JP5107198B2 - PERMANENT MAGNET, PERMANENT MAGNET MANUFACTURING METHOD, AND MOTOR USING THE SAME - Google Patents

Description

The present invention relates to a permanent magnet, in particular, a permanent magnet having a low coercive force and a high squareness ratio suitable for a motor, a method for manufacturing the same , and a motor using the same .

Conventionally, as permanent magnets, alnico magnets, ferrite magnets, Sm-Co magnets, Nd-Fe
-B magnets etc. are known, and these permanent magnets are suitable as key parts for various electric devices besides VCM, various motors such as spindle motor, measuring instrument, speaker, medical MRI, etc. A magnet is used.

Among these magnets, a large amount of Fe or Co and rare earth elements are contained. Fe,
Co contributes to an increase in saturation magnetic flux density, while rare earth elements bring about a very large magnetic anisotropy derived from the behavior of 4f electrons in the crystal field. Realize the characteristics.

In recent years, there is a growing demand for miniaturization and energy saving of various electrical devices, and the permanent magnets that are key component materials for these devices also have a higher maximum energy product [(BH) _max ], a large coercive force, and improved temperature characteristics of magnet properties. Has been demanded.
As an application field of permanent magnets, motors are especially attracting attention from the viewpoint of energy saving, and when used in this, the loss can be greatly reduced compared to conventional induction type, so as an energy saving technology for various applications such as in-vehicle and home appliance applications. It is spreading.

Generally, permanent magnet motors are roughly divided into two types. These are a surface magnet type permanent magnet motor in which a permanent magnet is attached to the outer periphery of a rotor core and an embedded type permanent magnet motor in which a permanent magnet is embedded in the rotor core. An embedded permanent magnet motor is suitable for the variable speed drive motor.

The configuration of the rotor of the embedded permanent magnet motor will be described with reference to FIG. In FIG.
Reference numeral 11 denotes a rotor, 12 denotes a rotor core, and 14 denotes a high coercive force permanent magnet. Rotor core 1
A rectangular cavity is provided in the outer periphery of 2 by the same number as the number of poles. FIG. 1 shows a four-pole rotor 11 in which four cavities are provided and a permanent magnet 14 is inserted. The permanent magnet 14 is magnetized in the radial direction of the rotor or in the direction perpendicular to the side facing the air gap surface in the rectangle of the cross section of the permanent magnet 14. The permanent magnet 14 is mainly an NdFeB permanent magnet having a high coercive force so as not to be demagnetized by a load current. The rotor core 12 is formed by laminating electromagnetic steel plates punched out of cavities. An example of such a motor is a permanent magnet type reluctance type rotating electrical machine described in JP-A-11-136912 (Patent Document 1).

In the permanent magnet type rotating electrical machine, the interlinkage magnetic flux of the permanent magnet is always generated at a constant value, so that the induced voltage by the permanent magnet increases in proportion to the rotational speed. When operating while changing the magnetization from low speed to high speed, the induced voltage by the permanent magnet becomes extremely high at high speed rotation, and the induced voltage by the permanent magnet is applied to the electronic components of the inverter, and the component exceeds the withstand voltage of the electronic components. Breaks down. For this reason, it is conceivable to perform a design in which the amount of magnetic flux of the permanent magnet is reduced so as to be equal to or lower than the withstand voltage, but the output and efficiency in the low speed region of the permanent magnet type rotating electrical machine are reduced.

When operation is performed while changing the magnetization close to constant output from low speed to high speed, the flux linkage of the permanent magnet is constant, so in the high-speed rotation range, the voltage of the rotating electrical machine reaches the upper limit of the power supply voltage and the current required for output No longer flows. As a result, the output is greatly reduced at high speeds, and further, it becomes impossible to drive over a wide range up to high speeds. Recently, flux-weakening control has begun to be applied as a method of expanding the operating range while changing the magnetization. In the flux weakening control, a demagnetizing field due to the d-axis current is applied to the high coercive force permanent magnet 4, and the magnetic operating point of the permanent magnet is moved within a reversible range to change the amount of magnetic flux. For this reason, a NdFeB magnet having a high coercive force is applied to the permanent magnet so that it is not irreversibly demagnetized by a demagnetizing field.

Since the interlinkage magnetic flux of the permanent magnet decreases due to the demagnetizing field of the d-axis current, the decrease of the interlinkage magnetic flux creates a voltage margin with respect to the voltage upper limit value. Since the current can be increased, the output in the high speed region increases. Further, the rotational speed can be increased by the voltage margin, and the range in which the operation can be performed while changing the magnetization is expanded.
However, it is necessary to continue to apply a demagnetizing field to the permanent magnet, and since the d-axis current that does not contribute to the output is continuously supplied, the copper loss increases and the efficiency deteriorates. Further, the demagnetizing field due to the d-axis current generates a harmonic magnetic flux, and the increase in voltage generated by the harmonic magnetic flux or the like is weakened, creating a limit of voltage reduction by the magnetic flux control. Therefore, even if the flux-weakening control is applied to the embedded permanent magnet type rotating electric machine, it is difficult to operate at a variable speed that is three times or more the base speed. Furthermore, the iron loss is increased by the harmonic magnetic flux, and vibration is generated by the electromagnetic force generated by the harmonic magnetic flux.

When an embedded permanent magnet motor is applied to a hybrid motor drive motor,
In the state driven only by the engine, the motor is rotated. At medium / high speed rotation, the induced voltage of the motor's permanent magnet exceeds the power supply voltage, and the d-axis current continues to flow under the flux-weakening control. In this state, since the motor generates only a loss, the overall operation efficiency is deteriorated.
For this reason, with respect to the problems of the prior art as described above, Japanese Patent Laid-Open No. 2006-280195 (Patent Document 2) enables operation while changing the magnetization in a wide range from low speed to high speed. Motors that can change the magnetization state of all or part of permanent magnets that can provide higher torque and higher output in the middle / high-speed rotation range, improved efficiency, and improved reliability (permanent magnet type) Rotating electric machines) have been proposed.

That is, this permanent magnet type motor includes a stator provided with a stator winding as shown in FIG. 2 (FIG. 1 of Patent Document 2), and a magnetic field generated by a current of the stator winding in a rotor core. And a rotor in which a low coercivity permanent magnet having a coercive force with which the magnetic flux density is irreversibly changed and a high coercivity permanent magnet having a coercivity more than twice that of the low coercivity permanent magnet are provided. It is a thing. In other words, a permanent magnet rotating electrical machine that enables variable speed operation in a wide range from low speed to high speed, realizing high torque in the low-speed rotation range, high output in the medium / high-speed rotation range, improved efficiency, and improved reliability. Can provide. As the magnet used for the permanent magnet motor, a high coercive force magnet is an NdFeB magnet, and a low coercive force magnet is an alnico magnet or an FeCrCo magnet.

Patent Document 2 discloses an Alnico magnet (AlNiCo) or FeCr as a low coercive force permanent magnet.
A Co magnet and a NdFeB magnet as a high coercive force permanent magnet are shown. The coercive force of the alnico magnet (magnetic field at which the magnetic flux density becomes 0) is 60 to 120 kA / m, which is 1/15 to 1/8 of the coercive force of 950 kA / m of the NdFeB magnet. The coercive force of the FeCrCo magnet is about 60 kA / m, which is 1/15 of the coercive force of the NdFeB magnet of 950 kA / m.
Alnico magnets and FeCrCo magnets have considerably lower coercive force than NdFeB high coercive force magnets, and this low coercive force can be used to change the magnetization state of all or part of permanent magnets. Make it. In the embodiment, a high coercive force permanent magnet having a coercive force 8 to 15 times that of the low coercive force permanent magnet is applied, thereby obtaining a rotating electrical machine having excellent characteristics.

On the other hand, NdFeB magnets aimed at developing a high coercive force have been disclosed. For example, various technologies are disclosed in the following patents.
Japanese Examined Patent Publication No. 63-65742 (Patent Document 3) discloses an Fe—BR ternary compound that is magnetically stable at room temperature or higher and has magnetic anisotropy (where R is one or two of Nd and Pr). And an alloy composition of R8-30%, B2-28% and the balance substantially consisting of Fe in atomic percentage. Fe-B-R ternary compounds which are magnetically stable at room temperature or higher and have magnetic anisotropy (wherein R is 50 atom% or more of Nd and Pr, or the balance Dy, At least one of Ho, Tb, La, Ce, Gd, and Y)
And the alloy composition is R8-30% in atomic percent, B2-28%, and the balance substantially F
and a ferromagnetic alloy characterized by comprising e. It has been found that some ferromagnetic alloys composed of R—Fe—B exhibit a Curie point around 300 ° C. and an anisotropic magnetic field reaches 100 kOe or more.

Japanese Patent Publication No. 3-19296 (Patent Document 4) discloses that at least one of Nd, Pr, Dy, Ho, and Tb is 8 to 30%, B2 to 28%, and the balance substantially as rare earth elements (R) in atomic percent. In the Fe-B-R system anisotropic magnetic permanent magnet made of Fe, a part of the Fe is substituted with Co of 50% or less (excluding 0%) with respect to the total composition. It is a permanent magnet. Also, in terms of atomic percentage, Nd, Pr, Dy, Ho, Tb as rare earth elements (R)
And at least one of La, Ce, Pm, Sm, Eu, Gd, Er, Tm, Yb, Lu
, Y, a total of 8 to 30%, B2 to 28%, and the balance substantially consisting of Fe. The permanent magnet is characterized by being substituted with 50% or less (excluding 0%) of Co. It has been reported that the substitution of Co can raise the Curie temperature and is effective in improving the temperature characteristics and corrosion resistance of the magnet.

In recent years, heavy rare earth elements (for example, Tb, D, etc.), which are essential elements for increasing the coercive force and heat resistance, are used.
Attempts have been made to reduce y) while maintaining the characteristics.
JP-A-2006-303433 (Patent Document _{5) R1 a R2 b T c} A d FeO f
A sintered magnet body having an M _g composition, F, and R2 is a constituent element thereof is distributed so that the average manner containing concentrations toward the magnet body surface than the magnet body center thickens, the sintered magnet bodies in (R1
, R2) In the grain boundary portion surrounding the main phase crystal grains composed of ₂ T ₁₄ A tetragonal crystal, the concentration of R2 / (R1 + R2) contained in the crystal grain boundary is R2 / (R1 + R2) in the main phase crystal grains. Disclosed is a rare earth permanent magnet having an (R1, R2) oxyfluoride in the grain boundary portion, which is on average higher than the concentration, and at least 20 μm deep from the surface of the magnet body at the grain boundary portion. Yes. That is, a powder composed of R2 (at least one selected from Tb or Dy) and F is present on the surface of the sintered magnet, diffused inside by heat treatment, and high coercive force is obtained by using a small amount of heavy rare earth elements. To get.

JP-A-2006-303434 (Patent Document 6) discloses that an R-Fe-B-based sintered magnet body is obtained by absorbing an E component and a fluorine atom from its surface, and R _a E _b T _{c Ad} F
eO _f M _g is a composition containing sintered magnet body, F is distributed such that the content level toward the magnet body surface than the magnet body center darkening, in the sintered magnet _{(R, E) 2 T 14} A tetragonal In the crystal grain boundary part surrounding the main phase crystal grains composed of crystals, the concentration of E / (R + E) contained in the crystal grain boundaries is on average higher than the E / (R + E) concentration in the main phase crystal grains. (R, E) oxyfluoride exists in a region at least 20 μm deep from the surface of the magnet body at the grain boundary, and in this region, oxyfluoride particles of 1 μm or more are present at a rate of 2,000 or more per 1 mm 2. Disclosed is a functionally graded rare earth permanent magnet in which the oxyfluoride occupies 1% or more of the area fraction and the surface resistance of the magnet body has a higher eddy current loss than the inside.
JP 2006-303435 (Patent Document _{7), R1 a R2 b T c A} d FeO f
A sintered magnet body having an M _g composition, the crystal grain boundary part surrounding the periphery of the main phase crystal grains consisting of sintered magnet bodies in the _{(R1, R2) 2 T 14} A tetragonal crystal grain boundaries Included in R2 / (
The distribution of R1 + R2) is such that the average concentration is higher than the R2 / (R1 + R2) concentration in the main phase crystal grains, and that the concentration of R2 is higher from the center of the magnet body toward the surface of the magnet body. In the gradient function, the (R1, R2) oxyfluoride is present in the crystal grain boundary part to a depth region of at least 20 μm from the surface of the magnet body in the crystal grain boundary part, and the coercive force of the surface layer part of the magnet body is higher than the inside. It is said that a permanent magnet having a magnetic structure in which the coercive force of the surface layer portion of the magnet body is higher than that of the inside and having improved heat resistance can be provided.

JP-A-2006-303436 (Patent Document _{8), R1 a R2 b T} c A d FeO
a sintered magnet body having an _f M _g composition, F, and R2 is a constituent element thereof is distributed so that the average manner containing concentrations toward the magnet body surface than the magnet body center thickens, R2 / of (R1 + R2) A three-dimensional network in which the grain boundary, which is higher in concentration than the R2 / (R1 + R2) concentration in the main phase crystal grains composed of (R1, R2) ₂ T ₁₄ A tetragonal crystals, is continuous to the depth of at least 10 μm from the magnet surface A rare earth permanent magnet in the form of is disclosed.
JP-A 2006-66853 (Patent Document 9) discloses R-Fe-B (R is a rare earth element).
A rare earth magnet in which a layered grain boundary phase is formed in a part of a grain boundary of Nd2Fe14B which is a main phase of a system magnet, wherein the grain boundary phase contains a fluorine compound, and the thickness of the fluorine compound is 10 μm or less, Alternatively, a magnet is disclosed in which the fluorine compound has a thickness of 0.1 μm or more and 10 μm or less, and the main phase particle coverage of the fluorine compound is 50% or more on average.
As described above, both are aimed at obtaining a high coercive force in a state where the amount of heavy rare earth elements is reduced, and are effective utilization techniques of recent rare metal resources.

JP-A-11-136912 JP 2006-280195 A Japanese Patent Publication No. 63-65742 Japanese Patent Publication No.3-19296 JP 2006-303433 A JP 2006-303434 A JP 2006-303435 A JP 2006-303436 A JP 2006-66853 A

None of these patent documents aims to increase the coercive force, and cannot fully demonstrate the concept of a low coercive magnet in a motor that can change the magnetization state of all or part of permanent magnets applied this time. . On the other hand, a low coercive force magnet applied to a motor that can change the magnetization state of all or part of permanent magnets is more than the case of using an alnico magnet.
Further, there has been a demand for improving efficiency by controlling the magnetic flux in a wide range.

The present invention sets an optimum amount of magnetic flux under a predetermined operating condition for further high output, improved efficiency, and improved reliability of a motor, particularly a motor capable of changing the magnetization state of the whole or a part of permanent magnets. An object of the present invention is to provide a permanent magnet suitable for this, particularly suitable for a low coercivity magnet, and a method of manufacturing the same. This permanent magnet motor provides a permanent magnet that is extremely effective for increasing the efficiency of motors of various capacities such as household appliances such as washing machines and air conditioners, in-vehicle applications, and train applications.

In the present invention, the main phase is a (rare earth) ₂ Fe ₁₄ B phase, satisfies the following general formula, and has Fe and at least one of R 1 and R 2, and at least one of O or F at the grain boundary. A square ratio expressed by a ratio of a residual magnetization to a magnetization in a magnetic field of 10 kOe having a coercivity at room temperature of 0.5 kOe to 5 kOe, a residual magnetic flux density of 7.9 kG to 10 kOe. Is a permanent magnet characterized in that it is 80% or more.
Formula _{(Ce 1-x-y R1} x R2 y) a Fe b Co c B d M e X f C g A h
R1: At least one selected from Nd, Pr, Sm R2: Tb, Dy, or at least one selected from elements not selected by R1 M: Ti, Zr, Hf, V, Nb, Ta, Cr, Mo At least one selected from W, Mn, Ni, Cu X: at least one selected from Ga, Si, Al A: at least one selected from F, O 0.1 ≦ x ≦ 0.5
0 ≦ y ≦ 0.1
0.1 ≦ x + y ≦ 0.5
7 ≦ a ≦ 18
50 ≦ b ≦ 80
1 ≦ c ≦ 30
4 ≦ d ≦ 18
0 ≦ e ≦ 6
0 ≦ f ≦ 6
0 ≦ g ≦ 5
0.01 ≦ h ≦ 3
a + b + c + d + e + f + g + h = 100 atomic%

The recoil permeability is preferably 1.00 to 1.08. The main phase (
Rare earth) ₂ Fe ₁₄ B phase tetragonal structure, grain boundary with Fe and at least one selected from R1 and R2 and at least one selected from O or F, or R2 and F
Or it is preferable that at least 1 phase of the phase which consists of at least 1 sort (s) chosen from O exists. The permanent magnet is preferably a sintered body. Moreover, it is suitable for the permanent magnet mounted on the motor. In particular, the squareness ratio expressed by the ratio of the residual magnetization to the magnetization in the magnetic field of 0.5 kOe or more and 3.5 kOe or less and 10 kOe is 80% or more, and the recoil permeability is 1.00 to 1.08. The permanent magnet provided is suitable for a permanent magnet for a motor that can change the magnetization state of the whole or a part of the permanent magnet.
Further, the method for producing a permanent magnet of the present invention includes a molding step of adjusting a molded body by molding an alloy powder satisfying the following general formula in a magnetic field, and the molded body in an inert atmosphere at 1000 ° C. or more and 120 ° C.
Sintering step of obtaining a sintered body by sintering at a temperature of 0 ° C. or lower for 10 minutes or longer and 10 hours or less, (R2) ₂ O ₃ or (R2) F ₃ placed on the surface of the sintered body, then 300 ° C. The step of performing heat treatment for 1 hour or more and 100 hours or less in the temperature range up to 50 ° C. below the sintering temperature, 400
A step of aging for 1 hour or more and 20 hours or less at a temperature of from ℃ to 800 ℃, and cooling to 200 ℃ at a subsequent cooling rate of 0.1 to 20 ℃ / min.
Formula _{(Ce 1-x-y R1} x R2 y) a Fe b Co c B d M e X f C g A h
R1: At least one selected from Nd, Pr, Sm, La R2: Tb, Dy, or at least one selected from elements not selected by R1 M: Ti, Zr, Hf, V, Nb, Ta, Cr , Mo, W, Mn, Ni, Cu At least one selected from X, Ga, Si, Al A: At least one selected from F, O 0.1 ≦ x ≦ 0.5
0 ≦ y ≦ 0.1
0.1 ≦ x + y ≦ 0.5
7 ≦ a ≦ 18
50 ≦ b ≦ 80
1 ≦ c ≦ 30
4 ≦ d ≦ 18
0 ≦ e ≦ 6
0 ≦ f ≦ 6
0 ≦ g ≦ 5
0.01 ≦ h ≦ 3
a + b + c + d + e + f + g + h = 100 atomic%

According to the present invention, a permanent magnet having a low coercive force and a high squareness ratio can be provided. Therefore, the low coercive force side of a motor permanent magnet, particularly a motor permanent magnet capable of changing the magnetization state of the whole or part of the permanent magnet. Suitable for magnets. Moreover, if it is the manufacturing method of this invention, the low coercive force and the permanent magnet of a high squareness ratio can be manufactured efficiently.

The permanent magnet of the present invention satisfies the following general formula, and has a squareness ratio represented by a ratio of residual magnetization to magnetization in a magnetic field of 0.5 kOe to 5 kOe and 10 kOe, which is 80%. To do.
That is, the following general formula is satisfied, and at least one phase of Fe and at least one of R1 and R2, at least one of O or F exists at the grain boundary, and the coercive force at room temperature is The permanent magnet is characterized by having a residual magnetic flux density of 0.5 kOe or more and 5 kOe or less, a residual magnetic flux density of 7.9 kG or more, and a squareness ratio represented by a ratio of residual magnetization to magnetization in a magnetic field of 10 kOe is 80% or more.
Formula _{(Ce 1-x-y R1} x R2 y) a Fe b Co c B d M e X f C g A h
R1: At least one selected from Nd, Pr, Sm R2: Tb, Dy, or at least one selected from elements not selected by R1 M: Ti, Zr, Hf, V, Nb, Ta, Cr, Mo At least one selected from W, Mn, Ni, Cu X: at least one selected from Ga, Si, Al A: at least one selected from F, O 0.1 ≦ x ≦ 0.5
0 ≦ y ≦ 0.1
0.1 ≦ x + y ≦ 0.5
7 ≦ a ≦ 18
50 ≦ b ≦ 80
1 ≦ c ≦ 30
4 ≦ d ≦ 18
0 ≦ e ≦ 6
0 ≦ f ≦ 6
0 ≦ g ≦ 5
0.01 ≦ h ≦ 3
a + b + c + d + e + f + g + h = 100 atomic%

First, the coercive force is 0.5 kOe or more and 5 kOe or less. If the coercive force is less than 0.5 kOe, the magnetic flux control range in the motor that can change the magnetization state of the whole or a part of the permanent magnet is narrowed, and if it exceeds 5 kOe, a great amount of electric energy is required to reverse the magnetization of this magnet. Energy saving effect is greatly reduced. Therefore, preferably 1 to 4 kO
e. As the operating temperature increases, the coercive force is preferably on the high coercive force side within the above range. In addition, the squareness ratio is 80% or more, and if it is less than 80%, the magnetic flux control range in the motor that can change the magnetization state of the whole or a part of the permanent magnets is narrow, so the range in which high-efficiency operation can be performed is narrow. Become. A preferable value of the squareness ratio is 90 to 100%. The squareness ratio of the present invention is a value expressed by the ratio of residual magnetization to magnetization in a magnetic field of 10 kOe. 10 kOe
Was selected because the permanent magnet of the present invention has a coercive force of 5 kOe or less and a low coercive force of 10 kO.
This is because it is almost magnetically saturated in the magnetic field e and is suitable for defining the squareness ratio. In the case of a permanent magnet, the value obtained by dividing the square of the residual magnetization by 4 is usually the theoretical value of the maximum energy product,
The value obtained by dividing the actual maximum energy product value by this value is the squareness ratio. However, since the permanent magnet of the present invention controls the coercive force at a relatively small value, it represents a new squareness. As a good indicator,
The squareness ratio applied to the soft magnetic material was used as a reference.

The recoil permeability is preferably 1.00 to 1.08. The recoil permeability is obtained when the magnetized magnet is once magnetically saturated, the magnetic field is reversed and changed to a magnetic field corresponding to the coercive force, and then reversed again to change the magnetic field to zero. Magnetic susceptibility. The recoil permeability is less than 1.00 in principle, and if it exceeds 1.08, the magnetic flux control amount of the motor that can change the magnetization state of the whole or a part of the permanent magnets is reduced. The range that can be operated efficiently is narrowed. A preferred recoil permeability is 1.07 or less.
Further, the recoil permeability may be obtained by the following method. That is, the sample vibration type magnetometer is used to determine the change in magnetization due to the magnetic field in the second and third quadrants, for example, the change from 15 kOe to zero magnetic field. Specifically, the direction opposite to the direction in which the sample magnetized with a pulse magnetic field of 60 kOe is −
Magnetization measurement is performed by applying a magnetic field up to 15 kOe and changing the strength of the magnetic field from there to 0.
Thereafter, after applying a magnetic field up to −14 kOe, the magnetic field is similarly changed to zero and the magnetization is measured. This is repeated every 1 kOe and measured in the range from the third quadrant to the second quadrant. The recoil permeability approximates a straight line, and is a value obtained by dividing each magnetic field (−15 kOe, −14 kOe,...) And the difference in magnetization when the magnetic field is zero by the amount of change in the magnetic field. Magnetic susceptibility.
The coercive force and the squareness ratio are normal measurements, and the coercivity when the full-loop measurement is performed with the maximum magnetic field of 10 kOe, and the squareness ratio is the residual magnetization with respect to the magnetization at 10 kOe.

Each element shown in the general formula will be described.
Here, Ce is an essential element of the present invention, and together with Fe and B, the permanent magnet of the present invention forms a (rare earth) ₂ Fe ₁₄ B phase having a tetragonal structure as a main phase. Ce is an element essential for controlling the coercive force at a low value within the scope of the present invention as a magnet. However, when the rare earth element is only Ce, the Curie temperature is too low, so R1 (ie, Pr, This value can be increased by substituting (at least one selected from Nd and Sm ). In addition, Pr and Nd of R1 can increase the magnetic anisotropy and are effective in controlling the coercive force. As for the amount, R1 has an x value of 0.1 or more and 0.5 or less. If the x value exceeds 0.5, the coercive force becomes too large, which is insufficient for the magnetic flux control of the permanent magnet motor.
R2 is at least one selected from Dy, Tb, or the remaining elements not selected in R1, but (R2) after disposing the powder made of F3 on the surface of the sintered body and then diffusing it, Mainly existing in the field contributes to control of coercive force and improvement of temperature characteristics. The y value is 0.1 or less. In the case of R1, similarly, if it exceeds 0.1, it is difficult to control the coercive force, which is insufficient for the magnetic flux control in the motor that can change the magnetization state of the whole or a part of the permanent magnets. The total amount (x + y) of R1 and R2 elements is 0.1 or more and 0.5 or less, and preferably 0.2 ≦ x + y ≦ 0.5. Further, Ce, R1, and R2 are rare earth elements, and from the viewpoint of coercive force control, the element with the highest content is preferably Ce.
Furthermore, the total amount a of the rare earth element is 7 at% or more and 18 at% or less, and within this range, a predetermined coercive force and squareness ratio and an appropriate recoil permeability can be obtained. Preferably they are 8 at% or more and 17 at%, More preferably, they are 9 at% or more and 15 at% or less.

Fe is an essential element which is the basis of this magnet together with rare earth elements and B, and has the same tetragonal structure as a so-called (rare earth element) ₂ Fe ₁₄ B ₁ magnet. The amount is 50 at% or more and 80 at% or less. If it is out of this range, a heterogeneous phase will precipitate, making it difficult to obtain a high squareness ratio. Preferably they are 53 at% or more and 78 at% or less, More preferably, they are 55 at% or more and 75 at% or less. Co can replace a part of the Fe site, but is particularly effective in improving the Curie temperature in the present invention. The amount is less effective at less than 1 at%,
If it exceeds 30 at%, the recoil permeability increases, and if it exceeds this, a high squareness ratio cannot be obtained. Preferably, they are 2 at% or more and 25 at% or less.

As described above, B (boron) is one of the basic elements in the magnet of the present invention, and is an essential element for forming a predetermined crystal structure. The amount is 4 at% or more and 18 at% or less. Preferably they are 5 at% or more and 16 at%, More preferably, they are 5.5 at% or more and 15 at%.
C (carbon) is an element that can replace the B site in the crystal structure while maintaining the crystal structure, and is effective in controlling magnetic anisotropy. The amount is 5 at% or less, preferably 0
. It is 01 at% or more and 3 at% or less. It is preferable from the manufacturing aspect that the content of C does not exceed the content of B, and when it exceeds, the variation in magnetic properties starts to increase.
M element is at least one selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Ni, and Cu, and is effective for controlling high squareness by controlling crystal grains, or controlling coercive force. It is. The amount e value is 6 at% or less, preferably 5 at% or less. Preferred elements are Zr, Nb, and Cu. Moreover, it is preferable that the minimum of e value is 0.01 at% or more.

The X element is at least one selected from Ga, Al, and Si, which is also an effective element for coercive force control. The amount is 6 at% or less, preferably 5 at% or less. Preferred elements are Ga and Al. Moreover, it is preferable that the minimum of f value is 0.01 at% or more.

F (fluorine) is in the form of a compound with the rare earth element R2, and is effective in controlling the coercive force by being mainly present at the grain boundary by diffusion by heat treatment from the magnet sintered body. The amount is determined in consideration of the amount of R2, but if it is less than 0.01, the effect is small, while if it exceeds 3%, the coercive force becomes too large. Preferably, 0.01 ≦ h ≦ 2.5.

Like F, O (oxygen) is in the form of a compound with a rare earth element R2 and is diffused by heat treatment from a magnet sintered body to mainly exist at the grain boundary, thereby bringing about an effect of controlling the coercive force.
It is also an element that enters the process. That is, in accordance with diffusion by heat treatment of (R2) ₂ F ₃ , it is possible to form a phase composed of R 2 -F—O by combining with these elements. The amount is preferably 3 atomic% or less from the viewpoint of magnet characteristics. More preferably 2.5at
% Or less.

The crystal structure of the main phase of the magnet in the present invention is a tetragonal structure, and is expressed in terms of atomic ratio (rare earth element):
(FeCo): B = 2: 14: 1. Also, rare earth-rich (R1, R2
) In addition to the phase composed of the Fe—O system, there is at least one phase composed of the R2-F system or the phase composed of the R2-F—O system, and further boron other than the oxyfluoride phase and the main phase. A chemical phase or the like may be contained.

In addition to the above composition, the magnet of the present invention has hydrogen of 2000 wtppm or less and nitrogen of 1000 wtp.
You may contain below pm. In particular, when hydrogen is used in a process such as hydrogen pulverization, hydrogen may remain somewhat, but there is no problem in characteristics. In addition, elements other than the above components (
0.1 wt% or less may be contained.

The grain boundary phase adjacent to the main phase includes at least one of Fe and at least one of R1 and R2 and at least one of O or F at the grain boundary. Even if it is uniformly dispersed throughout, there may be a concentration gradient from the surface. This is the magnet thickness (
Depending on the distance to be diffused), it is preferable that there is a concentration gradient of R1 and R2 between the grain boundary and the main phase.
In the presence of this phase, the coercive force can be controlled in the range of 0.5 to 5 kOe,
It is also effective for improving temperature characteristics. The amount is 1 to 20% by area ratio. Preferably 2
~ 18%. This can be measured by a combination of EPMA and SEM, or TEM and EDX.
“Fe and at least one of R1 and R2 and at least one of O or F” are Fe—R1-O, Fe—R1-F, Fe—R2—
O phase, Fe-R2-F phase, Fe-R1-R2-O phase, Fe-R1-R2-F phase, Fe-R
1-O—F phase, Fe—R 2 —O—F phase, Fe—R 1 —F 2 —O—F phase is one or more, and even if these phases are present in two or more phases good. In this specification, “F
e and at least one of R1 and R2, at least one of O or F
The “phase consisting of seeds” is indicated as (R1, R2) -Fe— (O, F).

Although the manufacturing method regarding the mother alloy of the permanent magnet of this invention is not specifically limited, The following is mentioned as a method to obtain efficiently. The above-mentioned magnets are processed in the same manner as ordinary rare earth-iron-B magnets, ie, alloy melting / casting, strip casting, grinding,
Predetermined magnetic properties can be exhibited in the steps of molding, sintering, and heat treatment in a magnetic field.
Here, for the casting or strip casting of the alloy, the strip casting method is preferable from the homogeneity of the mother alloy, and the thickness of the obtained flake is approximately 70 μm or more and 2 mm or less. Preferably, the main component is 100 μm or more and 1 mm or less. Coarse grinding is performed using a jaw crusher, a stamp mill, or the like. In the case of a sample obtained by strip casting, coarse pulverization may be unnecessary. In addition, the sample produced by strip casting is effective in stabilizing the characteristics because the secondary phase is homogeneously dispersed.

Moreover, it is preferable to perform fine pulverization after coarse pulverization, and it is preferable to use a jet mill for the fine pulverization treatment, and it is preferable to use an average particle diameter of 1 to 50 μm. If the thickness is 1 μm or less, it is difficult to obtain a sufficient sintered density, and oxidation is likely to occur during processing, which causes deterioration of characteristics. On the other hand, when the thickness exceeds 50 μm, the squareness deteriorates and the recoil permeability after sintering also increases. Preferably it is 2-40 micrometers, More preferably, it is 3-30 micrometers. On the other hand, hydrogen pulverization using hydrogen may be used, but since this method may not reach a predetermined average particle diameter, hydrogen storage / release is repeated a plurality of times, or after hydrogen pulverization, a wet method such as a ball mill or Further pulverization may be performed by a dry method such as a jet mill.
Forming in a magnetic field may be a longitudinal magnetic field or a transverse magnetic field, and the magnetic field at that time is preferably stronger in order to be oriented, but it may be 10 to 20 kOe. Moreover, although the one where a shaping | molding pressure is higher is preferable, this should just be 100 kg / cm < ² > or more.

Sintering is performed at a temperature range of 1000 ° C. to 1200 ° C. for 10 minutes to 10 hours. Thereafter, the cooling rate is 1 to 100 ° C./min. Cool with. If it is less than 1000 ° C., sintering does not proceed and high remanent magnetization cannot be obtained. On the other hand, if it exceeds 1200 ° C., too much liquid phase will come out,
The shape molded into a predetermined shape cannot be maintained, and the effect of molding in a magnetic field is drastically reduced. In addition, when the sintering time is less than 10 minutes, the sintering does not proceed, and when it exceeds 10 hours, there is no difference from the time less than that,
10 hours or less is preferable from the viewpoint of energy consumption. Preferably, it is 30 minutes or more and 8 hours or less. When the cooling rate is less than 1 ° C./min, variation in the magnet characteristics becomes large.
If it exceeds 0 ° C./min, precipitation of the low melting point phase becomes difficult, and the coercive force varies. Moreover, a crack may enter into the produced sintered compact depending on the case. The sintering temperature is preferably 20 to 80 ° C. lower than the melting point of the main phase.

After (R2) ₂ O ₃ or (R2) F ₃ is disposed on the surface of the sintered body, heat treatment is performed for 1 hour to 100 hours in a temperature range of 300 ° C. or more and 50 ° C. below the sintering temperature. Here, (R2) F ₃ is preferably DyF ₃ , TbF ₃ , NdF ₃ , or PrF ₃ . Also, (R2
) ₂ O ₃ is preferably Dy ₂ O ₃ Tb ₂ O ₃ , Nd ₂ O ₃ , or Pr ₂ O ₃ . These materials can be applied with an alcohol-based material or powder can be disposed on the sintered body. The heat treatment is aimed at diffusing these oxides and fluorides into the magnet, but the heat treatment temperature is less than 300 ° C., and diffusion hardly occurs. On the other hand, when the temperature approaches the sintering temperature, the diffusion becomes too fast. Since it enters the main phase on average, it becomes the same situation as a normal magnet due to the small amount. Therefore, the upper limit temperature of the heat treatment for diffusion is up to 50 ° C. below the sintering temperature. The time is in the range of 1 hour to 100 hours, and the diffusion of oxide or fluoride whose characteristics can be sufficiently controlled can be performed. Furthermore, an aging treatment for adjusting the coercive force is performed by 4
It is performed at a temperature of 00 ° C. or higher and 800 ° C. or lower for 1 hour or more and 20 hours or less. This is because it is difficult to precipitate a low melting point phase (rare earth rich phase) at 400 ° C. or lower, and it is difficult to adjust the coercive force. On the other hand, when it exceeds 800 ° C., the effect of aging is reduced. The subsequent cooling rate is 0.1-20.
Cool to 200 ° C at a rate of ° C / min.

The aging treatment is preferably 450 ° C. or higher and 750 ° C. or lower. If the aging time is less than 10 minutes, it is difficult to obtain the effect, while if it exceeds 20 hours, the improvement of the magnet characteristics is not observed. For this reason, 2
0 hour or less is preferable. More preferably, it is 30 minutes or more and 15 hours or less. The aging treatment may be a multi-stage heat treatment of two or more stages, but in any case, the aging temperature is preferably moved from the high temperature side to the low temperature side, and the squareness is improved by the multi-stage treatment. In addition, also when it is set as multistage processing, the range of 10 minutes-20 hours is preferable for the total of heat processing time.
Moreover, the cooling rate after an aging treatment needs to be 0.1-20 degree-C / min. If the cooling rate is less than 0.1 ° C / min, the low melting point phase mainly composed of rare earths is partially aggregated, making it difficult to control the coercive force. If the cooling rate exceeds 20 ° C / min, the low melting point phase is precipitated. It becomes insufficient, and the variation in coercive force becomes large. Moreover, a preferable cooling rate is 1-10 degreeC / min.

In addition, as an aging treatment, a temperature range of 400 ° C. to less than 800 ° C. may be cooled at a constant cooling rate by a cooling method such as air cooling or water cooling in the aging treatment instead of the multi-stage aging treatment,
The cooling rate at that time needs to be 1 ° C./min to 20 ° C./min. These aging treatments may be performed as they are after sintering, or may be performed after cooling to room temperature and then raising the temperature again.
The atmosphere in this process is preferably a non-oxidizing atmosphere, and treatment in Ar, nitrogen and vacuum is preferred. The sintered density may be 95% or more, preferably 98% or more. The sintered density is determined by (actual measured value / theoretical density by Archimedes method) × 100%.

The magnet obtained by the above process has a main phase with high magnetic anisotropy (a rare earth-iron-boron phase mainly composed of tetragonal crystals) and a rare earth-rich (R1, R2) -Fe- In addition to the phase composed of (O, F), at least one phase composed of R2- (F, O) is preferably present. The ratio of the nonmagnetic rare earth-rich phase and the like is preferably 1 to 20 area% or less. Beyond this, the saturation magnetic flux density and the residual magnetic flux density decrease, and the control of the magnetic flux becomes insufficient. On the other hand, when it is 1% or less, the nonmagnetic phase becomes too small, and the number of places where the nonmagnetic phase does not exist between the main phases increases, making it difficult to control the coercive force and the squareness.
The rare earth-rich phase, that is, the (R1, R2) —Fe— (O, F) phase is mainly composed of 50 to 90 at% of the rare earth metal element. In addition, other nonmagnetic phases, for example, a rare earth oxide phase, a boride phase, and the like may be included at 10% by area or less.
The obtained magnet can be used in various environments by performing various surface treatments such as Ni plating, Cu plating, and Al plating in order to provide oxidation resistance.

(Example)
(Examples 1-30)
About the composition shown in Table 1, after preparing raw material powder, it melt | dissolved in the high frequency induction heating furnace, and produced the flake-like sample with a plate thickness of 100-300 micrometers by strip casting method as it is. The obtained sample was pulverized to an average particle size shown in Table 1 by a jet mill, and then a magnetic field of 10 kO.
e. Molding was performed in a magnetic field under the condition of a pressing pressure of 0.5 t / cm 2. The obtained molded body was sintered at a temperature 20 to 80 ° C. lower than the melting point of the matrix phase for 3 hours, and cooled to room temperature at a rate of 50 ° C./min. After this, Examples 1-15 are fluorides, odd numbers are DyF ₃ and even numbers are TbF.
3 and Examples 16 to 30 were oxides, odd numbers Dy ₂ O ₃ and even numbers Tb ₂ O ₃ dissolved in an alcohol-based solution and applied to the surface of the sintered body with a thickness of about 1 mm. After drying, 800
After heat treatment at ˜900 ° C. for 8 hours, aging treatment is carried out at 500˜550 ° C. for 10 hours and 2 ° C./m
It was cooled at the rate of in. The permanent magnet according to each example is a sintered body having a density of 98% or more.
In any case, 100 samples were prepared, and the residual magnetic flux density (Br), the coercive force (Hc), the squareness ratio, the recoil permeability, and the Hc range were measured as evaluation of the magnet characteristics. Residual magnetic flux density (Br)
, Coercive force (Hc), squareness ratio, recoil permeability were measured using the methods described above, and 10
The average value was zero. The Hc range shows the variation in coercive force, and was obtained from “maximum value−minimum value” of 100 coercive forces (Hc). The results are shown in Table 1.

As a result of evaluating the magnet characteristics of these examples, as shown in Table 1, a high squareness ratio, a low coercive force, and a small recoil permeability were obtained. In addition, the ratio of the grain boundary phase was 8 to 15% in any area ratio by SEM observation, and a phase composed of any of (R1, R2) —Fe— (O, F) phases could be confirmed.

(Comparative example)
(Comparative Examples 1-7)
The materials prepared in the compositions of Comparative Examples 1 to 7 shown in Table 1 are melted by high frequency, cast into a water-cooled mold, coarsely pulverized to 35 mesh through with a stamp mill, and then time is 30 minutes with a ball mill.
Milled for 3 hours. The average particle size is 4.8 μm. The obtained powder was oriented at a magnetic field of 10 kOe and molded at 1.5 t / cm ² . The molded body was 1150 ° C. for 1 hour, Ar
After sintering in the atmosphere, it was allowed to cool. Comparative Examples 1 to 7 have compositions that do not contain Ce.
(Comparative Example 8)
For the alloy of Comparative Example 8 shown in Table 2, the magnet raw material was first melted in a high frequency induction furnace. The crucible was an aluminum crucible and cast into a water-cooled copper mold to make a master alloy. The mother alloy obtained by dissolution was coarsely pulverized by 35 mesh, and further pulverized by a ball mill so that an average particle size of 8.5 μm was obtained. Thereafter, the powder was molded at a predetermined pressure in a magnetic field. 1 molded body
Ar atmosphere sintering was performed at 150 ° C. for 2 hours, and then heat treatment was performed at 700 ° C. for 3 hours. The cooling rate after the aging heat treatment is left to cool at 100 ° C./min.
(Comparative Examples 9 and 10)
The alloys shown in Comparative Examples 9 and 10 were melted at high frequency and cast into a water-cooled copper mold. Next, coarsely pulverized to 35 mesh through with a stamp mill, then finely pulverized with a ball mill for 3 hours,
The average particle size was 7 μm. Then, orientation and molding in a magnetic field (10 kOe) (pressurization at 1.5 t / cm 2), the obtained molded body was sintered in an Ar atmosphere at 1160 ° C. for 1 hour, and allowed to cool after cooling (cooling) Speed was 200 ° C./min).

(Comparative Example 11)
An alloy having the composition of Comparative Example 11 was melted in an Ar gas arc, and then cast into a water-cooled copper mold. This alloy was coarsely pulverized to 40 mesh or less with a stamp mill and then average particle size 7 in an organic solvent.
Finely pulverized to a μm by a ball mill. The obtained powder was 1.0 ton in a 15 kOe magnetic field.
After pressure molding at a pressure of / cm ² , it is 106 in 99.999% pure 180 Torr Ar.
Sintering was carried out at 0 ° C. for 2 hours, and after sintering, the mixture was cooled to room temperature at a cooling rate of 350 ° C./min. 6 more
An aging treatment was performed at 725 ° C. for 2 hours in 00 TorrAr. The cooling rate after the aging heat treatment is left to cool at 100 ° C./min.
(Comparative Examples 12-15)
The alloys shown in Comparative Examples 12 to 15 were melted at high frequency and cast into water-cooled copper molds. Next, coarsely pulverized to 35 mesh through with a stamp mill, then finely pulverized with a ball mill for 3 hours,
The average particle size was 5 μm. Thereafter, orientation in a magnetic field (10 kOe) and molding (pressurization at 1.5 t / cm ² ), the molded body was sintered in an Ar atmosphere at 1150 ° C. × 1 hour, and allowed to cool after sintering (200
° C / min).

(Comparative Examples 18-20)
About the composition of Comparative Examples 18-20, after producing a mother alloy by high frequency melt | dissolution, it rapidly_cool | quenched by the single roll method, The plate-shaped sample of 20-40 micrometers in thickness was obtained. This was pulverized by a jet mill and then molded in a magnetic field under the same conditions as in Comparative Example 1. In this comparative example, the crystal grains are as small as nm, and as a result, the magnet is only isotropic. In addition, since the magnetic properties of the molded body thus obtained deteriorated when sintered, the ground sample was solidified with a resin and measured. Therefore, the characteristics as a sintered magnet are insufficient.

(Comparative Examples 21-23)
About the composition of Comparative Examples 21-23, it melt | dissolves in Ar gas using a high frequency melting furnace. The alloy is pulverized into a fine powder having a particle size in the range of 2 μm to 5 μm using a ball mill. The fine powder was compression-molded in a magnetic field, and the compact was subjected to a solution treatment at 1100 ° C. for 1 hour and after sintering at 1070 ° C. for 2 hours, and then rapidly cooled, and further subjected to an aging treatment at 800 ° C. for 2 hours. The cooling rate after the aging heat treatment is left to cool at 100 ° C./min.
(Comparative Examples 24 and 25)
About the composition of the comparative examples 24 and 25, it melt | dissolves in Ar gas using a high frequency melting furnace. The alloy is made into a fine powder having a particle size of 2 μm to 5 μm using a ball mill. This powder is compression-molded in a magnetic field, and the compact is sintered at 1100 ° C. for 1 hour, then subjected to solution treatment at 1070 ° C. for 2 hours, rapidly cooled, and further subjected to aging treatment at 800 ° C. for 4 hours to obtain a permanent magnet. It was. In addition, after aging heat processing, it stood to cool with the cooling rate of 100 degrees C / min.

(Comparative Examples 26, 27, 28)
About the composition of Comparative Examples 26-28, it melt | dissolves in Ar gas using a high frequency melting furnace. And this alloy is grind | pulverized to the fine powder of the particle size range of 2 micrometers-5 micrometers using a ball mill. This powder was compression-molded in a magnetic field, and the compact was sintered at 1100 ° C. for 1 hour, then subjected to solution treatment at 1070 ° C. for 2 hours, quenched, and further subjected to aging treatment at 800 ° C. for 2 hours. In addition, after aging heat processing, it stood to cool with the cooling rate of 100 degrees C / min.
(Comparative Examples 29 and 30)
About the composition of the comparative examples 29 and 30, it melt | dissolves in Ar gas using a high frequency melting furnace. The alloy is made into a fine powder having a particle size of 2 μm to 5 μm by a ball mill. This powder is compression-molded in a magnetic field, the molded body is sintered at 1100 ° C. for 1 hour, and then subjected to a solution treatment for 1070 ° C. for 2 hours, followed by rapid cooling,
Further, a permanent magnet was obtained by aging treatment at 800 ° C. for 4 hours. The cooling rate is 1 after aging heat treatment.
It is cooled at 00 ° C./min.

(Comparative Examples 31-33)
After preparing the raw material powder having the composition shown in Table 2, it was melted in a high frequency induction heating furnace, and a flake sample having a plate thickness of 100 to 300 μm was produced by the strip casting method as it was. The obtained sample was finely pulverized with a jet mill to an average particle size of 5 to 8 μm, and then molded in a magnetic field under conditions of a magnetic field of 10 kOe and a press pressure of 0.5 t / cm 2. The obtained molded body is 5 from the melting point of the parent phase.
Sintering was performed at a low temperature of 0 ° C. for 3 hours, and then cooled to room temperature at a rate of 50 ° C./min. Thereafter, heat treatment was performed at 700 ° C. for 3 hours, and cooling was performed at a rate of 10 ° C./min. These processes are all performed in an Ar atmosphere.
In any case, 100 samples were prepared, and the residual magnetic flux density (Br), the coercive force (Hc), the squareness ratio, the recoil permeability, and the Hc range were measured as evaluation of the magnet characteristics. Residual magnetic flux density (Br)
, Coercive force (Hc), squareness ratio, recoil permeability were measured using the methods described above, and 10
The average value was zero. The Hc range shows the variation in coercive force, and was obtained from “maximum value−minimum value” of 100 coercive forces (Hc). The results are shown in Table 1.
Table 2 also shows the results of evaluating the magnet characteristics under the same measurement conditions as in the examples for the magnets of each comparative example. In any of the comparative examples, it can be seen that the coercive force is too large or too small, and the squareness is deteriorated.

(Application to motor)
The characteristics when Examples 1 to 30 and Comparative Examples 1 to 20 were incorporated into a permanent magnet motor were evaluated at room temperature. As an evaluation of the motor characteristics, the permanent magnets according to the respective examples and comparative examples are incorporated in the low coercive force magnet portion of the motor capable of changing the magnetization state of all or part of the permanent magnets shown in FIG. NdFeB magnet (Hc = 21 kOe, Br = 12.
4kG) was used to evaluate the efficiency of the motor. Table 2 shows an alnico magnet as Comparative Example 34.
The permanent magnet motors used as references are all based on the efficiency when using NdFeB magnets (Comparative Example 35: the same magnet as the low coercive force side is used for the low coercive force side) as the reference, and the relative efficiency of the example and the comparative example. Shown as a value. The evaluation condition is an average value of efficiency at high speed rotation (3000 rpm), medium speed rotation (2000 rpm), and low speed rotation (1000 rpm) of the motor. These conditions are low torque, medium torque, and high torque when torque is used as an index, and the efficiency under each operating condition is reflected.
The results are shown in Tables 1 and 2 together. When the permanent magnet according to this example is used, NdF
It can be seen that the efficiency is significantly improved as compared with a permanent magnet motor using only an eB magnet, and that the efficiency is higher than when an alnico magnet is used.

In addition, although applied to the motor which can change the magnetization state of the whole or a part of permanent magnet of the structure shown in FIG. 2 as an embodiment this time, a magnet having a high coercive force and a magnet having a relatively small coercive force. As long as the permanent magnet of the present embodiment is used as a permanent magnet motor magnet constituted by the combination, the motor structure is not particularly limited.

(Examples 31-36, Comparative Examples 36-37)
The permanent magnets of Example 3 were used and the production conditions were changed as shown in Table 3. For each of the examples and comparative examples, the same measurement as in Example 3 was performed. The results are shown in Table 3 below.

  It can be seen that the desired characteristics can be obtained under the manufacturing conditions according to this example.

The figure which shows an example of a permanent magnet motor. The figure which shows an example of the motor using the permanent magnet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Rotor core 3 ... Low coercivity permanent magnet 3A ... High coercivity permanent magnet 3B ... High coercivity permanent magnet 4 ... High coercivity permanent magnet 4A ... Low coercivity permanent magnet 4B ... High coercivity permanent magnet 5 ... First 1 cavity 6 ... 2nd cavity 7 ... magnetic pole part of iron core 11 ... slit 12 ... slit 14 ... permanent magnet

Claims (12)

In addition to satisfying the following general formula, at least one of Fe and at least one of R1 and R2, or O or F is present at the grain boundary, and the coercivity at room temperature is 0. A permanent magnet having a remanent magnetic flux density of 7.9 kG or more and a squareness ratio expressed by a ratio of residual magnetization to magnetization in a magnetic field of 10 kOe is 80% or more.
Formula _{(Ce 1-x-y R1} x R2 y) a Fe b Co c B d M e X f C g A h
R1: At least one selected from Nd, Pr, Sm R2: Tb, Dy, or at least one selected from elements not selected by R1 M: Ti, Zr, Hf, V, Nb, Ta, Cr, Mo At least one selected from W, Mn, Ni, Cu X: at least one selected from Ga, Si, Al A: at least one selected from F, O 0.1 ≦ x ≦ 0.5
0 ≦ y ≦ 0.1
0.1 ≦ x + y ≦ 0.5
7 ≦ a ≦ 18
50 ≦ b ≦ 80
1 ≦ c ≦ 30
4 ≦ d ≦ 18
0 ≦ e ≦ 6
0 ≦ f ≦ 6
0 ≦ g ≦ 5
0.01 ≦ h ≦ 3
a + b + c + d + e + f + g + h = 100 atomic%   The permanent phase according to claim 1, wherein the phase composed of Fe and at least one of R1 and R2, and at least one of O or F has a total of R1 and R2 of 50 atomic% or more. magnet.   The permanent magnet according to any one of claims 1 and 2, wherein at least one selected from R2-Fe-F, R2-Fe-O, and R2-Fe-FO is included. 4. The permanent magnet according to claim 1, wherein the main phase is based on tetragonal structure (Ce, R ₁ ) ₂ Fe ₁₄ B _{1. 5} .   5. The permanent magnet according to claim 1, wherein the phase existing in the grain boundary has an area ratio of 1 to 20% in terms of area ratio.   The permanent magnet according to any one of claims 1 to 5, wherein a recoil permeability is 1.00 to 1.08.   The permanent magnet according to claim 1, wherein the permanent magnet is a sintered body.   The permanent magnet according to claim 1, wherein the permanent magnet is mounted on a motor. A molding step for adjusting a molded body by molding an alloy powder satisfying the following general formula in a magnetic field, and sintering the molded body at a temperature of 1000 ° C. to 1200 ° C. for 10 minutes to 10 hours in an inert atmosphere. Sintering step to obtain a sintered body, (R2) ₂ O ₃ or (R2) F ₃ is disposed on the surface of the sintered body, and then for 1 hour in a temperature range of 300 ° C. or more and 50 ° C. below the sintering temperature The step of performing the heat treatment within 100 hours, the step of aging at a temperature of 400 ° C. or higher and 800 ° C. or lower for 1 hour or longer and 20 hours or shorter, and then cooling to 200 ° C. at a cooling rate of 0.1 to 20 ° C./min. A method for manufacturing a permanent magnet.
Formula _{(Ce 1-x-y R1} x R2 y) a Fe b Co c B d M e X f C g A h
R1: At least one selected from Nd, Pr, Sm R2: Tb, Dy, or at least one selected from elements not selected by R1 M: Ti, Zr, Hf, V, Nb, Ta, Cr, Mo At least one selected from W, Mn, Ni, Cu X: at least one selected from Ga, Si, Al A: at least one selected from F, O 0.1 ≦ x ≦ 0.5
0 ≦ y ≦ 0.1
0.1 ≦ x + y ≦ 0.5
7 ≦ a ≦ 18
50 ≦ b ≦ 80
1 ≦ c ≦ 30
4 ≦ d ≦ 18
0 ≦ e ≦ 6
0 ≦ f ≦ 6
0 ≦ g ≦ 5
0.01 ≦ h ≦ 3
a + b + c + d + e + f + g + h = 100 atomic% At least a portion (R2) ₂ O ₃ or (R2) method for producing a permanent magnet according to claim 9, wherein in that a F ₃ of the sintered body surface.   The coercive force at room temperature is 0.5 kOe or more and 5 kOe or less, and the squareness ratio expressed by the ratio of the residual magnetization to the magnetization in a magnetic field of 10 kOe is 80% or more. A method for manufacturing a permanent magnet. A motor comprising the permanent magnet according to any one of claims 1 to 8.

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