Magnetic materials and rotating electric machines

Abstract

To provide a magnetic material and a rotary electric machine having excellent magnetic characteristics, mechanical characteristics, and thermal stability.SOLUTION: Disclosed is a magnetic material according to an embodiment which contains at least one first element X selected from the group consisting of Fe, Co, and Ni and has a host phase and particles containing at least one second element Y and C selected from Ta, W, Nb and Mo.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to magnetic materials and rotating electrical machines.

Background Art

[0002] Currently, soft magnetic materials are applied to cores and magnetic wedges of various systems and device components such as rotating electrical machines (e.g., motors, generators, etc.), transformers, inductors, transformers, magnetic inks, antenna devices, etc., and are very important materials. Note that a magnetic wedge is like a lid for a slot part where a coil is placed in a rotating electrical machine. Usually, a non-magnetic wedge is used, but by adopting a magnetic wedge, the density of magnetic flux density is alleviated, harmonic losses are reduced, and motor efficiency and power generation efficiency are improved. Soft magnetic materials are required to have high magnetic permeability and low losses in the frequency band used, and high saturation magnetization is also required to prevent magnetic saturation. Losses are mainly composed of hysteresis losses and eddy current losses. To reduce hysteresis losses, it is important to reduce coercive force, and to reduce eddy current losses, it is important to improve electrical resistivity and reduce the size of metal components, etc. In addition, other characteristics required when incorporated into each system and device include high thermal stability, high strength, high toughness, etc. Also, for application to complex shapes, powder compacts and sintered compacts are more preferable than plates and ribbons. In the case of powder compacts and sintered compacts, it is known that the characteristics deteriorate in terms of saturation magnetization, magnetic permeability, loss, strength, toughness, etc., and improvement of the characteristics is preferable.

[0003] Next, the types and problems of existing soft magnetic materials will be described. Existing soft magnetic materials for systems below 10 kHz include silicon steel sheets (FeSi). Silicon steel sheets have a long history and are materials that are mostly adopted for the core materials of rotating electrical machines and transformers that handle large power. The properties have been improved from non-oriented silicon steel sheets to grain-oriented silicon steel sheets, and although they have evolved compared to when they were first discovered, in recent years, the improvement of properties has reached a plateau. As properties, it is particularly important to simultaneously satisfy high saturation magnetization, high magnetic permeability, and low loss. In the world, research on materials exceeding silicon steel sheets has been actively conducted mainly on amorphous and nanocrystalline compositions, but no material composition that exceeds silicon steel sheets in all aspects has been found yet. Also, research on powder compacts and sintered compacts applicable to complex shapes has been carried out, but powder compacts and sintered compacts have the drawback of having worse properties compared to sheets and ribbons.

[0004] Existing soft magnetic materials for systems from 10 kHz to 100 kHz include Sendust (Fe-Si-Al), nanocrystalline fine metals (Fe-Si-B-Cu-Nb), ribbon or powder compacts of Fe-based or Co-based amorphous glass, or MnZn-based ferrite materials. However, none of them completely satisfy high magnetic permeability, low loss, high saturation magnetization, high thermal stability, high strength, and high toughness, and they are insufficient.

[0005] Existing soft magnetic materials above 100 kHz (MHz band and above) include NiZn-based ferrites, hexagonal ferrites, etc., but their magnetic properties at high frequencies are insufficient.

[0006] From the above, it is preferable to develop magnetic materials having high saturation magnetization, high magnetic permeability, low loss, high thermal stability, and excellent mechanical properties. In particular, it is preferable to develop magnetic materials having the properties of high saturation magnetization, low loss, high thermal stability, and high strength.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

[0008] The problem that this invention aims to solve is to provide a magnetic material having excellent magnetic properties, mechanical properties, and thermal stability, as well as a rotating electric machine. [Means for solving the problem]

[0009] The magnetic material of this embodiment comprises at least one first element X selected from the group consisting of Fe, Co, and Ni. and Si A magnetic material comprising a matrix phase and The first element X, A second element Y selected from at least one element from Ta, W, Nb, and Mo 、 Particles containing C, and The Si content is 1 atomic% or more and 25 atomic% or less relative to the entire magnetic material, and the particles are present on the surface of the magnetic material, at the grain boundaries of the matrix phase, and at least one location within the grains of the matrix phase in the sintered body. magnetic material. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the morphology of precipitated particles in the magnetic material of the first embodiment. [Figure 2] This is a schematic diagram showing a cross-section when evaluating the Si content in the magnetic material of the first embodiment. [Figure 3] This is a conceptual diagram of the motor system according to the second embodiment. [Figure 4] This is a conceptual diagram of the motor according to the second embodiment. [Figure 5] This is a conceptual diagram of the motor core (stator) of the second embodiment. [Figure 6] This is a conceptual diagram of the motor core (rotor) of the second embodiment. [Figure 7] This is a conceptual diagram of a transformer in the second embodiment. [Figure 8] This is a conceptual diagram of the inductor (ring-shaped inductor, rod-shaped inductor) according to the second embodiment. [Figure 9]This is a conceptual diagram of an inductor (chip inductor, planar inductor) according to the second embodiment. [Figure 10] This is a conceptual diagram of a generator according to the second embodiment. [Modes for carrying out the invention]

[0011] The embodiments will be described below with reference to the drawings. In the drawings, identical or similar parts are denoted by the same or similar reference numerals.

[0012] (First Embodiment) The magnetic material of this embodiment is a magnetic material comprising at least one first element selected from the group consisting of Fe, Co, and Ni, and having a matrix phase and precipitated particles containing Ta and C.

[0013] The magnetic material of this embodiment is a magnetic material comprising at least one first element X selected from the group consisting of Fe, Co, and Ni, and having a matrix phase and particles comprising at least one second element Y selected from Ta, W, Nb, and Mo, and C. These particles are also called precipitated particles.

[0014] Furthermore, it is preferable that the particles have a cubic crystal structure, contain the first element X, and have a compound phase of type X3Y3C. For example, it is preferable that they have a compound phase such as Ta3Co3C, Nb3Fe3C, Nb3Co3C, W3Fe3C, W3Co3C, W3Ni3C, Mo3Fe3C, Mo3Co3C, Mo3Ni3C, etc. In this case, it is more preferable that the crystal structure has a space group of Fd3m. The lattice constant will vary depending on the content of Fe, Si, etc., but for example, it is preferable to have about 11.2 Å. Furthermore, it is preferable that the matrix phase on which the precipitated particles are arranged has a cubic crystal structure, and more preferably has a body-centered cubic crystal structure. The lattice constant will vary depending on the contained elements and their content, but for example, it is preferable to have about 2.85 Å. Furthermore, it is preferable that among the precipitated particles, there are precipitated particles that are oriented with respect to the matrix phase. The orientation relationship is, for example, (0-40)母相 , 母相 , 母相 , 母相 , 母相 , 母相 , 粒子 , 粒子 , 粒子 , 粒子 , 粒子 , 粒子 / / (0 - 10) 母相 or (-404) 粒子 / / (-101) 母相 Preferably, it has the relationship of. More preferably, for example, (0 - 40) 粒子 / / (0 - 10) 母相 and (-404) 粒子 / / (-101) 母相 Preferably, it has the relationship of. These orientation relationships are just examples, and it is preferable to have an orientation relationship equivalent to the above. Also, it is preferable that two or more precipitation particles contained in one said parent phase are oriented to each other. Further, it is preferable that the precipitation particles oriented with respect to the parent phase have a lattice mismatch of 10% or less with respect to the parent phase. More preferably 5% or less, and even more preferably 2% or less. Incidentally, when the precipitation particles have a cubic crystal structure of the X3Y3C type and the parent phase has a body-centered cubic crystal structure, the lattice mismatch is calculated by the formula: lattice mismatch = |lattice constant of precipitation particle / 4 - lattice constant of parent phase| / lattice constant of parent phase × 100 (%). By including such particles in a magnetic material, the mechanical properties such as strength and thermal stability are significantly improved by the precipitation strengthening mechanism.

[0015] In addition, the measurement method for examining the orientation relationship is not limited, but for example, it is performed by electron beam diffraction or the like. From an electron beam diffraction image or the like, if a "certain crystal plane" of the particle and a "certain crystal plane" of the parent phase are parallel or substantially parallel, it is determined that they are oriented. Also, since (hkl) is parallel to (nh nk nl) (n is a positive or negative integer), for example, (0 - 40) 粒子 / / (0 - 10)<000001​​​​​​​​​​​​​​​​​​​​​​​母相 (0-20) 粒子 / / (0-10) 母相 This has the same meaning as (010). 粒子 / / (0-10) 母相 (010) 粒子 / / (010) 母相 (0-10) 粒子 / / (010) 母相 (0-10) 粒子 / / (0-10) 母相 It has the same meaning as [the other statement].

[0016] Preferably, the first element X of the particles is Co, and the second element Y is Ta. More preferably, the particles contain at least one of Fe and Si, and even more preferably, both Fe and Si. It is also preferable that the particles contain elements contained in the matrix phase in which the particles are arranged (excluding obvious impurity elements, for example, less than 0.1%). This is preferable because it makes the composition of the precipitated particles similar to that of the matrix phase, thereby improving thermal stability and mechanical properties such as strength and hardness.

[0017] The magnetic material contains at least one first element selected from the group consisting of Fe, Co, and Ni. The magnetic material contains Fe and Co, and preferably the amount of Co is 10 atomic% to 60 atomic% of the total amount of Fe and Co, and more preferably 10 atomic% to 40 atomic%. This is preferable because it easily imparts a moderately large magnetic anisotropy, improving magnetic properties (high permeability, low loss, etc.). Furthermore, the Fe-Co system is preferable because it easily achieves high saturation magnetization. It is also preferable that the composition range of Fe and Co falls within the above range, as this allows for even higher saturation magnetization.

[0018] The magnetic material preferably contains at least one non-magnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Y, Nb, Pb, Cu, In, Sn, and rare earth elements. This can improve the thermal stability and oxidation resistance of the magnetic material. Among these, Al and Si are particularly preferred because they readily solid-solve with Fe, Co, and Ni, which are the main components of the magnetic material, and contribute to improving thermal stability and oxidation resistance. Of these, Si is particularly preferred in terms of improving thermal stability and oxidation resistance. The amount of the non-magnetic metal is preferably 1 atomic% to 25 atomic% of the total magnetic material, more preferably 5 atomic% to 20 atomic% and even more preferably 5 atomic% to 15 atomic%.

[0019] The magnetic material preferably contains precipitated particles containing Ta and C. The inclusion of such precipitated particles in the magnetic material significantly improves mechanical properties such as strength and thermal stability through a precipitation strengthening mechanism. Furthermore, the precipitated particles preferably also contain Co. More preferably, they contain at least one of Fe and Si, and even more preferably, both Fe and Si. It is also preferable that the precipitated particles contain elements present in the matrix phase (excluding obvious impurity elements, for example, less than 0.1%). This results in similar compositions between the precipitated particles and the matrix phase, which is preferable as it improves thermal stability and mechanical properties such as strength and hardness.

[0020] The precipitated particles preferably have a cubic crystal structure of Ta3Co3C (preferably containing at least one of Fe and Si), and more preferably have a space group of Fd3m. The lattice constant varies depending on the content of Fe, Si, etc., but is preferably around 11.2 Å. Furthermore, the matrix phase on which the precipitated particles are arranged preferably has a cubic crystal structure, and more preferably a body-centered cubic crystal structure. The lattice constant varies depending on the elements contained and their content, but is preferably around 2.85 Å. Furthermore, it is preferable that some of the precipitated particles are oriented relative to the matrix phase. The orientation relationship is, for example, (020). 析出粒子 / / (0-10) 母相 , or (20-2) 析出粒子 / / (-101) 母相 It is preferable to have the following relationship. More preferably, for example, (020) 析出粒子 / / (0-10) 母相 , and, (20-2) 析出粒子 / / (-101) 母相 It is preferable to have the following relationship. Alternatively, (020) 析出粒子 / / (010) 母相 , or (20-2) 析出粒子 / / (10-1) 母相 It is preferable to have the following relationship. More preferably, for example, (020) 析出粒子 / / (010) 母相 , and, (20-2) 析出粒子 / / (10-1) 母相It is preferable that the following relationship exists. These orientation relationships are just examples, and it is preferable that an equivalent orientation relationship exists. It is also preferable that two or more precipitate particles contained within one matrix are oriented toward each other. Furthermore, it is preferable that the precipitate particles oriented toward the matrix have a lattice mismatch of 10% or less with respect to the matrix. More preferably, it is 5% or less, and even more preferably 2% or less. When the precipitate particles have a cubic crystal structure of Ta3Co3C and the matrix has a body-centered cubic crystal structure, the lattice mismatch is calculated using the formula: Lattice mismatch = |Lattice constant of precipitate particles / 4 - Lattice constant of matrix| / Lattice constant of matrix × 100 (%).

[0021] All of these methods are effective in improving the mechanical properties, such as the strength, and thermal stability of magnetic materials.

[0022] The average particle size of the precipitated particles is preferably 1 nm to 10 μm, more preferably 1 nm to 1 μm, and even more preferably 1 nm to 100 nm. This allows for improved mechanical properties such as high strength and thermal stability, and enables low coercivity (low hysteresis loss) by minimizing pinning of the magnetic domain walls. In addition, the arrangement of precipitated particles also provides the effect of reducing eddy current loss. The average particle size can be determined by observation using a TEM (Transmission Electron Microscope) or SEM (Scanning Electron Microscope). It can also be determined by image analysis of microscopic photographs on a computer. In any case, it is preferable to determine the average particle size by targeting 10 or more precipitated particles in multiple fields of view. It is preferable to determine the average particle size by targeting as many precipitated particles as possible in order to obtain average information. If it is not possible to observe 10 or more precipitated particles, it is preferable to observe as many precipitated particles as possible and adopt the average value obtained from them.

[0023] Figure 1 shows the morphology of the precipitated particles. Preferably, the precipitated particles 2 are arranged at at least one location (surface, grain boundary, or inside the grain) among the surface 8 of the magnetic material 100, the grain boundaries 6 of the matrix 4, or inside the grains of the matrix. More preferably, they are arranged at two or more locations (surface and grain boundary, surface and inside the grain, grain boundary and inside the grain), and even more preferably, at three locations (surface, grain boundary, and inside the grain). In particular, it is preferable that they be arranged at the grain boundaries of the matrix. This greatly enhances the effect of "improvement of mechanical properties such as strength and thermal stability due to precipitation strengthening."

[0024] In particular, by being placed at the grain boundaries of the matrix phase, the grain boundaries are strengthened, and the effect of inhibiting the progression of grain boundary fracture is easily achieved, which is preferable. This greatly enhances the effect of "improvement of mechanical properties such as strength and thermal stability through precipitation strengthening."

[0025] In magnetic materials, it is preferable that the Si content of the surface is 1.1 times or more than the Si content of the center of the magnetic material. This is preferable because it enables low coercivity and low hysteresis loss, and the Si-rich surface suppresses eddy current loss.

[0026] Regarding the Si content, it is preferable to evaluate it using the following procedure. First, as shown in Figure 2, in a magnetic material, the direction of the longest side is defined as the "length direction," the direction of the shortest side as the "thickness direction," and the direction of the side that is shorter than the length direction side and longer than the thickness direction side as the "width direction." At this time, the plane perpendicular to the length direction in the central part of the length direction is defined as the "cross-section." In this cross-section, the material is divided into nine squares with respect to the center line of the thickness direction, and the Si content of the central part and the Si content of the surface (average of two locations) are compared and evaluated. The Si content is evaluated using energy-dispersive X-ray spectroscopy (EDX) such as SEM or TEM.

[0027] Furthermore, it is preferable that the first element consists of Fe and Co. The Si content is preferably 1 atomic% to 25 atomic% of the total magnetic material, more preferably 5 atomic% to 20 atomic% and even more preferably 5 atomic% to 15 atomic%. This is preferable because it enables low coercivity and low hysteresis loss, allows for a high electrical resistivity, and suppresses eddy current loss.

[0028] The magnetic material has a density of 6 g / cm³. 3 Preferably, it is 7 g / cm³ or more. 3 More preferably 7.5 g / cm³ 3 That concludes the explanation. Density can be evaluated by methods such as the Archimedes method or simply by weight / volume measurement. Furthermore, the relative density is preferably 90% or higher, and more preferably 95% or higher.

[0029] The magnetic material preferably has a three-point bending strength of 200 MPa or more as a mechanical property, more preferably 300 MPa or more, and even more preferably 500 MPa or more. The three-point bending strength can be measured according to the three-point bending test method specified in standards such as JIS-R1601.

[0030] The magnetic material preferably has a coercivity of 80 A / m or less, more preferably 40 A / m or less, and even more preferably 20 A / m or less. This enables low hysteresis loss. The coercivity can be easily evaluated using a vibrating sample magnetometer (VSM) or the like. If the coercivity is low, a low magnetic field unit can be used to measure coercivity of 8 A / m (0.1 Oe) or less. When calculating coercivity with a VSM, the value obtained by dividing the difference in magnetic fields between two points that intersect the horizontal axis (magnetic fields H1 and H2 where magnetization is zero) by 2 can be used (i.e., coercivity can be calculated as |H2-H1| / 2).

[0031] The magnetic material preferably has a saturation magnetization of 1.7T or higher, and more preferably 1.8T or higher. The mass saturation magnetization is preferably 180 emu / g or higher, and more preferably 190 emu / g or higher. This suppresses magnetic saturation, allowing the magnetic properties to be fully exhibited in the system, which is preferable.

[0032] With the above configuration, it is possible to achieve excellent magnetic properties such as high saturation magnetization, low coercivity, and low losses (low hysteresis loss, low eddy current loss), as well as excellent mechanical properties such as high thermal stability and high strength.

[0033] Next, a method for manufacturing the magnetic material of this embodiment will be described. Note that the manufacturing method is not particularly limited and is described merely as an example.

[0034] As described above, the method for manufacturing the magnetic material of this embodiment, as explained below, is merely an example. Therefore, the manufacturing process for the precipitated particles of this embodiment is not limited to the following. Thus, the "precipitated particles" of this embodiment are just one example of "particles."

[0035] The first step is the preparation step for molding. For example, a magnetic metal ribbon is manufactured, heat-treated, then crushed and molded. In this case, the magnetic metal ribbon is manufactured using a film deposition device such as a roll quenching device or a sputtering device. A roll quenching device is desirable because it is suitable for large-scale synthesis. A single-roll quenching device is particularly simple and preferable. When heat-treating the magnetic metal ribbon, the ribbon may be cut to an appropriate size to make it easier to place in the electric furnace for heat treatment. For example, it may be cut to an appropriate size using a mixer device. Heat treatment is preferable because it makes it easier to improve the pulverability. The atmosphere for heat treatment is preferably a vacuum atmosphere with a low oxygen concentration, an inert atmosphere, or a reducing atmosphere, and more preferably a reducing atmosphere such as H2 (hydrogen), CO (carbon monoxide), or CH4 (methane). This is because even if the magnetic metal ribbon is oxidized, heat treatment in a reducing atmosphere makes it possible to reduce the oxidized metal back to its original metal state. This process can also reduce oxidized magnetic metal ribbons, whose saturation magnetization has decreased, and restore their saturation magnetization. The heat-treated magnetic metal ribbons are then pulverized to produce flattened magnetic metal particles. Before this pulverization, the magnetic metal ribbons or thin films may be cut to an appropriate size using a mixer or similar device. In this pulverization process, pulverization is carried out using a pulverizing device such as a bead mill, planetary mill, or mixer. The type of pulverizing device is not particularly limited. Examples include planetary mills, bead mills, mixer-type rotary ball mills, vibrating ball mills, agitated ball mills (attritors), jet mills, centrifugal separators, or methods combining mills and centrifugal separators. The resulting flattened magnetic metal particles are then molded. For example, molding can be done by uniaxial press molding, hot press molding, CIP molding, HIP molding, etc. A high press pressure is preferable, preferably 10,000 kgf / cm². 2 The above is preferable. Furthermore, it is preferable for densification (increased density, improved saturation magnetization) to perform the following operation multiple times (e.g., two or more times): after pressing once, heat treatment (for example, heat treatment at 1000°C in an H2 atmosphere), and then pressing again. This is done to obtain a molded body.

[0036] The second step is to heat-treat the obtained molded body. At this time, it is preferable to perform the heat treatment in a vacuum. At this time, it is preferable to place the molded body on the Ta foil when performing the heat treatment in a vacuum.

[0037] Alternatively, it is preferable to place the molded body on an alloy foil containing one or more of the following: Nb foil, W foil, Mo foil, Ta, Nb, W, or Wo. The composition of particles precipitated during heat treatment can be controlled by the type of foil used. Using Ta foil results in particles containing Ta; using Nb foil results in particles containing Nb; using W foil results in particles containing W; and using Mo foil results in particles containing Mo. The following explanation will use the case of Ta foil as an example (the same applies to Nb, W, and Mo).

[0038] The heat treatment temperature is preferably 1100°C or higher, and more preferably 1200°C or higher. A high degree of vacuum is preferred. -1 It is preferably Pa or less, and more preferably 10 -2 Pa or less, more preferably 10 -3 The pressure should be below Pa. Furthermore, it is preferable that carbon is arranged around the inside of the furnace where the heat treatment is performed.

[0039] Furthermore, when using a vacuum pump to achieve a high vacuum during heat treatment, it is preferable to use an oil containing carbon, such as alkylnaphthalene, as the oil for the oil rotary pump or oil diffusion pump (carbon is generated when the oil flows back into the furnace and evaporates).

[0040] As described above, during vacuum heat treatment, sintering proceeds while Fe, Co, Si, etc. partially evaporate. At this time, Fe and Co evaporate more easily than Si (due to their higher vapor pressure), so the composition after sintering deviates from the raw material composition (it becomes slightly Si-rich, Fe and Co-poor). The material surface, in particular, becomes slightly Si-rich and Fe and Co-poor compared to the center. Also, during vacuum heat treatment, Ta diffuses from the Ta foil into the material, and carbon in the furnace or atmosphere also diffuses into the material. These behaviors only occur when the material is placed on a Ta foil, carbon is placed in the furnace or atmosphere, and heat treatment is performed at a high temperature in a vacuum. Through this vacuum heat treatment, precipitated particles of Ta-Co-C (including Fe and Si) are generated in the matrix phase. It is preferable that the raw material composition includes Ta and C, but even if they are not included in the raw material composition, it is possible to incorporate Ta and C during the process and generate precipitated particles as described above. Furthermore, by setting appropriate vacuum levels and heat treatment temperatures, precipitated particles having a cubic crystal structure of Ta3Co3C (including Fe and Si) are generated. The precipitated particles are oriented relative to the matrix phase, resulting in a low lattice mismatch. It is preferable to remove lattice strain to an appropriate extent from the resulting molded body (magnetic material) by heat treatment. This heat treatment is preferably carried out under an inert atmosphere or a reducing atmosphere, and more preferably under a reducing atmosphere such as H2, CO, or CH4.

[0041] Furthermore, since the magnetic material manufactured using the above method is produced by sintering a compacted powder (molded body), it can be applied to complex shapes. Alternatively, in the first step, it is also acceptable to prepare an electromagnetic steel sheet (silicon steel sheet) with an adjusted composition as is. Subsequently, in the second step, the electromagnetic steel sheet (silicon steel sheet) is heat-treated in a vacuum to obtain the magnetic material of this embodiment.

[0042] As described above, this embodiment makes it possible to provide a magnetic material with excellent magnetic properties such as low magnetic loss, excellent mechanical properties such as high strength, and thermal stability.

[0043] (Second Embodiment) The system and device of this embodiment have the magnetic material of the first embodiment. Therefore, the description of the contents that overlap with the first embodiment will be omitted. The magnetic material components included in this system and device include, for example, cores of various rotating electric machines such as motors and generators (e.g., motors, generators, etc.), transformers, inductors, transformers, choke coils, filters, etc., and magnetic wedges for rotating electric machines. Figure 3 is a conceptual diagram of a motor system of the second embodiment. The motor system is an example of a rotating electric machine system. A motor system is a system that includes a control system for controlling the rotational speed and power (output power) of a motor. Methods for controlling the rotational speed of a motor include control by a bridge servo circuit, proportional current control, voltage comparison control, frequency synchronization control, PLL (Phase Locked Loop) control, etc. As an example, the control method by PLL is shown in Figure 3. A motor system that controls the rotational speed of a motor using a PLL comprises a motor, a rotary encoder that detects the rotational speed of the motor by converting the mechanical displacement of the motor's rotation into an electrical signal, a phase comparator that compares the rotational speed of the motor given by a command with the rotational speed of the motor detected by the rotary encoder and outputs the difference between the two rotational speeds, and a controller that controls the motor to reduce the difference in rotational speed. On the other hand, methods for controlling the motor's power include control methods such as PWM (Pulse Width Modulation), PAM (Pulse Amplitude Modulation), vector control, pulse control, bipolar drive, pedestal control, and resistance control. Other control methods include microstep drive control, multiphase drive control, inverter control, and switching control. As an example, a control method using an inverter is shown in Figure 3. A motor system that controls the motor's power using an inverter comprises an AC power supply, a rectifier that converts the output of the AC power supply into a DC current, an inverter circuit that converts the DC current into an AC at an arbitrary frequency, and a motor controlled by the AC.

[0044] Figure 4 shows a conceptual diagram of a motor according to the second embodiment. Motor 200 is an example of a rotating electric machine. In motor 200, a first stator and a second rotor are arranged. The figure shows an inner rotor type in which the rotor is located inside the stator, but an outer rotor type in which the rotor is located outside the stator is also acceptable.

[0045] Figure 5 is a conceptual diagram of the motor core (stator) of the second embodiment. Figure 6 is a conceptual diagram of the motor core (rotor) of the second embodiment. The motor core 300 (motor core) includes the cores of the stator and the rotor. This point will be explained below. Figure 5 is an example of a cross-sectional conceptual diagram of the first stator. The first stator has a core and windings. The windings are wound around a part of a projection that the core has, which is provided on the inside of the core. The magnetic material of the first embodiment can be placed inside this core. Figure 6 is an example of a cross-sectional conceptual diagram of the first rotor. The first rotor has a core and windings. The windings are wound around a part of a projection that the core has, which is provided on the outside of the core. The magnetic material of the second embodiment can be placed inside this core.

[0046] Figures 5 and 6 show only one example of a motor, and the application of magnetic materials is not limited to this. They can be applied to all types of motors as a core to facilitate the guidance of magnetic flux.

[0047] Figure 7 is a conceptual diagram of a transformer in the second embodiment. Figure 8 is a conceptual diagram of an inductor (ring-shaped inductor, rod-shaped inductor) in the second embodiment. Figure 9 is a conceptual diagram of an inductor (chip inductor, planar inductor) in the second embodiment. These are also shown as examples only. In transformers 400 and inductors 500, as with motor cores, magnetic materials can be applied to all types of transformers and inductors to facilitate magnetic flux guidance or to utilize high permeability.

[0048] Figure 10 is a conceptual diagram of a generator 600 according to a second embodiment. The generator 600 is an example of a rotating electric machine. The generator 600 comprises either or both of a second stator 630 using the magnetic material of the first embodiment as a core, and a second rotor 640 using the magnetic material of the first embodiment as a core. In the figure, the second rotor 640 is located inside the second stator 630, but it may also be located outside. The second rotor 640 is connected to a turbine 610 provided at one end of the generator 600 via a shaft 620. The turbine 610 is rotated by a fluid supplied from an external source (not shown), for example. Alternatively, instead of a turbine rotated by fluid, the shaft can be rotated by transmitting dynamic rotation, such as regenerative energy from an automobile. Various known configurations can be adopted for the second stator 630 and the second rotor 640. Furthermore, the second rotor 640 becomes charged due to static electricity from the turbine 610 and shaft currents associated with power generation. For this reason, the generator 600 is equipped with brushes 650 to discharge the charge from the second rotor 640.

[0049] The shaft is in contact with a commutator (not shown) located on the opposite side of the turbine from the second rotor. The electromotive force generated by the rotation of the second rotor is boosted to the grid voltage and transmitted as power to the generator via a phase-separated busbar (not shown) and a main transformer (not shown). The second rotor becomes charged due to static electricity from the turbine and shaft currents associated with power generation. Therefore, the generator is equipped with brushes to discharge the charge from the second rotor.

[0050] Furthermore, the rotating electric machine of this embodiment can be preferably used in railway vehicles. For example, it can be preferably used in a motor 200 that drives a railway vehicle, or in a generator 500 that generates electricity for driving a railway vehicle.

[0051] Furthermore, the rotating electric machine of this embodiment can be preferably used in various types of generators.

[0052] To be applied to the above systems and devices, magnetic materials are subject to various processing. For example, sintered bodies can be machined by polishing or cutting, and powders can be mixed with resins such as epoxy resin or polybutadiene. Further surface treatments may be applied as needed. Winding may also be performed as needed.

[0053] According to the system and device apparatus of this embodiment, it is possible to realize motor systems, motors, transformers, inductors, and generators having excellent characteristics (high efficiency, low loss).

[0054] (Examples) Examples 1 to 4 are described in more detail below, in comparison with Comparative Example 1. Table 1 summarizes the presence or absence of precipitated particles, the composition of the precipitated particles, the crystal structure of the precipitated particles, the presence or absence of orientation of the precipitated particles, the lattice mismatch between the precipitated particles and the matrix, and the average particle size of the precipitated particles for the magnetic materials obtained by the examples and comparative examples shown below.

[0055] (Example 1) First, using a single-roll quenching device, Fe-Co-Si-Ta-C(Fe 70 Co 30 A ribbon (atomic %) - 5 wt% Si) is prepared. Next, the obtained ribbon is heat-treated at 300°C in an H2 atmosphere. Then, this ribbon is crushed using a mixer to obtain flattened magnetic metal particles. After that, the obtained flattened magnetic metal particles are subjected to a 12000 kgf / cm³ treatment. 2 Uniaxial press molding is performed, followed by heat treatment at 1000°C in an H2 atmosphere. Then, the uniaxial press molding and 1000°C heat treatment in an H2 atmosphere are repeated five times to obtain a molded body. After that, the molded body is placed on a Ta foil and heated in a vacuum (10 -2 After heat treatment at 1200°C (with carbon placed inside the furnace) at a temperature of Pa or less, the magnetic material was obtained by heat treatment at 1000°C in an H2 atmosphere. The average particle size of the precipitated particles contained in the obtained magnetic material was approximately 10 nm. The lattice mismatch between the precipitated particles and the matrix phase was approximately 1%.

[0056] (Example 2) The procedure was almost identical to Example 1, except that the average particle size of the precipitated particles was set to approximately 100 nm by controlling the vacuum heat treatment conditions. At this time, the lattice mismatch between the precipitated particles and the matrix phase was approximately 2%.

[0057] (Example 3) The procedure was almost identical to Example 1, except that the average particle size of the precipitated particles was reduced to approximately 1 μm by controlling the vacuum heat treatment conditions. At this time, the lattice mismatch between the precipitated particles and the matrix phase was approximately 5%.

[0058] (Example 4) The procedure was almost identical to Example 1, except that the average particle size of the precipitated particles was reduced to approximately 2 μm by controlling the vacuum heat treatment conditions. In this case, the precipitated particles and the matrix phase were not oriented.

[0059] (Example 5) Fe-Co-Si-Ta-C(Fe 70 Co 30 (Atomic %) - 5 wt% Si) instead of Fe-Co-Si-Nb-C(Fe 70 Co 30 The material was almost identical to that of Example 1, except that Nb foil was used instead of Ta foil (atomic %) - 5 wt% Si). The average particle size of the precipitated particles contained in the obtained magnetic material was approximately 10 nm. The lattice mismatch between the precipitated particles and the matrix was approximately 1%.

[0060] (Example 6) Fe-Co-Si-Ta-C(Fe 70 Co 30 (atomic %) - 5 wt% Si) instead of Fe-Co-Si-WC(Fe 70 Co 30 The material is almost identical to that of Example 1, except that (atomic %) - 5 wt% Si) was used, and W foil was used instead of Ta foil. The average particle size of the precipitated particles contained in the obtained magnetic material was approximately 10 nm. The lattice mismatch between the precipitated particles and the matrix was approximately 1%.

[0061] (Example 7) Fe-Co-Si-Ta-C(Fe 70 Co 30(Atomic %) - 5 wt% Si) instead of Fe-Co-Si-Mo-C (Fe 70 Co 30 The material is almost identical to that of Example 1, except that (atomic %) - 5 wt% Si) was used, and Mo foil was used instead of Ta foil. The average particle size of the precipitated particles contained in the obtained magnetic material was approximately 10 nm. The lattice mismatch between the precipitated particles and the matrix was approximately 1%.

[0062] (Comparative Example 1) The composition is Fe-Co-Si(Fe 70 Co 30 The composition was (atomic %) - 5 wt% Si), and the procedure was almost the same as in Example 1, except that Ta foil was not used during heat treatment and the atmosphere was an Ar atmosphere. No precipitated particles were observed in the obtained magnetic material.

[0063] Next, the rate of change over time for saturation magnetization, coercivity, iron loss, flexural strength (3-point flexural strength), and flexural strength (3-point flexural strength) was evaluated for the evaluation magnetic materials of Examples 1 to 5 and Comparative Example 1. The rate of change over time for iron loss and flexural strength was evaluated using the following method. The evaluation results are shown in Table 2.

[0064] (1) Iron loss: Measure the iron loss under operating conditions of 100 Hz and 1 T using a BH analyzer. If direct measurement is not possible under the conditions of 100 Hz and 1 T, measure the frequency dependence and magnetic flux density dependence of the iron loss, and estimate the iron loss at 100 Hz and 1 T from that data (and adopt this estimated value).

[0065] (2) Change in bending strength over time: After heating the evaluation sample at 100°C in air for 100 hours, measure the bending strength and determine the change over time (bending strength after 100 hours of heating / bending strength without heating).

[0066] [Table 1]

[0067] [Table 2]

[0068] As is clear from Table 1, the magnetic materials of Examples 1 to 4 had a Ta-Fe-Co-Si-C composition and contained precipitated particles with a Ta3Co3C(X3Y3C) cubic crystal structure. In Examples 1 to 3, the precipitated particles were oriented relative to the matrix, and the lattice mismatch was 10% or less. The average particle size of the precipitated particles was between 1 nm and 1 μm. In Example 4, the precipitated particles were not oriented relative to the matrix, and the average particle size of the precipitated particles was relatively large at approximately 2 μm. In contrast, no precipitated particles were formed in Comparative Example 1.

[0069] The magnetic material in Example 5 had a Nb-Fe-Co-Si-C composition, the magnetic material in Example 6 had a W-Fe-Co-Si-C composition, and the magnetic material in Example 7 had a Mo-Fe-Co-Si-C composition. All three contained precipitated particles with an X3Y3C cubic crystal structure. The precipitated particles were oriented relative to the matrix, and the lattice mismatch was 10% or less. The average particle size of the precipitated particles was between 1 nm and 1 μm.

[0070] As is clear from Table 2, the magnetic materials of Examples 1 to 7 are superior to the magnetic material of Comparative Example 1 in terms of saturation magnetization, coercivity, iron loss, bending strength, and rate of change of bending strength over time. In other words, they are superior in terms of magnetic properties, thermal stability, and mechanical properties (strength). Furthermore, among Examples 1 to 4, Examples 1 to 3 are particularly superior to Example 4 in terms of magnetic properties, thermal stability, and mechanical properties (strength).

[0071] The above results are due to the inclusion of precipitated particles with a Ta3Co3C cubic crystal structure in a Ta-Fe-Co-Si-C composition. Furthermore, the properties are further improved when the precipitated particles are oriented relative to the matrix, lattice mismatch is low, and the average particle size of the precipitated particles is between 1 nm and 1 μm.

[0072] Alternatively, the above results are obtained by including precipitated particles with an X3Y3C cubic crystal structure in a Ta(Nb,W,Mo)-Fe-Co-Si-C composition. Furthermore, the properties are further improved when the precipitated particles are oriented relative to the matrix, lattice mismatch is low, and the average particle size of the precipitated particles is between 1 nm and 1 μm.

[0073] While several embodiments and examples of the present invention have been described, these embodiments and examples are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0074] Furthermore, the above embodiments can be summarized in the following technical proposal. Technical proposal 1 A magnetic material comprising at least one first element X selected from the group consisting of Fe, Co, and Ni, Maternal features and A particle containing at least one second element Y and C selected from Ta, W, Nb, and Mo, A magnetic material. Technical proposal 2 The particles have a cubic crystal structure, contain the first element X, and are a magnetic material according to Technical Proposal 1 having an X3Y3C type compound phase. Technical proposal 3 The particles are present at the grain boundaries of the matrix phase and are part of the magnetic material according to Technical Proposal 1 or Technical Proposal 2. Technical proposal 4 A magnetic material according to any one of Technical Proposals 1 to 3, wherein the first element X is Co and the second element Y is Ta. Technical proposal 5 The aforementioned particles are magnetic materials according to any one of the Technical Proposals 1 to 4, comprising at least one of Fe and Si. Technical proposal 6 A magnetic material according to any one of Technical Proposals 1 to 5, wherein the particles contain elements included in the matrix phase on which the particles are arranged. Technical proposal 7 The aforementioned particles are magnetic materials according to any one of Technical Proposals 1 to 6, having a cubic crystal structure of Ta3Co3C. Technical proposal 8 The matrix on which the particles are arranged has a body-centered cubic crystal structure, as described in any one of Technical Proposals 1 to 7. Technical proposal 9 The magnetic material according to any one of the technical proposals 1 to 8, wherein the particles are oriented with respect to the matrix. Technical proposal 10 The magnetic material according to Technical Proposal 9, wherein the particles oriented with respect to the matrix have a lattice mismatch of 10% or less with respect to the matrix. Technical proposal 11 In the invention of the invention, two or more of the particles contained within one matrix are oriented toward each other. Or technical proposal 10 Magnetic materials as described above. Technical proposal 12 The particles are (020) relative to the matrix. 粒子 / / (0-10) 母相 or (20-2) 粒子 / / (-101) 母相 Technical proposals oriented in this way Technical proposal from 9 11 any one of the following items Magnetic materials as described above. Technical proposal 13 The particles are (0-40) relative to the matrix phase. 粒子 / / (0-10) 母相 Or (-404) 粒子 / / (-101) 母相 Technical proposals oriented in this way Any one of the items from 9 to Technical Proposal 12 Magnetic materials as described above. Technical proposal 14 A magnetic material according to any one of Technical Proposals 1 to 13, wherein the average particle size of the aforementioned particles is 1 nm or more and 10 μm or less. Technical proposal 15 A magnetic material according to any one of Technical Proposals 1 to 14, wherein the Si content of the surface portion of the magnetic material is 1.1 times or more than the Si content of the center portion of the magnetic material. Technical proposal 16 A magnetic material according to any one of Technical Proposals 1 to 15, wherein the first element consists of Fe and Co, and the Si content is 1 atomic% or more and 25 atomic% or less relative to the entire magnetic material. Technical proposal 17 Density is 6 g / cm³ 3 The magnetic material described in any one of the above technical proposals 1 to 16. Technical proposal 18 A magnetic material described in any one of Technical Proposals 1 to 17, having a three-point bending strength of 200 MPa or more. Technical proposal 19 A magnetic material described in any one of Technical Proposals 1 to 18, having a coercivity of 80 A / m or less. Technical proposal 20 A magnetic material described in any one of Technical Proposals 1 to 19, wherein the saturation magnetization is 1.7T or higher. Technical proposal 21 A rotating electric machine equipped with a magnetic material described in any one of Technical Proposals 1 to 20. [Explanation of symbols]

[0075] 2: Precipitated particles 4: Mother phase 6: Grain boundary 8: Surface 100: Magnetic material 200: Motor (rotating electric machine) 300: Motor core 400: Transformers 500: Inductor 600: Generator (rotating electric machine) 610: Turbine 620: Shaft 630: Second stator 640: Second rotor 650: Brush

Claims

1. A magnetic material comprising at least one first element X selected from the group consisting of Fe, Co and Ni, and Si, Maternal features and A particle comprising the first element X, at least one second element Y selected from Ta, W, Nb, and Mo, and C, A magnetic material having the following properties, wherein the Si content is 1 atomic% or more and 25 atomic% or less relative to the entire magnetic material, and the particles are present on the surface of the magnetic material, at the grain boundaries of the matrix phase, and at least one location within the grains of the matrix phase in a sintered body.

2. The aforementioned particles have a cubic crystal structure, X ３ Y ３ The magnetic material according to claim 1, having a C-type compound phase.

3. The magnetic material according to claim 1, wherein the particles are present at the grain boundaries of the matrix phase.

4. The magnetic material according to claim 1, wherein the first element X is Co and the second element Y is Ta.

5. The magnetic material according to claim 1, wherein the particles include at least one of Fe and Si.

6. The magnetic material according to claim 1, wherein the particles contain an element included in the matrix phase on which the particles are arranged.

7. The aforementioned particles are Ta 3 Co 3 The magnetic material according to claim 1, having a cubic crystal structure of C.

8. The magnetic material according to claim 1, wherein the matrix on which the particles are arranged has a body-centered cubic crystal structure.

9. The magnetic material according to claim 1, wherein the particles are oriented with respect to the matrix.

10. The magnetic material according to claim 9, wherein the particles oriented with respect to the matrix have a lattice mismatch of 10% or less with respect to the matrix.

11. The magnetic material according to claim 9, wherein two or more of the particles contained within one matrix are oriented toward each other.

12. The particles are (020) relative to the matrix. 粒子 / / (0-10) 母相 or (20-2) 粒子 / / (-101) 母相 The magnetic material according to claim 9, which is oriented in a certain way.

13. The particles are (0 - 40) with respect to the matrix phase 粒子 / / (0 - 10) 母相 or (-40 4) 粒子 / / (-10 1) 母相 The magnetic material according to claim 9, which is oriented.

14. The magnetic material according to claim 1, wherein the average particle size of the particles is 1 nm or more and 10 μm or less.

15. The magnetic material according to claim 1, wherein the Si content of the surface portion of the magnetic material is 1.1 times or more than the Si content of the center portion of the magnetic material.

16. The magnetic material according to claim 1, wherein the first element comprises Fe and Co.

17. Density is 6 g / cm³ ３ The magnetic material according to claim 1, wherein the above is true.

18. The magnetic material according to claim 1, wherein the three-point bending strength is 200 MPa or more.

19. The magnetic material according to claim 1, wherein the coercivity is 80 A / m or less.

20. The magnetic material according to claim 1, wherein the saturation magnetization is 1.7 T or higher.

21. A rotating electric machine comprising the magnetic material described in claim 1.

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