JP3040895B2 - Rare earth bonded magnet and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnet roll,
Rare earth bonded magnets suitable for speakers, magnetic circuits for magnetic sensors, various meter and focusing magnets, motors and actuators, and methods of manufacturing the same. Fe of a specific composition with low rare earth element content.
-VBR, Fe-VBRM (M = Al, S
i) The alloy melt is made to have an amorphous structure by a rapid quenching method using a rotating roll, a splat quenching method, a gas atomizing method or a combination thereof, and iron having a body-centered tetragonal Fe ₃ P type crystal structure is obtained by a specific heat treatment. An alloy powder consisting of a fine crystal aggregate of a boride phase as a main component and a constituent phase of the Nd ₂ Fe ₁₄ B type crystal structure is obtained, and this is bonded with a resin. The present invention relates to a rare-earth bonded magnet for obtaining an Fe-BR-based bonded magnet having a residual magnetic flux density Br of 5 kG or more and a method of manufacturing the same.

[0002]

2. Description of the Related Art Permanent magnets used in magnet rolls for electrostatic development, motors for electric components, actuators, and the like have been mainly limited to hard ferrite magnets. There is a problem that the ceramic material has a low mechanical strength due to a low mechanical strength, so that cracking and chipping are likely to occur, and a complicated shape is difficult to obtain.

[0003] Today, there is a strong demand for automobiles to improve fuel efficiency by reducing the weight of the vehicles in order to save resources, and it is required to further reduce the size and weight of electrical components for automobiles. Also,
Designs to maximize the performance-to-weight ratio are also being considered for applications such as motors for home appliances other than automotive electrical components, and the current motor structure is optimal for magnet materials with a Br material of about 5 to 7 kG. It has been. That is,
When Br of the magnet material to be used is 8 kG or more, the current motor structure needs to increase the cross-sectional area of the iron plate of the rotor or the stator which becomes the magnetic path, which leads to an increase in weight. If so, the performance to weight ratio can be maximized.

Accordingly, a magnetic material for a small motor is required to have a residual magnetic flux density Br of at least 5 kG in terms of magnetic properties, but cannot be obtained with a conventional hard ferrite magnet. For example, an Nd—Fe—B-based bonded magnet satisfies such magnetic properties, but Nd or the like, which requires a large number of steps and large-scale facilities for metal separation and purification or reduction reaction, is required.
Since it contains １５15 at%, it is significantly more expensive than a hard ferrite magnet, and at present, a magnet material having Br of about 5 to 7 kG that can be mass-produced and can be provided at low cost has not been found.

[0005]

On the other hand, Nd-Fe-B
Recently, a magnetic material having a main phase of a Fe ₃ B type compound in the vicinity of Nd ₄ Fe ₇₇ B ₁₉ (at%) has been proposed as a system magnet (R. Coehoorn et al., J. de Phys., C.
8, 1988, 669-670). This magnet material is obtained by heat-treating an amorphous ribbon to obtain a magnet material having a crystal texture of metastable Fe ₃ B and a metastable phase of Nd ₂ Fe ₁₄ B. However, iHc is 2-3 kOe.
The heat treatment conditions for obtaining this iHc are narrow and limited, and are not practical for industrial production.

Researches have been published to improve the performance by adding an additional element to the magnetic material having the Fe ₃ B-type compound as a main phase to make it multi-component. One of them is to improve iHc by using Dy and Tb in addition to Nd as a rare earth element. In addition to the problem of adding an expensive element, the added rare earth element has a magnetic moment of Nd or Fe. There is a problem that magnetization decreases due to coupling in anti-parallel to the moment (R. Coehorn, J. Magn, Magn, M
at. , 83 (1990) 228-230).

[0007] Other studies (Shen Bao-gen et al.,
J. See Magn, Magn, Mat. , 89 (1991)
(Pp. 335-340) is to improve the temperature coefficient of iHc by replacing a part of Fe with Co to improve the temperature coefficient of iHc, but there is a problem that Br is reduced with the addition of Co.

In any case, Fe ₃ B type Nd-Fe-B
The system magnet can be made into a hard magnet material by heat treatment after being made amorphous by a super-quenching method. For example, stable industrial production cannot be performed, and it cannot be provided at a low cost as a substitute for a hard ferrite magnet.

The present invention focuses on Fe ₃ B type Fe—BR based magnets (R is a rare earth element) and focuses on iHc and (BH) m
ax has been improved, a manufacturing method that enables stable industrial production has been established, and a residual magnetic flux density Br of 5 kG or more has a cost performance comparable to that of hard ferrite magnets.
It is intended to provide a Fe ₃ B type Nd-Fe-B based bonded magnet and a manufacturing method thereof can be provided at low cost.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been studied variously for the purpose of improving the iHc and (BH) max of a Fe ₃ B type Fe—BR magnet and enabling a stable industrial production. As a result, a rare-earth element content is low, and V or at least one of Al and Si is added in a small amount to form a molten alloy having a specific composition of an iron-based alloy having an amorphous structure by a super-quenching method or the like. The present inventors have found that by obtaining a fine crystal aggregate by heat treatment, a bonded magnet having a residual magnetic flux density Br of 5 kG or more, which cannot be obtained with a hard ferrite magnet, can be obtained, and the present invention has been completed.

According to the present invention, the composition formula is represented by Fe _100-xyz V _x B
_y R _z (where R is Pr or one or two of Nd) expressed as, or even a composition formula Fe _100-xyz V _x B _y
R _z M _w (where R is one or two of Pr or Nd,
M represents one or two types of Al or Si), and the symbols x, y, z, and w that limit the composition range satisfy the following values, and iron having a body-centered tetragonal Fe ₃ P type crystal structure is mainly used. When the boride phase as a component and the constituent phase having the Nd ₂ Fe ₁₄ B type crystal structure coexist in the same powder particle, and the average crystal grain size of each constituent phase is in the range of 5 nm to 100 nm, Expresses the required intrinsic holding power of 4 kOe or more and has an average particle size of 3 μm
By bonding powder having a size of about 500 μm with a resin and molding and solidifying it into a required shape, a metastable crystal structure phase can be provided in a form usable as a bond magnet without decomposition of a metastable crystal structure phase at around room temperature. 0.01 ≦ x ≦ 10 at% 16 ≦ y ≦ 22 at% 3 ≦ z ≦ 5.5 at% 0.1 ≦ w ≦ 3 at%

Further, the present invention is, (1) the composition formula _{Fe 100-xyz V x B y} R z ( where R is P
It represents r or one or two of Nd) with, or in addition, one or two of the compositional formula _{Fe 100-xyz V x B y} R z M w ( where R is Pr or Nd, M is Al or Si
And the symbols x, y, z, and w, which limit the composition range, satisfy the above-mentioned values. An ultra-rapid cooling method using a rotating roll, a splat quenching method, a gas atomizing method, or any of these methods. And quenched, practically 9
0% or more has an amorphous structure. (2) During the heat treatment, the temperature is raised from 1 ° C./min from around the temperature at which a boride phase mainly composed of iron having an Fe ₃ P type crystal structure is precipitated. 620 ℃ by heating up to ~ 15 ℃ / min
(3) a boride phase mainly composed of iron having an Fe ₃ P type crystal structure and a constituent phase having an Nd ₂ Fe ₁₄ B type crystal structure Are obtained in the same powder particles, and a microcrystalline aggregate having an average crystal grain size of each constituent phase in the range of 5 nm to 100 nm is obtained. A rare earth bonded magnet, wherein the magnet alloy powder is bonded with a resin.

Reasons for Restriction of Composition Only when the rare earth element R contains one or two kinds of Pr or Nd in a specific amount, high magnetic properties can be obtained.
For example, in Ce and La, iHc characteristics of 2 kOe or more cannot be obtained, and middle rare earth elements and heavy rare earth elements after Sm cause deterioration of magnetic characteristics and make the magnet expensive, which is not preferable. If R is less than 3 at%, iHc of 4 kOe or more cannot be obtained, and if it exceeds 5.5 at%, F
R ₂ F, a metastable phase that does not produce e ₃ B phase and shows no hard magnetism
Since e ₂₃ B ₃ phase folding out iHc is not preferable because it decreases significantly, and the range of 3~5.5at%.

If B is less than 16 at% or more than 22 at%, iHc of 4 kOe or more cannot be obtained.
２２22 at%.

V is effective for improving iHc.
If it is less than 01 at%, such an effect cannot be obtained and 10 at%
Is exceeded, the squareness of Br and the demagnetization curve is significantly reduced, and Br of 6 kG or more cannot be obtained.
The range is 0 at%.

Al and Si increase the temperature range of the heat treatment and improve the squareness of the demagnetization curve.
H) has an effect of increasing max, and at least 0.1 at% or more is required to obtain such an effect, but if it exceeds 3 at%, the squareness is rather deteriorated,
Since (BH) max also decreases, the range is 0.1 to 3 at%.

[0017] Fe accounts for the residual content of the above-mentioned elements.

Reasons for Limiting Constituent Phase of Powder The alloy powder constituting the bonded magnet according to the present invention is 1.6.
It is characterized in that the main phase is a boride phase mainly composed of iron having a body-centered tetragonal Fe ₃ P type crystal structure having a high saturation magnetization of T. In the boride phase, Fe ₃ B or a part of Fe therein is replaced by Co. This boride phase is metastable in a specific range in the space group P ₄ / nmn
Nd _{2 (} Fe, N) having the Nd ₂ Fe ₁₄ B type crystal structure
i) Can coexist with _14B ferromagnetic phase. The coexistence of these boride phase and ferromagnetic phase requires high magnetic flux density and sufficient iHc
For example, in the casting method or the like, the Fe ₂ B phase having the C16 type crystal structure and the body-centered tetragonal α-Fe phase are indispensable for obtaining In the main phase, high magnetization is obtained, but iHC is 1 kOe.
It is not preferable because it deteriorates below and cannot be used as a magnet.

Reasons for Limiting Crystal Grain Size and Powder Grain Size A boride phase containing iron as a main component and having a body-centered tetragonal Fe ₃ P type crystal structure coexisting in the alloy powder constituting the bonded magnet of the present invention, and Nd Each of the ₂ Fe ₁₄ B-type crystal structures is a ferromagnetic phase, but the former phase alone is magnetically soft, and the coexistence of the latter phase is indispensable for expressing iHc. However, simply coexisting both phases is not sufficient, and if the average crystal grain size of both is not in the range of 5 nm to 100 nm, the squareness of the second quadrant of the demagnetization curve deteriorates,
Since a permanent magnet cannot take out sufficient magnetic flux at the operating point, the average crystal grain size is 5 nm to 100 n.
m. To perform high-precision molding by taking advantage of the characteristics of bonded magnets that can produce magnets with complex shapes and thin shapes, the particle size of the powder must be sufficiently small, but the particle size obtained by atomization must be 100 μm. The excess alloy powder is not sufficiently cooled to the inside of the powder during rapid cooling, and most of it is α-Fe
Phase, so that Fe ₃ B and Nd ₂ F
e ₁₄ B phase does not precipitate and cannot be a hard magnetic material. If the particle diameter is less than 3 μm, a large amount of resin must be used with an increase in the specific surface area, and the packing density is undesirably reduced. Therefore, the powder particle diameter is limited to 3 μm to 500 μm.

The bonded magnet according to the present invention is an isotropic magnet, and has the following compression molding, injection molding, extrusion molding,
Any known production method such as rolling molding and resin impregnation may be used. In the case of compression molding, it is obtained by adding and mixing a thermosetting resin, a coupling agent, a lubricant and the like to the magnetic powder, and then compressing and curing the heated resin. In the case of injection molding, extrusion molding, and rolling molding, add a thermoplastic resin, a coupling agent, a lubricant, etc. to the magnetic powder and mix them. can get. In the resin impregnation method, after magnetic powder is compression-molded, heat-treated if necessary, then impregnated with a thermosetting resin, and heated to cure the resin. Further, the magnetic powder is obtained by compression molding, heat-treating as necessary, and then impregnating with a thermoplastic resin.

In the present invention, the weight ratio of the magnetic powder in the bonded magnet varies depending on the above-mentioned manufacturing method.
5 wt%, and the remaining 0.5 to 30 wt% is resin and others. In the case of compression molding, the weight ratio of the magnetic powder is 95 to 9
9.5 wt%, in the case of injection molding, the filling rate of the magnetic powder is 9
In the case of the resin impregnation method, the weight ratio of the magnetic powder is preferably 96 to 99.5 wt%. As the synthetic resin in the present invention, any of thermosetting and thermoplastic properties can be used, but a thermally stable resin is preferable.
For example, polyamide, polyimide, phenol resin, fluorine resin, silicon resin, epoxy resin and the like can be appropriately selected.

Reasons for Limiting Manufacturing Conditions In the present invention, the temperature at which the molten alloy having the above-mentioned specific composition is made amorphous by a rapid quenching method and a boride phase mainly composed of iron having an Fe ₃ P type crystal structure is precipitated. The temperature is raised from 1 ° C / min to 15 ° C / min.
By performing heat treatment at 750 ° C. for 10 seconds to 6 hours, a Fe ₃ B phase having a Fe ₃ P type crystal structure and a Nd ₂ Fe ₁₄ B type crystal structure which are thermodynamically Ferromagnetic phases coexist and the average crystal grain size of each constituent phase is 5n
It is most important to obtain a microcrystal aggregate in the range of m to 100 nm. For the ultra-quenching treatment of the molten alloy, a known ultra-quenching method using a rotating roll can be employed.
If an amorphous content of not less than% is obtained, a splat quenching method, a gas atomizing method, or a quenching method combining these may be employed in addition to the ultra-quenching method using a rotating roll. For example, when a Cu roll is used, it is preferable that the roll surface peripheral speed is in the range of 10 to 50 m / sec because a suitable structure can be obtained. In other words, if the peripheral speed is less than 10 m / sec, it does not become amorphous and the precipitation amount of the α-Fe phase increases, which is not preferable. If the roll surface peripheral speed exceeds 50 m / sec, a quenched alloy is formed as a continuous ribbon. However, the alloy pieces are scattered, and the recovery rate and recovery efficiency when recovering the alloy from the apparatus are undesirably reduced. However, even if a trace amount of the α-Fe phase is present in the quenched ribbon, the characteristics are not remarkably deteriorated but are acceptable.

In the present invention, after the molten alloy having the above-mentioned specific composition is made substantially 90% or more amorphous by the ultra-quenching method, the heat treatment for maximizing the magnetic properties depends on the composition. If the temperature is lower than 620 ° C., Nd ₂ Fe ₁₄ B
No phase was precipitated, iHc of 4 kOe or more was not obtained, and when the temperature exceeded 750 ° C., the α-Fe phase which is a thermal equilibrium phase and Fe ₂
Since B or Nd _1.1 Fe ₄ B ₄ phase is generated iHc is not expressed, the heat treatment temperature is limited to not more than six hundred and twenty to seven hundred fifty ° C.. The heat treatment atmosphere is preferably an inert gas atmosphere such as Ar gas. The heat treatment time may be short, but if it is less than 10 seconds, a sufficient microstructure is not formed, and the squareness of iHc and demagnetization curve is deteriorated.
e, iHc longer than e cannot be obtained.
Limited to 0 seconds to 6 hours.

An important feature of the present invention is the rate of temperature rise from the temperature at which a boride phase mainly composed of iron having an Fe ₃ P type crystal structure is precipitated during heat treatment.
At a heating rate of less than ° C./min, the crystal grain size of the Nd ₂ Fe ₁₄ B phase and the Fe ₃ B phase grows too large during the heating, so that iHc is deteriorated and iHc of 4 kOe or more cannot be obtained. Also, 1
At a heating rate exceeding 5 ° C./min, the Nd ₂ Fe ₁₄ B phase generated after passing 620 ° C. is not sufficiently precipitated,
The precipitation amount of the α-Fe phase increases, and the magnetization curve becomes a demagnetization curve with a decrease in magnetization near the Br point in the second quadrant of the magnetization curve.
H) It is not preferable because max is deteriorated. However, the presence of a small amount of the α-Fe phase is acceptable. The rate of temperature rise is arbitrary up to a temperature lower than the temperature at which a boride phase mainly composed of iron having an Fe ₃ P-type crystal structure is precipitated during heat treatment, and it is possible to increase the processing efficiency by applying rapid heating or the like. it can.

The crystal phase of the rare earth magnet and the rare earth magnet alloy powder according to the present invention is mainly composed of a boride mainly composed of iron having an Fe ₃ P type crystal structure, and has a Nd ₂ Fe ₁₄ B type crystal structure. Having an average crystal grain size of 5 nm to 100 n
It is characterized by comprising a fine crystal aggregate of m. In the present invention, the average grain size of the magnet alloy is 100 nm.
Is exceeded, the squareness of the demagnetization curve is significantly deteriorated, and Br ≧
Magnetic properties of 5 kG and (BH) max ≧ 6 MGOe cannot be obtained. The average crystal grain size is preferably as small as possible, but it is difficult to obtain an average crystal grain size of less than 5 nm in industrial production, so the lower limit is set to 5 nm.

[0026]

According to the present invention, a molten Fe—V—B—R alloy having a specific composition containing a small amount of rare earth element (R is Nd or Pd)
r) or Fe-VBRM alloy melt (M is A
(1 or 2 types of Si) by the above-mentioned ultra-quenching method to form substantially 90% or more of an amorphous structure, and to obtain the obtained ribbon, flake, and spherical powder from 1 to 15 from the Fe ₃ B precipitation temperature or higher. After raising the temperature at a rate of 60 ° C./min,
By performing heat treatment at 50 ° C. for 10 seconds to 6 hours, thermodynamically, it has a Fe ₃ B phase having a Fe ₃ P type crystal structure and a Nd ₂ Fe ₁₄ B type crystal structure, which are metastable phases. Ferromagnetic phases coexist, and the average crystal grain size of each structural phase is 5 nm to 1
A microcrystalline aggregate in the range of 00 nm is obtained. At this time, V
In a composition containing no, when the temperature exceeds 700 ° C., an α-Fe phase and a Fe ₂ B phase, which are thermal equilibrium phases, or Nd _1.1 Fe ₄ B ₄ are formed and iHc is not expressed, whereas in a composition containing V, the Fe ₃ B phase and Nd _{The 2} Fe ₁₄ B phase is more thermally stable than the composition without V, and exhibits higher iHc than the composition without V in a wide temperature range of about 620 ° C. to 750 ° C. Further, by containing one or two kinds of Al and Si simultaneously with V, it is possible to improve the deterioration of Br and the square of the demagnetization curve when V is contained, iHc ≧ 4 kG, Br ≧ 6 kG,
(BH) It is possible to obtain a bonded magnet having a magnetic property of max ≧ 6MGOe.

[0027]

Example 1 Example 1 of Table 1 Purity 99.5 so as to have a composition of 1 to 4.
% Or more of metals of Fe, V, B, Nd, Pr, Al, and Si, weighed so that the total amount becomes 30 gr, and put into a quartz crucible having an orifice with a diameter of 0.8 mm at the bottom and pressure. After melting by high frequency heating in an Ar atmosphere of 56 cmHg and setting the melting temperature to 1300 ° C.,
A molten metal is jetted from a height of 0.7 mm onto the outer peripheral surface of a Cu roll which is pressurized with r gas and rotates at a high speed at a roll peripheral speed of 20 m / sec at room temperature.
A 40 μm ultra-quenched ribbon was produced. The obtained ultra-quenched ribbon was confirmed to be amorphous by characteristic X-rays of CuKα.

After the ultra-quenched ribbon was rapidly heated to 580 ° C. in Ar gas, the temperature was raised to 580 ° C. or more at the heating rate shown in Table 1, and kept at the heat treatment temperature shown in Table 1 for 10 minutes. After cooling to room temperature, take out the ribbon, width 2-3mm,
A sample having a thickness of 30 to 40 μm and a length of 3 to 5 mm is prepared,
Magnetic properties and average crystal grain size were measured using VSM. Table 2 shows the measurement results. The measurement results of the sample show that the main phase is Fe ₃ B phase in which tetragonal and orthorhombic are mixed, and Nd ₂ Fe ₁₄ B
It was a multiphase structure in which a phase and an α-Fe phase were mixed, and the average crystal grain size was 100 nm or less in each case. V substitutes a part of Fe in each of these phases. However, Al and Si could not be analyzed due to the small amount of addition and ultrafine crystals. This ribbon is pulverized to a particle size of 5 to 120 μm.
After obtaining a powder having an average particle size of 60 μm distributed over the powder, 98% by weight of the powder is mixed with 2% by weight of the epoxy resin, and then compression molded at a pressure of 6 ton / cm ² and cured at 150 ° C. A bonded magnet was obtained. The density of this bonded magnet was 6.0 gr / cm ³ , and the magnet properties are shown in Table 3 .

Comparative Example No. 1 in Table 1 A super-quenched ribbon was produced under the same conditions as in Example 1 using Fe, B, and Nd having a purity of 99.5% or more so as to obtain a composition of No. 5. The obtained ribbon was subjected to a heat treatment under the same conditions as in Example 1, and after cooling, crushed under the same conditions as in Example 1 to obtain a powder having an average particle diameter of 60 μm, and then bonded under the same conditions as in Example 1. Created a magnet. Table 3 shows the magnet properties of the obtained bonded magnet .

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

According to the present invention, a molten Fe—V—B—R alloy (R is Nd or Pr) or a molten Fe—V—B—R—M alloy (M: Al or Si) is made into an amorphous structure by substantially 90% or more by the above-mentioned ultra-quenching method to obtain an obtained ribbon, flake, or spherical powder, and heat-treated under a specific condition. As a result, an Fe ₃ B phase having an Fe ₃ P-type crystal structure and a ferromagnetic phase having an Nd ₂ Fe ₁₄ B-type crystal structure, which are thermodynamically metastable phases, coexist, and the average crystal grain of each constituent phase is present. A microcrystalline aggregate having a diameter in the range of 5 nm to 100 nm is obtained. At this time, when the composition does not contain V, if the temperature exceeds 700 ° C., the α-Fe phase, which is a thermal equilibrium phase, and the Fe ₂ B phase or N ₂
Although _d1.1 Fe ₄ B ₄ is formed and iHc is not expressed, in the V-containing composition, the Fe ₃ B phase and the Nd ₂ Fe ₁₄ B phase are more thermally stable than the composition without addition of V, and are 620 ° C. to 750 ° C.
I higher than V-free composition over a wide temperature range of about ° C
Hc is expressed. Further, by containing one or two kinds of Al and Si simultaneously with V, the deterioration of the square of the Br and demagnetization curves when V is contained is improved, so that iHc ≧ 4.
It is possible to obtain a bonded magnet having magnetic characteristics of kG, Br ≧ 6 kG, and (BH) max ≧ 6MGOe. Also,
The present invention provides a bonded magnet having a residual magnetic flux density of 5 kG or more and a magnetic performance exceeding that of a hard ferrite magnet because the content of a rare earth element is small, the manufacturing method is simple, and it is suitable for mass production. it can.

Claims (4)

(57) [Claims] [Claim 1] represents the composition formula _{Fe 100-xyz V x B y} R z ( where R is Pr or one or two of Nd), symbol x to limit the composition range, y, z are the following value Satisfactory, a boride phase mainly composed of iron having a body-centered tetragonal Fe ₃ P type crystal structure and a constituent phase having an Nd ₂ Fe ₁₄ B type crystal structure coexist in the same powder particle. The average grain size of the phase is in the range of 5 nm to 100 nm, and the average grain size is 3 μm.
A rare-earth bonded magnet, wherein powder having a size of about 500 μm is bonded with a resin. 0.01 ≦ x ≦ 10 at% 16 ≦ y ≦ 22 at% 3 ≦ z ≦ 5.5 at% 2. A method composition formula _{Fe 100-xyz V x B y} R z M w
(Where R is one or two of Pr or Nd, M is Al
Or one or two types of Si), and the symbols x, y, z, and w that limit the composition range satisfy the following values, and are mainly composed of iron having a body-centered tetragonal Fe ₃ P-type crystal structure. The boride phase and the constituent phase having the Nd ₂ Fe ₁₄ B type crystal structure coexist in the same powder particle, and the average crystal grain size of each constituent phase is 5n.
m to 100 nm, and the average particle size is 3 μm to 50 μm.
A rare earth bonded magnet, wherein powder having a particle size of 0 μm is bonded with a resin. 0.01 ≦ x ≦ 10 at% 16 ≦ y ≦ 22 at% 3 ≦ z ≦ 5.5 at% 0.1 ≦ w ≦ 3 at% 3. A represents a composition formula _{Fe 100-xyz V x B y} R z ( where R is Pr or one or two of Nd), symbol x to limit the composition range, y, z are the following value rapid quenching the satisfactory alloy melt using a rotating roll, splat quenching method, and quenched in conjunction gas atomizing method or these, substantially no more than 90% amorphous structure, further during heat treatment, Fe ₃ P type The temperature is raised from about the temperature at which the boride phase mainly composed of iron having a crystal structure is precipitated at a rate of 1 ° C./min to 15 ° C./min to 620 ° C. to 750 ° C.
℃ heat treatment of holding for 10 seconds to 6 hours, Fe ₃ P
A boride phase containing iron as a main component and having a crystalline structure;
A component phase having a d ₂ Fe ₁₄ B type crystal structure coexists in the same powder particle, and the average crystal grain size of each component phase is 5 nm to 10 nm.
Average particle size of 3 nm to 500 composed of microcrystalline aggregate of 0 nm
A method for producing a rare-earth bonded magnet, wherein a μm magnet alloy powder is bonded with a resin. 0.01 ≦ x ≦ 10 at% 16 ≦ y ≦ 22 at% 3 ≦ z ≦ 5.5 at% The 4. A composition formula _{Fe 100-xyz V x B y} R z M w
(Where R is one or two of Pr or Nd, M is A
g, Al or Si), and the symbols x, y, z, and w that limit the composition range satisfy the following values: a super-quenching method using a rotating roll, a splat quenching method, A gas atomizing method or a combination thereof is quenched to substantially form an amorphous structure of substantially 90% or more, and at the vicinity of a temperature at which a boride phase mainly composed of iron having an Fe ₃ P type crystal structure precipitates during heat treatment. From 620 ° C to 750 at a rate of 1 ° C / min to 15 ° C / min.
℃ heat treatment of holding for 10 seconds to 6 hours, Fe ₃ P
A boride phase containing iron as a main component and having a crystalline structure;
A constituent phase having a d ₂ Fe ₁₄ B type crystal structure coexists in the same powder particle, and the average crystal grain size of each constituent phase is 5 nm to 100 nm.
Average particle size of 3 μm consisting of microcrystalline aggregates in the range of nm
A method for producing a rare-earth bonded magnet, wherein a magnet alloy powder of about 500 μm is bonded with a resin. 0.01 ≦ x ≦ 10 at% 16 ≦ y ≦ 22 at% 3 ≦ z ≦ 5.5 at% 0.1 ≦ w ≦ 3 at%