire to the diameter of the composite magnetic wire is 95% or less, the ratio of the cross-sectional area of ​​the coating material to the cross-sectional area of ​​the composite magnetic wire will not become too small, and tensile residual stress will be easily introduced into the magnetic wire through twisting during the manufacturing process of the composite magnetic wire, and the output characteristics of the magnetic wire are likely to be high.

[0027] (9) In the composite magnetic wire described in (7) or (8) above, the melting point of the coating material may be greater than 850°C.

[0028] If the melting point of the coating material is above 850°C, heat treatment can be performed during the manufacturing process of the composite magnetic wire.

[0029] (10) In any of the composite magnetic wires described in (7) to (9) above, the Vickers hardness of the coating material may be 200 HV or more.

[0030] If the Vickers hardness of the coating material is 200 HV or higher, tensile residual stress is more easily introduced into the magnetic wire through twisting during the manufacturing process of the composite magnetic wire, which tends to improve the output characteristics of the magnetic wire.

[0031] (11) A method for manufacturing a magnetic wire according to an embodiment of the present disclosure comprises the steps of: producing a drawn wire by drawing a material made of an alloy mainly composed of iron and cobalt; producing a heat-treated material by heat-treating the drawn wire; and producing a magnetic wire by electrically heating the heat-treated material while twisting it. The electric heating is performed at a predetermined current density for 3.0 seconds or more and 6.0 seconds or less.

[0032] With the magnetic wire manufacturing method described above, after heat-treating the wire material that will become the magnetic wire, a magnetic wire with excellent output characteristics can be manufactured by applying electric heating while twisting it. Applying electric heating while twisting makes it easier to form a structure in which the proportion of the specific B2 ordered phase is high and the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more. When a structure with the above ratio of 1.0% or more is formed, the output characteristics of the magnetic wire having that structure are improved.

[0033] [Details of Embodiments of the Disclosure] Specific examples of magnetic wires, composite magnetic wires, and methods for manufacturing magnetic wires of the Disclosure will be described with reference to the drawings. Identical reference numerals in the drawings indicate the same or corresponding parts. In each drawing, some parts of the configuration may be exaggerated or simplified for illustrative purposes. The dimensional ratios of parts in the drawings may also differ from those of the actual components. The present invention is not limited to these examples, but is indicated by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0034] <Magnetic Wire> The magnetic wire 1 of the embodiment will be described with reference to Figures 1 and 2. The magnetic wire 1 generates a large Barkhausen jump phenomenon when an external magnetic field is applied. The magnetic wire 1 is made of an alloy mainly composed of iron and cobalt. One of the features of the magnetic wire 1 of the embodiment is that it has a structure in which the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more.

[0035] ≪Composition≫ The composition of the alloy constituting the magnetic wire 1 mainly consists of iron (Fe) and cobalt (Co). "Mainly consisting of Fe and Co" means that Fe and Co together make up 75% by mass or more. The composition of the magnetic wire 1 may also contain 80% by mass or 85% by mass or more of Fe and Co together. The content ratio of each element in the composition is the mass ratio of each element when the composition of the alloy is set to 100% by mass. The melting point of the alloy constituting the magnetic wire 1 is, for example, about 1300°C.

[0036] The composition of the alloy constituting the magnetic wire 1 may include additive elements other than Fe and Co. For example, the composition may include silicon (Si) in an amount of 0.2% to 0.4% by mass and manganese (Mn) in an amount of 0.5% to 0.7% by mass. A magnetic wire 1 made of an alloy containing Si and Mn in the above ranges tends to have high output characteristics. The composition may also include vanadium (V) in an amount of 6.0% to 8.0% by mass. A magnetic wire 1 made of an alloy containing V in the above range tends to have high output characteristics.

[0037] A specific example of the composition of the alloy constituting the magnetic wire 1 contains 40.0 mass% to 70.0 mass% of Co, 0.2 mass% to 0.4 mass% of Si, 0.5 mass% to 0.7 mass% of Mn, and 6.0 mass% to 8.0 mass% of V, with the balance consisting of Fe and unavoidable impurities. The magnetic wire 1 made of an alloy having such a composition tends to have high output characteristics. The content ratio of Co may be 42.0 mass% to 63.0 mass%, 45.0 mass% to 55.0 mass%, or 48.0 mass% to 53.0 mass%. The content ratio of Si may be 0.25 mass% to 0.35 mass%, or 0.27 mass% to 0.33 mass%. The content ratio of Mn may be 0.55 mass% to 0.65 mass%, or 0.57 mass% to 0.63 mass%. The content ratio of V may be 6.5 mass% to 7.8 mass%, or 6.7 mass% to 7.7 mass%.

[0038] The composition of the alloy constituting the magnetic wire 1 may further contain one or more elements selected from the group consisting of Ti, Al, Ni, Cr, Mo, Nb, W, and Cu, in addition to the above elements. These elements have the effect of improving the output characteristics of the magnetic wire 1. The content ratio of each of these elements is, for example, more than 0 mass% and 1.0 mass% or less, or 0.1 mass% to 0.8 mass%.

[0039] The composition of the magnetic wire 1 can be determined by, for example, ICP optical emission spectrometry (Inductively Coupled Plasma Optical Emission Spectrometry), or EDX method (Energy Dispersive X-ray Spectroscopy).

[0040] <<Microstructure>> In the microstructure of the magnetic wire 1, the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more. The magnetic wire 1 having a microstructure with the above ratio of 1.0% or more has high output characteristics, as shown in the test examples described later. The magnetic wire 1 having a microstructure with the above ratio of 1.0% or more has small output variation. In the microstructure of the magnetic wire 1, the above ratio satisfies 1.0% or more due to a high proportion of a specific B2 ordered phase. As explained in the manufacturing method described later, the specific B2 ordered phase is easily formed by subjecting a wire rod as the material of the magnetic wire 1 to wire drawing and heat treatment, and then performing electric current heating while subjecting the heat-treated material to twisting. The ratio of the diffraction intensity is 1.2% or more, 1.3% or more, or 1.4% or more. The upper limit of the above ratio is, for example, 5.0% or less. The ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane in the microstructure of the magnetic wire 1 is, for example, 1.0% to 5.0%, 1.2% to 4.5%, 1.3% to 4.0%, or 1.4% to 3.5%.

[0041] The ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is determined by an X-ray diffraction method (X-Ray Diffraction: XRD). Specifically, the above ratio is determined as the ratio of the integrated intensity of the (100) plane to the integrated intensity of the (200) plane, which is measured by XRD with the X-ray energy set to the energy near the Fe-K absorption edge (7086 eV). The specific measurement method will be described in the test examples described later.

[0042] <<Vickers Hardness>> The Vickers hardness of the magnetic wire 1 is, for example, 470 HV or more and 530 HV or less. As described later, the magnetic wire 1 is manufactured by subjecting a wire rod as the material of the magnetic wire 1 to heat treatment, and then performing electric current heating while performing twisting. When the Vickers hardness of the magnetic wire 1 is within the above range, tensile residual stress is easily introduced into the magnetic wire 1 by twisting in the manufacturing process of the magnetic wire 1, and the output characteristics are likely to be high. The Vickers hardness of the magnetic wire 1 may be 480 HV or more and 520 HV or less, or 490 HV or more and 510 HV or less.

[0043] The Vickers hardness of magnetic wire 1 is determined as follows: In the cross-section of magnetic wire 1, the center of magnetic wire 1 and four different points around the center are determined. The four different points around the center are selected from four straight lines that are equally spaced around the center, among several straight lines that radiate from the center. The points selected from each of the four straight lines are midpoints between the center and the outer edge of magnetic wire 1. As shown in Figure 1, if magnetic wire 1 is a round wire and the shape of the cross-section of magnetic wire 1 is circular, the four different points around the center are points that are equally spaced around the center on the circumference of concentric circles with a diameter of 1 / 2 the diameter D1 of magnetic wire 1. A micro-Vickers hardness test is performed on the center of magnetic wire 1 and these four different points around the center, for a total of five points. The average value of the Vickers hardness of the five measured points is considered to be the Vickers hardness of magnetic wire 1. The four points are determined to be equally spaced around the axis of magnetic wire 1. The micro-Vickers hardness test will be conducted in accordance with JIS Z 2244:2009 "Vickers hardness test". The test force will be 0.98 N (0.1 kgf).

[0044] <Twist Marks> As shown in Figure 2, the magnetic wire 1 may have twist marks 4 on its outer surface. The magnetic wire 1 is manufactured by drawing a wire material to produce a drawn wire 6, then heat-treating the drawn wire 6, and then twisting it, as will be described later with reference to Figure 3. Multiple drawing marks are formed on the outer surface of the drawn wire 6 that has been drawn. Drawing marks are thin, streak-like marks that extend in a straight line along the axis of the drawn wire 6. Drawing marks can be caused by friction with the die 81 during the drawing process. Drawing marks are formed along the entire length of the drawn wire 6. When the heat-treated material 7, which is the drawn wire 6, is twisted, the drawing marks deform and twist marks 4 are formed. Twist marks 4 are thin, streak-like marks that extend in a spiral on the surface of the magnetic wire 1. Even if there are no drawing marks on the outer surface of the drawn wire 6 after the drawing process, if the heat-treated material 7, which is the drawn wire 6, is subjected to twisting, the surface of the heat-treated material 7 may deform and twist marks 4 may be formed. A magnetic wire 1 having twist marks 4 is more likely to maintain the residual tensile stress introduced into the magnetic wire 1 by the twisting process.

[0045] The twist marks 4 are inclined with respect to the axis of the magnetic wire 1, as shown in Figure 2, when the twisted wire remains in its twisted state. "Remaining in a twisted state" means that the twisting process is completed with the wire in a twisted state. A twisted magnetic wire 1 can be obtained by rotating the wire in only one direction during the twisting process. Alternatively, a twisted magnetic wire 1 can be obtained by rotating the wire clockwise and counterclockwise during the twisting process, such that the total number of clockwise rotations and the total number of counterclockwise rotations are different.

[0046] The angle θt of the twist mark 4 with respect to the axis of the magnetic wire 1 is, for example, 2° to 60°. When the angle θt of the twist mark 4 is within the above range, tensile residual stress along the longitudinal direction of the magnetic wire 1 is easily introduced uniformly along the entire length of the magnetic wire 1. As a result, the output characteristics of the magnetic wire 1 tend to be higher. The angle θt of the twist mark 4 may also be 4° to 60°, 5° to 55°, or 20° to 40°.

[0047] The angle θt of the twist marks 4 is determined as follows: Observe the outer surface of the magnetic wire 1 with an optical microscope. Measure the inclination angle of the twist marks 4 with respect to the axis of the magnetic wire 1. Measure the inclination angles of 20 or more twist marks 4 and take the average value as the angle θt of the twist marks 4.

[0048] ≪Shape≫ The shape of the magnetic wire 1 can be selected as appropriate. The magnetic wire 1 shown in Figure 1 is a round wire. The cross-sectional shape of the magnetic wire 1 is circular. The cross-sectional shape of the magnetic wire 1 may also be non-circular. Non-circular shapes include, for example, polygonal, flattened, or elliptical shapes. Polygonal shapes include, for example, quadrilaterals or hexagons. Quadrilaterals include rectangles, squares, trapezoids, rhombuses, etc. Elliptical shapes here also include oblong shapes. An oblong shape is a so-called racetrack shape, consisting of two parallel lines and two semicircular arcs connecting the ends of the two lines. The lengths of the two lines are equal. The lengths of the two semicircular arcs are equal. Flattened shapes here refer to all shapes that are flatter than a perfect circle. Flattened shapes include rectangular and elliptical shapes, etc.

[0049] ≪Size≫ The diameter D1 of the magnetic wire 1 can be selected as appropriate. The diameter D1 of the magnetic wire 1 is the diameter of a circle having an area equal to the area of ​​the cross-section of the magnetic wire 1. The diameter D1 of the magnetic wire 1 is, for example, 0.1 mm or more and 1.0 mm or less. A magnetic wire 1 with a diameter D1 within the above range can be suitably used as a core for magnetic sensors and the like. The diameter D1 of the magnetic wire 1 may also be 0.15 mm or more and 0.8 mm or less, or 0.2 mm or more and 0.6 mm or less.

[0050] The cross-sectional area of ​​the magnetic wire 1 can be selected as appropriate. The cross-sectional area of ​​the magnetic wire 1 is the area of ​​the cross-section of the magnetic wire 1. For example, the cross-sectional area of ​​the magnetic wire 1 is 0.007 mm². ２ The above is 0.800 mm ２ The following applies: A magnetic wire 1 with a cross-sectional area within the above range can be suitably used as a core for magnetic sensors and the like. The cross-sectional area of ​​the magnetic wire 1 is 0.017 mm². ２ The above is 0.510 mm ２ The following, or 0.030 mm ２ Above 0.300 mm ２ The following is also acceptable.

[0051] The length L1 of the magnetic wire 1 can be selected as appropriate. The length L1 of the magnetic wire 1 is the length from the first end to the second end of the magnetic wire 1. For example, the length L1 of the magnetic wire 1 is 3 mm or more and 25 mm or less. A magnetic wire 1 with a length L1 within the above range can be suitably used as a core for a magnetic sensor or the like. The length L1 of the magnetic wire 1 may also be 4 mm or more and 20 mm or less, or 5 mm or more and 15 mm or less.

[0052] Generally, if the diameter D1 of the magnetic wire 1 is small or the length L1 of the magnetic wire 1 is short, the volume of the magnetic wire 1 decreases, which tends to lower the output of the magnetic wire 1. If the length L1 of the magnetic wire 1 is short, the effect of the demagnetizing field becomes larger, which tends to cause fluctuations in the output of the magnetic wire 1. The magnetic wire 1 of the embodiment provides high output and low output fluctuation. Therefore, even if the diameter D1 of the magnetic wire 1 is small or the length L1 of the magnetic wire 1 is short, a stable output can be easily obtained. The magnetic wire 1 of the embodiment has sufficient output characteristics even if the diameter D1 is small or the length L1 is short. When a magnetic wire 1 with a diameter D1 and length L1 within the above range is used as the core of a magnetic sensor, the magnetic sensor can be miniaturized. Magnetic sensors can be used in, for example, magnetic encoders, motors, water meters, generators, etc.

[0053] <Method for Manufacturing Magnetic Wire> The method for manufacturing the magnetic wire 1 of this embodiment will be described with reference to Figure 3. The method for manufacturing the magnetic wire 1 of this embodiment comprises a first step of producing a drawn wire 6 from a material 5, a second step of producing a heat-treated material 7 from the drawn wire 6, and a third step of producing the magnetic wire 1 from the heat-treated material 7. The magnetic wire 1 is obtained by sequentially producing the drawn wire 6 and the heat-treated material 7 from the material 5.

[0054] ≪First Process≫ In the first process, as shown in the upper diagram of Figure 3, a drawn wire 6 is produced by drawing the material 5. The material 5 is made of an alloy mainly composed of iron and cobalt. The composition of the alloy constituting the material 5 is the same as the composition of the magnetic wire 1 described above. The composition of the material 5 is the same as the composition of the magnetic wire 1 to be manufactured. The melting point of the material 5 is higher than the temperature of the heat treatment performed in the second process. The melting point of the material 5 is, for example, about 1300°C. The material 5 is, for example, a cast material or an extruded material. Cast materials include continuously cast materials and continuously cast rolled materials. The material 5 may also be a continuously cast material. Continuously cast rolled materials have less variation in structure and higher productivity. The material 5 may also be a hot forged material that is forged while being heated to a high temperature after casting.

[0055] Drawing is a method of processing a material 5 into a wire using a die 81. Drawing includes not only the normal drawing process in which the material 5 is passed through the holes of a die, but also drawing using a roller die or drawing using a Turkshead. When drawing is performed at a cold temperature, it is easier to obtain a drawn wire 6 with high dimensional accuracy.

[0056] The drawing process involves processing the material 5 into a drawn wire 6 of a predetermined shape, so that the diameter of the drawn wire 6 is a predetermined diameter. The cross-sectional shape of the drawn wire is the same as the cross-sectional shape of the magnetic wire 1 to be manufactured. The diameter of the drawn wire 6 is the same as the diameter of the magnetic wire 1 to be manufactured. The drawing process may be performed multiple times until the diameter of the drawn wire 6 reaches a predetermined diameter. When multiple drawing processes are performed, heat treatment may be performed in the middle of the drawing process. This heat treatment is mainly intended to soften the wire during the drawing process and improve its workability. This heat treatment is called intermediate heat treatment. The temperature of the intermediate heat treatment is, for example, 750°C to 1100°C. The higher the temperature of the intermediate heat treatment, the easier it is to improve workability. The temperature of the intermediate heat treatment may also be 780°C to 900°C, or 780°C to 850°C. The time of the intermediate heat treatment is, for example, 10 minutes to 720 minutes. The intermediate heat treatment may be performed under a hydrogen atmosphere. After the intermediate heat treatment, the wire is cooled. The cooling rate after the intermediate heat treatment is, for example, 1°C / second or more. The cooling rate may also be 5°C / second or more, or 10°C / second or more. The faster the cooling rate, the easier it is to improve the workability of the wire. If the cooling rate is too slow, regular transformation will occur, resulting in poor workability of the wire.

[0057] The first step may include a step in which the material 5 is drawn to a degree of processing of 10% or more when processing the material 5 into a drawn wire 6. This degree of processing is, if the above intermediate heat treatment is performed, the degree of processing from the last intermediate heat treatment to the final drawing. When the above intermediate heat treatment is performed, the degree of processing is the ratio obtained by dividing the difference between the cross-sectional area of ​​the wire at the stage when the last intermediate heat treatment is performed and the cross-sectional area of ​​the drawn wire 6 after the final drawing by the cross-sectional area of ​​the wire at the stage when the last intermediate heat treatment is performed. If the above intermediate heat treatment is not performed, the above degree of processing is the same as the total degree of processing from the start to the end of the drawing process. The total degree of processing is the ratio obtained by dividing the difference between the cross-sectional area of ​​the material before drawing and the cross-sectional area of ​​the drawn wire 6 after the final drawing by the cross-sectional area of ​​the material before drawing. By having the above degree of processing of 10% or more, it is easier to control the structure of the drawn wire 6 to become the desired structure. The above degree of processing may be 30% or more, or 40% or more. The upper limit of the total processing degree depends on the diameter of the material 5 or the diameter of the drawn wire 6 to be produced, but for example, it is 99.99%. The total processing degree may also be 10% to 99.99%, 30% to 99.9%, or 40% to 99.5%.

[0058] ≪Second Step≫ In the second step, as shown in the middle diagram of Figure 3, the drawn wire 6 is heat-treated to produce a heat-treated material 7. The heat treatment is performed, for example, in a furnace 82. The heat treatment temperature is, for example, between 750°C and 850°C. If the heat treatment temperature is too low, it will be difficult to twist the heat-treated material 7 in the third step. The optimal temperature range for heat treatment varies depending on the composition of the alloy. For example, in the case of a composition containing 40.0% to 70.0% by mass of Co, and especially 45.0% to 55.0% by mass, the heat treatment temperature is, for example, between 760°C and 840°C, between 780°C and 820°C, or between 790°C and 810°C. The heat treatment time is, for example, between 10 minutes and 720 minutes. The heat treatment may be performed in batches or continuously.

[0059] After heat treatment, the heat-treated material 7 is cooled to room temperature. The room temperature is 20°C ± 15°C. The cooling rate after heat treatment is, for example, 1°C / second or more. The cooling rate may also be 5°C / second or more, or 10°C / second or more.

[0060] ≪Third Step≫ In the third step, as shown in the lower diagram of Figure 3, a magnetic wire 1 is produced by applying electric heating to the heat-treated material 7 while twisting it. Twisting refers to twisting the heat-treated material 7 around its axis of rotation. Twisting is performed, for example, by gripping both ends of the heat-treated material 7 with chucks 91 and 92 and rotating one of the chucks 91. Before twisting, the heat-treated material 7 is gripped with chucks 91 and 92 and cut to a suitable length for twisting. By twisting the heat-treated material 7, a magnetic wire 1 with high output characteristics can be obtained. Twisting causes a processing-induced transformation. Applying electric heating while twisting increases the proportion of the specific B2 ordered phase. The wire that has been twisted and heated is cut to a predetermined length. This predetermined length is the same as the length of the magnetic wire 1.

[0061] The twisting process may be performed under conditions such that the amount of strain on the outer surface of the twisted heat-treated material 7 is between 1.0 and 4.5. By performing the twisting process so that the above amount of strain is between 1.0 and 4.5, magnetic wires 1 with high output characteristics can be stably manufactured. The above amount of strain may also be between 1.5 and 4.0.

[0062] Referring to Figure 1, the method for determining the amount of strain will be explained. Here, the magnetic wire 1 shown in Figure 1 is considered to be the heat-treated material 7. The amount of strain δ is calculated as rθ / L1. The radius of the heat-treated material 7 is represented by r. The unit of radius r is mm. Radius r is D1 / 2. The twist angle is represented by θ. The unit of twist angle θ is rad. When the heat-treated material 7 is twisted one full turn, the twist angle θ is 2π. The length of the heat-treated material 7 is represented by L1. The unit of length L1 is mm.

[0063] The strain amount is determined by the total number of rotations, in addition to the radius r and the length L1 of the heat-treated material 7. A specific example of the method for obtaining the strain amount will be described. In this description, it is assumed that the radius r of the heat-treated material 7 is 0.15 mm and the length L1 is 30 mm. When the heat-treated material 7 is twisted under the condition of 30 clockwise rotations followed by 30 counterclockwise rotations, the strain amount δ is (30 + 30) × {0.15 × 2π / 30} = 60 × 0.01π, which is about 1.8. When the heat-treated material 7 is twisted in the order of 15 clockwise rotations, 30 counterclockwise rotations, and 15 clockwise rotations, the strain amount δ is (15 + 30 + 15) × {0.15 × 2π / 30} = 60 × 0.01π, which is about 1.8. These two conditions have the same total number of rotations by twisting, and the same total number of clockwise rotations and total number of counterclockwise rotations.

[0064] The twisting conditions can be changed as appropriate. For example, the operation of twisting a clockwise rotations and b counterclockwise rotations may be defined as one set, and this set may be repeated a plurality of times. Alternatively, the operation of twisting in the order of c clockwise rotations, d counterclockwise rotations, and e clockwise rotations may be defined as one set, and this set may be repeated a plurality of times. Further, the total number of clockwise rotations and the total number of counterclockwise rotations may be different.

[0065] In the electric resistance heating, the heat-treated material 7 is caused to generate heat directly by passing an electric current directly through the heat-treated material 7. In the electric resistance heating, electrodes 93 and 94 are arranged at both ends of the heat-treated material 7, and an electric current is passed through the electrodes 93 and 94 for a short time. The electric resistance heating is performed at a predetermined current density for 3.0 seconds or more and 6.0 seconds or less. When the electric resistance heating time is 3.0 seconds or more, the heat-treated material 7 is heated to a predetermined temperature, and a specific B2 ordered phase is formed. If the electric resistance heating time is too long, phases other than the specific B2 ordered phase are likely to be formed. When the electric resistance heating time is 6.0 seconds or less, the proportion of the specific B2 ordered phase increases. The electric resistance heating time may be 3.2 seconds or more and 4.5 seconds or less, or 3.5 seconds or more and 4.2 seconds or less.

[0066] The current density of the electric resistance heating is, for example, 24.0 A / mm ２ or more and 28.0 A / mm ２ or less. The current density of the electric resistance heating is 24.0 A / mm ２If the above conditions are met, the heat-treated material 7 is heated to a predetermined temperature, and the specific B2 ordered phase is formed. If the current density for electrical heating is too high, phases other than the specific B2 ordered phase are likely to form. The current density for electrical heating is 28.0 A / mm². ２ The proportion of specific B2 ruled phases increases if the following conditions are met: The current density for energized heating is 25.0 A / mm². ２ 27.0A / mm or more ２ The following, or 25.5 A / mm ２ 26.5A / mm or more ２ The following is also acceptable.

[0067] The temperature reached by the heat-treated material 7 through electric heating is, for example, 90°C or higher and less than 150°C. The temperature of the heat-treated material 7 through electric heating can be measured with an infrared thermal camera. If the temperature of the heat-treated material 7 through electric heating is 90°C or higher, a specific B2 ordered phase is formed. If the temperature of the heat-treated material 7 through electric heating is less than 150°C, the proportion of the specific B2 ordered phase increases. The temperature of the heat-treated material 7 through electric heating may also be 95°C or higher and 130°C or lower, or 100°C or higher and 120°C or lower.

[0068] In this example, when a predetermined current density is applied to the heat-treated material 7, the heating time should be appropriately selected so that the temperature of the heat-treated material 7 falls within the above range.

[0069] In the electric heating process, the heating rate may be set to 10°C / s or higher. If the heating rate is 10°C / s or higher, the heat-treated material 7 is heated rapidly, and the specific B2 ordered phase is easily formed. The faster the heating rate, the easier it is for the specific B2 ordered phase to form. The heating rate may be 15°C / s or higher, or 20°C / s or higher. The upper limit of the heating rate is, for example, 150°C / s or less.

[0070] The heat-treated material 7, which has been heated by electric current, is cooled to a predetermined temperature. The cooling rate at this time is, for example, 10°C / s or higher. If the cooling rate is 10°C / s or higher, the heat-treated material 7 that has been heated by electric current is cooled rapidly, and the specific B2 ordered phase formed by electric current heating is more likely to be maintained even after cooling. The cooling rate may also be 11°C / s or higher, or 12°C / s or higher. The upper limit of the cooling rate is, for example, 150°C / s or lower.

[0071] The heat-treated material 7, which has been subjected to electric heating while being twisted, is the magnetic wire 1 described above. By performing electric heating while being twisted, a structure is easily formed in which the proportion of the specific B2 ordered phase is high and the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1% or more. The formation of a structure with the above ratio of 1% or more improves the output characteristics of the magnetic wire 1 having that structure.

[0072] <Composite Magnetic Wire> The composite magnetic wire 2 of the embodiment will be described with reference to Figure 4. The composite magnetic wire 2 comprises the magnetic wire 1 described above and a metallic coating material 3. The coating material 3 is arranged on the outer surface of the magnetic wire 1. The outer surface of the magnetic wire 1 and the inner surface of the coating material 3 are in direct contact.

[0073] The metals constituting the coating material 3 are, for example, iron, iron alloys, copper, copper alloys, aluminum, aluminum alloys, nickel, or nickel alloys. Iron alloys are, for example, stainless steel or carbon steel. Stainless steel is, for example, SUS403, SUS430, SUS304, SUS316, SUS304L, or SUS316L. Copper alloys are, for example, phosphor bronze. Nickel alloys are, for example, permalloy, nitinol, or nichrome. The coating material 3 may be magnetic or non-magnetic. The material of the coating material 3 can be determined, for example, from the results of compositional analysis of the coating material 3 by the EDX method.

[0074] The composite magnetic wire 2 is manufactured, for example, by heat-treating a coated wire in which a metal coating material 3 is placed on the outer surface of the wire material that will be used as the base for the magnetic wire 1, and then by applying electric heating while twisting it. When a metal coating material 3 is placed on the outer surface of the magnetic wire 1, tensile residual stress is easily introduced into the magnetic wire 1 by the twisting process during the manufacturing of the composite magnetic wire 2, and the output characteristics of the magnetic wire 1 tend to be higher. As a result, the composite magnetic wire 2 tends to produce a high output.

[0075] The coating material 3 is clad on the outer surface of the magnetic wire 1, for example. In this example, the coating material 3 is joined to the outer surface of the magnetic wire 1 in a state where a cylindrical coating material 3 is fitted onto it. The coating material 3 may also be plated onto the outer surface of the magnetic wire 1.

[0076] The melting point of the coating material 3 is, for example, above 850°C. If the melting point of the coating material 3 is above 850°C, heat treatment can be performed during the manufacturing process of the composite magnetic wire 2. The melting point of the coating material 3 may be 900°C or higher, or 950°C or higher. The melting point of the coating material 3 is determined as follows: Measure the initial size of the composite magnetic wire 2. For example, measure the diameter D2 of the composite magnetic wire 2. Heat and then cool the composite magnetic wire 2. The heating temperature at which the coating material 3 melts and changes shape is taken as the melting point of the coating material 3. If the coating material 3 has not melted, heat the composite magnetic wire 2 to a higher temperature and then cool it. Repeat heating and cooling until the coating material 3 melts. The heating temperature is set, for example, from 100°C to 1300°C in 50°C increments. The time for holding the composite magnetic wire 2 in a heated state is, for example, 5 minutes or more.

[0077] The Vickers hardness of the coating material 3 is, for example, 200 HV or higher. If the Vickers hardness of the coating material 3 is 200 HV or higher, tensile residual stress is easily introduced into the magnetic wire 1 by twisting during the manufacturing process of the composite magnetic wire 2, and the output characteristics of the magnetic wire 1 tend to be higher. The Vickers hardness of the coating material 3 may be 300 HV or higher, or 380 HV or higher. The upper limit of the Vickers hardness of the coating material 3 is, for example, 700 HV or lower. The Vickers hardness of the coating material 3 may be 200 HV to 700 HV, 300 HV to 600 HV, or 380 HV to 480 HV.

[0078] The Vickers hardness of the coating material 3 is determined as follows: The midpoint of the thickness of the coating material 3 is determined in the cross-section of the composite magnetic wire 2. The midpoint of the thickness of the coating material 3 is the midpoint between the inner circumference and the outer circumference of the coating material 3. If the cross-sectional shape of the coating material 3 is cylindrical, the midpoint of the thickness of the coating material 3 is located on the circumference of a concentric circle having a diameter obtained by adding the inner diameter and outer diameter of the coating material 3 and dividing by 2. The inner diameter of the coating material 3 is the diameter D1 of the magnetic wire 1, and the outer diameter of the coating material 3 is the diameter D2 of the composite magnetic wire 2. Micro-Vickers hardness tests are performed on four of the midpoints of the thickness of the coating material 3. The average value of the Vickers hardness of the four measured points is considered to be the Vickers hardness of the coating material 3. The four points are determined to be equally spaced around the central axis of the coating material 3. The method for testing the micro-Vickers hardness of the coating material 3 is the same as the method for testing the micro-Vickers hardness of the magnetic wire 1. However, the test force is 0.098 N (0.01 kgf).

[0079] The ratio of the diameter D1 of the magnetic wire 1 to the diameter D2 of the composite magnetic wire 2 is, for example, 45% to 95%. If the ratio of diameter D1 to diameter D2 is 45% or more, the ratio of the cross-sectional area of ​​the magnetic wire 1 to the cross-sectional area of ​​the composite magnetic wire 2 does not become too small, and the output characteristics of the composite magnetic wire 2 tend to be high. If the ratio of diameter D1 to diameter D2 is 95% or less, the ratio of the cross-sectional area of ​​the coating material 3 to the cross-sectional area of ​​the composite magnetic wire 2 does not become too small. Because the ratio of the cross-sectional area of ​​the coating material 3 is relatively large, tensile residual stress is easily introduced into the magnetic wire 1 by twisting during the manufacturing process of the composite magnetic wire 2, and the output characteristics of the magnetic wire 1 tend to be high. The ratio of diameter D1 to diameter D2 may also be 48% to 95%, 55% to 90%, or 60% to 85%.

[0080] The shape of the composite magnetic wire 2 can be selected as appropriate. The composite magnetic wire 2 shown in Figure 4 is a round wire. The cross-sectional shape of the composite magnetic wire 2 is circular. The cross-sectional shape of the composite magnetic wire 2 may also be non-circular. The cross-sectional shape of the covering material 3 is cylindrical.

[0081] The diameter D2 of the composite magnetic wire 2 can be selected as appropriate. The diameter D2 of the composite magnetic wire 2 is the diameter of a circle having an area equal to the area of ​​the cross-section of the composite magnetic wire 2. For example, the diameter D2 of the composite magnetic wire 2 is between 0.105 mm and 3.0 mm. A composite magnetic wire 2 with a diameter D2 within the above range can be suitably used as a core for magnetic sensors and the like. The diameter D2 of the composite magnetic wire 2 may also be between 0.11 mm and 2.0 mm, between 0.12 mm and 1.0 mm, between 0.15 mm and 0.8 mm, or between 0.2 mm and 0.6 mm.

[0082] The length L2 of the composite magnetic wire 2 can be selected as appropriate. The length L2 of the composite magnetic wire 2 is the length from the first end to the second end of the composite magnetic wire 2. The length L2 of the composite magnetic wire 2 is the same as the length L1 of the magnetic wire 1 described above.

[0083] The composite magnetic wire 2 may have twist marks, which are not shown. The composite magnetic wire 2 is manufactured, for example, by heat-treating a coated wire in which a metallic coating material 3 is placed on the outer surface of the wire material that will be used as the base material for the magnetic wire 1, and then by twisting it. The twist marks are formed by the twisting process. The twist marks formed on the composite magnetic wire 2 are the same as the twist marks 4 formed on the magnetic wire 1 described above.

[0084] <Method for Manufacturing Composite Magnetic Wires> Composite magnetic wire 2 can be manufactured through the same process as the method for manufacturing magnetic wire 1 described above. The method for manufacturing composite magnetic wire 2 includes a step of producing a coated wire in which a metal layer coating material 3 is placed on the outer surface of a wire that will be the material for magnetic wire 1. In the method for manufacturing composite magnetic wire 2, the first, second, and third steps described in the method for manufacturing magnetic wire 1 are performed in order on this coated wire.

[0085] In the process of manufacturing coated wires, a coating material 3 is formed on the outer surface of the wire that will be the material for the magnetic wire 1 by a cladding method. The cladding method is a method of joining the coating material 3 to the outer surface of the wire by inserting the wire into a cylindrical coating material 3 and then pulling it out. The thickness of the coating material 3 can be appropriately selected so that the ratio of the diameter D1 of the magnetic wire 1 to the diameter D2 of the composite magnetic wire 2 to be manufactured is within a predetermined range. In the process of manufacturing coated wires, the coating material 3 may also be formed on the outer surface of the wire that will be the material for the magnetic wire 1 by a plating method.

[0086] In the first step of the manufacturing method for the composite magnetic wire 2, a drawn wire 6 is produced by drawing out the coated wire. The first step of the manufacturing method for the composite magnetic wire 2 differs from the first step of the manufacturing method for the magnetic wire 1 described above in that it involves drawing out the coated wire. The drawing process is the same as the drawing process described in the manufacturing method for the magnetic wire 1 described above.

[0087] The second step in the manufacturing method of the composite magnetic wire 2 is the same as the second step in the manufacturing method of the magnetic wire 1 described above.

[0088] The third step in the manufacturing method of the composite magnetic wire 2 is the same as the third step in the manufacturing method of the magnetic wire 1 described above. However, the amount of strain due to twisting in the manufacturing method of the composite magnetic wire 2 is different from the amount of strain due to twisting in the manufacturing method of the magnetic wire 1 described above. In the manufacturing method of the composite magnetic wire 2, the twisting is performed, for example, under conditions such that the amount of strain on the surface of the twisted heat-treated material 7 is between 0.8 and 3.0. By performing the twisting so that the above amount of strain is between 0.8 and 3.0, a composite magnetic wire 2 with high output characteristics can be stably manufactured. The above amount of strain may also be between 1.0 and 2.0. The method for determining the amount of strain of the composite magnetic wire 2 differs from the method for determining the amount of strain of the magnetic wire 1 described above in that the diameter D2 of the composite magnetic wire 2 including the coating material 3 is used. Other than the amount of strain in the third step, it is the same as the third step in the manufacturing method of the magnetic wire 1 described above.

[0089] [Test Examples] In the test examples, the microstructure and output characteristics of magnetic wires or composite magnetic wires manufactured by various manufacturing methods were investigated.

[0090] <Samples> <Samples No. 1 to No. 3 and No. 12> Samples No. 1 to No. 3 and No. 12 are composite magnetic wires in which a coating material is arranged on the outer surface of the magnetic wire. The composition of the magnetic wire is the same for all samples. The alloy constituting the magnetic wire contains 52.5 mass% Co, 0.3 mass% Si, 0.6 mass% Mn, and 7.5 mass% V, with the remainder being Fe and unavoidable impurities. The coating material for all samples is made of SUS316L. The melting point of the coating material is 1300°C or higher. For all samples, the ratio of the diameter of the magnetic wire to the diameter of the composite magnetic wire is 85%.

[0091] Samples No. 1 through No. 3 and Sample No. 12 were all manufactured by drawing a coated wire, which had a metal coating material placed on its outer surface, to produce a drawn wire; then, after heat treatment of the drawn wire, they were heated by applying electricity while being twisted. Samples No. 1 through No. 3 and Sample No. 12 differed in the amount of time they were heated by electricity.

[0092] First, a drawn wire was produced by drawing a coated wire, which had a metallic coating on its outer surface, to form the base material for the magnetic wire. The shape of the drawn wire was round; that is, the cross-section of the drawn wire was circular. The diameter of the drawn wire was 5.0 mm. The drawing process was performed cold. Multiple drawing processes were carried out, with intermediate heat treatment performed during the drawing process. The intermediate heat treatment was performed once when the drawn wire was drawn to a diameter of 1.0 mm. After the intermediate heat treatment, the drawn wire was drawn until its diameter was 0.4 mm. After the intermediate heat treatment, the degree of completion until the final drawing process was 84%. The temperature of the intermediate heat treatment was 800°C. The duration of the intermediate heat treatment was 60 minutes. The intermediate heat treatment was performed in a hydrogen atmosphere. The cooling rate after the intermediate heat treatment was 20°C / second. The total degree of completion was 99.99%.

[0093] Next, heat-treated material was prepared by heat-treating the drawn wire. The heat treatment temperature was set to 800°C. The heat treatment time was set to 60 minutes. The heat treatment was carried out under a hydrogen atmosphere. After the heat treatment, the heat-treated material was cooled to room temperature. The cooling rate after heat treatment was set to 20°C / second.

[0094] Finally, composite magnetic wires were fabricated by electrically heating the heat-treated material while twisting it. The twisting process was performed by cutting the heat-treated material to a length of 55 mm, gripping both ends of the cut heat-treated material with chucks, and rotating one of the chucks. The length of each end of the heat-treated material gripped by the chucks was set to 2.5 mm so that the distance between the chucks was 50 mm. The length of the portion to be twisted was 50 mm. The twisting process was performed under conditions such that the amount of strain on the surface of the twisted heat-treated material was 1.62. Specifically, each sample was twisted in the following order: 6.3 rotations clockwise, 12.6 rotations counterclockwise, 12.6 rotations clockwise, and 33 rotations counterclockwise.

[0095] For the electric heating method, electrodes were placed at both ends of the cut heat-treated material, and a short current was passed through the electrodes. For all samples, the current density during electric heating was 26.0 A / mm². ２ The following was done. The time of electrical heating for each sample is shown in Table 1. Table 1 also shows the temperature reached by the heat-treated material by electrical heating. The temperature reached by the heat-treated material by electrical heating was measured using an infrared thermal camera. Table 1 also shows the heating rate by electrical heating. The heat-treated material that underwent electrical heating was cooled to 40°C. The cooling rate is as shown in Table 1.

[0096] After the heat-treated material, which had been electrically heated, cooled, 20 mm was cut from both ends of a 50 mm wire, and the properties of the remaining 10 mm wire were evaluated. The reason for excluding both ends of the wire from evaluation is that heat escapes from the chuck at both ends, and therefore they are not sufficiently electrically heated.

[0097] <<Sample No. 4>> Sample No. 4 is a magnetic wire, and its outer surface is not coated. The composition of the magnetic wire in Sample No. 4 is the same as that of the magnetic wire in Sample No. 1.

[0098] Sample No. 4 was manufactured by drawing a wire that would become the material for the magnetic wire, then heat-treating the drawn wire, and finally heating it with electricity while twisting it. Sample No. 4 differs from Sample No. 1 in that it is made by drawing a wire that does not have a coating, but the conditions for drawing and heat treatment are the same as for Sample No. 1.

[0099] Finally, magnetic wires were fabricated by applying electric heating while twisting the heat-treated material. The length of the heat-treated material to be twisted, the length of the heat-treated material held by the chuck, and the length of the portion to be twisted were the same as in Sample No. 1. Furthermore, the amount of strain on the surface of the twisted heat-treated material, i.e., the specific twisting operation of the heat-treated material, was also the same as in Sample No. 1.

[0100] ≪Sample No. 11≫ Sample No. 11 is a composite magnetic wire in which a coating material is placed on the outer surface of the magnetic wire. The composition of the magnetic wire and the material of the coating material of Sample No. 11 are the same as those of Sample No. 1.

[0101] Sample No. 11 was manufactured by drawing a coated wire, which had a metal coating placed on the outer surface of the wire material that would become the magnetic wire, then heat-treating the drawn wire and twisting it. Sample No. 11 was not subjected to electrical heating. The conditions for drawing, heat treatment, and twisting of Sample No. 11 were the same as those of Sample No. 1, except that electrical heating was not performed. Since electrical heating was not performed for Sample No. 11, the achieved temperature in Table 1 is shown as 25°C, which is room temperature.

[0102] ≪Sample No. 13≫ Sample No. 13 is a composite magnetic wire in which a coating material is placed on the outer surface of the magnetic wire. The composition of the magnetic wire and the material of the coating material of Sample No. 13 are the same as those of Sample No. 1.

[0103] Sample No. 13 was manufactured by drawing a coated wire, which had a metal coating placed on the outer surface of the wire material that would become the magnetic wire, and then performing a second heat treatment on the drawn wire while twisting it in a furnace. Sample No. 13 was not subjected to electric heating. The conditions for drawing, heat treatment, and twisting were the same as for Sample No. 1, except that the second heat treatment was performed in the furnace while twisting was performed without electric heating. In Sample No. 13, the temperature reached in Table 1 represents the heat treatment temperature in the furnace. In Sample No. 13, the holding time at the reached temperature was 1 minute.

[0104] <Twist Marks> The twist marks on the outer surfaces of the composite magnetic wires of samples No. 1 to No. 3 and No. 11 to No. 13, and the magnetic wire of sample No. 4 were examined. Specifically, the outer surfaces of the composite magnetic wires or magnetic wires of each sample were observed with an optical microscope, and the inclination angle of the twist marks with respect to the axis of the magnetic wire was measured. The inclination angles of 20 or more twist marks were measured, and the average value was defined as the twist mark angle θt. As a result, the twist mark angle θt for all samples was within the range of 2° to 60°.

[0105] <Structure of Magnetic Wires> The structure of the magnetic wires in each sample was determined by X-ray diffraction. First, each sample was cut with a plane parallel to the axis of the wire. The shape of the cut sample was a rectangle with a long side parallel to the axis of the wire and a short side along the diameter of the wire. The cut surface of this sample was smoothed by mechanical polishing. The surface roughness of the cut surface after polishing was approximately 0.2 μm in arithmetic mean roughness Ra. For mechanical polishing, for example, 2000-grit waterproof sandpaper can be used. The entire polished cut surface was subjected to X-ray diffraction. X-ray diffraction was performed using BL16 located at the SAGA-LS synchrotron radiation facility. The wavelength of the X-rays was 0.175 nm and the energy was 7086 eV. The slit width was set to 0.1 mm × 3.0 mm so that X-rays were incident only on the magnetic wires. The detector used was a commercially available two-dimensional detector, the PILATUS 100K manufactured by Dectris. The distance from the cross-section of the sample to the two-dimensional detector was set to 0.512 m.

[0106] The diffraction intensity was calculated by fitting the X-ray profile data at each measurement point and using the integral value of this fitting curve. The fitting function used was the Lorentz function. For this diffraction intensity, the ratio of the integral intensity of the (100) plane to the integral intensity of the (200) plane was determined. The results are shown in Table 1. In Table 1, it is written as "(100) / (200)".

[0107] <Output Characteristics> The output characteristics of the magnetic wires of each sample were evaluated. The output characteristics were evaluated as follows: A power generation element was fabricated by winding a coil around a magnetic wire or composite magnetic wire. The output of the power generation element was connected to a full-wave rectifier circuit connected to a capacitor and a resistor. An AC magnetic field of 20 Hz was applied to the power generation element connected to the full-wave rectifier circuit in the range of 20 Oe to 200 Oe. In measuring the generated voltage, the peak voltage after rectification of the generated pulse by the power generation element was measured each time the direction of the AC magnetic field was reversed. The peak voltage was measured 2500 times, and the average value of the 2500 measured peak voltages was calculated. This average value of the peak voltage is shown as the output in Table 1.

[0108] <Vickers Hardness> The Vickers hardness of the magnetic wires in each sample was measured. As described above, the Vickers hardness of the magnetic wire is the average of five Vickers hardness values ​​measured by performing micro-Vickers hardness tests at four different points: the center of the magnetic wire and the midpoint of the magnetic wire's radius. For samples No. 1 to No. 3 and samples No. 11 to No. 13, the Vickers hardness of the coating material was also measured. As described above, the Vickers hardness of the coating material is the average of four Vickers hardness values ​​measured by performing micro-Vickers hardness tests at four different points: the midpoint of the coating material's thickness. The results are shown in Table 1.

[0109]

[0110] As shown in Table 1, in samples No. 1 to No. 4, the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane was 1.0% or more, and the output was high, exceeding 2.3V. It is thought that in samples No. 1 to No. 4, a large amount of the specific B2 ordered phase was formed because short-term electrical heating was performed while twisting the samples. As described above, the specific B2 ordered phase is a phase in which a body-centered cubic lattice (bcc) is used as the unit cell, with iron atoms arranged at each vertex of the unit cell and cobalt atoms arranged at the body-center position.

[0111] In samples No. 11 to No. 13, the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane was less than 1.0%, and the output was low, at 2.3V or less. In sample No. 11, no electric heating was performed, making it difficult for the specific B2 ordered phase to form, which is thought to have resulted in the decrease in the above ratio. In sample No. 12, although electric heating was performed while twisting, the electric heating time was long, so a phase other than the specific B2 ordered phase was formed, which is thought to have resulted in the decrease in the above ratio. In sample No. 13, heat treatment was performed in a furnace instead of electric heating, so the magnetic wire could not be heated and cooled in a short time, making it difficult for the specific B2 ordered phase to form, which is thought to have resulted in the decrease in the above ratio.

[0112] From these results, it can be seen that by performing a short period of electrical heating while twisting, a specific B2 ordered phase can be effectively formed, and the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane becomes 1.0% or more, resulting in improved output characteristics.

[0113] 1 Magnetic wire 2 Composite magnetic wire 3 Coating material 4 Twist mark 5 Material 6 Drawn wire 7 Heat-treated material 81 Die 82 Furnace 91, 92 Chuck 93, 94 Electrode D1, D2 Diameter, L1, L2 Length, r Radius θ Twist angle, θt Angle of twist mark

Claims

1. A magnetic wire made of an alloy mainly composed of iron and cobalt, having a structure in which the ratio of the diffraction intensity of the (100) plane to the diffraction intensity of the (200) plane is 1.0% or more.

2. The magnetic wire according to claim 1, wherein the alloy contains 6.0% by mass or more and 8.0% by mass or less of vanadium.

3. The magnetic wire according to claim 1 or claim 2, wherein the alloy contains 0.2% by mass or more and 0.4% by mass or less of silicon and 0.5% by mass or more and 0.7% by mass or less of manganese.

4. A magnetic wire according to any one of claims 1 to 3, wherein the Vickers hardness is 470 HV or more and 530 HV or less.

5. The magnetic wire according to any one of claims 1 to 4, wherein the magnetic wire has a twist mark on its outer surface, and the angle of the twist mark with respect to the axis of the magnetic wire is 2° or more and 60° or less.

6. The magnetic wire according to any one of claims 1 to 5, wherein the diameter of the magnetic wire is 0.1 mm or more and 1.0 mm or less, and the length of the magnetic wire is 25 mm or less.

7. A composite magnetic wire comprising a magnetic wire according to any one of claims 1 to 6, and a metallic coating material disposed on the outer surface of the magnetic wire.

8. The composite magnetic wire according to claim 7, wherein the ratio of the diameter of the magnetic wire to the diameter of the composite magnetic wire is 45% or more and 95% or less.

9. The composite magnetic wire according to claim 7 or claim 8, wherein the melting point of the coating material is greater than 850°C.

10. The composite magnetic wire according to any one of claims 7 to 9, wherein the Vickers hardness of the coating material is 200 HV or more.

11. A method for manufacturing a magnetic wire, comprising: a step of producing a drawn wire by drawing a material made of an alloy mainly composed of iron and cobalt; a step of producing a heat-treated material by heat-treating the drawn wire; and a step of producing a magnetic wire by electrically heating the heat-treated material while twisting it, wherein the electric heating is performed at a predetermined current density for 3.0 seconds or more and 6.0 seconds or less.

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