JP2000260614A - Composite anisotropic bonded magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the uniformity in the magnetizing property, the heat- resisting property, and the surface magnetic flux density by mixing the specified R-T-N magnetic material powder, the ferrite powder having a specified magnetic anisotropy, and the resin, at a specified composition rate. SOLUTION: An R-T-N magnetic material powder has a magnetic anisotropy and has an average grain diameter of about 2-10 μm and satisfies a composition of main ingredients shown by formula I (wherein R is one or more kinds of rare earth elements including Y, T is Fe or Fe and Co, and 5 atomic %<=α<=20 atomic %, 5 atomic %<=β<=30 atomic %). The ferrite powder having a magnetic anisotropy satisfies a composition of main ingredients shown by a formula II (wherein A is Sr and/or Ba, R is one or more kinds of rare earth elements and contains La as an essential, and 0.01<=x<=0.04, (x/(2.6n))<=y<=(x/(1.6n)), 5<=n<=6) and has an average grain diameter of about 0.9-2 μm. A bonded magnet consists of about 20-80 pts.wt. of the R-T-R magnet material powder, about 80-20 pts.wt. of the ferrite powder, and the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is useful in a wide range of magnet-applied product fields, such as various types of rotating machines, acoustic speakers, buzzers, magnets for attracting or generating magnetic fields, etc. The present invention relates to a composite type anisotropic bonded magnet having an equivalent or higher maximum energy product ((BH) max) and improved magnetism and heat resistance. The present invention also relates to a composite type anisotropic bonded magnet having (BH) max equal to or higher than that of an anisotropic sintered ferrite magnet, and having improved magnetization, heat resistance, and variations in surface magnetic flux density.

[0002]

2. Description of the Related Art In recent years, poor magnetization and a measure of heat resistance, for example, a permeance coefficient: Pc = 1 to 2 (Pc = B
d / (− Hd); Nd ₂ Fe ₁₄ B type intermetallic compound having a considerably large irreversible demagnetization rate evaluated by Bd and Hd (B value and H value at an operating point on a BH demagnetization curve) as a main phase. As a substitute for a rare-earth bonded magnet using isotropic or anisotropic magnet powder, for example, Sm ₂ Fe ₁₇
N _x (x = 2 to 6) magnet material (Japanese Patent No. 2703281)
No.) is being put to practical use. However, Sm ₂ F
rare earth bonded magnet using the e ₁₇ N _x, the miniaturization of the recent magnet applied products, heat resistance to meet the needs of high performance, magnetizability is not sufficient, it is expected future improvements.

[0003] WO98 / 38654 (PCT / JP98 / 00764) contains a ferrite having a hexagonal structure as a main phase, and contains Sr, B
A is at least one element selected from a, Ca and Pb, which always contains Sr, and is at least one element selected from rare earth elements (including Y) and Bi and La is Assuming that R is always included and M is Co or Co and Zn, the total composition ratio of each metal element of A, R, Fe and M is A: 1 to 13 with respect to the total amount of metal elements. Atomic%, R: 0.05-10
It describes a bonded magnet composed of ferrite particles containing an oxide magnetic material having a composition of atomic%, Fe: 80 to 95 atomic%, and M: 0.1 to 5 atomic%. As a specific example of this bonded magnet, the final composition is Sr _0.7 La
_0.3 Fe _12-7 Co _0.3 O ₁₉ (% by weight before calcination
Add 0.2% of SiO ₂ and 0.15% of CaCO ₃
Of the calcined body of Example 1 was pulverized by a
There is a description that a coercive force iHc of a ferrite powder for a bonded magnet produced by annealing at 5 ° C. × 5 minutes is 4.31 kOe. However, the (BH) max of the anisotropic bonded magnet is less than the (BH) max of the anisotropic sintered ferrite magnet, and it is difficult to substitute the use of the anisotropic sintered ferrite magnet.

Japanese Patent Application Laid-Open No. 60-223095 discloses that a hard ferrite powder and a rare earth cobalt magnet powder are blended at a predetermined ratio and are bonded with a resin, and have a temperature coefficient of magnetic flux density of -0.03. A field magnet which is incorporated in a magnetic field device for a bubble memory device and has a temperature of −−0.20% / ° C. is described. However, this field magnet adjusts the temperature coefficient of magnetic flux density to the above range,
It does not aim to improve heat resistance, magnetism, etc.

[0005] Rare Metal News, No. 1936 (published date 1
On February 8, 999), Sm-Fe-
By blending the N-based magnet powder and the ferrite magnet powder at a predetermined ratio, there is a possibility that magnetic properties can be improved up to an anisotropic sintered ferrite magnet (maximum energy product: (BH) max = 4 to 5 MGOe). There is suggestion. However, according to the study of the present inventors, conventional Sm-Fe-N-based magnet powder for bonded magnets having magnetic anisotropy and ferrite magnet powder are blended at a predetermined ratio and bound with resin. When a composite type anisotropic bonded magnet is manufactured, (BH) max (3.2 to 5 MGOe) is higher than that of an anisotropic sintered ferrite magnet.
It has been found that it is difficult to realize a composite type anisotropic bonded magnet having improved magnetism, heat resistance and uniformity of surface magnetic flux density which are important for practical use.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide (B) which is equal to or more than the anisotropic sintered ferrite magnet.
H) An object of the present invention is to provide a composite type anisotropic bonded magnet having a maximum and improved magnetization and heat resistance. Further, an object of the present invention is to provide a (B
H) To provide a composite type anisotropic bonded magnet having a maximum and improved uniformity of magnetization, heat resistance and surface magnetic flux density.

[0007]

The present invention which has solved the above-mentioned problems has a magnetic anisotropy, an average particle diameter of 2 to 10 μm, and a main component composition of R _α T _100-α-β N _β (R is one or two or more rare earth elements including Y, T is Fe or Fe and Co, α and β are each atomic%, and 5 ≦ α ≦ 2
20 to 80 parts by weight of an RTN-based magnetic material powder represented by 0, 5 ≦ β ≦ 30, and (A _1-x R _x ) On · ((Fe _1-y Co _y ) ₂ O ₃ )
(Atomic ratio) (A is Sr and / or Ba, R is one or more kinds of rare earth elements including Y and always includes La), 0.1.
01 ≦ x ≦ 0.4, (x / (2.6n)) ≦ y ≦ (x / (1.
6n)) having a main component composition represented by 5 ≦ n ≦ 6,
Total Ca content in terms of Si content and CaO in terms of SiO ₂ is more than 0.2 wt%, _Al 2 O
₃ in terms of Al content and C in terms of Cr ₂ O ₃
80 to 20 parts by weight of magnetically anisotropic ferrite powder having a total r content of 0.13% by weight or less and having a magnetoplumbite type crystal structure and an average particle size of 0.9 to 2 μm And a resin portion that binds the two types of magnet material powder. The composite anisotropic bonded magnet has (BH) max equal to or higher than that of the anisotropic sintered ferrite magnet, and has improved magnetizability and heat resistance. The composite type anisotropic bonded magnet provided with radial anisotropy or polar anisotropy is rich in practicality.

Further, the present invention has a magnetic anisotropy, an average particle diameter of 2 to 10 μm, and a main component composition of R _α T
_100-α-β N _β (R is one or two or more rare earth elements including Y, T is Fe or Fe and Co, α and β are each atomic%, and 5 ≦ α ≦ 20, 5 ≦ β ≦ 20) to 80 parts by weight of an RTN-based magnet material powder represented by 30), and (A _1-x R _x ) On · ((Fe _1-y Co _y ) ₂ O ₃ )
(Atomic ratio) (A is Sr and / or Ba, R is one or more kinds of rare earth elements including Y and always includes La),
01 ≦ x ≦ 0.4, (x / (2.6n)) ≦ y ≦ (x / (1.
6n)) having a main component composition represented by 5 ≦ n ≦ 6,
And a resin binding the ferrite powder having substantially an magnetoplumbite type crystal structure and having an average particle diameter of more than 2 μm and having magnetic anisotropy of 10 μm or less and 80 to 20 parts by weight, and the two types of magnet material powders And a composite type anisotropic bonded magnet. The composite type anisotropic bonded magnet has (BH) max equal to or higher than that of the anisotropic sintered ferrite magnet, and has improved magnetization, heat resistance and uniformity of surface magnetic flux density. The composite type anisotropic bonded magnet provided with radial anisotropy or polar anisotropy is rich in practicality.

The RTN-based magnetic material powder used in the present invention will be described below. Since the RTN-based magnet material powder used in the present invention has good magnetic anisotropy, the average particle size is set to 2 to 10 μm. If the average particle size is less than 2 μm, oxidative deterioration becomes remarkable, and the packing density decreases (B
H) max decreases greatly. If it exceeds 10 μm, the magnetic anisotropy decreases, and the ratio of the RTN-based powder having a portion where the core is not nitrided or has insufficient nitriding increases, and (BH) max decreases. As the RTN-based magnet material powder, for example, Th ₂ Zn ₁₇ type, Th ₂ Ni
Sm-TN magnet alloy powder (T is Fe or Fe and Co) having any one of the _17- type and TbCu _7- type crystal structures as the magnet main phase can be used. The R content is preferably 5 to 20% in atomic%. If it is less than 5%, iHc is greatly reduced. If it exceeds 20%, the residual magnetic flux density Br is greatly reduced. It is permissible for R to inevitably contain one or more rare earth elements including Y. I more than 5KOe
In order to secure Hc, the ratio of Sm to R in atomic% is preferably 50% or more, more preferably 90% or more, and ideally R = Sm excluding inevitable impurities. Nitrogen is preferably 5 to 30% by atomic%. If it is less than 5%, the magnetic anisotropy becomes small, and iHc is largely reduced. If it exceeds 30%, the magnetic anisotropy and the saturation magnetization become small, which is not practically useful. Part of Sm or Fe is Co, Ni, Ti, C
r, Mn, Zn, Cu, Zr, Nb, Mo, Ta, W,
It can be substituted with one or more of Ru, Rh, Hf, Re, Os, and Ir. These substitution amounts are Sm except for Co.
And about 10 atomic% or less based on the total amount of Fe and Fe. If it is more than this, the saturation magnetization becomes small, which is not preferable. In the case of Co substitution, since the decrease in saturation magnetization is small,
It can be substituted within the range of 0.1 to 70 atomic% with respect to the amount, and an effect of increasing the Curie temperature can be obtained. Part of N can be replaced by one or more of C, P, Si, S, and Al. The substitution amount is about 10 atomic% or less with respect to the N content, and the addition amount larger than this is not preferable because iHc decreases.

[0010] Examples R-T-N magnet material powder, and a magnet main phase ThMn ₁₂ type crystal structure _{phase, Nd 5~10 T bal N 3~13 (} T in atomic percentages of Fe or Fe And Co), and a magnet alloy powder having an average crystal grain size of 2 to 10 μm can be used. If Nd is out of 5 to 10 at% and N is out of 3 to 13 at%, it is difficult to realize useful magnetic properties of the present invention.

As a raw material alloy of the RTN-based magnetic material powder, an RT-based master alloy adjusted to a corresponding main component composition by a melting method and / or an R / D method can be used. The production of the RT master alloy powder to be subjected to the nitriding treatment or the pulverization for atomizing the powder after the nitriding treatment are performed by a hammer mill, a disc mill, a vibration mill, an attritor, a jet mill, or the like maintained in an inert gas atmosphere. It is good to perform efficiently. Then, the ground R-
The T-based mother alloy powder is subjected to a nitriding treatment to impart a high saturation magnetization and an anisotropic magnetic field. In the nitriding treatment, the master alloy powder for nitriding is mixed with a nitrogen gas, a mixed gas of nitrogen and hydrogen, an ammonia gas, or a reducing mixed gas containing ammonia (for example, a mixed gas of ammonia and hydrogen, a mixed gas of ammonia and nitrogen, and a mixed gas of ammonia and ammonia). It is performed by heating and holding in a mixed gas of argon) atmosphere (in an air stream) at 300 to 650 ° C. × 0.1 to 30 hours. If the temperature is less than 300 ° C. × 0.1 hour and the temperature exceeds 650 ° C. × 30 hours, it is difficult to obtain the above-mentioned optimum nitrogen content. The mother alloy powder for nitriding contains hydrogen inevitably irrespective of the presence or absence of the nitriding treatment, but finally contains 0.01 to 10 atomic% of hydrogen by being exposed to a nitriding gas containing hydrogen.

The ferrite powder constituting the composite type anisotropic bonded magnet of the present invention will be described below. The value of n (molar ratio) is preferably set to 5. to 6. When n exceeds 6, a different phase other than the magnetoplumbite phase (for example, α-F
e ₂ O ₃ ) is generated, and the magnetic properties are greatly reduced. When n is less than 5, Br is significantly reduced. The value of x is 0.
01 ≦ x ≦ 0.4. When 0.01 ≦ x ≦ 0.4, a beneficial effect (improvement of Br and iHc) according to the present invention is obtained, but when x exceeds 0.4, Br and iHc decrease. When x is less than 0.01, the effect of addition is not recognized. R is one or more of rare earth elements including Y, and La is essential. La and Nd, P as R raw materials
A mixed rare earth oxide containing one or more of r and Ce may be used. In order to increase the saturation magnetization, the proportion of La in R is preferably at least 50 atomic%, more preferably at least 70 atomic%, particularly preferably at least 99 atomic%. Is also good. To achieve the purpose of charge compensation, y = x between y and x
/(2.0n) must be satisfied, but y is x
If it is not less than /(2.6n) and not more than x / (1.6n), the effect of the charge compensation is not substantially impaired. In the present invention, when the value of y deviates from x / (2.0n), Fe ²⁺ may be contained, but there is no problem. On the other hand, when the x / ny value exceeds 2.6 or is less than 1.6, a remarkable decrease in magnetic properties is observed. Therefore, the range of x / ny is 1.6 to 2.6. When this is rearranged for y,
The value of y is (x / (2.6n)) ≦ y ≦ (x / (1.6
n)). In a typical example, the preferred range of y is 0.04 or less, especially 0.005 to 0.03.

The average particle diameter of the ferrite powder is 0.9 to 0.9.
In the case of 2 μm, Si contained as an impurity by weight% is used.
O₂Si content converted to Ca and Ca converted to CaO
Total of content: (SiO₂+ CaO) is less than 0.2%
Yes, Al₂O₃Al content and Cr converted to₂O
₃Total Cr content converted to:₂O₃+ Cr ₂
O₃) Needs to be 0.13% or less. (SiO₂
+ CaO) is more than 0.2% or (Al₂O₃+ Cr
₂O₃) Is more than 0.13%, Nd in the present invention.
₂Fe₁₄B using isotropic magnet powder with B as the main phase
It is difficult to obtain (BH) max more than earth bonded magnet
is there. More preferably, (SiO₂+ CaO) is 0.1
5% or less, (Al₂O₃+ Cr₂O₃) Is 0.1
% Or less. However, from the viewpoint of industrial production,
Purity and contamination of Si, Cr, etc. from the crusher used
Inevitably, (SiO₂+ CaO) 0.005% or less
And (Al₂O₃+ Cr₂O₃) Is 0.005% or less
Is difficult in practice. This average particle size is 0.9
Ferrite powder having a thickness of about 2 μm
Powder powder. " The first ferrite powder is, for example, a solid
Mixing of raw material powder using phase reaction method
(Solid phase reaction) → grinding → heat treatment → disintegration
It can be manufactured depending on the process. For ferrite formation reaction (solid phase reaction)
The purity of the iron oxide used is important;
Abundant (SiO₂And Ca content (converted to CaO)
Is preferably 0.06% or less, more preferably
Is 0.05% or less, particularly preferably 0.04% or less.
And the Al content (Al₂O₃Conversion) and Cr included
Amount (Cr₂O₃Is preferably 0.1%
Or less, more preferably 0.09% or less, particularly preferably
0.08% or less. For this reason, high-purity iron oxide
Obtained by spraying and roasting hydrochloric acid washing waste liquid of steel
It is preferable to use iron oxide. Recycled iron oxide
Obtained through iron ore → fine grinding → classification → magnetic separation process
Iron oxide from refined iron ore, or mill scale or
Low impurities compared to scrap-treated iron sulfate-based iron oxide
Of quantity. The first ferrite powder is
It is preferable to make the composition of the target main component. That is, R
The element and Co compounds are added during the mixing stage of the manufacturing process.
Those who have undergone two high-temperature heat treatments of calcination and heat treatment
And the diffusion in the solid progresses, resulting in a more homogeneous ferrite group.
A product is obtained. Also, A'O.nFe₂O₃(A 'is
Sr and / or Ba, n = 5 to 6)
After obtaining a calcined powder of ferrite having a composition of R,
Compound is added at the time of grinding or added before heat treatment,
By mixing, the main component composition may be adjusted.
No. Mixing, calcining and grinding are almost the same as for sintered ferrite magnets.
Manufacturing conditions can be employed. For example, after wet mixing,
Heat in air at 1150-1300 ° C for 1-5 hours.
Cellite reaction. Ferrite below 1150 ° C
Insufficient sintering, the calcined body becomes hard when it exceeds 1300 ° C
The crushing efficiency decreases. Known coarse crusher and fine crusher
Combining and crushing is optional, and
Or wet attritor, bo mill, vibrating ball mill
And so on. The finely pulverized average particle size is preferably 0.8 to
1.9 μm, more preferably 0.9 to 1.4 μm, especially
Preferably it is 0.95 to 1.2 μm. Heat treatment is air
Heating conditions of 750 to 950 ° C. × 0.5 to 3 hours are preferable.
Good. 750 ° C x 0.5 hours less increase iHc
It is difficult to do it.
The agglomeration of the powders becomes remarkable, and Br decreases. Heat treatment
Or fluidized bed type heat treatment
It is preferable to use a device. Ferrite powder after heat treatment
The average particle size is from 0.05 to the average particle size of the finely pulverized powder.
It becomes larger by about 0.1 μm. Therefore, after heat treatment
The average particle size of the powder is preferably 0.9 to 2 μm.
More preferably 1.0 to 1.5 μm, particularly preferably 1.
05 to 1.3 μm. When the average particle size is less than 0.9μm
Indicates that the magnetic powder filling property of Br and mixed compounds is reduced, and
In this case, the density (BH) max is greatly reduced. 2μ
If m exceeds (BH) max, iHc ≧ 3.5 kOe
Is difficult to obtain. Average of first ferrite powder
The particle size is measured by the air permeation method (Fisher surfacsizer).
You.

Among the ferrite powders having magnetic anisotropy having an average particle diameter of more than 2 μm and 10 μm or less, the following anisotropic granulated powder is hereinafter referred to as “second ferrite powder”. The second ferrite powder (anisotropic granulated powder) is mixed with the raw material powder, for example, by a solid-phase reaction method → ferritization (solid-phase reaction)
For sintering, pulverization, molding in a magnetic field, disintegration, heat treatment, and disintegration treatment. In this case, the iron oxide used must be of high purity as in the case of the first ferrite powder. The calcined body adjusted to the main component composition has an average particle size of preferably 0.9 to 1.4 μm, more preferably 0.95 to 1.35 μm, and particularly preferably 1.0 to 1.3 μm. Finely pulverize. When the average particle size of the fine powder is less than 0.9 μm, Br of the second ferrite powder is greatly reduced. If the thickness exceeds 1.4 μm, Br and iH
c decreases. Subsequently, molding is performed in a wet or dry magnetic field to obtain a molded body. In either of the wet or dry method, molding in a magnetic field is carried out at room temperature while applying a magnetic field of 8 to 15 kOe,
It is preferable to carry out at a molding pressure of about 35 to 0.45 ton / cm ² . The density of the anisotropic molded article thus obtained is about 2.6 to 3.2 g / cm ³ . Subsequently, the compact is crushed by a jaw crusher or the like, and then sieved or classified by wind power, and finally the average particle size of the crushed powder is adjusted to more than 2 μm and 10 μm or less. Next, heat treatment is performed under the same conditions as the first ferrite powder. Anisotropic granulated powder having a magnetic anisotropy having an average particle diameter of more than 2 μm and 10 μm or less and having an easy axis of magnetization substantially aligned in a specific direction by subjecting the heat-treated powder obtained as necessary to agglomeration is obtained. can get. Average particle size of anisotropic granulated powder is 2μ
m more than 10 μm, more preferably 2.5-5 μm
m, particularly preferably 3 to 4 μm. Average particle size is 2μ
Below m, there is no merit with respect to the first ferrite powder. Those having a diameter of more than 10 μm have a remarkable decrease in Br.
The average particle size of the anisotropic granulated powder is JEOL Co., Ltd.
It is measured with a Rhodes particle size distribution analyzer. The anisotropic granulated powder has a higher iHc and Br equal to or higher than the conventional Sr and / or Ba ferrite powder, and the compound has a large average particle size, so that the flowability (moldability) of the compound is improved. . Therefore, the length in the axial direction is 20 to 50.
When a 0 mm long cylindrical cylindrical anisotropic bonded magnet (for example, a solid cylinder or a ring capable of forming 4 to 24 symmetric or asymmetric magnetic poles by magnetization) is formed, anisotropic granulation is performed. Compared to the conventional case, there is obtained an advantage that the variation of the surface magnetic flux density along the axial direction of the outer peripheral magnetic pole is improved.

Among the ferrite powders having magnetic anisotropy having an average particle diameter of more than 2 μm and 10 μm or less, an anisotropic sintered body having the following main component composition is crushed, and if necessary, the same heat treatment as above is performed. The crushed one is hereinafter referred to as “third ferrite powder”. The third ferrite powder is (A _1−x R _x ) On · ((Fe _1−y Co _y ) ₂ O ₃ )
(Atomic ratio) (A is Sr and / or Ba, R is one or more kinds of rare earth elements including Y and always includes La), 0.1.
01 ≦ x ≦ 0.4, (x / (2.6n)) ≦ y ≦ (x / (1.
6n)) having a main component composition represented by 5 ≦ n ≦ 6,
It is a polycrystalline powder having magnetic anisotropy. The preferred average particle size of the third ferrite powder is the same as that of the second ferrite powder, and the average particle size is measured by a Heros-Rhodes particle size distribution analyzer. The third ferrite powder can be produced in the following steps: mixing of raw material powder → ferrite formation by calcination (solid phase reaction) → pulverization → molding in a magnetic field → sintering → pulverization → heat treatment → pulverization treatment. An appropriate amount of SiO is added to the sintered body (anisotropic sintered ferrite magnet) constituting the third ferrite powder.
It is good to contain ₂ and CaO to obtain a dense sintered body structure. SiO ₂ is an additive that suppresses the growth of crystal grains during sintering, and has a content of 0.05 to 0.5% by weight.
Is preferred. If it is less than 0.05%, crystal grain growth proceeds excessively during sintering, and iHc decreases. If it exceeds 0.5%, the growth of crystal grains is excessively suppressed, and the improvement of the degree of orientation that proceeds with the growth of crystal grains becomes insufficient, and the Br decreases. On the other hand, CaO is an element that promotes crystal grain growth, and its content is preferably 0.35 to 0.85% by weight. If it exceeds 0.85%, crystal grain growth proceeds excessively during sintering, and iHc decreases. If it is less than 0.35%, the growth of crystal grains is excessively suppressed, and the improvement of the degree of orientation that progresses with the growth of crystal grains becomes insufficient, and the Br decreases.

As the ferrite powder used in the present invention, the first to third ferrite powders may be mixed at a predetermined ratio and used.

[0017] Upon the heat treatment, after mixing were added 0.2-0.6 wt% of Bi compound with respect to the ferrite fine powder in terms _{of Bi} 2 _{O 3} is above the melting point of _Bi 2 _{O 3} in air 825～ By heating at 950 ° C. × 0.5 to 3 hours, strain is removed and high magnetization and coercive force are provided. When the heat treatment condition is less than 825 ° C. × 0.5 hour, the effect of suppressing the aggregation by Bi ₂ O ₃ liquid phase is insufficient, and the iHc is also insufficient. When the temperature exceeds 950 ° C. × 3 hours, iHc increases, but Br decreases relatively. Bi compound is Bi ₂ O ₃
By adding 0.2 to 0.6% by weight in terms of heat treatment and then performing heat treatment, the thickness of the particles in the c-axis direction is increased as compared with the case where no additives are added, and a rounded particle form tends to be obtained.
A rounded particle form is preferable for improving dispersibility in a binder, filling property, and magnetic field orientation. The amount added is 0.
If less than 2% by weight, the effect of addition is not recognized, and 0.6% by weight
If it exceeds, the effect of addition is saturated.

It is preferable that the compounding weight ratio of the RTN-based magnet powder and the ferrite powder is 20 to 80:80 to 20. If the ratio is out of the above range, it is difficult to realize useful magnetic properties of the present invention.

As the binder resin, a known thermosetting resin, thermoplastic resin or rubber material is used. A thermosetting resin is preferred when using a compression molding method, and a thermoplastic resin is preferred when using an extrusion molding method or an injection molding method. For example, when producing a composite type anisotropic bonded magnet by a compression molding method in a magnetic field, it is preferable to select a binder resin having a low viscosity at the time of magnetic field orientation, 3 to 10 kOe, more preferably 3 to 10 kOe.
It is suitable for realizing a high (BH) max under a practical orientation magnetic field strength of ６6 kOe, particularly preferably 3-5 kOe. This is the same when the extrusion molding method in a magnetic field and the injection molding method in a magnetic field are applied. In particular, it is preferable to dilute the binder resin with an organic solvent, and perform compression molding in a magnetic field, extrusion molding in a magnetic field, or injection molding in a magnetic field at room temperature in a state in which the magnet material powder is substantially uniformly dispersed in a low-viscosity resin. preferable.
Alternatively, extrusion molding or injection molding in a warm state maintained in an inert gas atmosphere is also effective. In this case, the pellet in which the magnet powder is dispersed is also heated to a predetermined temperature, so that R-
Since the coercive force of the TN-based magnet powder is reduced and the viscosity of the binder resin is also reduced, good anisotropy can be imparted under the above-mentioned practical orientation magnetic field strength.

The radial or polar anisotropic bonded magnet of the present invention has an outer diameter of 1 to 200 mm and a diameter of 0.1 to 200 mm.
Ring shapes having an axial length dimension of １００100 mm are useful. If the outer diameter is less than 1 mm, it is difficult to impart anisotropy, and if it exceeds 200 mm, it does not meet the needs for miniaturization of magnet applied products. If the length is less than 0.1 mm, the strength becomes fragile and handling becomes difficult, and if it exceeds 100 mm, it does not meet the needs for miniaturization.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

(Example 1) (Preparation of RTN-based magnet powder) RTN-based magnet powder
Has an average particle size of 15 μm and an atomic% of Sm_9.
1Fe_76.8Mn_0.5N_13.6Having the main component composition of
Magnetic powder was prepared. Then, use a jet mill to flatten
Finely pulverized to an average particle size of 4.0 μm, and further using hexane
Pulverized by a wet ball mill into Heros Rhodes granules
Average particle size of 2.3μm by particle size distribution measuring device, particle size
A fine powder having a distribution of 0.5 to 30 μm was obtained. Jet mill fine
The reason for combining grinding and wet ball milling is that
0.5 to 30 μm sharp particles in wet mill pulverization
Fine powder with a diameter distribution can be obtained, but the average particle size is less than 4 μm
This is because the grinding efficiency is poor and is not suitable for industrial production.
In addition, non-wet ball mill pulverization alone
This is because many fine submicron particles are always generated.
You. (Preparation of first ferrite powder) Iron oxide (α
Fe₂O₃) 99.4% pure, 0.056% Cl, SO
₄0.02%, MnO 0.290%, SiO₂0.01
0%, CaO 0.018%, Cr₂O₃0.027%,
Al₂O₃0.060% high-purity recycled iron oxide,
SrCO with a purity of 99% or more₃, La₂O₃And Co
Using an oxide, (Sr_1-xLa_x) On ・ ((Fe
_1-yCo_y)₂O₃)
And n = 5.85, x = 0.15, y = x / 2n.
And mixed by wet method. Then at 1200 ° C 2
It was calcined in the atmosphere for a time. Dry calcined powder with a roller mill
Pulverization was performed to obtain a coarse pulverized powder. Next, crush the ball mill
Pot (10 liters, made of SUJ3)
10 kg of steel ball (diameter 6 mm, made of SUJ3)
Ethyl alcohol (initial addition amount 50 cc), coarse grinding
700 g of powder is put and sealed, and at a peripheral speed of 0.7 m / sec.
Perform dry pulverization with a ball mill, and use the air permeation method (Fissi
1.05 μm average particle size
Light fine powder was obtained. Next, 0.2% by weight based on the fine powder
Considerable Bi₂O₃% Heat-resistant container
And set in a heating furnace in an air atmosphere, 830 ± 2
Perform heat treatment (strain relief annealing) for 3 hours at ℃ to reach room temperature
Cool. Next, immersing the heat-treated powder in water
Dissolves the aggregation of ferrite powder particles generated by heat treatment.
After heating, remove water by heating to 100 ° C and cool to room temperature.
Rejected. Subsequently, the mixture is passed through a 150-mesh sieve to obtain an average particle size.
1. 10 μm ferrite powder for bonded magnet (first ferrite powder)
Ferrite powder). This ferrite powder was converted
(SiO₂+ CaO) content is 0.133% by weight, converted
(Al₂O₃+ Cr₂O₃) Content is 0.082
% By weight. (Preparation of Composite Type Anisotropic Bonded Magnet) The RTN-Based Magnet
The stone powder and the first ferrite powder are combined with a weight of 80/20.
The components blended in the quantitative ratio were put into a mixer and mixed. Next
2.8 parts by weight of 100 parts by weight of the mixed magnetic powder
Liquid epoxy resin and 0.7 parts by weight of curing agent (DD
S; diaminodiphenylsulfone) and organic solvents
The same weight as the liquid epoxy resin (2.8 parts by weight)
Weigh methyl ethyl ketone (boiling point 79.5 ° C) and stir
I put it in the plane. Then, 100 parts by weight of the mixed magnetic powder
Into a stirrer and stirred at 20 rpm for 20 minutes.
Rally. Using this slurry, at room temperature,
Field strength 6 kOe, 8 tons / cm²Wet magnetic field at molding pressure
Medium compression molded. Heat the molded body at 85 ° C for 1 hour to demelt
After the medium, the mixture was cured by heating at 170 ° C. for 2 hours.
o. Thus, a composite anisotropic bonded magnet of No. 1 was obtained. Next, the R
The TN-based magnet powder and the first ferrite powder
/ 50, 20/80
Similarly, No. 1 shown in Table 1 was used. A few composite anisotropic holes
And a magnet. Next, assuming practical built-in magnetization
No. After demagnetizing the bonded magnets of 1 to 3 and then to 20 ° C
At 10kOe by BH tracer to reduce
A magnetic curve was drawn and iHc and (BH) max were measured. N
o. The demagnetization curve of No. 3 is shown in FIG. Next, No. 1-3
The magnetization was evaluated. For magnetizing, the magnetizing magnetic field strength is 5 kOe.
Br value at the time of (Br_5kOe) And the magnetizing magnetic field strength is 50
Br value at kOe (Br_50kOe) And
And is defined by the following equation. Table 1 shows the evaluation results of magnetization.
You. In addition, No. Fig. 3 Dependence of magnetization on magnetization field strength
It is shown in FIG. (Magnetization) = (Br_5kOe) / (Br_50kOe) ×
100 (%). For each of the items 1-3, permance
Number (Pc) is 2; (thickness in magnetization direction) / (diameter) = 0.
7 was machined. Next, at 20 ° C
It was magnetized at 30 kOe and the total magnetic flux (Φ) was measured. Next
For each of the three machined bonded magnet samples,
40 ° C, 45 ° C, 50 ° C, 55 ° C, 60 ° C, 65 ° C, 7
0 ° C, 75 ° C, 80 ° C, 85 ° C, 90 ° C, 95 ° C, 10
0 ° C, 105 ° C, 110 ° C, 115 ° C, 120 ° C, 12
1 hour at each temperature of 5 ℃, 130 ℃, 135 ℃, 140 ℃
After heating, a product cooled to room temperature was obtained. Each of the above after cooling
The total magnetic flux (Φ ') of the sample was measured, and the total
Temperature at which the rate of change of magnetic flux (irreversible decrement) reaches -5%
No. Heat resistance temperature of composite type anisotropic bonded magnet of 1-3
Was evaluated. Table 1 shows the results. (Irreversible decay rate) = (Φ−Φ ′) / (Φ) × 100 (%) (Comparative Example 1) Since only the RTN-based magnet powder was used
Outside, an anisotropic bonded magnet was produced in the same manner as in Example 1,
The evaluation results are shown in Table 1. 11 is shown. No.
FIG. 2 shows the magnetization field strength dependence of the magnetization of No. 11. (Comparative Example 2) Except that the first ferrite powder was used.
An anisotropic bonded magnet was prepared and evaluated in the same manner as in Example 1.
The results are shown in Table 1. FIG. Comparative Example 3 MQI (Magnequench
International) MQA-T material (HDDR method)
Nd made from₂Fe₁₄Anisotropic with B as the main phase
Magnet powder) was used in the same manner as in Example 1 except that
A magnet was prepared and evaluated. The results are shown in Table 1. 13
Show. In addition, no. 13 Dependence of Magnetization Field Strength on Magnetization
The properties are shown in FIG. (Comparative Example 4) MQP-B material manufactured by MQI as a magnet powder
(Nd₂Fe₁₄Isotropic magnet powder with B as the main phase)
The same as in Example 1, except that
Then, a bonded magnet was prepared and evaluated. The results are shown in Table 1
o. It is shown in FIG. In addition, No. Figure 14 shows the demagnetization curves of 14
FIG. 2 shows the dependence of the magnetization on the strength of the magnetizing magnetic field. (Reference Example 1) SrO · 5.85Fe₂O₃ Indicated by
Average particle size in the same manner as in Example 1 except that the main component composition was used.
1.10 μm of ferrite powder for a bonded magnet was obtained. This
Weight ratio of ferrite and R-T-N magnet powder
Are set to 20/80, 50/50, 80/20.
A composite type anisotropic bonded magnet was prepared and evaluated in the same manner as in Example 1.
Valued. The results are shown in Table 1. 15 to 17. (Reference Example 2) SiO is used during dry ball mill pulverization.₂And Cr
₂O₃(SiO 2)₂+ CaO) included
The weight was converted to 0.25% by weight (Al₂O₃+ Cr
₂O ₃) Prepare the one with a content of 0.18% by weight
Was. This ferrite powder is called "ferrite (a)".
U. The same procedure as in Example 1 was performed using the ferrite powder.
To produce three types of composite anisotropic bonded magnets
did. The results are shown in Table 1. 18 to 20. (Example 2) In Example 1, the first ferrite powder was used.
Example 1 except that the dry ball mill pulverization conditions were changed.
Similarly, in weight%, the average particle size is 0.94 μm, (S
iO ₂+ CaO) content of 0.178%, (Al₂O₃
+ Cr₂O₃) Bonded magnet with 0.083% content
A ferrite powder for stone was obtained. This first ferrite powder
And the mixing weight ratio of the RTN-based magnet powder to 20/8
Except that it was set to 0, the composite anisotropic button was used in the same manner as in Example 1.
A magnet was manufactured and evaluated. The results are shown in Table 1. 21
Shown in (Example 3) In Example 1, the first ferrite powder
Example 1 except that the dry ball mill pulverization conditions were changed.
Similarly, in weight%, the average particle size is 1.98 μm, (S
iO ₂+ CaO) content of 0.041%, (Al₂O₃
+ Cr₂O₃) Bonded magnet with 0.076% content
A ferrite powder for stone was obtained. This first ferrite powder
And the mixing weight ratio of the RTN-based magnet powder to 20/8
Except that it was set to 0, the composite anisotropic button was used in the same manner as in Example 1.
A magnet was manufactured and evaluated. The results are shown in Table 1. 22
Shown in

[0023]

[Table 1]

From Table 1, it can be seen that No. In 1-3
(BH) max is 4.3MGOe or more, and magnetization is 70% or less.
Above, it can be seen that the heat resistance temperature has been improved to 85 ° C or higher.
You. The average particle size of the first ferrite powder is 0.94
μm Example 2 (No. 21) and First Ferrite
Example 3 (No. 2) in which the average particle size of the powder was 1.98 μm.
2) Even with (BH) max of 8.1 MGOe or more,
70% or more, and heat resistant temperature was 80 ° C or more. Comparative Example 1
No. In the case of No. 11, the magnetization is 67% and the heat resistance temperature is 60 ° C.
Inferior to Examples 1-3. 1st ferrite
No. of Comparative Example 2 containing only powder. (BH) max is low in 12
No. Nd₂Fe₁₄Ratio using magnet powder with B as main phase
No. 3 of Comparative Example 3. No. 13 (anisotropic); 14
(Isotropic) bonded magnets have poor magnetization. In addition, No.
No. 14 compared to No. 14 (BH) max is higher for 1 and 2
It's getting worse. In Reference Example 1, the RTN-based magnet powder
No. with high ratio No. 15 for No. (BH) ma higher than 14
x was obtained, but the ratio of the RTN-based magnet powder was 70%.
In the following, no. (BH) max was lower than 14. Also
When compared at the same mixing ratio, Nos. 15 to 17 are Nos. 1
(BH) max, iHc, heat resistant temperature
Inferior degree. In Reference Example 2, (SiO 2)₂
+ CaO) content exceeding 0.2%, (Al ₂O₃+ Cr
₂O₃) The same mixture because the content is more than 0.13%
When compared by ratio, Nos. 21 to 23 are Nos. Compared to 1-3
In all cases, (BH) max was low.

Example 4 (Preparation of Second Ferrite Powder) The calcined coarse powder prepared in Example 1 was finely pulverized with a wet attritor (solvent: water) to an average particle size of 0.90 μm. Using the obtained slurry, wet molding was performed in a magnetic field of 10 kOe to obtain a molded body. After demagnetization, it was heated to 100 ° C. or lower in the air to remove water and cooled. The formed body was crushed by a jaw crusher, and then sieved to prepare a powder having an average particle diameter of more than 2 μm and 15 μm or less, and subjected to a heat treatment at 750 to 1000 ° C. × 1 hour in the atmosphere. Thereafter, immersion in water, drying and crushing by sieving were performed in the same manner as in Example 1 to obtain an anisotropic granulated powder. The magnetic properties of the obtained anisotropic granulated powder having an average particle diameter of 3 μm were measured by VSM. Measurement is VSM
The holder was filled with anisotropic granulated powder and wax having different heat treatment temperatures at a specific ratio and a constant total weight, and then sealed and set in a VSM. Next, heating was performed while applying a parallel magnetic field of 6 kOe to melt the wax, and then solidified to fix the magnetic powder. In this state, a demagnetization curve was drawn at room temperature, and Br and iHc corrected to 100% magnetic powder were obtained.
The measurement results are shown in FIGS. As shown in FIGS. 6 and 7, when a heat treatment temperature of 750 to 950 ° C. is selected, 3.5 to
3.75 kG Br and 2.85-4.75 kOe iHc were obtained. When the average particle diameter is more than 10 μm, a decrease of Br of about 5% or more is recognized as compared with the same heat treatment temperature in FIG. An anisotropic granulated powder (second ferrite powder) having an average particle size of 3 μm subjected to a heat treatment at 900 ° C. × 1 hour was prepared. (Preparation of Composite Type Anisotropic Bonded Magnet) A certain amount of the second ferrite powder was put into a Henschel mixer, and aminosilane (KBM-603; Shin-Etsu Chemical Co., Ltd.) was stirred.
0.25% by weight based on the ferrite powder charged
A considerable amount was added and mixed. Then, at 80 ℃ × 3 in the atmosphere
Surface treatment of heating for an hour and cooling to room temperature was performed. Also,
The RTN-based magnet powder was also subjected to the same surface treatment as the second ferrite powder. Next, the two surface-treated powders were mixed at a mixing weight ratio of 20/80, 50/50, 8
0/20 and mixed with a mixer. Next, in terms of density, the ratio of each of the three types of mixed magnetic powder was 60% by volume, and nylon 12 (P-3014U; Ube Industries, Ltd.)
3% of a raw material for compounding, in which stearic acid amide (AP-1; manufactured by Nippon Kasei Co., Ltd.) was added in an amount corresponding to 0.4% by weight to the above-mentioned mixture. Was blended, and each was mixed with a mixer. These were sequentially kneaded with a biaxial kneader in an argon atmosphere to obtain three types of pellets. Each of the three types of pellets was put into an injection molding machine, the injection temperature was 280 ° C., and the injection pressure was 1000.
Cavity of mold with magnetic circuit attached to injection molding machine under condition of kgf / cm ² (Orientation field strength = 5.0 ± 0.2 k)
Oe) to obtain a composite anisotropic bonded magnet.
After that, the results of evaluation of the magnetic characteristics in the same manner as in Example 1 are shown in Table 2. 31 to 33 are shown. In addition, No. 31,3
FIG. 3 shows the evaluation results of the irreversible demagnetization rate of No. 2. (Comparative Example 5) Using only the RTN-based magnet powder of Example 1 as the magnet powder, (RTN-based magnet powder) / (Nylon 1
A compounding raw material in which the volume ratio of 2) was 60/40, and stearic acid amide was added in an amount corresponding to 0.4% by weight to the above-mentioned compounding agent, was mixed, and mixed with a mixer. Thereafter, an anisotropic bonded magnet was prepared and evaluated in the same manner as in Example 4. The results are shown in Table 2. 41. Comparative Example 6 An anisotropic bonded magnet was prepared and evaluated in the same manner as in Comparative Example 5, except that only the second ferrite powder of Example 4 was used as the magnet powder. The results are shown in Table 2.
42. (Comparative Example 7) An anisotropic bonded magnet was prepared and evaluated in the same manner as in Comparative Example 5, except that MQA-T manufactured by MQI was used as the magnet powder. 43. (Comparative Example 8) An isotropic bonded magnet was prepared and evaluated in the same manner as in Comparative Example 5 except that compression molding was performed in the absence of a magnetic field using an MQP-B material manufactured by MQI as a magnet powder.
No. 44. (Comparative Example 9) Using the RTN-based magnet powder of Example 1 and the conventional Sr ferrite powder of Reference Example 1, the compounding weight ratio of both was 20/80, 50/50, 80/20. Thereafter, a composite anisotropic bonded magnet was manufactured and evaluated in the same manner as in Example 4. The results are shown in Table 2. 45-
Shown at 47.

[0026]

[Table 2]

From Table 2, it can be seen that No. 31-33
Is No. 5 of Comparative Example 5. Magnetization and heat resistance are improved as compared with 41. (BH) max of Comparative Example 6 is very low. Those of Comparative Examples 7 and 8 have poor magnetization. From a comparison between Example 4 and Comparative Example 9, it can be seen that, when viewed at the same compounding ratio, (BH) max, iHc, and heat resistance temperature of Example 4 are all improved.

Next, No. 2 (Example 1) composite anisotropic
Nos. Bonded magnets and No. 14 (Comparative Example 4)
BH demagnetization curve at 20 ° C and 75 ° C
The lines are shown in FIG. Further, from the BH demagnetization curve of FIG.
Change from 20 ° C to 75 ° C for Pc = 1 and 2 respectively
Of the magnetic flux density at the time of performing: dBd and demagnetization rate.
Table 3 shows the evaluation results. dBd = Bd_{20 ° C}-Bd_{75 ℃}  (Demagnetization rate) = (dBd / Bd_{20 ° C}) × 100 (%)

[0029]

[Table 3]

From Table 3, it can be seen that The superiority of the bonded magnet No. 2 is apparent. In addition, in Example No. 1, The same evaluation as in FIG. 4 was performed on the composite anisotropic bonded magnets of Examples 1 and 3 and Examples 2, 3 and 4, and it was confirmed that the demagnetization rate was 5% or less in each case. On the other hand, no. 14
In Comparative Example 4, the demagnetization rate exceeded 10%.

(Embodiment 5) 2 (Example 1) is a slurry used for producing the composite type anisotropic bonded magnet, and has an outer diameter of 2
It has a cavity of 5 mm and an inner diameter (core outer diameter) of 22 mm, and has a symmetrical 8-pole polar anisotropic alignment magnetic field (alignment magnetic field strength of about 4 k
Oe) Using a compression molding machine equipped with a molding die equipped with a generating coil, molding was performed in a wet magnetic field at room temperature at a molding pressure of 8 ton / cm ² , and a symmetrical 8-pole ring-shaped molded product having a polar anisotropy (25 m in outer diameter)
m, inner diameter 22 mm, thickness 1.5 mm). The molded body was heated to 80 ° C. to remove the solvent, and then heat-cured to obtain a composite type polar anisotropic ring-shaped bonded magnet. Magnetization of this bonded magnet along the direction of polar anisotropy (magnetizing field strength 10 kOe)
Thereafter, the surface magnetic flux density waveform in the circumferential direction of the outer diameter surface was measured. FIG. 5 shows the results. As shown in FIG. 5, the maximum value of the surface magnetic flux density was a high value of 2700 to 2750G. (Comparative Example 8) In the same manner as in Example 5 except that the slurry of Comparative Example 3 was used, a polar anisotropic symmetric 8-pole ring-shaped bonded magnet (outer diameter 25 mm, inner diameter 22 mm, thickness 1.5 mm) was prepared. It was fabricated and the surface magnetic flux density waveform was measured. FIG. 5 shows the results. As shown in FIG. 5, the surface magnetic flux density of this polar anisotropic bonded magnet was a low value of about 1900G.

(Example 6) (Preparation of third ferrite powder) Same SrC as in Example 1.
O₃, Fe₂O₃Using SrO.5.9Fe₂O
₃Was blended in the main component composition indicated by
Thereafter, it was calcined at 1250 ° C. for 2 hours in the air. Calcined powder
Dry pulverization was performed by a roller mill to obtain coarse pulverized powder. That
After that, wet pulverization is performed with an attritor, and the average particle size is reduced.
A slurry containing a finely ground powder of about 0.6 μm was obtained. This fine
The same La as in Example 1 at the beginning of the grinding₂O_3,Co oxide and
And Fe₃O₄Coarse powder charged with (magnetite) into a fine pulverizer
2.5%, 1.2% and 6.
0% was added. At the same time, SrCO₃,
CaCO₃And SiO₂In the weight ratio to the finely ground powder
0.3%, 1.0% and 0.3% were added respectively. Profit
Using the milled slurry obtained in a 10 kOe magnetic field
Formula molding was performed. The molded body was sintered at 1200 ° C for 2 hours.
Was. The sintered body had the following main component composition. (Sr_1-xLa_x) On [(Fe_1-yCo_y)
₂O₃X = 2ny, x = 0.15, n = 5.55 Next, after coarsely crushing the sintered body, dry crushing was performed with a roller mill.
Coarse pulverized powder was used. Next, finely pulverize with a dry ball mill
The average particle size was 3.1 μm. Next, 830 ± 2 ° C x 2 hours
Heat treatment. Next, heat into a water-filled mixer.
Put the treated powder and immerse it in water, 60r.p.m. × 30 seconds
After stirring and crushing, heat to 80 ° C to remove moisture and cool
did. This was used as a third ferrite powder. (Production of compound) Long radial type for rotary machine
The following 4 types for extruding an isotropic ring bonded magnet
Prepared the compound. (Compound A) (RTN) prepared in Example 4
Mixture ratio of (system magnet powder) / (second ferrite powder)
Nylon 12-based compaw using 50/50 mixed magnetic powder
Was prepared. (Compound B) (the RTN-based magnet powder) /
(1st ferrite powder) mixing ratio of 50/50
Produced in the same manner as Compound A except using magnetized powder
The prepared nylon 2 type compound was prepared. (Compound C) (R-T-N magnet powder) /
(Third ferrite powder) mixture ratio of 50/50
Produced in the same manner as Compound A except using magnetized powder
The prepared nylon 2 type compound was prepared. (Compound D) (R-T-N magnet powder) /
The mixing ratio of (ferrite powder of Reference Example 1) is 50/50.
Except that compounded magnetic powder was used.
The prepared nylon 2 compound was prepared.

(Explanation of Extrusion Machine) FIG. 9 is a cross-sectional view showing the overall configuration of an extruder for a radially anisotropic ring-shaped bonded magnet, and FIG. 10 shows details of an orientation mold of the molding apparatus of FIG. FIG. In FIG. 9, a twin-screw kneading type extruder 6 constituting a molding apparatus has a barrel 62 divided into a plurality having a hopper 61 on one end side, and two screws 63 (in FIG. Only one is shown)
And an adapter 64 installed at the tip of the barrel 62. The orientation mold 7 is connected to a discharge port of the adapter 64. The orientation mold 7 has a ring-shaped spacer 71, a mandrel 72, and a cylindrical space 73 formed between them, and a magnetic field generating member 74 disposed around the ring-shaped spacer 71. Having. Using the molding apparatus 6, a radial anisotropic bonded magnet can be manufactured as follows. A shear force is applied to the compound charged into the barrel 62 via the hopper 61 by rotating a pair of screws 63, and the compound is conveyed into the orientation mold 7 while being heated and melted at a temperature of 230 to 280 ° C, where a magnetic field is generated. While passing, it is passed through a molding space narrowed down to a predetermined cross-sectional area. A practical magnetic field strength of 3 to 6 kOe is useful. When molded in a radial anisotropic or polar anisotropic magnetic field having this level of orientation magnetic field strength, a radially or polar anisotropic composite ring bonded magnet that can withstand practical use is obtained. If it is less than 3 kOe, it is difficult to provide useful magnetic properties.

(Preparation and Evaluation of Composite Type Radial Anisotropic Ring Bonded Magnet) Each of Compounds A to D was charged into an extruder shown in FIGS. Radial anisotropy was imparted when passing through the mold 7. The obtained four types of cylindrical molded bodies are cooled,
It was demagnetized and then cut to size. Cut ring-shaped molded product (outer diameter 25 mm x inner diameter 22 m x length 100 mm)
Was subjected to the same symmetric 8-pole magnetization as in Example 5. In each of the four ring-like bonded magnets after magnetization, the surface magnetic flux density along the axial direction of any one magnetic pole on each outer diameter surface was measured. The evaluation results of the average value (relative value) of the surface magnetic flux density (Bo) and the dispersion of the surface magnetic flux density (dBo = maximum value of Bo−minimum value of Bo), which are evaluated excluding the measurement results of 10 mm portions from both ends, are shown in the table. It is shown in FIG. Further, FIG. 8A shows a compound A, and FIG. 8B shows a dBo of the radial anisotropic ring-shaped bonded magnet formed by using the compound D.
Is shown.

[0035]

[Table 4]

From Table 4, it can be seen that Compound A in which the RTN-based magnet powder and the first ferrite powder are blended at the optimum ratio.
It can be seen that the average value of Bo is improved when is used. When Compounds B and C are used, the average value of Bo is improved as compared with the case where Compound D is used, reflecting the magnetic anisotropy of the magnetic powder to be compounded. At the same time, the effect of suppressing dBo is obtained. This is an effect of improving the fluidity (moldability) of the compound because the average particle diameter is large.

[0037]

As described above, according to the present invention, it is possible to provide a composite type anisotropic bonded magnet having improved magnetization, heat resistance, and uniformity of surface magnetic flux density.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a demagnetization curve.

FIG. 2 is a diagram showing an example of evaluation results of magnetization.

FIG. 3 is a diagram illustrating an example of an irreversible demagnetization rate.

FIG. 4 is a demagnetization curve showing an example of heat resistance.

FIG. 5 is a diagram showing an example of a surface magnetic flux density waveform.

FIG. 6 is a diagram showing an example of a correlation between a heat treatment temperature of a ferrite powder used in the present invention and Br.

FIG. 7 is a diagram showing an example of a correlation between a heat treatment temperature of a ferrite powder used in the present invention and iHc.

FIG. 8 is an example showing variations in surface magnetic flux density of a long radial ring bonded magnet.

FIG. 9 is a sectional view showing an extruder.

FIG. 10 is a cross-sectional view showing an orientation mold.

[Explanation of symbols]

 6 extruder, 7 orientation mold, 74 magnetic field generating member.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Mikio Shindo 5200 Sankejiri, Kumagaya-shi, Saitama Hitachi Metals Co., Ltd. Magnetic Materials Research Laboratories (72) Inventor Hiroshi Okashima 5200 Sankejiri, Kumagaya-shi, Saitama Hitachi Metals Research Co., Ltd. In-house F-term (reference) 5E040 AA03 AA19 AB04 AB09 BB03 CA01 HB06 NN01 NN02 NN06

Claims (4)

[Claims] Claims: 1. A magnetic anisotropy having an average particle size of 2 to 10.
μm, and the main component composition is R _α T _100-α-β N
_β (R is one or more kinds of rare earth elements including Y, T
Is Fe or Fe and Co, α and β are each atomic%,
20 to 80 parts by weight of an RTN-based magnet material powder represented by 5 ≦ α ≦ 20, 5 ≦ β ≦ 30, and (A _1-x R _x ) On · ((Fe _1-y Co _y ) ₂ O ₃ )
(Atomic ratio) (A is Sr and / or Ba, R is one or more kinds of rare earth elements including Y and always includes La), 0.1.
01 ≦ x ≦ 0.4, (x / (2.6n)) ≦ y ≦ (x / (1.
6n)) having a main component composition represented by 5 ≦ n ≦ 6,
Total Ca content in terms of Si content and CaO in terms of SiO ₂ is more than 0.2 wt%, _Al 2 O
₃ in terms of Al content and C in terms of Cr ₂ O ₃
80 to 20 parts by weight of magnetically anisotropic ferrite powder having a total r content of 0.13% by weight or less and having a magnetoplumbite type crystal structure and an average particle size of 0.9 to 2 μm And a resin portion binding the two types of magnetic material powder. 2. The composite anisotropic bonded magnet according to claim 1, wherein radial anisotropy or polar anisotropy is provided. 3. It has magnetic anisotropy and has an average particle size of 2 to 10.
μm, and the main component composition is R _α T _100-α-β N
_β (R is one or more kinds of rare earth elements including Y, T
Is Fe or Fe and Co, α and β are each atomic%,
20 to 80 parts by weight of an RTN-based magnet material powder represented by 5 ≦ α ≦ 20, 5 ≦ β ≦ 30, and (A _1-x R _x ) On · ((Fe _1-y Co _y ) ₂ O ₃ )
(Atomic ratio) (A is Sr and / or Ba, R is one or more kinds of rare earth elements including Y and always includes La),
01 ≦ x ≦ 0.4, (x / (2.6n)) ≦ y ≦ (x / (1.
6n)) having a main component composition represented by 5 ≦ n ≦ 6,
80 to 20 parts by weight of a ferrite powder having a magnetoplumbite type crystal structure and having an average particle diameter of more than 2 μm and 10 μm or less, and a resin binding the two kinds of magnet material powders And a composite type anisotropic bonded magnet comprising: 4. The composite type anisotropic bonded magnet according to claim 3, wherein radial anisotropy or polar anisotropy is provided.