JP2003203808A - Composite bonded magnet and rotating machine using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an SmFeN-based bonded magnet, having small surface roughness and improving magnetization and irreversible demagnetizing factor. <P>SOLUTION: The composite bonded magnet, having a main component composition expressed by R<SB>α</SB>T<SB>100-(α+β+γ+δ)</SB>M<SB>β</SB>B<SB>γ</SB>N<SB>δ</SB>in atom.% (R is at least one kind of rare earth element, containing Y and necessarily contains Sm; T is Fe or Fe and Co; M is at least one kind among Al, Ti, V, Cr, Mn, Cu, Ga, Zr, Nb, Mo, Hf, Ta and W; and 5≤α≤18, 0≤β≤10, 0≤γ≤4 and 4≤δ≤30) comprises R-T-N based anisotropic fine powder, whose average particle diameter d1 is 1 μm<d1≤10 μm and R-T-N based isotropic fine powder, whose average particle diameter d2 is 1-10 μm, and a binder binding the two kinds of magnetic powder. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a conventional isotropic Sm.
The present invention relates to a composite bond magnet in which the magnetism of an FeN bond magnet is improved, and a composite bond magnet in which the irreversible demagnetization rate (heat resistance) of an anisotropic SmFeN bond magnet is improved and the dimensional accuracy is extremely high. The present invention also relates to a high-performance rotating machine configured by using the composite bond magnet.

[0002]

2. Description of the Related Art Recently developed magnetic powders for SmFeN-based bonded magnets are classified into magnetic powders for isotropic bonded magnets and anisotropic bonded magnets depending on the manufacturing process. The isotropic magnetic powder is produced by, for example, a superquenching method or an HDDR method. The anisotropic magnetic powder is fine powder in which the particle size of the magnetic powder is adjusted to 10 μm or less, and becomes an anisotropic bonded magnet by applying a magnetic field to orient it. As a method for adjusting the particle size to 10 μm or less, there is a method other than pulverization, such as a method of obtaining fine powder without pulverization using a reduction diffusion method. These magnetic powders are made into bond magnets by compression molding, injection molding, extrusion molding, sheet molding, or the like.

Conventionally, isotropic SmFeN bonded magnets are difficult to magnetize and have a relatively low energy product, but have good thermal stability. On the other hand, an anisotropic SmFeN bonded magnet has the contradictory characteristics of being easily magnetized and obtaining a high energy product, but having low thermal stability.

In practice, it is often difficult to secure a sufficient magnetizing magnetic field strength to bring out the magnetic characteristics peculiar to the rare earth bonded magnet. The larger the difference between the iHc peculiar to the rare earth bonded magnet magnetized with a magnetic field strength at which the magnetic characteristics are saturated and the weak magnetic field strength of 1989.5 kA / m (25 kOe) or less at room temperature, which is often used practically, The variation in the characteristics becomes large, and the variation in the output of the magnet application product increases. In addition, the heat resistance evaluated by the irreversible demagnetization factor is anisotropic S
In case of mFeN bonded magnet, 100 ℃ which is necessary for practical use
The irreversible demagnetization ratio in 5: 5% or less cannot be satisfied, and there is a problem in reliability. Further, when it is incorporated in a rotating machine, it is usually adhered to a rotor core or a stator by using an adhesive, but if the surface roughness is large, the thickness of the adhesive layer also becomes large. Therefore, the adhesion strength is not the adhesive strength but the resin strength of the adhesive agent, so that peeling of the magnet when assembled is a problem. Therefore, it is desired that the surface roughness be small. Further, the gap of the magnetic circuit tends to become narrower year by year due to the improvement of output and miniaturization, and there is a problem that dimensional accuracy sufficient to obtain sufficient reliability cannot be obtained if the surface roughness is large.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a bond magnet in which the magnetizability of a conventional SmFeN isotropic bond magnet is improved, and to improve the irreversible demagnetization rate of the conventional SmFeN anisotropic bond magnet. In addition, the present invention provides a bonded magnet having improved surface roughness and improved peeling of the magnet when incorporated in a rotary machine, and improved dimensional accuracy. Moreover, the subject of this invention is providing the high performance rotary machine comprised using the said composite-type bond magnet.

[0006]

SUMMARY OF THE INVENTION The composite bonded magnet of the present invention, which has solved the above-mentioned problem, is R _α T _{100− (α +
β + γ + δ)} M _β B _γ N _δ (R is at least one rare earth element including Y and always contains Sm, T is Fe or Fe and Co, M is Al, Ti, V, Cr, Mn,
At least one of Cu, Ga, Zr, Nb, Mo, Hf, Ta and W, and 5 ≦ α ≦ 18,0 ≦ β ≦ 10,0 ≦
γ ≦ 4,4 ≦ δ ≦ 30) and an R—T—N anisotropic fine powder having an average particle size of 1 to 10 μm and an R−T—N average particle size of 1 to 10 μm. TN isotropic fine powder, and a binder that binds the two types of magnetic powder,
The average surface roughness can be 0.5 μm or less, further 0.3 μm or less. Further, (R-T-N-based isotropic fine powder): (R-T-N-based anisotropic fine powder) = 50 to 95 parts by weight: 50 to 5 parts by weight of magnetic powder and binder,
[Magnetic field strength: Residual magnetic flux density Br when magnetized at 800 kA / m (10 kOe)] / [Magnetic field strength: 4000 kA / m (50 kOe)
The residual magnetic flux density when magnetized in [Br] x 100% has a magnetization rate of 85% or more and the permeance coefficient (Pc)
It has a good magnetizability of irreversible demagnetization rate of 3.5% or less when heated to 100 ° C. for 1 hour in the atmosphere and returned to room temperature. Further, (R-T-N type isotropic fine powder): (R-T-N type anisotropic fine powder) = 50 to 5 parts by weight: 50
It is composed of up to 95 parts by weight of magnetic powder and a binder, and has good heat resistance such as a magnetization rate of 80% or more and an irreversible demagnetization rate of 5.0% or less.

The composite-type bonded magnet (especially with a thickness of 0.05 to
A rotary machine (a fan motor, a spindle motor, a vibration motor mounted on a mobile communication device, or the like) configured by using a 2 mm sheet-shaped one or a high-strength one by compression molding is useful. Further, a magnet roll used in an electrostatic development type printer, a copying machine, or the like, which is configured by using the composite bond magnet, is useful. It is also useful as an acoustic speaker, a buzzer, a magnet for attracting or generating a magnetic field, and the like.

In the present invention, the R-T-N type isotropic fine powder refers to R-T by, for example, high frequency melting or arc melting.
Using an RT master alloy obtained by producing a molten metal adjusted to the main component composition of an RT master alloy corresponding to -N magnetic powder and then solidifying it by a mold casting method or a strip casting method, if necessary. Coarse crushing process, hydrogenation / cracking reaction process and dehydrogenation / recombination reaction process (HDDR process), such as crystal refining process, nitriding process, and fine crushing process, are used to produce particles having a particle size of 1 to 10 μm. Point to. Alternatively, the molten RT alloy may be subjected to a crystal refining step by ultraquenching.

Further, the R-T-N anisotropic fine powder is a molten metal adjusted to the main component composition of the R-T master alloy corresponding to the R-T-N magnetic powder by, for example, high frequency melting or arc melting. After the production, using the RT master alloy obtained by solidifying by the mold casting method or the strip casting method, the nitriding step is performed without performing the crystal refining step so that the uniaxial crystal grain size becomes 1 to It is finely pulverized to 10 μm.

R always includes Sm, and Y, L other than Sm
a, Ce, Pr, Nd, Eu, Gd, Tb, Dy, H
It is allowed to contain at least one of o, Er, Tm, Yb and Lu. A mixture of two or more kinds of rare earth elements such as Sm misch metal and didymium may be used. As R, more preferably Sm or Sm and La and Y, C
at least one of e, Pr, Nd, Gd, Dy and Er
It is preferred that a combination of species, more preferably a combination of Sm or Sm and La with at least one of Y, Ce, Pr and Nd, especially R consisting of Sm or Sm and La. In terms of Sm purity, iHc ≧ 397.9
In order to achieve kA / m (5 kOe), the Sm ratio in R is preferably 50 atom% or more, more preferably 70 atom% or more. It is permissible for R to contain inevitable impurities such as O, H, C, Al, Si, Na, Mg, and Ca, which are unavoidable from the viewpoint of manufacturing, in a total amount of 10 atom% or less of R. The R content (α) is preferably 5 to 18 atom%, more preferably 6 to 12 atom%. If the R content is less than 5 atomic%, it is difficult to obtain iHc ≧ 397.9 kA / m (5 kOe), and if it exceeds 18 atomic%, the (BH) max is greatly reduced.

Al, Ti, V, Cr, Mn, Cu, G
The content (β) of the M element consisting of at least one of a, Zr, Nb, Mo, Hf, Ta and W is preferably 0 to 10 atomic%. IHc increases with the increase of M element, but when the content of M element exceeds 10 atomic%, ThMn ₁₂
Type Sm (Fe, M) ₁₂ N _z phase is generated and iHc is greatly reduced. The B content (γ) is preferably 0 to 4 atomic%. IHc increases as the amount of B increases,
If it exceeds 4 atomic%, iHc is greatly reduced. The nitrogen content (δ) is preferably 4 to 30 atom%, more preferably 10 to 20 atom%. Below 4 atom% and above 30 atom%, iHc, (B
H) max is greatly reduced. 0.01 to 30 atom% of a part of Fe
Of Co is preferable, and 1 to 20 atomic% of Co
More preferably, Although the Curie temperature and the temperature coefficient of iHc are improved by containing a predetermined amount of Co, (BH) max and iHc are significantly reduced when the Co content exceeds 30 atomic%, and the addition effect is less than 0.01 atomic%. unacceptable.

When the reduction / diffusion method is used, it is inexpensive RT
-N-based magnetic powder can be provided. Further, it is obtained by producing a molten metal adjusted to the main component composition of the RT master alloy corresponding to the RTN magnetic powder by high frequency melting or arc melting, and then solidifying it by a mold casting method or a strip casting method. The R-T-based magnetic powder can be produced by using the R-T-based master alloy.

Preferred manufacturing conditions for manufacturing the RTN magnetic powder by the reduction / diffusion method will be described below. First, the oxide of R and the oxide of Fe or Fe are separated by RT
-The compound is added to the main component composition of the RT master alloy corresponding to the N magnet powder. Further, the amount of the reducing agent (Ca, which is 0.5 to 2 times the amount of the R oxide and, if necessary, the Fe oxide, which is 100% reduced in the chemical reaction formula (this is called the stoichiometrically required amount). , Mg, CaH ₂ and MgH ₂ ) are added to the formulation and then mixed. Subsequently, the mixture is heated in an inert gas atmosphere at 1000 to 1300 ° C. for 1 to 20 hours to reduce oxides of R and the like, and then to reduce R and Fe.
After sufficiently diffusing and, the mixture is cooled to room temperature. If the amount of the reducing agent added is less than 0.5 times the stoichiometrically required amount, the reduction reaction useful in industrial production will not be realized, and if it exceeds 2 times, the amount of the reducing agent remaining in the magnetic powder will increase and the magnetic properties Cause decline. Also, the heating condition in an inert gas atmosphere is 1000 ° C ×
If it is less than 1 hour, the reduction / diffusion reaction beneficial for industrial production does not proceed, and if it exceeds 1300 ° C x 20 hours, the reduction / diffusion reaction furnace is significantly deteriorated. Next, the reaction product is put into a cleaning liquid to add CaO.
After washing away reaction by-products such as the above, dehydration and vacuum drying are performed to obtain an RT master alloy by a reduction / diffusion method. Next, if necessary, the RT master alloy is subjected to homogenizing heat treatment by heating it in an inert gas atmosphere containing no nitrogen for 1010 to 1280 ° C. for 1 to 40 hours to remove αFe and other segregated phases. After making a solid solution, it is cooled to room temperature. If the homogenization heat treatment condition is less than 1010 ° C x 1 hour, the solid solution of αFe and other segregated phases does not proceed, and if it exceeds 1280 ° C x 40 hours, the effect of the homogenization heat treatment is saturated and the composition shift due to evaporation of Sm etc. occurs. It will be noticeable.

The RT master alloy thus obtained is Ca
The content is preferably 0.4% by weight or less, more preferably 0.2
% By weight or less, particularly preferably 0.1% by weight or less, the oxygen content is preferably 0.8% by weight or less, more preferably
0.4 wt% or less, particularly preferably 0.2 wt% or less,
The carbon content is preferably 0.3% by weight or less, more preferably 0.2% by weight or less, and particularly preferably 0.1% by weight or less. Next, 1.0 × 10 ^{4 to} 1.0 × 10 ⁶ Pa (0.1 to 10 atm)
Hydrogenation / decomposition reaction treatment by heating in 675 to 900 ° C. for 0.5 to 8 hours in hydrogen gas or an inert gas (excluding nitrogen gas) having a partial pressure of hydrogen gas, and then 1.3 Pa (1 × 10
Dehydrogenation / recombination reaction treatment is performed by heating at 700 to 900 ° C. for 0.5 to 10 hours in a high vacuum of ⁻² Torr or less. The mother alloy is decomposed into a hydride RHx phase of the rare earth element R by a hydrogenation / decomposition reaction. Then, by dehydrogenation / recombination reaction,
By recombining with the mother alloy phase, a mother alloy composed of fine recrystallized grains having an average grain size of 0.01 to 1 μm is obtained. The individual recrystallized grains are randomly oriented. If the hydrogen partial pressure of the hydrogenation / cracking reaction is less than 1.0 × 10 ⁴ Pa (0.1 atm), the cracking reaction does not occur, and if it exceeds 1.0 × 10 ⁶ Pa (10 atm), the vacuum exhaust facility becomes large and the cost increases. Therefore, the hydrogen partial pressure is 1.0 × 10 ^{4 to} 1.0.
× 10 ⁶ Pa (0.1 to 10 atm) is preferable, 5.0 × 10 ^{4 to} 5.0
× 10 ⁵ Pa (0.5 to ⁵ atm) is more preferable. If the heating condition of the hydrogenation / cracking reaction is less than 675 ° C (corresponding to the lower limit of hydrocracking temperature) x 0.5 hours, the mother alloy only absorbs hydrogen and does not decompose into the RHx phase, etc., and exceeds 900 ° C x 8 hours. Then, after dehydrogenation, the mother alloy becomes coarse-grained, and the iH
c is greatly reduced. Therefore, the heating conditions for the hydrogenation / cracking reaction are preferably 675 to 900 ° C x 0.5 to 8 hours, and 675 to 875
More preferably 0.5 ° C. × 0.5 to 8 hours. Hydrogen partial pressure of dehydrogenation-recombination reaction takes a long time to process the low vacuum than ^{1.3Pa (1 × 10 -2 Torr)} , 1.3 × 10 -4 Pa (1 × 10 - 6 Tor
If the vacuum is higher than that of r), the size and cost of the vacuum exhaust device will increase. Heating conditions for dehydrogenation / recombination reaction are 700 ℃ ×
Degradation of RHx, etc. does not proceed in less than 0.5 hours, 900 ° C x 10
If the time is exceeded, the recrystallized structure will become coarse and iHc will decrease significantly. Therefore, in order to set the average recrystallized grain size to 0.01 to 1 μm, the heating conditions for the dehydrogenation / recombination reaction are 700 to 900 ° C. × 0.
It is preferably 5 to 10 hours, more preferably 725 to 875 ° C x 0.5 to 10 hours. Next, if necessary, pulverization is performed, and then nitriding treatment is performed to obtain the R-T-M magnetic powder used in the present invention. It is preferable to adjust the particle size distribution by classifying or sieving as needed before nitriding in order to realize a uniform nitriding structure and to improve the moldability and density of the rare earth bonded magnet.

Nitriding is performed at 2.0 × 10 ^{4 to} 1.0 × 10 ⁶ Pa (0.2 to
10 atm) nitrogen gas, hydrogen is 1 to 95 mol% and the balance is nitrogen (hydrogen + nitrogen) mixed gas, and NH ₃ is 1 mol%
Gas nitriding, which heats at 300 to 650 ° C. for 0.1 to 30 hours in any atmosphere of a mixed gas of (NH ₃ + hydrogen) with the balance being hydrogen at ˜50% is highly practical. The heating conditions for gas nitriding are preferably 300 to 650 ℃ × 0.1 to 30 hours, 400 to 550 ℃
× 0.5 to 20 hours is more preferable. Nitriding does not proceed at less than 300 ° C. × 0.1 hours, and RN phase is generated conversely at more than 650 ° C. × 30 hours to lower iHc. The pressure of nitrogen alone gas or nitrogen-containing gas in nitriding is 2.0 × 10 ^{4 to} 1.0 × 10 ⁶ Pa (0.2
~ 10 atm) is preferable, and 5.0 x 10 ^{4 to} 5.0 x 10 ⁵ Pa (0.5
~ 5 atm) is more preferred. When it is less than 2.0 × 10 ⁴ Pa (0.2 atm), the nitriding reaction becomes very slow, and 1.0 × 10 ⁶ Pa (10 atm)
If it exceeds m, high pressure gas equipment will become large and cost will increase. After nitriding, iHc can be further increased by performing heat treatment in vacuum or in an inert gas (excluding nitrogen gas) at 300 to 600 ° C. for 0.5 to 50 hours. RT-obtained in this way
The N-based magnetic powder may contain 0.01 to 10 atomic% of hydrogen.

The average particle size of the R-T-N isotropic fine powder and anisotropic fine powder used in the present invention is preferably 1 to 10 μm.
-5 μm is more preferable. When the average particle size is less than 1 μm, the moldability is deteriorated, and the oxidation becomes remarkable, and (BH) max is greatly reduced. If the average particle size exceeds 10 μm, the surface roughness of the composite bonded magnet body deteriorates, making it difficult to apply it to applications where the gap of the magnetic circuit is small. Isotropic fine powder 10 μm
If the above is used, the oxidation resistance is further improved,
A surface roughness average of 0.5 μm or less intended by the present application cannot be obtained. Therefore, although the magnetic characteristics are slightly lowered, it has an advantage in applications such as small motors that require a narrow gap.

The main phase of the R-T-N isotropic fine powder is a hard magnetic phase having a 2-17 type or 1-7 type crystal structure and a high (BH) m.
In order to have ax and good heat resistance, the average crystal grain size of the hard magnetic phase is preferably 0.01 to 1 μm, and 0.01 to 1 μm.
0.4 μm is more preferable, and 0.01 to 0.3 μm is particularly preferable. If the average crystal grain size exceeds 1 μm, iHc is 397.9 kA / m (5 kO
Less than e). In order to improve magnetic properties, R-T-N
The content ratio of αFe in the isotropic fine powder is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less in terms of the average value of the area ratio. Hard magnetic phase and α
The identification of Fe and the calculation of the area ratio of these phases are performed in consideration of the cross-sectional structure photograph taken by an electron microscope and an optical microscope, the electron diffraction result, the X-ray diffraction result, and the like. For example, it can be determined by matching the transmission electron micrograph of the cross section of the target R-N-N magnetic powder particles and the identification result of the cross-sectional structure.

The R-T-N anisotropic fine powder is roughly crushed with a hammer mill, a jaw crusher, etc., using an RT mother alloy obtained by a reduction / diffusion method, a mold casting method or a strip casting method. After nitriding, it can be obtained by finely pulverizing with a ball mill, jet mill or the like.

A thermosetting resin, a thermoplastic resin or a rubber material is suitable as the binder of the composite bonded magnet of the present invention. In the case of the compression molding method or the calendar roll method, a thermoplastic resin or a thermosetting resin is preferable, and a thermosetting liquid resin is particularly suitable. As specific examples, liquid resins such as epoxy resin, polyimide resin, polyester resin, phenol resin, fluororesin, silicon resin or polyphenylene sulfide resin (PPS) are useful. Liquid epoxy resins are the most preferable because they are easy to handle, exhibit good heat resistance, and are inexpensive.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION (Examples)
BEST MODE FOR CARRYING OUT THE INVENTION The invention will be described in detail, but the present invention is
It is not limited. (Example 1) Master alloy for nitriding by strip casting method
The R-TN type isotropic magnetic powder using was produced. Purity 99.9
% Of Sm, Fe, Ti, and B with the following nitriding
Molten metal adjusted to the main component composition of the master alloy corresponding to magnetic powder
Is a twin roll type strip caster made of copper with a diameter of 300 mm.
Pour molten metal onto the cooling roll surface (peripheral speed 1 m / sec)
It was cooled and solidified to obtain a plate-shaped master alloy having a plate thickness of about 150 μm. Next
, 1.0 × 10 in mother alloy⁵800 in Pa (1 atm) hydrogen gas
After hydrogenation / decomposition reaction treatment by heating at ℃ × 1 hour,
Hydrogen partial pressure (in vacuum) of about 6.7Pa (5 x 10^-2Torr) 800
A dehydrogenation / recombination reaction treatment was performed by heating at ℃ × 1 hour.
Next, after crushing in a nitrogen gas atmosphere using a hammer mill
Sieve to 75 μm under. Then 1.0 x 10⁵Pa (1at
m) Nitrogen gas is subjected to nitriding treatment by heating at 450 ° C for 10 hours.
And cooled. After that, in an argon gas stream, 400 ° C x 3
Heat treated for 0 minutes, main component composition is atomic% Sm_8.1
Fe_balTi _2.0B_1.0N_12.0, Average particle size
Of 56.2 μm and a particle size distribution of 26 to 74 μm were obtained.
Average particle size and particle size distribution are laser diffraction particle size manufactured by Sympatec
Distribution measuring device: measured by Heros Rhodes. this
Nitride magnetic powder has a hard magnetic phase (Th
_TwoZn₁₇Type) and a small amount of αFe, and αFe is
The average area ratio was less than 1%, which was very small.
The above-mentioned magnetic nitride powder was finely pulverized with a ball mill to obtain an average particle size of
It was a 1-10 μm R-T-N type isotropic fine powder.

Next, a nitriding mother by the strip casting method
An R-T-N anisotropic magnetic powder using an alloy was produced. R-
A plate shape with a thickness of about 150 μm, similar to T-N isotropic magnetic powder
A mother alloy was obtained. Next, using a hammer mill, use a nitrogen gas atmosphere.
After crushing in air, it was sieved to 75 μm under. Then 1.0 x 1
0⁵Heat at 450 ℃ for 10 hours in Pa (1atm) nitrogen gas
It was subjected to a nitriding treatment and cooled. After that, argon gas flow
Heat treatment at 400 ℃ for 30 minutes at a main component composition of atomic%
 Sm_8.1Fe_balTi_2.0B_1.0N
_12.0, Average particle size 56.2μm, particle size distribution 26-74μ
m nitride magnetic powder was obtained. The above-mentioned nitrided magnetic powder was ball milled.
Finely pulverized to a uniaxial crystal grain size close to 1 to 10μ
m of R-T-N anisotropic fine powder. (Measurement of surface roughness) R-TN type isotropic fine powder and R
-T-N based anisotropic fine powder is mixed in a weight ratio of 70:30.
Then, add the silane coupling agent and add it to the mixer.
And mixed. Then 2.8 parts by weight of liquid epoxy resin and
And compounding agent DDS
I got a hand. Then, using the compound,
Power 7.8 × 10⁸Pa (8 tons / cm^Two), The permeance coefficient (P
c) is 2; (thickness) / (diameter) = 0.7 pressed into a solid cylindrical shape
It was compression molded. Next, the molded body is heated in air at 200 ° C for 2 hours.
After thermosetting, it was cooled to room temperature to obtain a composite bonded magnet. This
The surface roughness of the composite bonded magnet of was measured along the axial direction.
It was A plot of the measurement results is shown in FIG. Largest table
The surface roughness is within 0.5 μm, and the average surface roughness is about 0.
It was 3 μm. (Comparative Example 1) Method for producing the above-mentioned R-T-N isotropic fine powder
No fine powder process was performed and the average particle size after nitriding was 5
Compared with the present invention by using 6.2 μm R-T-N type isotropic coarse powder.
Compared. The R-T-N anisotropic fine powder was the same as in Example 1.
I used a similar one. R-T-N type isotropic coarse powder and R-T-
N-type anisotropic fine powder was mixed in a weight ratio of 70:30 to prepare silane.
Add a system coupling agent and add it to the mixer to mix
It was Then 2.8 parts by weight of liquid epoxy resin and cure
Compound DDS was added to obtain compound for composite type bonded magnet
It was Next, using the compound, the same as in Example 1
To obtain the composite bonded magnet and measure the surface roughness.
It was A plot of the measurement results is shown in FIG. Largest table
Surface roughness is 1.4μm, average surface roughness is about 0.6μ
It was m.

(Preparation of Composite Type Isotropic Bonded Magnet) The above-mentioned R-T-N isotropic fine powder and R-T-N anisotropic fine powder are 90:10, 70:30, 50:50. The silane coupling agent was added and added to the mixer and mixed. Then, 2.8 parts by weight of the liquid epoxy resin and the curing agent DDS were added to obtain a compound for a composite bonded magnet. Next, using the above compound, at a molding pressure of 7.8 × 10 ⁸ Pa (8 ton / cm ² ), the permeance coefficient (P
c) is 2; (thickness) / (diameter) = 0.7, and compression molded into a solid cylindrical shape. Next, the molded body was heat-cured in the air at 200 ° C. for 2 hours and then cooled to room temperature to obtain a composite bonded magnet.
(Examples 2 to 4) Next, except that the R-T-N isotropic fine powder and the R-T-N anisotropic fine powder were mixed in a weight ratio of 40:60 and 100: 0, respectively. Comparative Example 2, in the same manner as in Examples 2 to 4.
A composite type bonded magnet of No. 3 was produced. The magnetizability was defined by the following formula. (Magnetization rate) = [Magnetic field strength: Br when magnetized at 800 kA / m (10 kOe)] / [Magnetic field strength: (4000 kA / m (50 kOe)]
Br) x 100 (%) when magnetized at 20% of the sample of each composite bond magnet with Pc = 2
After magnetizing at 7.4 kA / m (30 kOe), the total amount of magnetic flux (φ) was measured. Then, the sample was exposed to 100 ° C. for 1 hour in the atmosphere and then cooled to room temperature, and the total magnetic flux amount (φ1) was measured. The irreversible demagnetization rate (rate of change of total magnetic flux) defined by the following formula was adopted and evaluated as an index of heat resistance. The results are shown in Table 1. (Irreversible demagnetization rate) = (φ-φ1) / (φ) × 100 (%)

[0023]

[Table 1] α: Irreversible demagnetization rate when heated to 100 ° C x 1 hour in the air and returned to room temperature

As shown in Table 1, the composite bonded magnets of Examples 2 to 4 in which the mixing weight ratio of the isotropic fine powder and the anisotropic fine powder was 10:90 to 50:50 wt%, the target magnetizability was 85. %
The characteristics were over, and the irreversible demagnetization rate was 3.5% or less.
On the other hand, Comparative Example 3 consisting of only the isotropic R-T-N fine powder had an irreversible demagnetization factor of -2.0, but the magnetizability was not sufficient. Further, in the case of Comparative Example 2, the magnetization rate is 97.
%, The α was -5.3 and the heat resistance was not sufficient.

(Example 5) Using the same magnetic powder as in Example 1,
Mixed magnetic powder: 91.94 parts by weight, natural rubber: 3 parts by weight, nitrile rubber: 3 parts by weight, chlorinated polyethylene: 2 parts by weight, bisphenol type epoxy resin: 0.05
Parts by weight and 0.01 parts by weight of calcium stearate were mixed and then kneaded while heating. After cooling the kneaded product, the particle size is 5
Milled to less than mm. After crushing, a rod-shaped molded body was extruded while heating in the air. Then, in the air, at a temperature of 50 ℃, the rod-shaped molded body is rolled by a rolling mill to a thickness of 1 mm,
A sheet-shaped molded product having a width of 100 mm was obtained. Then, the sheet-shaped molded body was cut into a length of 80 mm. After that, in order to remove impurities, heat treatment is performed by heating in the air at 50 ° C for 10 hours, followed by vulcanization in the air (150 ° C x 2
Time) to obtain a sheet-shaped bonded magnet. The surface roughness was measured in the same manner as in Example 1. The maximum surface roughness was 0.5 μm and the average surface roughness was about 0.3 μm.

(Examples 6 to 8) Using magnetic powders having the same blending weight ratio as in Examples 2 to 4, with respect to mixed magnetic powders: 91.94 parts by weight, natural rubber: 3 parts by weight, nitrile rubber: 3 parts by weight, respectively. Parts, chlorinated polyethylene: 2 parts by weight, bisphenol type epoxy resin: 0.05 parts by weight and calcium stearate: 0.01 parts by weight, and then kneaded while heating. The kneaded product was cooled and then pulverized to a particle size of 5 mm or less. After crushing, a rod-shaped molded body was extruded while heating in the air. Then, the bar-shaped compact was rolled in air at 50 ° C. by a roll mill to obtain a sheet-shaped compact having a thickness of 1 mm and a width of 100 mm. Then, the sheet-shaped molded body was cut into a length of 80 mm. After that, a heat treatment of heating at 50 ° C. for 10 hours in the atmosphere to remove impurities was performed, and then a vulcanization treatment (150 ° C. for 2 hours) was performed in the atmosphere to obtain a sheet-shaped bonded magnet (Examples) 6-8). Table 2 shows (BH) max, magnetization rate, and α of these sheet-like bonded magnets.

[0027]

[Table 2] α: Irreversible demagnetization rate when heated to 100 ° C x 1 hour in the air and returned to room temperature

From Table 2, R-TN type isotropic fine powder and R-N
The blending weight ratio with the TN anisotropic fine powder is 95: 5-5.
With the composite type bonded magnets of Examples 6 to 8 with 0:50, the target magnetization ratio was over 85% and the irreversible demagnetization ratio was 3.5% or less. On the other hand, Comparative Example 5 containing only the R-T-N coarse powder had a magnetization rate of 81%, and in the case of Comparative Example 4 of 40:60, the magnetization rate was 97% but α was -5.4 and heat resistance was high. The sex was not enough.

(Production of Composite Anisotropic Bonded Magnet) The above-mentioned R—T—N isotropic fine powder and R—T—N anisotropic fine powder were used in the same blending weight ratio as in Examples 2-4. The powder was made into magnetic powder, and each was put into a mixer together with a silane coupling agent and mixed. Then, 2.8 parts by weight of the liquid epoxy resin and the curing agent DDS were added to obtain a compound for a composite bonded magnet. Then, using the compound, a molding pressure of 7.8 × 10
⁸ Pa (8 ton / cm ² ) and a permeance coefficient (Pc) of 2;
(Thickness) / (Diameter) = 0.7 A solid cylindrical shape was compression molded in a magnetic field. Next, the molded body was heat-cured in the air at 200 ° C. for 2 hours and then cooled to room temperature to obtain composite bonded magnets (Examples 9 to 11). When these surface roughnesses were measured in the same manner as in Example 1, almost the same results were obtained. Also,
Next, the anisotropic R-T-N-based fine powder and the isotropic R-T-N are used.
Composite bonded magnets of Comparative Examples 8 to 10 were produced in the same manner as in Examples 12 to 17 except that the fine powder was mixed in a weight ratio of 40:60 and 100: 0.

[0030]

[Table 3] α: Irreversible demagnetization rate when heated to 100 ° C x 1 hour in the air and returned to room temperature

From Table 3, the compounding weight ratio of anisotropic R-T-N type fine powder to isotropic R-T-N type fine powder is 95-50: 5-50.
With the composite bond magnets of Examples 9 to 11, the target magnetizability was over 80% and the irreversible demagnetization ratio was 5% or less. On the other hand, in Comparative Example 7 containing only anisotropic RTN fine powder, α was −7.0%, and in Comparative Example 6 of 40:60, α was −3.7% and the magnetization rate was 78%. Was not enough.

Using the same magnetic powder as in Examples 9 to 11, natural rubber: 3 parts by weight, nitrile rubber: 3 parts by weight, chlorinated polyethylene: 2 with respect to mixed magnetic powder: 91.94 parts by weight, respectively.
Parts by weight, bisphenol type epoxy resin: 0.05 parts by weight and calcium stearate: 0.01 parts by weight were mixed and then kneaded while heating. The kneaded product was cooled and then pulverized to a particle size of 5 mm or less. After the crushing, a magnetic field was applied to the extruded product while heating the rod-shaped product in the atmosphere. Then, the sheet-shaped molded body was cut into a length of 80 mm. Then, in order to remove impurities, a heat treatment of heating at 50 ° C. for 10 hours in the atmosphere was performed, and then a vulcanization treatment (150 ° C. for 2 hours) was performed in the atmosphere to obtain a sheet-shaped bonded magnet. When these surface roughnesses were measured in the same manner as in Example 5, almost the same results were obtained. (BH) ma of these sheet-shaped bonded magnets
Table 4 shows x, magnetization rate, and α.

[0033]

[Table 4]

From Table 4, the blending weight ratio of the anisotropic R-T-N fine powder to the isotropic R-T-N fine powder is 95-50: 5-50.
In the composite bonded magnets of Examples 12 to 14, the target magnetizability was over 80% and the irreversible demagnetization ratio was 5% or less. On the other hand, in Comparative Example 9 containing only the anisotropic R-T-N fine powder, α was -7.0%, and in the case of 40:60, the magnetization rate of 79% when α was -3.7% was not sufficient. There wasn't.

(Preparation of Sheet-shaped Composite Type Bonded Magnet and Evaluation on Rotating Machine) (Example 15) Using the sheet-shaped composite type isotropic bonded magnet having a thickness of 1.0 mm prepared in Example 5, as shown in FIG. The results of evaluation of the fan motor 10 which is configured will be described below.
2A is a front view of a main part of an example of the fan motor of the present invention, and FIG. 2B is a view seen from the back side of FIG. In FIG. 2 (a), 1 is a ring-shaped field magnet formed by winding the sheet-shaped composite type isotropic bonded magnet once, and the inner circumference of the ring-shaped ferromagnetic yoke 2 (SS400, etc.) It is fixed to the surface side with an adhesive. The surface roughness of the sheet-shaped composite type anisotropic bonded magnet is very small, and it is possible to firmly and uniformly adhere while maintaining precise dimensional accuracy. Reference numeral 1a is a joint of the field magnet 1, and a symmetrical 4-pole magnetic pole 1b is formed on the inner peripheral surface side of the field magnet 1. Reference numeral 3 denotes a rotary shaft of the fan motor 10, and the rotary shaft 3 (rotor 7) is rotated via a bearing 6 at a predetermined speed. The rotating shaft 3 and the yoke 2 are arranged coaxially, and are integrally held and fixed by an injection molding member 4 made of glass-containing polybutylene terephthalate resin. The holding member 4 includes a fan 4a, a rim 4b,
It consists of the spokes 4c and the back surface 4d, and gives the rotor 7 sufficient strength for practical use. The field magnet 1 can be magnetized by arranging the rotor 7 in a magnetizing zone (not shown) of a predetermined magnetizer and then magnetizing it, so that industrial production efficiency can be improved. The rotor 7 and the stator (armature) 8 are arranged so as to face each other via an air gap 9. A stator magnetic pole (symmetrical 4 poles) is formed on the outer peripheral surface side of the stator 8 and receives a rectangular wave energization (180 degrees electric angle energization) signal from a fan motor drive control circuit (not shown) to produce a fan 4a. Rotates efficiently. After the fan motor 10 incorporating the rotor 7 was mounted on a blower fan and continuously operated for one month, no cracks or cracks were observed in the field magnet 1 after the continuous operation, and the field magnet 1 had a normal appearance. Further, no performance deterioration of the fan motor 10 due to this continuous operation was observed.

(Example 16) Thickness produced in Example 13
The vibration motor 20 for a pager shown in FIG. 3 was constructed using a 1.0 mm sheet-shaped composite anisotropic bonded magnet, and the evaluation results are described below. FIG. 3A is a sectional view of a main part of the motor 20, and FIG. 3B is a sectional view taken along the line AA of FIG. The field magnet 24 is made of a ferromagnetic material (S4
It was formed by adhering just one roll to the surface of the rotor yoke 26 made of 5C) and adhering it. The surface roughness of the sheet-shaped composite type anisotropic bonded magnet is very small, and it is possible to firmly and uniformly adhere while maintaining precise dimensional accuracy. Reference numeral 24a is a seam of the bonded sheet-shaped bonded magnets. Since the rotor yoke 26 and the rotating shaft 28 are fixed, the occurrence of iron loss in the rotor yoke 26 can be ignored. The field magnet 24 is symmetrically quadrupole magnetized in the circumferential direction of the outer peripheral surface. The stator 35 includes a stator iron core 22 and windings 30. The number of teeth 22a of the stator iron core is 6, and the number of windings of each tooth 22a is 36 turns. The stator iron core 22 is a thin plate made of a ferromagnetic material (silicon steel plate: JIS50A350) having a thickness of 0.5 mm in the L direction (L
= 10 mm). A substantially semi-cylindrical eccentric weight 33 is attached to the tip of the rotary shaft 28,
It is designed to rotate together with 28. When the motor 20 is driven, the eccentric weight 33 rotates while being eccentric, and the motor 20
Noticeable vibration occurs. The motor 20 rotates efficiently by the rotation control by the three-phase AC energization method. This motor 20
Embedded in a predetermined mobile communication device (mobile phone)
After using it for a month, it was disassembled and the condition of the field magnet 24 was examined. As a result, it was found that the field magnet 24 was not cracked or cracked, and the motor performance that could withstand practical use was maintained.

In order to improve the corrosion resistance, the surface of the composite type bonded magnet of the present invention may be coated with a corrosion resistant coating (epoxy resin coating or the like) having an average film thickness of 0.5 to 10 μm to enhance the corrosion resistance. If the average thickness of the corrosion-resistant coating is less than 0.5 μm, the corrosion resistance is not enhanced, and if it exceeds 10 μm, the effect of imparting corrosion resistance is saturated.

[0038]

As described above, according to the present invention, the surface roughness is small and the magnetism and anisotropy R-T-N of the conventional isotropic R-T-N type bonded magnet are obtained. It is possible to provide a composite-type bonded magnet having characteristics that the heat resistance of the system-based bonded magnet is improved. Further, it is possible to provide a highly safe and high-performance rotating machine using the composite bond magnet.

[Brief description of drawings]

FIG. 1 is a plot diagram comparing the surface roughness of the present invention with that of a conventional one.

FIG. 2 is a front view (a) of a main part showing an example of a rotating machine of the present invention, and a view (b) viewed from the back side of (a).

FIG. 3 is a front view (a) of a main part showing another example of the rotating machine of the present invention, and a sectional view (b) taken along the line AA of (a).

[Explanation of symbols]

10 fan motor, 20 pager motor.

Claims (7)

[Claims] 1. R _α T _{100- (α + β + γ + δ) in} atomic%
M _β B _γ N _δ (R is at least 1 of rare earth elements including Y)
It is a seed and always contains Sm, T is Fe or Fe and Co, M is Al, Ti, V, Cr, Mn, Cu, Ga,
At least one of Zr, Nb, Mo, Hf, Ta and W
5 ≦ α ≦ 18, 0 ≦ β ≦ 10, 0 ≦ γ ≦ 4, 4 ≦
δ ≦ 30), and the average particle size is
1-10 μm R-T-N anisotropic fine powder with an average particle size of 1
A composite-type bonded magnet comprising: an R-T-N isotropic fine powder having a particle size of up to 10 μm; and a binder that binds the two types of magnetic powder. 2. The composite bonded magnet according to claim 1, which has an average surface roughness of 0.5 μm or less. 3. The composite bonded magnet according to claim 1, wherein (R—T—N isotropic fine powder) :( R—T—N anisotropic fine powder) = 50 to 95 parts by weight. : 50 to 5 parts by weight of magnetic powder and binder, [Magnetic field strength: 800kA / m (10k
Oe) residual magnetic flux density Br] / [magnetizing magnetic field strength: 4000kA / m (50kOe) residual magnetic flux density B]
r] x 100%, the magnetization rate is 85% or more, and the irreversible demagnetization rate is 3.5% or less when heated to room temperature at 100 ° C x 1 hour in the atmosphere with permeance coefficient (Pc) = 2 A composite bond magnet. 4. The composite bonded magnet according to claim 1, wherein (R—T—N isotropic fine powder) :( R—T—N anisotropic fine powder) = 50 to 5 parts by weight. : 50 to 95 parts by weight of magnetic powder and binder, [Magnetic field strength: 800kA / m (10k
Oe) residual magnetic flux density Br] / [magnetizing magnetic field strength: 4000kA / m (50kOe) residual magnetic flux density B]
r] x 100%, the magnetization rate is 80% or more, and the irreversible demagnetization rate is 5.0% or less when heated to room temperature at 100 ° C x 1 hour in the atmosphere with the permeance coefficient (Pc) = 2 A composite bond magnet. 5. The composite bond magnet according to any one of claims 1 to 4, which has a ring shape manufactured by compression molding or injection molding. 6. The composite bond magnet according to claim 1, which has a sheet shape with a thickness of 0.05 to 2 mm. 7. A rotating machine using the composite bond magnet according to claim 1.