Permanent magnet and motor and generator that use this

Abstract

Permanent magnet, including: a composition, expressed by a composition formula: R p Fe q M r Cu3Co 100-p-q-r-s , where R is at least one element selected from rare earth elements, M is at least one element selected from Zr, Ti and Hf, p is a number that satisfies 10.8 ≤ p ≤ 13.5 atom%, q is a number that satisfies 28 ≤ q ≤ 40 atom%, r is a number that satisfies 0.88 ≤ r ≤ 7.2 atom%, and s is a number that satisfies 3.5 ≤ s ≤ 13.5 atom%; and a metallic structure that combines a cell phase with a Th2Zn 17 -crystal phase as well as a cell wall phase that surrounds the cell phase, wherein the Cu concentration in the cell wall phase is in a range of 30 atomic% to 70 atomic%, wherein a full width at half the maximum of a Cu concentration profile in the cell wall phase is 5 nm or less, wherein the cell phase has a composition that is expressed by a composition formula: R p1 Fe q1 M r1 Cu 31 Co 100-p1-q1-r1-s1 where p1, q1, r1 and s1 are numbers that each satisfy the following: p1 is a number that satisfies 8 ≤ p1 ≤ 18 atom%, q1 is a number that satisfies 28 ≤ q1 ≤ 45 atom%, r1 is a number that satisfies 0.1 ≤ r1 ≤ 3 atom% and s1 is a number that satisfies 0.5 ≤ s ≤ 10 atom%; and wherein the cell wall phase has a composition that is expressed by a composition formula: R p2 Fe q2 M r2 Cu s2 Co 100-p2-q2-r2-s2 where p2 is a number that satisfies 12 ≤ p2 ≤ 28 atom%, q2 is a number that satisfies 4 ≤ q2 ≤ 20 atom%, r2 is a number that satisfies 0.1 ≤ r2 ≤ 3 atom% and s2 is a number that satisfies 30 ≤ s2 ≤ 70 atom%.

Description

Area

[0001] The embodiments disclosed herein generally relate to a permanent magnet and a motor and generator that use it. background

[0002] High-performance permanent magnets include rare-earth magnets, such as those based on Sm-Co and Nd-Fe-B. When a permanent magnet is used in the motor of an electric hybrid vehicle (HEV) or an electric vehicle (EV), heat resistance is a requirement. In an HEV or EV motor, a permanent magnet is used whose heat resistance is enhanced by Dy, which replaces a portion of the Nd in the Nd-Fe-B-based magnet. Since Dy is a rare-earth element, there is a demand for a permanent magnet that does not use Dy. High-efficiency motors and generators include variable magnetic flux motors and variable magnetic flux generators, which utilize a variable magnet and a stationary magnet, respectively.To improve the performance and efficiency of the variable magnetic flux motor and the variable magnetic flux generator, there is a need to improve the coercive force and magnetic flux density of the variable magnet and the stationary magnet.

[0003] It is known that the Sm-Co-based magnet, due to its high Curie temperature, exhibits excellent heat resistance without the use of Dy and is capable of achieving good motor characteristics, etc., at high temperatures. Among the Sm-Co-based magnets, one magnet is made of Sm2Co. 17Due to its coercive force-exhibiting mechanism, etc., this type of magnet can be used as a variable magnet. An improvement in coercive force and magnetic flux density is also needed for the Sm-Co-based magnet. To increase the magnetic flux density of the Sm-Co-based magnet, it is effective to increase the Fe concentration; however, the coercive force tends to decrease in a composition with a high Fe concentration. Under such circumstances, there is a need for a technique to make a high-Fe-concentration Sm-Co-based magnet exhibit high coercive force.

[0004] US 2012 / 0146444A1 describes a rare-earth permanent magnet that incorporates an intragranular phase with Th2Zn 17 -crystal structure and grain boundary phase, as well as its use in a motor or generator.

[0005] US 2013 / 0241333A1 describes a rare-earth permanent magnet that has a phase with Th2Zn 17-crystal structure and a Cu-rich phase, wherein in a cross-section that follows the c-axis of the Th2Zn 17 -Crystal phase contains the mean distance between the Cu-rich phases is 120 nm or less. Brief description of the drawings Fig. Figure 1 is an image showing an example of concentration profiles of the constituent elements near a cell wall phase in a permanent magnet of one embodiment. Fig. Figure 2 is a view showing a permanent magnet motor of one embodiment. Fig. Figure 3 is a view showing a variable magnetic flux motor of one embodiment. Fig. Figure 4 is a view showing a power generator of one embodiment. Detailed description

[0006] According to one embodiment, a permanent magnet is provided which includes the following: a composition formula: R pFe q M r Cu s Co 100-p-q-r-s (1) a composition expressed in terms of which R is at least one element selected from rare earth elements, M is at least one element selected from Zr, Ti and Hf, p is a number satisfying 10.8 ≤ p ≤ 13.5 atom%, q is a number satisfying 28 ≤ q ≤ 40 atom%, r is a number satisfying 0.88 ≤ r ≤ 7.2 atom%, and s is a number satisfying 3.5 ≤ s ≤ 13.5 atom%; and a metallic structure comprising a cell phase and a cell wall phase. The cell phase has a Th₂Zn 17 Crystal phase. The cell wall phase is present to surround the cell phase. In the permanent magnet described above, the copper concentration in the cell wall phase ranges from 30 atomic percent to 70 atomic percent.

[0007] Furthermore, the full width at half the maximum of a Cu concentration profile in the cell wall phase is 5 nm or less, and the cell phase and the cell wall phase each have a composition as defined by formulas (2) and (3) respectively given below.

[0008] The permanent magnet of this embodiment is described in detail below. In the composition formula (1), at least one rare-earth element, including yttrium (Y), is used as element R. Each of the elements R provides high magnetic anisotropy and imparts a high coercivity to the permanent magnet. Preferably, at least one element selected from samarium (Sm), cerium (Ce), neodymium (Nd), and praseodymium (Pr) is used as element R, and the use of Sm is particularly preferred. If 50 atomic percent or more of element R is Sm, it is possible to improve the performance, especially the coercivity, of the permanent magnet with good reproducibility. Furthermore, 70 atomic percent or more of element R is Sm is preferred.

[0009] The element R content (p) is adjusted to a range of not less than 10.8 atomic percent and not more than 13.5 atomic percent. If the element R content (p) is less than 10.8 atomic percent, it is not possible to obtain sufficient coercivity, for reasons such as the precipitation of a large amount of an α-Fe phase. Conversely, if the element R content (p) is above 13.5 atomic percent, the saturation magnetization decreases significantly. The element R content (p) is preferably adjusted to a range of 11.0 atomic percent to 13 atomic percent, and more preferably to a range of 11.2 atomic percent to 12.5 atomic percent.

[0010] Iron (Fe) is an element primarily responsible for the magnetization of the permanent magnet. A high Fe content increases the saturation magnetization of the permanent magnet. However, excessive Fe content leads to precipitation of the α-Fe phase, making it difficult to achieve the desired two-phase separation structure described later, which reduces the coercive force. Therefore, the Fe content (q) is adjusted to a range of not less than 28 atomic percent and not more than 40 atomic percent. Preferably, the Fe content (q) is adjusted to a range of 29 atomic percent to 38 atomic percent, and more preferably to a range of 30 atomic percent to 36 atomic percent.

[0011] The element M is selected to be at least one element from titanium (Ti), zirconium (Zr), and hafnium (Hf). The inclusion of element M enables a high coercivity to be exhibited, even with a high iron (Fe) concentration in the composition. The element M content (r) is set to a range of not less than 0.88 atomic percent and not more than 7.2 atomic percent. By setting the element M content (r) to 0.88 atomic percent or more, the permanent magnet with a high iron concentration can exhibit a high coercivity. Conversely, if the element M content (r) exceeds 7.2 atomic percent, the magnetization decreases significantly. The element M content (r) is preferably set to a range of 1.3 atomic percent to 4.3 atomic percent, and more preferably to a range of 1.5 atomic percent to 2.6 atomic percent.

[0012] The element M can be any of Ti, Zr, and Hf, but preferably contains at least Zr. In particular, if 50 atomic percent or more of the element M is Zr, it is possible to further improve the coercivity of the permanent magnet. On the other hand, Hf in element M is particularly expensive, and therefore, even if Hf is used, the amount employed is preferably small. The Hf content is preferably adjusted to less than 20 atomic percent of the element M.

[0013] Copper (Cu) is an element used to give the permanent magnet a high coercivity. The Cu content (s) is adjusted to a range of not less than 3.5 atomic percent and not more than 13.5 atomic percent. If the Cu content (s) is less than 3.5 atomic percent, it is difficult to achieve a high coercivity. If the Cu content (s) is above 13.5 atomic percent, the magnetization decreases significantly. The incorporated amount (s) of Cu is preferably adjusted to a range of 3.9 atomic percent to 9 atomic percent, and more preferably to a range of 4.2 atomic percent to 7.2 atomic percent.

[0014] Cobalt (Co) is an element responsible not only for the magnetization of the permanent magnet but also for its high coercivity. A high Co content results in a high Curie temperature, which improves the thermal stability of the permanent magnet. If the Co content is too low, these effects cannot be sufficiently achieved. Conversely, an excessively high Co content reduces the relative iron content, impairing magnetization. Therefore, the Co content is adjusted in relation to the iron, metal, and copper content, ensuring that the iron content meets the aforementioned requirements.

[0015] A portion of the cobalt can be replaced by at least one element A selected from nickel (Ni), vanadium (V), chromium (Cr), manganese (Mn), aluminum (Al), gallium (Ga), niobium (Nb), tantalum (Ta), and tungsten (W). These replacement elements A contribute to improving the magnetic properties, such as the coercivity. However, excessive replacement of cobalt by element A is responsible for deteriorating the magnetization, and therefore the amount of substitution by element A is preferably 20 atomic percent of the cobalt or less.

[0016] In the permanent magnet of this embodiment, the Cu concentration in the cell wall phase falls in the range of 30 atomic percent to 70 atomic percent. A mechanism for demonstrating the coercive force of a magnet made of Sm₂Co₆ is known. 17-Type of domain wall pinning type, and that the coercive force originates from a nano-phase separation structure formed by heat treatment. The nano-phase separation structure (two-phase separation structure) encloses a cell phase with a Th2Zn 17 -structure / 2-17 phase) and a cell wall phase formed such that it surrounds a perimeter of the cell phase and exhibits a CaCu5 crystal phase (a crystal phase with a CaCu5 structure / 1-5 phase). The cell wall phase is assumed to act as a pinning center of the domain wall to prevent displacement of the domain wall, thus exhibiting a coercive force of the domain wall pinning type.

[0017] One possible reason why the displacement of the domain wall by the cell wall phase is prevented is a difference in domain wall energy between the cell phase and the cell wall phase. This difference in domain wall energy is thought to arise from the ratio of the constituent elements of the cell phase and the cell wall phase, and it is particularly important that copper is condensed in the cell wall phase to form a potential well. Therefore, it was thought that making the cell phase and the cell wall phase different in copper concentration would be effective. In fact, with respect to a conventional magnet, the Sm₂Co 17 -Type with a composition with low Fe concentration reports that the Cu concentration in the cell wall phase is higher than in the cell phase, and that the Cu concentration in the cell wall phase is increased to about 20 atom%.

[0018] However, in a magnet from Sm2Co 17-Type with high Fe concentration, although it has been confirmed that the Cu concentration in the cell wall phase is approximately 20 atomic percent, sufficient coercivity is not obtained. Extensive studies have revealed a possible reason for this, namely that in a magnet of Sm2Co 17 -Type with a composition in which the Fe concentration is 28 atomic percent or more, Cu and Fe, Co diffuse mutually, and even if the Cu concentration in the cell wall phase becomes about 20 atomic percent, similar to that in a conventional magnet from Sm2Co 17In a type with a low Fe concentration, the Fe concentration in the cell wall phase remains high. If the Fe concentration in the cell wall phase is kept high, the high concentration of Fe reduces the magnetic anisotropy, thus weakening the effect of the cell wall phase as a domain wall pinning center. This is thought to be one reason why a sufficient coercivity force in the conventional magnet of Sm₂Co₆ is not achieved. 17 -Type with high Fe concentration is not obtained.

[0019] In this embodiment of the permanent magnet, the Cu concentration in the cell wall phase ranges from 30 atomic percent to 70 atomic percent. Even when a composition with a high Fe concentration is used, the cell wall phase, by further increasing the Cu concentration, acts as a pinning center for the domain wall. Accordingly, it is possible to control the coercivity of the magnet from the Sm₂Co₆. 17-Type with a composition whose Fe concentration is 28 atomic percent or more. If the composition with an Fe concentration of 28 atomic percent or more is used, it is not possible to make the cell phase and the cell wall phase sufficiently different in domain wall energy if the Cu concentration in the cell wall phase is less than 30 atomic percent. Therefore, it is not possible to improve the magnet from Sm2Co. 17 -type to exhibit a large coercivity. If the Cu concentration in the cell wall phase, which in conventional magnets is Sm2Co 17 -Type is realized, i.e., approximately 20 atom%, so it is not possible to achieve a sufficient coercivity of the magnet from Sm2Co. 17 -Type with high Fe concentration to be achieved.

[0020] If the copper concentration in the cell wall phase is too high, the crystal structure of the cell wall phase becomes unstable, making it impossible to produce a stable cell wall phase. This makes it impossible to achieve the coercive force of the domain wall pinning type. Consequently, when using a composition with an iron concentration of 28 atomic percent or more, the copper concentration in the cell wall phase is adjusted to a range of not less than 30 atomic percent and not more than 70 atomic percent. The copper concentration in the cell wall phase is preferably 65 atomic percent or less, and more preferably 60 atomic percent or less. To improve the function of the cell wall phase as a domain wall pinning center, the copper concentration in the cell wall phase is preferably 35 atomic percent or more, and more preferably 45 atomic percent or more.

[0021] The fact that Cu condenses into the cell wall phase and progresses means that the mutual diffusion of Cu and Fe proceeds more effectively. Consequently, if the Cu concentration in the cell wall phase increases, the Fe concentration in the cell wall phase decreases. This also increases the difference in domain wall energy between the cell wall and the cell wall phases and can thus increase the coercive force of the magnet from the Sm2Co. 17 -Type with high Fe concentration further increases. The Fe concentration in the cell wall phase preferably falls in the range of 4 atomic percent to 20 atomic percent. Since element R, such as Sm, is also condensed in the cell wall phase, the concentration of element R in the cell wall phase preferably falls in the range of 12 atomic percent to 28 atomic percent. The concentration of element M in the cell wall phase preferably falls in the range of 0.1 atomic percent to 3 atomic percent.

[0022] When the copper concentration in the cell wall phase falls into the range of 30 to 70 atomic percent, the cell wall phase can function sufficiently as a pinning center for the domain wall. A typical example of a cell wall phase is the previously mentioned 1-5 phase, but the cell wall phase is not limited to this. If the cell wall phase has a sufficient copper concentration, it functions as a pinning center for the domain wall. The cell wall phase only needs to be such a phase. Besides the 1-5 phase, examples of cell wall phases include a TbCu7 crystal phase (a crystal phase with a TbCu7 structure / 1-7 phase), which is a high-temperature phase (structure prior to phase separation), a precursor phase of the 1-5 phase, which is formed in an initial stage of the two-phase separation of the 1-7 phase, and similar phases.

[0023] To improve the magnetization of the permanent magnet, the Fe concentration in the cell phase preferably falls within a range of 28 atomic percent to 45 atomic percent. Condensation of Cu and element R, such as Sm, in the cell wall phase progresses, so that the concentrations of Cu and R become lower than in the initial alloy composition (composition of the magnetic powder as raw material for a sintered compression product). Therefore, the Cu concentration in the cell phase preferably falls within a range of 0.5 atomic percent to 10 atomic percent. The concentration of element R in the cell phase preferably falls within a range of 8 atomic percent to 18 atomic percent. The concentration of element M in the cell phase preferably falls within a range of 0.1 atomic percent to 3 atomic percent.

[0024] According to the invention, the cell phase has a composition that is expressed by the following composition formula (2). According to the invention, the cell wall phase has a composition that is expressed by the following composition formula (3). Composition formula: R p1 Fe q1 M r1 Cu s1 Co 100-p1-q1-r1-s1 (2) where p1 is a number that satisfies 8 ≤ p1 ≤ 18 Atom%, q1 is a number that satisfies 28 ≤ q1 ≤ 45 Atom%, r1 is a number that satisfies 0.1 ≤ r1 ≤ 3 Atom%, and s1 is a number that satisfies 0.5 ≤ s ≤ 10 Atom%. Composition formula: R p2 Fe q2 M r2 Cu s2 Co 100-p2-q2-r2-s2 (3) where p2 is a number that satisfies 12 ≤ p2 ≤ 28 Atom%, q2 is a number that satisfies 4 ≤ q2 ≤ 20 Atom%, r2 is a number that satisfies 0.1 ≤ r2 ≤ 3 Atom%, and s2 is a number that satisfies 30 ≤ s2 ≤ 70 Atom%.

[0025] It is assumed that in the permanent magnet, which includes a sintered compression product expressed by composition formula (1), the Cu concentration difference between the cell phase and the cell wall phase arises during aging or subsequent gradual cooling. However, if the composition with a high Fe concentration is used, it is difficult to achieve a sufficient Cu concentration difference between the cell phase and the cell wall phase solely through controlled aging conditions. Therefore, to realize the aforementioned Cu concentration in the cell wall phase, it is necessary to increase the density of the sintered compression product to enlarge the diffusion surface. However, a high Fe-concentration Sm-Co-based magnetic powder has a low sintering capacity, making it difficult to achieve a high density of the sintered compression product.When the iron concentration of the alloy powder is high, a heterophase readily forms, characterized by high concentrations of copper and metal (M). This heterophase is believed to impair sinterability. To promote the mutual diffusion of iron and copper, it is necessary to suppress the formation of this heterophase and thus improve the sinterability of high-iron magnetic powder.

[0026] The sintering of Sm-Co-based magnetic powder (alloy powder) is generally carried out in an inert gas atmosphere, such as argon gas, or in a vacuum atmosphere. Sintering in an inert gas atmosphere has the advantage of suppressing the evaporation of Sm, which has a high vapor pressure, thus making compositional deviations unlikely. However, it is difficult to prevent the formation of heterophases in an inert gas atmosphere. Furthermore, the inert gas, such as argon gas, remains in the pores, making it difficult to achieve pore closure and thus hindering the ability to increase the density of the sintered compression product. On the other hand, it has been demonstrated that sintering in a vacuum atmosphere can suppress heterophase formation.However, in a vacuum atmosphere, the amount of evaporated Sm or similar high vapor pressure becomes large, making it difficult to control the composition of the sintered compression product as an alloy composition suitable for the permanent magnet.

[0027] As a solution to such difficulties, it is effective to perform a final sintering step (main sintering step) in an inert gas atmosphere of argon gas or similar, following a preprocessing step (temporary sintering step) in a vacuum atmosphere. By employing such a sintering step, with a preprocessing step in a vacuum atmosphere and a main sintering step in an inert gas atmosphere, it is possible to suppress the evaporation of smoldering steel or similar substances with high vapor pressure, while simultaneously suppressing the formation of the heterophase, in which the concentrations of copper and molten metal are high. Therefore, it is possible to obtain a sintered compression product with high density and low compositional deviation when using magnetic powder (alloy powder) with a high iron concentration.By obtaining a sintered compression product with high density and low compositional variation, it is possible to allow the mutual diffusion of Fe and Cu to proceed fully during subsequent solution treatment and aging. This makes it possible to sufficiently increase the Cu concentration in the cell wall phase.

[0028] When the magnetic powder (alloy powder) with an Fe concentration of approximately 20 atomic percent is sintered, adjusting the temperature of the temporary sintering step to a certain degree lower than the temperature of the main sintering step is effective in increasing the density. Conversely, when the magnetic powder (alloy powder) with an Fe concentration of 28 atomic percent or more is sintered, it is preferable to maintain a vacuum atmosphere until the temperature approaches the temperature of the main sintering step as closely as possible. Furthermore, it is also effective to maintain the vacuum atmosphere until the temperature of the main sintering step is reached. In this case as well, switching to an inert gas simultaneously with reaching the temperature of the main sintering step can suppress the evaporation of smoldering material or similar substances during sintering.It is assumed that one reason for maintaining the vacuum atmosphere until the temperature approaches the temperature of the main sintering step, when the composition is in a region with high Fe concentration, is that maintaining the vacuum atmosphere until the temperature is as high as possible makes it possible to suppress the formation of the heterophase more effectively. Specific conditions in the magnetic powder sintering step will be described in detail later.

[0029] By subjecting the aforementioned high-density sintered compression product to solution treatment and aging, it is possible to increase the Cu concentration in the cell wall phase with good reproducibility. This makes it possible to improve the coercivity of the Sm-Co-based magnet, which has a high Fe concentration. In particular, the permanent magnet of this embodiment achieves improved magnetization based on an Fe concentration of 28 atomic percent or more, while simultaneously improving coercivity by adjusting the Cu concentration to the range of 30 to 70 atomic percent. This means that the permanent magnet of this embodiment achieves both high coercivity and high magnetization in the Sm-Co-based magnet.The coercive force of the permanent magnet of this embodiment is preferably 800 kA / m or more, and the residual magnetization is preferably 1.15 T or more.

[0030] The density of the sintered compression product of the Sm-Co-based magnetic powder (alloy powder) is preferably 8.2 × 10 3 kg / m 3or more from a practical point of view. By achieving such a density of the sintered compression product, it is possible to allow the mutual diffusion of Fe and Cu to proceed fully in the solution treatment step and the aging step in order to sufficiently increase the Cu concentration in the cell wall phase. The permanent magnet of the embodiment is preferably a sintered magnet that encloses a sintered compression product comprising the composition expressed by composition formula (1) and a metallic structure with the cell phase and the cell wall phase, wherein the density of the sintered compression product is 8.2 × 10 3 kg / m 3 or more.

[0031] It is possible to observe the metallic structure with a cell-like structure using a transmission electron microscope (TEM). The concentrations of the corresponding elements in the cell phase and the cell wall phase can be measured, for example, using TEM energy-dispersive X-ray spectroscopy (TEM-EDX) or a three-dimensional atom probe (3DAP). The TEM observation is preferably carried out at a magnification of 100k- to 200k-fold. In the permanent magnet enclosing a sintered compression product, whose magnetic field is oriented, a cross-section is preferably observed that includes a c-axis of the 2-17 phase, which is the cell phase.

[0032] 3DAP is preferably used to measure the concentrations of the relevant elements in the cell wall phase. It is possible that TEM-EDX observations may not accurately measure the concentrations of these elements in the cell wall phase, as the transmission electron beams penetrate both the cell wall and the cell phase, even when the cell wall phase is being observed. For example, the Sm concentration or similar values ​​may sometimes appear somewhat high (approximately 1.2 to 1.5 times a 3DAP measurement).

[0033] The measurement of element concentrations in the cell wall phase by 3DAP is performed according to the following procedure. A sample is thinned by in-cube cutting, and a needle-shaped sample for the pickup atom probe (AP) is prepared from the thinned sample using a focused ion beam (FIB). An atomic map is generated based on an intermediate plane interval (approximately 0.4 nm) of the atomic planes (0003) of the 2-17 phase parallel to a plate-shaped phase rich in elements such as Zr (M-rich phase), formed perpendicular to the c-axis in the 2-17 phase. Based on the atom probe data thus generated, a profile of Cu alone is produced, and the location where Cu is condensed is specified. This Cu-rich region is the cell wall phase.

[0034] The concentration profiles of the corresponding elements are analyzed in a direction perpendicular to the cell wall phase. An analysis area from the concentration profiles is preferably 10 × 10 × 10 nm or 5 × 5 × 10 nm. An example of the concentration profiles of the corresponding elements obtained by such an analysis is shown in Fig. Figure 1 shows that the concentrations of the corresponding elements in the cell wall phase are measured using such concentration profiles. When the Cu concentration in the cell wall phase is measured, a highest value (P) is derived from the Cu profile. Cu ) the Cu concentration is found. Such a measurement is performed for 20 points in the same sample, and a mean value of these is defined as the Cu concentration in the cell wall phase. The concentration of element R, such as Sm, is measured in the same way. When the Fe concentration in the cell wall phase is measured, a lowest value (P) is determined.Fe The Fe concentration is determined from the Fe profile. Such a measurement is performed for 20 points in the same sample, and the mean value is defined as the Fe concentration in the cell wall phase. The concentration of the element M, such as Zr, and the concentration of Co are measured in the same way.

[0035] Measurement using TEM-EDX or 3DAP is performed on the interior of the sintered compression product. Measuring the interior of the sintered compression product means the following: The composition is measured in a surface section and in the interior of a cross-section intersected by a central segment of the longest side in the surface with the largest area, perpendicular to the side (perpendicular to a tangent of the central segment in the case of a curve). The measurement points are as follows.Reference lines 1, drawn from the half-positions of the corresponding sides in the aforementioned cross-section as starting points to end sections towards an inner side perpendicular to the sides, and reference lines 2, drawn from the centers of the corresponding corners as starting points to end sections towards the inner side at the half-positions of the inner angles of the corner sections, are provided. The 1% positions of the lengths of the reference lines from the starting points of these reference lines 1 and 2 are defined as surface sections, and the 40% positions are defined as the interior. Note that if the corner sections have curvatures due to chamfering or similar features, points of intersection of the extensions of adjacent sides are defined as end sections of the sides (centers of the end sections).In this case, the measurement points are positions that are not determined on the basis of intersections but on the basis of sections in contact with the reference lines.

[0036] If the measuring points are positioned as described above, for example, if the cross-section is a quadrilateral, then the total number of reference lines is eight, comprising four reference lines 1 and four reference lines 2. The number of measuring points is eight in each of the surface section and the interior. In this embodiment, the eight points in each of the surface section and the interior preferably all have a composition within the aforementioned range, but at least four points in each of the surface section and the interior must have a composition within the aforementioned range. In this case, a relationship between the surface section and the interior of a reference line is not defined. The observation is carried out after an observation surface of the interior of the sintered compression product, as defined above, has been smoothed by polishing.For example, the observation points in TEM-EDX are any 20 points in the cell phase and the cell wall phase, and an average of the measurements, excluding the maximum and minimum values ​​at these points, is calculated, and this average is set as the concentration of each element. This also applies to measurements by 3DAP.

[0037] In the results of the aforementioned cell wall phase concentration measurements using 3DAP, the sharper the Cu concentration profile in the cell wall phase, the more advantageous it is. Specifically, a full width at half maximum (FWHM) of the Cu concentration profile is 5 nm or less according to the invention. In such a case, a higher coercive force can be obtained. This is because, when the Cu distribution in the cell wall phase is sharp, a difference in domain wall energy between the cell phase and the cell wall phase occurs sharply, and the domain wall is more easily pinned.

[0038] The full width at half maximum (FWHM) of the Cu concentration profile in the cell wall phase is determined as follows. Based on the previously mentioned procedure, the highest value (P) is calculated. Cu) the Cu concentration from the 3DAP Cu profile and the peak width with a value that is half the previously mentioned value (P Cu / 2) is, that is, the full width at half maximum (FWHM) is determined. Such a measurement is performed for ten peaks, and the mean of the obtained values ​​is defined as the full width at half maximum (FWHM) of the Cu profile. If the full width at half maximum (FWHM) of the Cu profile is 3 nm or less, the coercivity improvement is further enhanced, and if it is 2 nm or less, an even greater coercivity improvement can be achieved.

[0039] The permanent magnet of this embodiment is manufactured, for example, as follows. First, an alloy powder containing predetermined amounts of the elements is produced. The alloy powder is produced by milling an alloy ingot obtained by casting molten metal using an arc melting or high-frequency process. The alloy powder can be produced by manufacturing a thin strip of alloy in flake form using a strip casting process and subsequently milling the thin alloy strip. In the strip casting process, it is preferred that the molten alloy metal is injected at an angle onto a cooling roller rotating at a peripheral speed of 0.1 m / second to 20 m / second, and a thin strip with a thickness of 1 mm or less is obtained continuously.If the peripheral speed of the cooling roller is less than 0.1 m / second, variation in composition within the thin strip is likely, and if the peripheral speed exceeds 20 m / second, the crystal grains become fine, down to a single domain size or less, and good magnetic properties cannot be achieved. The peripheral speed of the cooling roller preferably falls within the range of 0.3 m / second to 15 m / second and more preferably within the range of 0.5 m / second to 12 m / second.

[0040] Other examples of methods for producing the alloy powder include mechanical deep drawing (ironing), mechanical milling, gas atomization, reduction diffusion, and similar processes. Alloy powder produced by any of these methods can be used. The alloy powder obtained in this way, or the alloy before milling, can be heat-treated for homogenization if necessary. A jet mill or ball mill is used to mill the flakes or ingot. Milling is preferably carried out in an inert gas atmosphere or in an organic solvent to prevent oxidation of the alloy powder.

[0041] Next, the alloy powder is placed in a mold installed in an electromagnet or similar device and compression-formed while a magnetic field is applied. This produces a compression-formed body with oriented crystal axes. Sintering the compression-formed body under suitable conditions yields a sintered compression product with high density. The sintering process preferably includes a preliminary step in a vacuum atmosphere and a main sintering step in an inert gas atmosphere, as previously described. A main sintering temperature Ts is preferably 1210°C or lower. If the iron concentration is high, the melting point is expected to decrease, and therefore smelters or similar components will readily evaporate if the main sintering temperature Ts is too high.The main sintering temperature Ts is more preferably 1205°C or lower, and even more preferably 1200°C or lower. However, to increase the density of the sintered compression product, the main sintering temperature Ts is preferably 1170°C or higher, and more preferably 1180°C or higher.

[0042] In the main sintering step under an inert gas atmosphere, the sintering time at the aforementioned main sintering temperature Ts is preferably 0.5 to 15 hours. This makes it possible to obtain a dense sintered compression product. If the sintering time is less than 0.5 hours, the density of the sintered compression product becomes uneven. If the sintering time exceeds 15 hours, smoldering iron or similar components in the alloy powder evaporate, making it impossible to obtain good magnetic properties. The sintering time is more preferably one to ten hours, and even more preferably one to four hours. The main sintering step is carried out under an inert gas atmosphere of argon gas or similar.

[0043] To transform the compression-formed body of the alloy powder with high Fe concentration into the sintered compression product of high density, the preprocessing step is preferably carried out in a vacuum atmosphere before the main sintering step, as described above. Furthermore, it is preferred that the vacuum atmosphere be maintained until the temperature approaches the main sintering temperature. Specifically, this ensures that the sintered compression product has a density of 8.2 × 10 3 kg / m 3The temperature (pre-processing temperature) T [°C] at the time of the changeover from the vacuum atmosphere to the inert gas atmosphere is preferably within a temperature range not lower than 50°C below the main sintering temperature Ts [°C] (Ts - 50°C) and not higher than the main sintering temperature Ts (Ts - 50°C ≤ T ≤ Ts). If the temperature T at the time of the atmosphere change is more than 50°C lower than the main sintering temperature Ts (T < Ts - 50°C), it might be impossible to sufficiently increase the density of the sintered compression product. Furthermore, the heterophase present in the compression-molded body, or the heterophase generated at the time of the temperature increase during the sintering step, remains even after the main sintering step, which is responsible for a reduction in magnetization.

[0044] If the temperature T during the atmospheric change is significantly lower than the main sintering temperature Ts, it is not possible to fully achieve the effect of suppressing heterophase formation in the preprocessing step under vacuum. Consequently, it is not possible to increase the density of the sintered compression product, which reduces both the magnetization and the coercive force. The temperature T during the atmospheric change is more preferably equal to or higher than a temperature 40°C lower than the main sintering temperature (Ts - 40°C), and even more preferably equal to or higher than a temperature 30°C lower than the main sintering temperature (Ts - 30°C).If the processing temperature T in a vacuum atmosphere is higher than the main sintering temperature Ts, Sm evaporates, which degrades the magnetic properties. Therefore, the temperature T is set to the main sintering temperature Ts or lower when changing atmospheres. The change from a vacuum atmosphere to an inert gas atmosphere can occur at the same time as the main sintering temperature Ts is reached.

[0045] The degree of vacuum of the vacuum atmosphere in the preprocessing step is preferably 9 × 10 -2 Pa or less. If the vacuum level of the preprocessing step is above 9 × 10 -2 If the vacuum level is too low, it is possible that an oxide of element R, such as Sm, will be excessively formed. By adjusting the vacuum level in the preprocessing step to 9 × 10⁻⁶ -2At a vacuum level of 5 × 10⁻⁶ Pa or less, it is possible to more clearly achieve the effect of increasing the Cu concentration in the cell wall phase. A vacuum level of 5 × 10⁻⁶ in the preprocessing step is preferred. -2 Pa or less, and even more strongly preferred, 1 × 10 -2 Pa or less. The processing time of the preprocessing step is preferably shorter than the main sintering time. If the processing time is too long, the amount of element R, such as Sm, that evaporates may increase.

[0046] Furthermore, it is also effective to maintain the vacuum atmosphere for one minute or more at the time of the changeover from the vacuum atmosphere to the inert gas atmosphere. This makes it possible to further promote the density increase of the sintered compression product. If the temperature T at the time of the atmosphere change is lower than the main sintering temperature Ts, then the temperature T at the time of the atmosphere change is maintained for a predetermined time. If the temperature T at the time of the atmosphere change is set to a temperature equal to the main sintering temperature Ts, then the temperature is increased to the main sintering temperature Ts after the temperature lower than the main sintering temperature Ts has been maintained in the vacuum atmosphere for a predetermined time, and the atmospheres are changed.

[0047] The main sintering step in the inert gas atmosphere follows the preprocessing step in a vacuum atmosphere. In this case, the switch from the vacuum atmosphere to the inert gas atmosphere occurs simultaneously when the main sintering temperature Ts is reached, or when the temperature T of the atmosphere change is reached that is equal to or higher than the temperature 50°C lower than the main sintering temperature Ts (Ts - 50°C), or after the temperature T of the atmosphere change has been maintained for a predetermined time. The preprocessing step in a vacuum atmosphere and the main sintering step in an inert gas atmosphere can be performed as separate steps.In this case, the temperature is raised to the atmosphere change temperature (preprocessing temperature) T in a vacuum atmosphere, and if necessary, after this temperature has been maintained for the predetermined time, cooling is carried out. Next, after switching from the vacuum atmosphere to the inert gas atmosphere, the temperature is raised to the main sintering temperature Ts, and the main sintering step is carried out.

[0048] Next, the resulting sintered compression product undergoes solution treatment and aging to control the crystal structure. The solution treatment is preferably a 0.5-hour to 8-hour heat treatment in the temperature range of 1100°C to 1200°C to obtain the 1-7 phase, which is the precursor of the phase separation structure. If the temperature is lower than 1100°C or higher than 1200°C, the ratio of the 1-7 phase in a sample subjected to solution treatment is low, and good magnetic properties are not obtained. The solution treatment temperature is more preferably in the range of 1120°C to 1180°C and even more preferably in the range of 1120°C to 1170°C.

[0049] If the solution treatment time is less than 0.5 hours, the build-up phase is likely to be uneven, making it impossible to achieve a sufficiently high density. If the solution treatment time exceeds eight hours, the element R, such as Sm, evaporates in the sintered compression product, preventing the attainment of good magnetic properties. The solution treatment time is more preferably in the range of one to eight hours, and even more preferably in the range of one to four hours. To prevent oxidation, the solution treatment is preferably carried out in a vacuum atmosphere or an inert gas atmosphere consisting of argon gas or similar.

[0050] Next, the sintered compression product, which has undergone solution treatment, is aged. Aging is a treatment used to control the crystal structure in order to improve the coercivity of the magnet. During aging, it is preferred that, after maintaining a temperature of 700°C to 900°C for 0.5 to 80 hours, the temperature is gradually reduced to 400°C to 650°C at a cooling rate of 0.2°C / minute to 2°C / minute, and then the temperature is subsequently reduced to room temperature. Aging can be carried out by a two-stage heat treatment. Specifically, the aforementioned heat treatment is the first stage, and after the temperature has been gradually reduced to 400°C to 650°C, the second-stage heat treatment is then performed.After the temperature of the second-stage heat treatment has been maintained for a certain period of time, it is reduced to room temperature by furnace cooling. To prevent oxidation, the heat treatment is preferably carried out in a vacuum atmosphere or in an inert gas atmosphere consisting of argon gas.

[0051] If the aging temperature is lower than 700°C or higher than 900°C, it is not possible to obtain a uniformly mixed structure of the cell phase and the cell wall phase, which is responsible for the deterioration of the magnetic properties of the permanent magnet. The aging temperature is more preferably 750°C to 880°C, and even more preferably 780°C to 850°C. If the aging time is less than 0.5 hours, the precipitation of the cell wall phase from the 1-7 phase may not be complete. If the holding time is higher than 80 hours, the thickness of the cell wall phase becomes large, so that the volume fraction of the cell phase decreases and the crystal grains become rough, which makes it impossible to obtain good magnetic properties. The aging time is more preferably four to 60 hours, and even more preferably eight to 40 hours.

[0052] If the cooling rate of the aging treatment is less than 0.2°C / minute, the thickness of the cell wall phase increases, reducing the volume fraction of the cell phase or causing the crystal grains to become rough, making it impossible to obtain good magnetic properties. If the cooling rate after the aging heat treatment exceeds 2°C / minute, it is not possible to obtain a uniformly mixed structure of the cell phase and the cell wall phase, resulting in a deterioration of the permanent magnet's magnetic properties. The cooling rate after the aging treatment is more preferably set to a range of 0.4°C / minute to 1.5°C / minute, and even more preferably to a range of 0.5°C / minute to 1.3°C / minute.

[0053] Note that aging is not limited to two-stage heat treatment, but can also be a multi-stage heat treatment, and multi-stage cooling is also effective. Furthermore, preliminary aging at a temperature lower than the aging temperature for a short period is also effective as a preparatory step. This further enhances the effect of increasing the Cu concentration in the cell wall phase, and the square shape of the magnetization curve is also expected to improve. Specifically, setting the preliminary aging temperature to 600°C to 780°C, the treatment time to 0.5 to 4 hours, and the gradual cooling rate after preliminary aging to 0.5°C / minute to 1.5°C / minute are expected to improve the properties of the permanent magnet.

[0054] The permanent magnet of this embodiment can be used in various types of motors and power generators. This permanent magnet can also be used as a stationary magnet and as a variable magnet in a variable magnetic flux motor and a variable magnetic flux power generator. Various types of motors and power generators are structured by the use of this permanent magnet. When this permanent magnet is used in a variable magnetic flux motor, the techniques disclosed in German Patent Applications JP 2008-29148A and JP 2008-43172A are applicable as the structure and drive system of the variable magnetic flux motor.

[0055] Next, a motor and a power generator of the embodiments will be described with reference to the drawings. Fig.Figure 2 shows a permanent magnet motor according to one embodiment. In the Fig. In the motor with permanent magnet 1 shown in Figure 2, a rotor (rotating part) 3 is incorporated into a stator (stationary part) 2. Permanent magnets 5 of this embodiment are embedded in an iron core 4 of the rotor 3. Based on the properties, etc., of the permanent magnets of this embodiment, it is possible to achieve efficiency improvements, size reductions, cost reductions, etc., for the motor with permanent magnet 1.

[0056] Fig. Figure 3 shows a variable magnetic flux motor according to one embodiment. In the Fig.In the variable magnetic flux motor 11 shown in Figure 3, a rotor (rotating part) 13 is incorporated into a stator (stationary part) 12. Permanent magnets of the embodiment are incorporated as stationary magnets 15 and variable magnets 16 in an iron core 14 of the rotor 13. The magnetic flux density (flux quantum) of the variable magnets 16 is variable. The variable magnets 16 are not affected by a current along the Q-axis because their magnetization direction is perpendicular to the direction of the Q-axis, and they can be magnetized by a current along the D-axis. A magnetized winding (not shown) is provided in the rotor 13. When a current from a magnetizing circuit is passed through the magnetized winding, its magnetic field acts directly on the variable magnets 16.

[0057] With the permanent magnet of this embodiment, it is possible to achieve a suitable coercive force in the stationary magnets 15. If the permanent magnets of this embodiment are used as variable magnets 16, the coercive force is regulated, for example, to a range of 100 kA / m to 500 kA / m by setting various conditions (aging conditions, etc.) in the aforementioned manufacturing process. Fig. In the variable magnetic flux motor 11 shown in Figure 3, the permanent magnets of the embodiment can be used both as stationary magnets 15 and as variable magnets 16, but the permanent magnets of the embodiment can be used as one of the magnets. The variable magnetic flux motor 11 is capable of delivering high torque with a small device size and is therefore suitable for motors of hybrid vehicles, electric vehicles and similar applications, whose motors require high output and small size.

[0058] Fig. Figure 4 shows a power generator according to one embodiment. The one in Fig. The power generator 21 shown in Figure 4 includes a stator (stationary part) 22 which incorporates the permanent magnet of the embodiment. A rotor (rotating part) 23, which is integrated into the stator (stationary part) 22, is connected via a shaft 25 to a turbine 24, which is provided at one end of the power generator 21. The turbine 24 rotates, for example, due to an externally supplied fluid. Instead of rotating the turbine 24 due to the fluid, it is also possible, for example, to rotate the shaft 25 by transmitting dynamic rotation, such as regenerative energy from a vehicle. Various types of generally known structures can be used as the stator 22 and rotor 23.

[0059] The shaft 25 is in contact with a commutator (not shown) mounted on the rotor 23 opposite the turbine 24, and an electromotive force generated by the rotation of the rotor 23 is charged to the system voltage to be transmitted as the output of the power generator 21 via an insulated phase bus and a traction transformer (not shown). The power generator 21 can be either a conventional power generator or a variable magnetic flux generator. Note that the rotor 23 is electrically charged due to an axial current that accompanies the static electricity from the turbine 24 and the power generation. Therefore, the power generator 21 includes a brush 26 for discharging the charged electricity of the rotor 23.

[0060] Next, examples and their evaluation results will be described. Examples 1, 2

[0061] After the raw materials were weighed and mixed in predetermined ratios, the resulting materials were melted in an argon gas atmosphere using an electric arc, producing alloy ingots. Following heat treatment at 1170°C for one hour, the alloy ingots were coarsely ground and then finely milled using a jet mill, producing the alloy powders that would serve as the raw material for the permanent magnets. The alloy powders were then compression-formed in a magnetic field, producing compression-molded bodies. Next, the compression-molded bodies were each placed in a chamber of a kiln, and the chamber was evacuated to a vacuum level of 9.5 × 10⁻⁵. -3Pa was present. In this state, the temperature in the chamber was increased to 1180°C, and then Ar gas was introduced into the chamber. The temperature in the chamber under the Ar atmosphere was increased to 1195°C, and while this temperature was maintained for three hours, the main sintering was carried out. The sintering conditions are shown in Table 2.

[0062] Following the main sintering step, the sintered compression products were held at 1140°C for three hours and subjected to solution treatment. Next, after the solution-treated sintered compression products were held at 740°C for two hours, they were gradually cooled to room temperature and then held at 820°C for 28 hours. After the sintered compression products, which had undergone aging under these conditions, were gradually cooled to 410°C, they were cooled to room temperature in an oven, yielding the desired sintered magnets. The compositions of the sintered magnets are shown in Table 1. The compositional analysis of the magnets was performed using inductively coupled plasma (ICP) chromatography.Following this procedure, the density of each of the sintered compression products, the Cu concentration in the cell wall phase, and the full width at half the maximum of a Cu concentration profile in the cell wall phase were measured. Furthermore, the magnetic properties of the sintered magnets were evaluated using a BH tracer, and their coercivity and residual magnetization were measured. The results are shown in Table 3.

[0063] Note that the composition analysis was performed by ICP according to the following procedure. First, a sample taken from the aforementioned measurement points was ground in a mortar, and a predetermined amount of this ground sample was weighed out and placed in a quartz beaker. A mixed acid (containing nitric and hydrochloric acids) was added to the quartz beaker, which was heated on a hot plate to approximately 140°C, causing the sample to melt completely. After being allowed to cool, it was transferred to a volumetric PFA flask and subjected to an isovolumetric procedure to serve as the sample solution. Amounts of the components of the sample solution were determined by a calibration curve procedure using an ICP emission spectrochemical analyzer.An SPS4000 (trade name) manufactured by SII Nano Technology Inc. was used as an ICP emission spectrochemical analyzer. Examples 3, 4

[0064] After the raw materials were weighed and mixed in predetermined ratios, the resulting materials were high-frequency melted in an argon gas atmosphere, producing alloy ingots. Following heat treatment at 1170°C for one hour, the alloy ingots were coarsely ground and then finely ground using a jet mill, producing alloy powders as the raw material powders for the permanent magnets. The alloy powders were pressure-formed in a magnetic field, producing compression-formed bodies. Next, the compression-formed bodies made from the alloy powders were placed in a chamber of a kiln, and the chamber was evacuated to a vacuum level of 9.5 × 10⁻⁵. -3The chamber was filled with argon. In this state, the temperature was increased to 1185°C, and then argon gas was introduced. The temperature in the chamber under an argon atmosphere was raised to 1195°C, and while this temperature was maintained for three hours, the main sintering was carried out. Subsequently, while the sintered compression products were held at 1130°C for four hours, they underwent solution treatment.

[0065] Next, after the solution-treated sintered compression products were held at 750°C for one hour, they were gradually cooled to room temperature. Subsequently, after being held at 800°C for 40 hours, they were gradually cooled to 400°C and further cooled to room temperature in an oven, yielding the desired sintered magnets. The compositions of the sintered magnets are as shown in Table 1. For each of the obtained sintered magnets, the density of the sintered compression product, the Cu concentration in a cell wall phase, the full width at half the maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Example 5

[0066] Alloy powders with the same composition as those of Example 4 were compression-formed in a magnetic field, producing a compression-formed body. This compression-formed body was placed in the chamber of a furnace, and the chamber was evacuated until its vacuum level reached 9.5 × 10⁻⁵. -3The chamber was initially filled with Pa. In this state, the temperature was increased to 1190°C, and then Ar gas was introduced. The temperature in the chamber under the Ar atmosphere was increased to 1195°C, and while this temperature was maintained for three hours, the main sintering was carried out. Subsequently, the solution treatment and aging were performed under the same conditions as in Example 4, resulting in the desired sintered magnet. The composition of the sintered magnet is as shown in Table 1. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Example 6

[0067] Alloy powders with the same composition as those of Example 4 were compression-formed in a magnetic field, producing a compression-formed body. This compression-formed body was placed in the chamber of a furnace, and the chamber was evacuated until its vacuum level reached 9.5 × 10⁻⁵. -3The chamber was initially filled with argon. In this state, the temperature in the chamber was increased to 1160°C, and then argon gas was introduced. The temperature in the chamber under the argon atmosphere was increased to 1195°C, and while this temperature was maintained for three hours, the main sintering was carried out. Subsequently, the solution treatment and aging were performed under the same conditions as in Example 4, resulting in the desired sintered magnet. The composition of the sintered magnet is as shown in Table 1. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half the maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Examples 7, 8

[0068] Alloy powders with the same composition as those of Examples 3 and 4 were compression-formed in a magnetic field, producing a compression-formed body. This compression-formed body was placed in the chamber of a kiln, and the chamber was evacuated until its vacuum level reached 2.5 × 10⁻⁶. -2The chamber was initially filled with Pa. In this state, the temperature was increased to 1180°C, and then Ar gas was introduced. The temperature in the chamber under the Ar atmosphere was increased to 1195°C, and while this temperature was maintained for three hours, the main sintering was carried out. Subsequently, the solution treatment and aging were performed under the same conditions as in Examples 3 and 4, resulting in the desired sintered magnet. The composition of the sintered magnet is as shown in Table 1. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Example 9

[0069] An alloy powder with the same composition as that of Example 4 was compression-formed in a magnetic field, producing a compression-formed body. This compression-formed body was placed in a chamber of a kiln, and the chamber was evacuated until the vacuum level reached 9.5 × 10⁻⁵. -3The chamber temperature was raised to 1160°C, and after holding this temperature for five minutes, argon gas was introduced. The temperature in the chamber under the argon atmosphere was then raised to 1195°C, and while this temperature was held for three hours, the main sintering was carried out. Subsequently, the solution treatment and aging were performed under the same conditions as in Example 4, resulting in the desired sintered magnet. The composition of the sintered magnet is as shown in Table 1. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Example 10

[0070] An alloy powder with the same composition as that of Example 4 was compression-formed in a magnetic field, producing a compression-formed body. This compression-formed body was placed in a chamber of a kiln, and the chamber was evacuated until the vacuum level reached 9.5 × 10⁻⁵. -3The chamber was heated to 1160°C, and after holding this temperature for five minutes, argon gas was introduced. The temperature in the chamber under the argon atmosphere was then raised to 1200°C, and while this temperature was held for three hours, the main sintering was carried out. Subsequently, the solution treatment and aging were performed under the same conditions as in Example 4, resulting in the desired sintered magnet. The composition of the sintered magnet is as shown in Table 1. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative example 1

[0071] A sintered magnet with the composition shown in Table 1 was produced using the same manufacturing process as in Example 1. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half the maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the resulting sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative example 2

[0072] A sintered magnet with the composition shown in Table 1 was produced using the same manufacturing process as in Example 3. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half the maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the resulting sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative example 3

[0073] An alloy powder with the same composition as in Example 4 was compression-formed in a magnetic field, producing a compression-formed body. This compression-formed body was placed in a chamber of a kiln, and the chamber was evacuated until its vacuum level reached 9.5 × 10⁻⁵. -3The chamber was initially filled with Pa. In this state, the temperature in the chamber was increased to 1130°C, and then Ar gas was introduced. The temperature in the chamber under the Ar atmosphere was increased to 1195°C, and while this temperature was maintained for three hours, the main sintering was carried out. Subsequently, the solution treatment and aging were performed under the same conditions as in Example 4, resulting in the desired sintered magnet. The composition of the sintered magnet is as shown in Table 1. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half the maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative example 4

[0074] An alloy powder with the same composition as in Example 4 was compression-formed in a magnetic field, producing a compression-formed body. This compression-formed body was placed in a chamber of a kiln, and the chamber was evacuated until its vacuum level reached 9.5 × 10⁻⁵. -3The chamber was initially filled with argon. In this state, the temperature in the chamber was increased to 1140°C, and then argon gas was introduced. The temperature in the chamber under the argon atmosphere was increased to 1195°C, and while this temperature was maintained for three hours, the main sintering was carried out. Subsequently, the solution treatment and aging were performed under the same conditions as in Example 4, resulting in the desired sintered magnet. The composition of the sintered magnet is as shown in Table 1. The density of the sintered compression product, the Cu concentration in the cell wall phase, the full width at half maximum of a Cu concentration profile in the cell wall phase, the coercive force, and the residual magnetization of the sintered magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 3. Table 1 Magnet composition (atomic %) Example 1 See 11,36 Faith 28,36 (Zr 0,83 To 0,17 ) 2,66 Cu 7,09 Co 50,53 Example 2 (Sm 0,88 Nd 0,12 ) 11,11 Fe 29,16 Zr 2,04 The 5,33 Co 52,36 Example 3 Sm 11,47 Fe 29,84 With 5,58 Zr 2,39 (Co 0,998 -R 0,002 ) 50,72 Example 4 Sm 11,07 Fe 30,68 With 5,25 Zr 2,01 Co. 50,99 Example 5 Sm 11,07 Fe 30,68 With 5,25 Zr 2,01 Co. 50,99 Example 6 Sm 11,07 Fe 30,68 With 5,25 Zr 2,01 Co. 50,99 Example 7 Sm 11,47 Fe 29,84 With 5,58 Zr 2,39 (Co 0,998 -R 0,002 ) 50,72 Example 8 Sm 11,07 Fe 30,68 With 5,25 Zr 2,01 Co. 50,99 Example 9 Sm 11,07 Fe 30,68 With 5,25 Zr 2,01 Co. 50,99 Example 10 Sm 11,07 Fe 30,68 With 5,25 Zr 2,01 Co. 50,99 Comparative example 1 See 11,36 Faith 24,82 (Zr 0,83 To 0,17 ) 2,66 Cu 7,09 Co 54,07 Comparative example 2 Sm 10,73 Fe 30,80 With 5,27 Zr 2,02 Co. 51,18 Comparative example 3 Sm 11,07 Fe 30,68 With 5,25 Zr 2,01 Co. 50,99 Comparative example 4 Sm 11,07 Fe 30,68 With 5,25 Zr 2,01 Co. 50,99 Table 2 Pre-processing step (Vacuum processing step) Main sintering step Processing temperature T (temperature at atmospheric changes) [°C] degree of vacuum [×10 -3 Pa) Holding time [minutes] Main sintering temperature Ts [°C] Example 1 1180 9,5 - 1195 Example 2 1180 9,5 - 1195 Example 3 1185 9,5 - 1195 Example 4 1185 9,5 - 1195 Example 5 1190 9,5 - 1195 Example 6 1160 9,5 - 1195 Example 7 1180 2,5×10 - 1195 Example 8 1180 2,5×10 - 1195 Example 9 1160 9,5 5 1195 Example 10 1160 9,5 5 1200 Comparative example 1 1180 9,5 - 1195 Comparative example 2 1185 9,5 - 1195 Comparative example 3 1130 9,5 - 1195 Comparative example 4 1140 9,5 - 1195 Table 3 density of the sintered Compression product [×10 3 kg / m 3 ] Cu concentration in the cell wall phase [Atom%] Full width at half Maximum of Cu concentration profile in the Cell wall phase Coercive force [came] Residual magnetization [T] Example 1 8,29 49,1 5,4 1290 1, 18 Example 2 8,28 39,4 3,7 1120 1,20 Example 3 8,31 45,2 2,2 1080 1, 22 Example 4 8,28 54,2 2,8 1160 1, 23 Example 5 8,29 58,7 2,4 1180 1,24 Example 6 8,27 52,4 2,5 1090 1,23 Example 7 8,27 40,1 6,1 990 1,16 Example 8 8, 25 37,3 5,4 870 1, 21 Example 9 8,30 59,5 2,3 1210 1,23 Example 10 8,31 57,7 1,8 1190 1,23 Comparative example 1 8,29 47,2 6, 2 1850 1,12 Comparative example 2 8,03 16,2 4,0 110 1,14 Comparative example 3 7,70 19, 4 3,4 240 1,07 Comparative example 4 7, 95 28,9 13, 1 410 1,11

[0075] As can be seen from Table 3, the sintered magnets of examples 1 to 10 all exhibit high density and a sufficiently increased Cu concentration in the cell wall phase, resulting in high magnetization and high coercivity. With a low Fe concentration, the sintered magnet of comparison example 1 has low magnetization despite its high density. With a low Sm concentration, the sintered magnet of comparison example 2 exhibits low magnetization and coercivity. The sintered magnets of comparison examples 3 and 4 have a low density of the sintered compression product and exhibit low magnetization and coercivity due to the low Cu concentration in the cell wall phase.

[0076] Furthermore, the compositions of the cell phase and the cell wall phase in the sintered magnet of Example 4 were measured according to the previously described procedure. The result was the concentration of the cell phase Sm. 14,5 Fe 34,9 Z 1,3 Cu 2,3 Co 47,0 and the composition of the cell wall phase was Sm 21,1 Fe 8,8 Z 1,5 Cu 54,2 Co 4,4. Measurements of the cell phase and cell wall phase compositions in the other examples confirmed that the cell wall phase has higher Cu and Sm concentrations and lower Fe concentrations compared to the overall composition, and the cell phase has lower Cu and Sm concentrations compared to the overall composition. It can be seen from this that the cell phase preferably has the composition expressed by the aforementioned formula (2) and the cell wall phase preferably has the composition expressed by the aforementioned formula (3).

Claims

[1] Permanent magnet, comprising: a composition, expressed by a composition formula: R p Fe q M r Cu3Co 100-p-q-r-s , where R is at least one element selected from rare earth elements, M is at least one element selected from Zr, Ti and Hf, p is a number that satisfies 10.8 ≤ p ≤ 13.5 atom%, q is a number that satisfies 28 ≤ q ≤ 40 atom%, r is a number that satisfies 0.88 ≤ r ≤ 7.2 atom%, and s is a number that satisfies 3.5 ≤ s ≤ 13.5 atom%; and a metallic structure that combines a cell phase with a Th2Zn 17 -crystal phase as well as a cell wall phase that surrounds the cell phase, wherein the Cu concentration in the cell wall phase is in a range of 30 atomic% to 70 atomic%, wherein a full width at half the maximum of a Cu concentration profile in the cell wall phase is 5 nm or less, wherein the cell phase has a composition that is expressed by a composition formula: R p1 Fe q1 M r1 Cu 31 Co 100-p1-q1-r1-s1 where p1, q1, r1 and s1 are numbers that each satisfy the following: p1 is a number that satisfies 8 ≤ p1 ≤ 18 atom%, q1 is a number that satisfies 28 ≤ q1 ≤ 45 atom%, r1 is a number that satisfies 0.1 ≤ r1 ≤ 3 atom% and s1 is a number that satisfies 0.5 ≤ s ≤ 10 atom%; and wherein the cell wall phase has a composition that is expressed by a composition formula: R p2 Fe q2 M r2 Cu s2 Co 100-p2-q2-r2-s2 where p2 is a number that satisfies 12 ≤ p2 ≤ 28 atom%, q2 is a number that satisfies 4 ≤ q2 ≤ 20 atom%, r2 is a number that satisfies 0.1 ≤ r2 ≤ 3 atom% and s2 is a number that satisfies 30 ≤ s2 ≤ 70 atom%. [2] Permanent magnet according to claim 1, wherein the Cu concentration in the cell wall phase is in a range of 35 atomic% to 60 atomic%. [3] Permanent magnet according to claim 1, comprising a sintered compression product including the composition and metallic structure, wherein the density of the sintered compression product is 8.2 × 10 3 kg / m 3 or more. [4] Permanent magnet according to claim 1, wherein the coercive force of the permanent magnet is 800 kA / m or more, and the residual magnetization of the permanent magnet is 1.15 T or more. [5] Permanent magnet according to claim 1, wherein 50 atomic percent or more of the element R is Sm, and 50 atomic percent or more of the element M is Zr. [6] Permanent magnet according to claim 1, wherein 20 atom% or less of the Co is replaced by at least one element A selected from Ni, V, Cr, Mn, Al, Ga, Nb, Ta, and W. [7] Motor comprising the permanent magnet according to claim 1. [8] Power generator comprising the permanent magnet according to claim 1.

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