JP2003158005A - Nanocomposite magnet and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mass-produce permanent magnets that show a high coercive force and high magnetization though the magnet contains a little amount of rare-earth elements and a demagnetizing curve having excellent squareness. SOLUTION: A nanocomposite magnet contains a hard magnetic phase and a soft magnetic phase expressed by the compositional formula of (Fe1-m Tm )100-x-y-z-n (B1-p Cp )x Ry Tiz M1n (wherein, T, R, and M respectively denote one ore more kinds of elements selected out of Co and Ni, one or more kinds of elements selected from among rare-earth elements including Y (yttrium), and one or more kinds of elements selected from among Al, Si, Sn, V, Cr, Mn, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, and Pb) and magnetically coupled with each other through an exchange interaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a permanent magnet suitable for use in various motors and actuators, and more particularly to an iron-based rare earth alloy magnet having a plurality of ferromagnetic phases and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, there has been a demand for higher performance, smaller size and lighter weight in household appliances, office automation equipment, electrical equipment and the like. Therefore, the permanent magnets used in these devices are required to maximize the performance-to-weight ratio of the entire magnetic circuit. For example, the residual magnetic flux density B _r is 0.5 T (tesla) or more. It is required to use a magnet. However, depending on the conventional relatively inexpensive hard ferrite magnet, the residual magnetic flux density B _{r is set} to 0.
It cannot exceed 5T.

At present, high residual magnetic flux density B of 0.5 T or more
_As a permanent magnet having _r , an Sm-Co based magnet manufactured by a powder metallurgy method is known. Other than Sm-Co magnets, Nd-F produced by powder metallurgy
e-B system sintered magnet, N produced by liquid quenching method
The d-Fe-B system quenched magnet can exhibit a high residual magnetic flux density B _r . The former Nd-Fe-B system sintered magnet is disclosed in, for example, Japanese Patent Application Laid-Open No. 59-46008, and the latter Nd-Fe-B system quenching magnet is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-9852. Has been done.

[0004]

[Problems to be Solved by the Invention] However, Sm-
Co-based magnets have the disadvantage that the price of the magnets is high because both Sm and Co, which are raw materials, are expensive.

In the case of an Nd-Fe-B system magnet, it is cheap F
Since e is contained as a main component (about 60% by weight to 70% by weight of the whole), it is cheaper than the Sm-Co based magnet, but there is a problem that the cost required for the manufacturing process is high. One of the reasons why the manufacturing process cost is high is that a large-scale facility and a large number of processes are required for the separation and purification of Nd whose content is about 10 atomic% to 15 atomic% and the reduction reaction. In addition, when the powder metallurgy method is used, the number of manufacturing steps is inevitably large.

On the other hand, the Nd-Fe-B system quenching magnet manufactured by the liquid quenching method can be obtained by a relatively simple process such as a melting process → a liquid cooling process → a heat treatment process. There is an advantage that the process cost is lower than that of the Fe-B magnet. However, in the case of the liquid quenching method, in order to obtain a bulk-shaped permanent magnet, it is necessary to mix the magnet powder prepared from the quenching alloy with the resin to form the bond magnet. The filling rate (volume ratio) is at most about 80%. Further, the quenched alloy produced by the liquid quenching method is magnetically isotropic.

For the above reasons, the Nd-Fe-B system quenched magnet produced by the liquid quenching method has a B content higher than that of the anisotropic Nd-Fe-B system sintered magnet produced by the powder metallurgy method.
_It has the problem of low _r .

As a method for improving the characteristics of the Nd-Fe-B system quenching magnet, a group consisting of Zr, Nb, Mo, Hf, Ta, and W, as described in JP-A-1-7502. At least one element selected from
It is effective to add at least one element selected from the group consisting of Ti, V, and Cr in a composite manner. The addition of such an element improves the coercive force H _cJ and the corrosion resistance, but an effective method for improving the residual magnetic flux density B _r is not known other than improving the density of the bonded magnet. Further, when the Nd-Fe-B quenching magnet contains 6 atomic% or more of a rare earth element, according to many prior arts, in order to increase the quenching rate of the molten metal, the molten metal is injected through a nozzle onto a cooling roll. The melt spinning method is used.

In the case of the Nd-Fe-B system quenching magnet, the composition in which the concentration of the rare earth element is relatively low, that is, Nd _3.8 F
A magnetic material having a composition near _77.2 B ₁₉ (atomic%) and a Fe ₃ B type compound as a main phase has been proposed (R. Coeho
Orn et al., J. de Phys, C8, 1998, pp. 669-670). This permanent magnet material is obtained by subjecting an amorphous alloy produced by a liquid quenching method to a crystallization heat treatment to obtain a fine crystal aggregate in which a soft magnetic Fe ₃ B phase and a hard magnetic Nd ₂ Fe ₁₄ B phase are mixed. It has a metastable structure formed from the body and is called a "nanocomposite magnet". It has been reported that such a nanocomposite magnet has a high residual magnetic flux density B _r of 1 T or more, but its coercive force H _cJ is 160 kA / m to 240 kA / m.
And relatively low. Therefore, the use of this permanent magnet material is
It is limited to applications where the operating point of the magnet is 1 or more.

Attempts have been made to improve the magnetic properties by adding various metal elements to the raw material alloy of the nanocomposite magnet (JP-A-3-261104, Japanese Patent No. 272750).
5, Gazette No. 2727506, International Publication No. WO003 / 03403, WCChan, et.al. "THE EFFECTS OF
REFRACTORY METALS ON THE MAGNETIC PROPERTIES OF
α-Fe / R ₂ Fe ₁₄ B-TYPE NANOCOMPOSITES ", IEEE, Tran
s. Magn.No. 5, INTERMAG. 99, Kyongiu, Korea pp.32
65-3267, 1999), and sufficient "characteristic value per cost" has not been obtained. This is because the nanocomposite magnet has not obtained a coercive force of a size that can be practically used, and therefore cannot exhibit sufficient magnetic characteristics in actual use.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a residual magnetic flux density B _r ≧
Provided is a method for manufacturing a permanent magnet, which can inexpensively manufacture an iron-based alloy magnet having excellent magnetic properties satisfying a high coercive force (eg, H _cJ ≧ 450 kA / m) that can be practically used while maintaining 0.75T. To do.

[0012]

The nanocomposite magnet according to the present invention has a composition formula (Fe _1-m T _m ).
_{100-xyzn (B 1-p} C p) x R y Ti z M n (T is at least one element selected from the group consisting of Co and Ni, R is from the group consisting of Y (yttrium) and the rare earth elements One or more selected elements, M is Al, Si, Sn,
V, Cr, Mn, Cu, Zn, Ga, Zr, Nb, M
one or more elements selected from the group consisting of o, Ag, Hf, Ta, W, Pt, Au, and Pb),
Composition ratio (atomic ratio) x, y, z, m, n, and p
Respectively, 15 <x ≦ 25 atomic%, 4 ≦ y <9 atomic%, 3 ≦ z ≦ 14 atomic%, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 1
0 atomic%, 0 ≦ p ≦ 0.4, and 0.3 ≦ z / x ≦
A nanocomposite magnet satisfying 0.7 and containing a hard magnetic phase and a soft magnetic phase magnetically coupled by exchange interaction, wherein the average crystal grain size of the hard magnetic phase is G
_hard , where _{Gso ft} is the average crystal grain size of the soft magnetic phase, 1 nm ≦ G _hard ≦ 200 nm, 1 nm ≦ G _soft ≦ 2
00 nm and 0.5 ≦ G _hard / G _soft ≦ 10 are satisfied.

In a preferred embodiment, C (carbon) is contained as an essential element, and 0.01 ≦ p ≦ 0.4 is satisfied.

In a preferred embodiment, the soft magnetic phase contains a ferromagnetic boride, and the boride occupies 50% or more by volume of the entire soft magnetic phase.

In a preferred embodiment, the volume ratio of the hard magnetic phase is 30% or more and 70% or less of the whole magnet, and the volume ratio of the soft magnetic phase is 20% or more and 70% or less of the whole magnet. The total volume ratio of the hard magnetic phase and the soft magnetic phase is 90% by volume or more of the entire magnet.

In a preferred embodiment, the hard magnetic phase is composed of crystals of R ₂ Fe ₁₄ B type compound.

In a preferred embodiment, the soft magnetic phase contains an iron-based boride.

Quenching for nanocomposite magnets according to the invention
The composition method of the alloy is (Fe _1-mT_m)
_100-xyzn(B_1-pC_p)_xR_yTi_zM_n(T is Co and
And one or more elements selected from the group consisting of Ni and R are
Selected from the group consisting of Y (yttrium) and rare earth elements
One or more selected elements, M is Al, Si, Sn,
V, Cr, Mn, Cu, Zn, Ga, Zr, Nb, M
o, Ag, Hf, Ta, W, Pt, Au, and Pb
Represented by one or more elements selected from the group consisting of
Composition ratio (atomic ratio) x, y, z, m, n, and p
Respectively, 15 <x ≦ 25 atom%, 4 ≦ y <9 atom
%, 3 ≦ z ≦ 14 atomic%, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 1
0 atomic%, 0 ≦ p ≦ 0.4, and 0.3 ≦ z / x ≦
Prepare a molten iron-based rare earth alloy that satisfies 0.7
Process and quenching the molten metal of the alloy to produce a quenched alloy
And steps.

Manufacture of nanocomposite magnets according to the invention
The method is the step of preparing the quenched alloy produced by the above method.
And exchange interaction by heating the quenched alloy
Containing a hard magnetic phase and a soft magnetic phase magnetically coupled by
A step of producing a nanocomposite structure having
However, the nanocomposite structure is an average of the hard magnetic phase.
Crystal grain size is G_hard, The average crystal grain size of the soft magnetic phase is G
_softAnd 1nm ≦ G _hard≤200 nm, 1 nm
≤ G_soft≦ 200 nm and 0.5 ≦ G_hard/ G
_softThe relationship of ≦ 10 is satisfied.

In a preferred embodiment, the crystallization heat treatment is performed by subjecting the quenched alloy to a temperature of 500 ° C. or higher and 850 ° C. or lower.
Including holding for 0 seconds or more.

In a preferred embodiment, a step of crushing the quenched alloy is included before the crystallization heat treatment.

In a preferred embodiment, in the cooling step, the compound phase first precipitated in the solidifying process of the molten alloy is a titanium boride compound.

In a preferred embodiment, in the cooling step, the R ₂ Fe ₁₄ B type compound is deposited next to the titanium boride type compound.

The method for producing a bonded magnet according to the present invention includes the steps of preparing a powder of the nanocomposite magnet produced by any one of the above methods and a step of producing a bonded magnet using the powder.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an alloy composition in which the content of the rare earth element R is less than 10 atomic% and the composition ratio of boron (and carbon in which a part of boron is substituted) exceeds 15 atomic%. In, a sufficient amount of Ti is added to form a nanocomposite structure in which coarsening of each constituent phase is suppressed.

In the present invention, an alloy structure in which a fine R ₂ Fe ₁₄ B type crystal phase is preferentially precipitated in the amorphous phase immediately after quenching is prepared, and then heat treatment is carried out, whereby the magnetization of the amorphous phase is changed. High boride and α-Fe
To form a nanocomposite structure in which fine constituent phases having an average crystal grain size of 1 nm or more and 200 nm or less are dispersed.

When Ti is not added to an alloy having a rare earth element content of less than 10 atomic% and a boron concentration of more than 15 atomic%, α-Fe takes precedence when the alloy melt is cooled to prepare a quenched alloy. Precipitates and becomes coarse. Also,
After the heat treatment, the non-magnetic amorphous phase containing a large amount of boron remains and does not function as a nanocomposite magnet.
However, in the present invention, due to the action of added Ti, α-
It is possible to suppress the preferential precipitation / coarsening of Fe, reduce the volume ratio of the boron-rich nonmagnetic amorphous phase, and instead generate fine boride having high magnetization in a dispersed state. As a result, the hard magnetic phase Nd ₂
It is possible to obtain a structure in which the crystal grains of the Fe ₁₄ B-based compound and the boride that is the soft magnetic phase are magnetically strongly bonded by exchange interaction, and it is possible to realize a nanocomposite magnet having excellent magnetic properties. .

The quenching alloy for nanocomposite magnets according to the present invention includes a melt spinning method in which a molten alloy is sprayed onto the surface of a cooling roll rotating at a high speed by using a nozzle, or a molten alloy is sprayed on the surface of the cooling roll without using a nozzle. Can be suitably prepared by the strip casting method. The melt spinning method provides an extremely high cooling rate, and is suitable for producing an amorphous quenched alloy. On the other hand, when the strip casting method is used, the molten alloy is cooled at a slower rate than the cooling rate in the conventional melt spinning method. However, in the present invention, due to the function of the additive element Ti, α-Fe is used in the rapid solidification step. It suppresses the precipitation of the phase and further suppresses the coarsening of the soft magnetic phase such as the α-Fe phase in the crystallization heat treatment step.

According to the present invention, the magnetization (residual magnetic flux density B _r ) and the coercive force H _cJ are high and the demagnetization curve has squareness even if the raw material alloy having a relatively small amount of rare earth element (less than 10 at%) is used. It is also possible to manufacture excellent permanent magnets on a mass production level. Increase of coercive force by the present invention, Nd ₂ F
This is achieved by preferentially precipitating and growing the e ₁₄ B phase in the cooling step, thereby increasing the volume ratio of the Nd ₂ Fe ₁₄ B phase as much as possible, but suppressing coarsening of the soft magnetic phase. The increase in magnetization is caused by the action of Ti, which produces a boride phase such as a ferromagnetic iron-based boride from the boron-rich nonmagnetic amorphous phase present in the rapidly solidified alloy, and the nonmagnetic amorphous phase remaining after the crystallization heat treatment. It is thought that it was obtained because the volume ratio of was reduced. In the present invention, the amount of B and / or C is increased, and the amount of Ti added is also increased to increase the volume ratio of the soft magnetic phase having high magnetization (20% by volume or more). The residual magnetic flux density B _r is improved to a sufficient level.

The method for manufacturing the iron-based rare earth alloy magnet of the present invention will be described in detail below.

First, the composition formula is (Fe _1-m T _m ).
_{100-xyzn (B 1-p} C p) x R y Ti z M n preparing a melt of the alloy represented by. Here, T is one or more elements selected from the group consisting of Co and Ni, and R is 1 selected from the group consisting of Y (yttrium) and rare earth elements.
More than one element, M is Al, Si, Sn, V, Cr, M
n, Cu, Zn, Ga, Zr, Nb, Mo, Ag, H
At least one element selected from the group consisting of f, Ta, W, Pt, Au, and Pb. The composition ratio (atomic ratio) x, y, z, m, n, and p are each 15
<X ≦ 25 atomic%, 4 ≦ y <9 atomic%, 3 ≦ z ≦ 14 atomic%, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 10 atomic%, 0 ≦ p ≦
0.4 and 0.2 ≦ z / x ≦ 0.7 are satisfied.

Next, a cooling step is performed in which the molten alloy described above is rapidly cooled in a reduced pressure atmosphere gas by a melt spinning method or a strip casting method to produce a rapidly cooled alloy. The structure of this quenched alloy has a fine R ₂ Fe ₁₄ B phase and / or boride phase, or is entirely an amorphous phase.

Then, the quenched alloy is subjected to a crystallization heat treatment to form a nanocomposite structure containing an R ₂ Fe ₁₄ B type compound phase and a ferromagnetic iron-based boride phase. The soft magnetic phase may include a fine α-Fe phase in addition to the iron-based boride. In such a structure, the hard magnetic phase (R ₂ F
e ₁₄ B type compound phase) has an average crystal grain size G _hard of 1 nm to 200 nm, and a soft magnetic phase has an average crystal grain size G _soft of 1 n.
The conditions for cooling the molten alloy and the conditions for heat treatment for crystallization are adjusted so that the thickness is m or more and 200 nm or less.

The average crystal grain size G _hard of the hard magnetic phase in the final magnet, the mean grain size G _soft soft magnetic phase,
It is preferable to satisfy the relational expression 0.5 ≦ G _hard / G _soft ≦ 10. When such a relationship is satisfied, if the average crystal grain size G _{soft of the soft} magnetic phase is 50 nm or less, the constituent phases are effectively coupled by exchange interaction, and the magnetization direction of the soft magnetic phase is the hard magnetic phase. Therefore, the alloy as a whole can exhibit excellent demagnetization curve squareness.

In the present invention, boron (and / or carbon)
And a relatively large amount of Ti and R ₂ Fe ₁₄ B
An iron-based boride having a saturation magnetization equal to or higher than that of the type compound phase is formed. The iron-based borides produced are, for example, Fe ₃ B (saturation magnetization 1.5 T) and F
e ₂₃ B ₆ (saturation magnetization 1.6 T). Where R ₂ Fe
The saturation magnetization of ₁₄ B is about 1.6 T when R is Nd. The volume ratio of the ferromagnetic iron-based boride in the soft magnetic phase is 50% or more. The volume ratio of the soft magnetic phase in the entire alloy is 20% or more and 70% or less.

According to the production method of the present invention, the reason why the above-mentioned ferromagnetic iron-based boride is likely to be produced is that the R ₂ Fe ₁₄ B type compound phase has priority over α-Fe due to the action of Ti. Therefore, the amorphous phase existing in the quenched alloy will inevitably contain an excessive amount of boron and / or carbon, but Ti acts to facilitate the bonding of this excess boron with iron, resulting in the magnetization. It is considered that this is because an iron-based boride having a high content easily precipitates and grows.

It is preferable to increase the composition ratio z of Ti to be added as the composition ratio x of boron and / or carbon increases. According to experiments, 0.2 ≦ z / x ≦ 0.7
Is preferably satisfied, and more preferably 0.3 ≦ z / x ≦ 0.6.

According to the experiments of the present inventor, only when Ti is added, unlike the case where other kinds of metals such as V, Cr, Mn, Nb, and Mo are added, the decrease in magnetization does not occur.
Rather, it was found that the magnetization was improved. In addition, when Ti was added, the squareness of the demagnetization curve was particularly good as compared with the other additive elements described above. From these facts, it is considered that Ti plays a particularly important role in suppressing the formation of boride having low magnetization. Therefore, the ratio (atomic ratio) of Ti in the additional element M is preferably 70% or more, and more preferably 85% or more.

When a metal element such as Nb, V, or Cr is added instead of Ti, the grain growth of the α-Fe phase significantly progresses, and the magnetization direction of the α-Fe phase becomes the hard magnetic phase. As a result of being effectively unrestrained by exchange coupling, the squareness of the demagnetization curve is greatly reduced. In addition, when V or Cr is added, compared with the case where Ti is added, these added metals easily form a solid solution with Fe and are antiferromagnetically coupled, so that the magnetization is greatly reduced.

When Nb, Mo or W is added in place of Ti and heat treatment is carried out in a relatively low temperature range in which α-Fe does not precipitate, good hard magnetic properties excellent in the squareness of the demagnetization curve are obtained. It is possible to obtain the characteristics. However, in the alloy heat-treated at such a temperature, it is presumed that the R ₂ Fe ₁₄ B type fine crystal phase is dispersed and present in the non-magnetic amorphous phase, and the structure of the nanocomposite magnet is formed. Not not. Further, if the heat treatment is performed at a higher temperature, the α-Fe phase will be precipitated out of the amorphous phase. This α-Fe phase is different from the case where Ti is added,
After precipitation, it grows rapidly and becomes coarse. Therefore, α-F
The magnetization direction of the e phase is not effectively restrained by the exchange coupling with the hard magnetic phase, and the squareness of the demagnetization curve is greatly deteriorated.

However, when Ti is added, α
Since the kinetics of precipitation / growth of the -Fe phase becomes slow and the precipitation / growth requires time, the precipitation / growth of the R ₂ Fe ₁₄ B phase starts before the precipitation / growth of the α-Fe phase is completed. It is thought that. Therefore, the R ₂ Fe ₁₄ B phase grows in a uniformly dispersed state before the α-Fe phase becomes coarse.

Only when Ti is added in this way, α-
Appropriately suppress coarsening of the Fe phase, ₂Fe₁₄Phase B (hard magnetic
Suitable for the iron-based boride (soft magnetic phase) and the ferromagnetic phase)
It becomes possible to form a dispersed structure having a diameter.

Ti is an element which, together with boron and carbon, plays an important role as an element that delays the crystallization of Fe primary crystals (γ-Fe which is later transformed into α-Fe) during liquid quenching and facilitates the formation of a supercooled liquid. Therefore, even if the cooling rate at the time of rapidly cooling the molten alloy is set to a relatively low value of about 10 ² ° C / sec to 10 ⁴ ° C / sec, R ₂ F can be formed without precipitating coarse α-Fe.
It is possible to preferentially precipitate the e ₁₄ B type crystal phase. Therefore, it becomes possible to manufacture a nanocomposite magnet having excellent characteristics even by the strip casting method with a relatively low cooling rate. In the present invention, the concentrations of B (boron) and C (carbon) are set to be high, but since these elements have a high amorphous forming ability, they work effectively together with Ti to effectively reduce the cooling rate. .

[Reason for limiting composition] When the total composition ratio x of B and C is 15 atomic% or less, when the cooling rate during quenching is relatively slow at about 10 ² ° C / sec to 10 ⁵ ° C / sec, R
It becomes difficult to produce a quenched alloy in which a ₂ Fe ₁₄ B type crystal phase and an amorphous phase coexist, and a high coercive force cannot be obtained even if a heat treatment is performed thereafter. The composition ratio x is 1
If it is 5 atomic% or less, the amount of iron-based borides exhibiting high magnetization decreases.

On the other hand, when the composition ratio x exceeds 25 atomic%, the volume ratio of the amorphous phase remaining after the crystallization heat treatment increases, and at the same time, the abundance ratio of α-Fe having the highest saturation magnetization in the constituent phases increases. Remaining magnetic flux density B
_r decreases.

From the above, the composition ratio x is 15 atom%.
It is preferable to set it so as to exceed 25 and be 25 atomic% or less. The upper limit of the more preferable composition ratio x is 20 atom%.

C replaces a part of B and enhances the ability to form amorphous like B. Further, the addition of C lowers the solidification start temperature of the molten metal when the molten metal is rapidly cooled, so that the tapping temperature can be lowered. As a result, the melting time can be shortened and the quenching rate can be improved. Furthermore, the addition of C lowers the viscosity of the molten alloy and improves the "wettability" with respect to the cooling roll, so that the adhesion between the cooling roll and the molten metal is improved, and the cooling efficiency by the cooling roll is improved. Although C has such an effect, the ratio of C to the total of B and C is p
When exceeds 0.4, the amount of α-Fe phase produced increases,
This is not preferable because it causes a problem of deterioration of magnetic characteristics. Therefore, the ratio p of C to the total of B and C is
The atomic ratio is preferably 0 or more and 0.4 or less. On the other hand, if the ratio p exceeds 0.5, TiC may precipitate and the magnetic properties may deteriorate. Further, in the case of the strip casting method, the molten metal viscosity increases as the ratio p increases, so that it becomes difficult to perform stable rapid cooling. In order to obtain the effect of adding C, the ratio p of C is 0.0
It is preferably 1 or more. If p is less than 0.01, the effect of adding C is hardly obtained. Ratio p
The lower limit of is preferably 0.02, and the upper limit of p is preferably 0.3 or less. The ratio p is more preferably 0.08 or more and 0.15 or less. When B and C are added simultaneously, it is desirable that the composition ratio of B exceeds 15 atom% of the entire alloy ((1-p) · x> 15 atom%).

R is at least one element selected from the group consisting of rare earth elements and Y (yttrium). In the presence of La or Ce, R ₂ Fe ₁₄ B phase R
Since (typically Nd) is replaced with La or Ce and coercive force and squareness are deteriorated, it is preferable that La and Ce are not substantially contained. However, a small amount of La or Ce
When (0.5 atomic% or less) is present as an impurity that is inevitably mixed, there is no problem in terms of magnetic properties. Therefore,
When it contains 0.5 atom% or less of La or Ce, La
It can be said that or Ce is not substantially included.

More specifically, R preferably contains Pr or Nd as an essential element, and a part of the essential element may be replaced with Dy and / or Tb. When the composition ratio y of R is less than 4 atom% of the whole, the compound phase having the R ₂ Fe ₁₄ B type crystal structure necessary for expressing the coercive force is not sufficiently precipitated, and a high coercive force H _cJ can be obtained. become unable. Further, when the composition ratio y of R is 9 atomic% or more, the amount of the iron-based boride having ferromagnetism decreases, and instead of B,
Since the abundance of the rich nonmagnetic layer increases, the nanocomposite structure is not formed and the magnetization decreases. Therefore, the composition ratio y of the rare earth element R is preferably adjusted in the range of 4 atomic% or more and less than 9 atomic%, for example, 4.5 atomic% or more and 8.5 atomic% or less. More preferable range of R is 5 atomic%
It is at least 8.5 at%, and a more preferable range of R is at least 5.5 at% and at most 8.0 at%. The range of R that gives the best magnetic properties is 6 atom% or more and 8 atom% or more.
It is the following.

The addition of Ti exerts the effect of precipitating and growing the hard magnetic phase earlier than the soft magnetic phase during the rapid cooling of the molten alloy, and also has the coercive force H _cJ and the residual magnetic flux density B.
It contributes to the improvement of _r and the squareness of the demagnetization curve, and improves the maximum energy product (BH) _max .

When the composition ratio z of Ti is less than 3 atomic% of the whole, the effect of adding Ti is not sufficiently exhibited. On the other hand, T
If the composition ratio z of i exceeds 14 atomic% of the whole, the volume ratio of the amorphous phase remaining after the crystallization heat treatment increases, and thus the residual magnetic flux density B _r is likely to decrease. From the above, the composition ratio z of Ti is preferably in the range of 3 atomic% or more and 14 atomic% or less. The more preferable lower limit of the range of z is 5 atom%, and the more preferable upper limit of the range of z is 10 atom%. A more preferable upper limit of the range of z is 8
It is atomic%.

Further, the higher the composition ratio x of Q composed of C and / or B, the easier the formation of an amorphous phase containing excess Q (for example, boron). It is preferable to promote the formation of iron-based borides. Ti is deposited in R ₂ Fe _{1 4} B type compound crystal,
As it grows, it is concentrated in the grain boundaries of the R ₂ Fe ₁₄ B phase type compound crystal, but if the ratio of Ti to B is too high,
Ti may enter the R ₂ Fe ₁₄ B compound rather than at the grain boundaries and reduce the magnetization. On the contrary, T for B
When i ratio is too low, will be B-rich amorphous phase of the non-magnetic is often produced, not only the magnetic characteristics deteriorate, R ₂ Fe ₂₃ B ₃ phase is precipitated instead of the R ₂ Fe ₁₄ B phase In some cases, hard magnetic properties cannot be obtained. According to experiments, it is preferable to adjust the composition ratio so as to satisfy 0.2 ≦ z / x ≦ 0.7, and 0.25 ≦ z / x ≦ 0.
It is more preferable to satisfy 6. More preferably, 0.3 ≦ z / x ≦ 0.55.

The metal element M may be added in order to obtain various effects. M is Al, Si, Sn, V, Cr, Mn,
Cu, Zn, Ga, Zr, Nb, Mo, Hf, Ta,
It is one or more elements selected from the group consisting of W, Pt, Pb, Au and Ag.

Fe occupies the remaining content of the above elements, but desired hard magnetic characteristics can be obtained even if a part of Fe is replaced with one or two transition metal elements (T) of Co and Ni. You can If the substitution amount of T with respect to Fe exceeds 50%, a high residual magnetic flux density B _{r of} 0.7 T or more cannot be obtained. Therefore, the substitution amount is preferably limited to the range of 0% to 50%. By substituting a part of Fe with Co, the squareness of the demagnetization curve is improved and the Curie temperature of the R ₂ Fe ₁₄ B phase is increased, so that the heat resistance is improved. The preferable range of the Fe substitution amount by Co is 0.5% or more and 40% or less.

Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1) First, a first embodiment of the present invention will be described.

In this embodiment, a rapidly solidified alloy is manufactured using the strip casting apparatus shown in FIG. In order to prevent the oxidization of the raw material alloy containing the rare earth element R or Fe, which is easily oxidized, the production of the quenched alloy is performed in the inert gas atmosphere. A rare gas such as helium or argon or nitrogen can be used as the inert gas. Since nitrogen is relatively easy to react with the rare earth element R, it is preferable to use a rare gas such as helium or argon.

The strip casting apparatus of FIG.
It is placed in a chamber whose inside can be a reduced pressure atmosphere of an inert gas (Ar gas or the like). This strip casting apparatus includes a melting furnace 1 for melting an alloy raw material, a cooling roll 7 for quenching and solidifying the molten alloy 3 supplied from the melting furnace 1, and a molten metal 3 from the melting furnace 1 to the cooling roll 7. A chute (guide means) 5 for guiding and a scraper gas ejector 9 for solidifying and easily peeling the ribbon-shaped alloy 8 from the cooling roll 7 are provided.

The melting furnace 1 can supply the melt 3 produced by melting the alloy raw material to the chute 5 at a substantially constant supply amount. This supply amount can be arbitrarily adjusted by controlling the operation of tilting the melting furnace 1.

The cooling roll 7 has an outer peripheral surface formed of a material having good thermal conductivity such as copper, and has a diameter of 30 cm to 100 cm and a width of 15 cm to 100 cm, for example. The cooling roll 7 can be rotated at a predetermined rotation speed by a driving device (not shown). By controlling this rotation speed, the peripheral speed of the cooling roll 7 can be arbitrarily adjusted. The cooling rate of the strip casting device is about 10 ² ° C / sec to about 2 × 10 ⁴ depending on the rotation speed of the cooling roll 7 or the like.
It can be controlled in the range of ° C / sec.

The surface of the chute 5 that guides the molten metal is inclined at an angle (inclination angle) α with respect to the horizontal direction, and the distance between the tip of the chute 5 and the surface of the cooling roll is kept at several mm or less. The line connecting the tip of the chute 5 and the center of the cooling roll 7 forms an angle β (0 ° ≦ 0 ° with respect to the horizontal direction.
β ≦ 90 °). Shoot 5
The inclination angle α is preferably 1 ° ≦ α ≦ 80 °, more preferably 5 ° ≦ α ≦ 60 °. The angle β preferably satisfies the relationship of 10 ° ≦ β ≦ 55 °.

The molten metal 3 supplied onto the chute 5 is fed from the tip of the chute 5 to the surface of the cooling roll 7 to form a molten metal paddle 6 on the surface of the cooling roll 7.

The chute 5 temporarily stores the molten metal 3 continuously supplied from the melting furnace 1 at a predetermined flow rate, delays the flow velocity, and can rectify the flow of the molten metal 3. The rectification effect can be further improved by providing a damming plate that can selectively dam the flow of the molten metal surface portion in the molten metal 3 supplied to the chute 5. By using the chute 5, the molten metal 3 can be supplied in a state where the cooling roll 7 is spread to a substantially uniform thickness over a certain width in the cylinder length direction (axial direction: vertical to the paper surface). By adjusting the inclination angle α of the molten metal guide surface of the chute 5, the molten metal supply rate can be finely adjusted. Due to its own weight, the molten metal flows along the inclined guide surface of the chute 5 and has a momentum component parallel to the horizontal direction (X-axis direction).
The larger the inclination angle α of the chute 5, the higher the flow velocity of the molten metal and the larger the momentum.

In addition to the above functions, the chute 5 also has a function of adjusting the temperature of the molten metal 3 immediately before reaching the cooling roll 7. The temperature of the molten metal 3 on the chute 5 is preferably 100 ° C. or more higher than the liquidus temperature. When the temperature of the molten metal 3 is too low, primary crystals such as TiB ₂ which adversely affect the alloy properties after quenching are locally nucleated,
This is because this may remain after solidification.
Further, if the temperature of the molten metal is too low, the viscosity of the molten metal increases, and splash is likely to occur. The molten metal temperature on the chute 5 can be controlled by adjusting the molten metal temperature at the time of pouring from the melting furnace 1 into the chute 5, the heat capacity of the chute 5 itself, and the like. 1 (not shown) may be provided.

The chute 5 in the present embodiment has a plurality of discharge portions provided at the ends arranged so as to face the outer peripheral surface of the cooling roll 7 and separated by a predetermined distance along the axial direction of the cooling roll. have. The width of this discharge part (width of one flow of molten metal) is preferably 0.5 cm to
It is set to 10.0 cm, and more preferably 0.7 cm to
It is set to 4.0 cm. In this embodiment, the width of each molten metal flow in the discharge part is set to 1 cm. In addition,
The width of the flow of molten metal tends to widen in the lateral direction as it moves away from the position of the discharge part. When a plurality of discharge parts are provided in the chute 5 to form a plurality of molten metal flows, it is preferable that adjacent molten metal flows do not contact each other.

The molten metal 3 supplied onto the chute 5 comes into contact with the cooling roll 7 along the axial direction of the cooling roll 7 with a width substantially the same as the width of each discharge portion. After that, the molten metal 3 that comes into contact with the cooling roll 7 with a predetermined tapping width moves on the roll peripheral surface (as if being pulled up by the cooling roll 7) as the cooling roll 7 rotates, and is cooled in this moving process. It In addition, in order to prevent molten metal leakage, the chute 5
It is preferable that the distance between the tip of the and the cooling roll 7 is set to 3 mm or less (particularly in the range of 0.4 to 0.7 mm).

The gap between the adjacent discharge portions is preferably 1c.
It is set to m to 10 cm. By thus dividing the molten metal contact portion (molten metal cooling portion) on the outer peripheral surface of the cooling roll 7 into a plurality of locations, the molten metal discharged from each discharge portion can be effectively cooled. As a result, a desired cooling rate can be realized even when the amount of molten metal supplied to the chute 5 is increased.

The form of the chute 5 is not limited to the above-mentioned form, and it may have a single discharge part.
The tapping width may be set larger.

The molten alloy 3 solidified on the outer peripheral surface of the rotating cooling roll 7 becomes a strip-shaped solidified alloy 8 and is separated from the cooling roll 7. In the case of this embodiment, the molten metal flowing out from each of the plurality of discharge portions becomes a band of a predetermined width and solidifies. The separated solidified alloy 8 is crushed and collected by a recovery device (not shown).

As described above, the strip casting method does not use a nozzle unlike the melt spinning method, and does not have a problem such as restriction of the jetting speed due to the nozzle diameter or clogging of the molten metal due to solidification at the nozzle portion. Suitable for Further, since heating equipment for the nozzle portion and a pressure control mechanism for controlling the pressure of the molten metal head are not required, initial equipment investment and running cost can be suppressed to be small.

Further, in the melt spinning method, since it is impossible to reuse the nozzle portion, it is necessary to dispose of the nozzle, which has a high processing cost, but in the strip casting method, the chute 5 can be repeatedly used. Therefore, the running cost is low. Furthermore, according to the strip casting method, compared to the melt spinning method,
Since the cooling roll can be rotated at a slow speed and the amount of molten alloy discharged can be increased, the quenched alloy ribbon can be thickened.

However, since the molten alloy is not strongly jetted onto the surface of the cooling roll in the strip casting method, when the cooling roll 7 rotates at a relatively high peripheral speed of 10 m / sec or more, the surface of the cooling roll 7 is There is a problem that it is difficult to stably form the paddle 6 of the molten metal. Further, when the nozzle is not used, the pressure of the molten alloy pressing on the roll surface is small, so that a minute gap is likely to occur between the molten alloy and the roll surface at the contact portion between the molten alloy and the roll surface. Therefore, the adhesiveness between the molten alloy and the roll surface is inferior in the strip casting method as compared with the melt spinning method.

In this embodiment, the molten metal supply rate (processing amount)
Is defined by the supply rate per unit contact width between the molten metal and the cooling roll. In the case of the strip casting method, the molten metal comes into contact with the cooling roll so as to have a predetermined contact width along the axial direction of the cooling roll, so that the cooling conditions of the molten metal largely depend on the molten metal supply rate per unit contact width.

If the molten metal supply rate is too fast, the cooling rate of the molten metal by the chill roll will decrease, and as a result, a quenched alloy containing a large amount of crystallized structure will be produced without promoting amorphization, and the nanocomposite magnet will be produced. It becomes impossible to obtain a raw material alloy suitable for. Therefore, in the present invention, the supply rate (kg / min) per unit contact width (cm) is 3 kg.
/ Min / cm or less is set.

As described above, for example, the contact width is about 2c.
When the molten metal is brought into contact with the cooling roll in a contact form of m × 3 pieces, a throughput of about 3 kg / min or more can be realized by setting the supply rate to about 0.5 kg / min / cm or more.

As described above, by supplying the molten metal to the cooling roll rotating at the peripheral speed in the specific range at the supply speed in the specific range, a desired quenched alloy can be produced even when the strip casting method is used. It can be manufactured with high flexibility. Unlike the melt spinning method, the strip casting method does not use a nozzle that significantly increases the manufacturing cost. Therefore, the cost for the nozzle is unnecessary, and the production is not stopped due to a nozzle clogging accident.

In this embodiment, the peripheral speed of the cooling roll can be set to 5 m / sec or more and less than 20 m / sec. If the roll peripheral speed is less than 5 m / sec, the desired quenched alloy cannot be obtained due to insufficient cooling capacity, and 20 m / sec.
If the time is longer than 2 seconds, it will be difficult to pull up the molten metal by the rolls, and the cooling alloy will scatter in the form of flakes, which may cause difficulty in recovery. The optimum peripheral speed may vary depending on the structure of the cooling roll, the material, the molten metal supply rate, etc., but if the peripheral speed is high, the ribbon-shaped alloy obtained will be extremely thin and bulky, making it difficult to handle. On the other hand, if the peripheral speed is too fast, the shape of the magnetic powder produced by crushing the ribbon-shaped alloy will be flat, so that the fluidity of the magnetic powder and the cavity filling rate will decrease when the magnetic powder is molded. On the other hand, if the peripheral speed is low, it becomes difficult to obtain a sufficient cooling speed. Therefore, the peripheral speed of the cooling roll is preferably 5 m /
It is set to more than 20 seconds and less than 20 seconds, more preferably 6 meters
/ Second or more and 15 m / second or less. A more preferable range of the peripheral speed of the cooling roll is 10 m / sec or more and 13 m / sec or less.

The supply rate per unit contact width is 3 k
If it exceeds g / min / cm, the predetermined cooling rate cannot be obtained,
It becomes difficult to produce the desired quenched alloy. The appropriate range of the feed rate per unit contact width may vary depending on the roll peripheral velocity, roll structure, etc., but is 2 kg / min / cm.
It is preferably below, and more preferably 1.5 kg / min / cm or below.

If the molten metal supply rate (processing rate) of the apparatus as a whole is less than 3 kg / min, productivity will be poor and inexpensive raw material supply cannot be realized. For this purpose, it is preferable that the supply rate per unit contact width is 0.4 kg / min / cm or more when the shapes of the chute and the cooling roll are appropriately selected.

For example, C having a diameter of about 35 cm and a width of about 15 cm
When the u-made roll is used, the roll peripheral speed is 5 m / sec to 1
If it is 0 m / sec, the supply speed per unit contact width is
It is preferably about 0.5 kg / min / cm to 2 kg / min / cm. In this case, the rapid cooling step can be performed at a supply rate of 0.5 kg / min to 6 kg / min.

By appropriately selecting the shape of the chute 5, the width and number of the molten metal discharge portion, the molten metal supply rate, etc.
The thickness (average value) and width of the obtained ribbon-shaped quenched alloy can be adjusted within an appropriate range. The width of the ribbon-shaped quenched alloy is 15 mm
It is preferably in the range of -80 mm. Also, if the thickness of the ribbon alloy is too thin, the bulk density will be low, and it will be difficult to collect it. If it is too thick, the cooling rate will be different between the roll contact surface and the free surface (melt surface), and Is not obtained, which is not preferable. Therefore, the thickness of the ribbon-shaped alloy is preferably 50 μm or more and 250 μm or less, and more preferably 60 μm or more and 200 μm or less. A more preferable range of the thickness of the quenched alloy is 70 μm or more and 90 μm or less.

The cooling may be performed by a method other than strip casting (eg, melt spinning method).

[Heat Treatment] In this embodiment, the heat treatment is performed in an argon atmosphere. Preferably, the heating rate is 5 ° C
/ Sec to 20 ° C / sec, the temperature is kept at 500 ° C or higher and 850 ° C or lower for 30 seconds or longer and 20 minutes or shorter, and then cooled to room temperature. By this heat treatment, metastable phase fine crystals are precipitated and grown in the amorphous phase, and a nanocomposite structure structure is formed. According to this embodiment, α-Fe
The coarsening of the phase and other crystal phases is suppressed, and the hard magnetic phase composed of the Nd ₂ Fe ₁₄ B type crystal phase and the boride are uniformly miniaturized.

When the heat treatment temperature is lower than 500 ° C.,
A large amount of amorphous phase remains after the heat treatment, and the coercive force may not reach a sufficient level depending on the rapid cooling conditions.
Further, when the heat treatment temperature exceeds 850 ° C., grain growth of each constituent phase is remarkable, the residual magnetic flux density B _r is lowered, and the squareness of the demagnetization curve is deteriorated. Therefore, the heat treatment temperature is preferably 500 ° C. or higher and 850 ° C. or lower, but a more preferable heat treatment temperature range is 570 ° C. or higher and 820 ° C. or lower.

The heat treatment atmosphere prevents the alloy from being oxidized.
Therefore, Ar gas or N of 50 kPa or less ₂Inert such as gas
Gas is preferred. Heat treatment in a vacuum of 0.1 kPa or less
You can go.

Nd ₂ Fe ₁₄ was added to the quenched alloy before heat treatment.
In addition to the B-type compound phase and the amorphous phase, Fe ₃ B
Phase, Fe ₂₃ B ₆ , R ₂ Fe ₁₄ B phase, and metastable phases such as R ₂ Fe ₂₃ B ₃ phase may be included. In that case, the heat treatment causes the R ₂ Fe ₂₃ B ₃ phase to disappear, and an iron-based boride (for example, Fe ₂₃ B ₆ ) exhibiting a saturation magnetization equal to or higher than the saturation magnetization of the R ₂ Fe ₁₄ B phase. And α-Fe can be crystal-grown. In the present specification, "Fe
_The " ₃ B phase" includes the "Fe _3.5 B phase".

In the case of the present invention, finally iron-based boride and α-
Even if a soft magnetic phase such as Fe is present, the soft magnetic phase and the hard magnetic phase are magnetically coupled by exchange interaction, so that excellent magnetic properties are exhibited.

The average grain size G _hard of the Nd ₂ Fe ₁₄ B type compound phase after the heat treatment is uniaxial grain size 300.
It is necessary that the thickness be 1 nm or less, preferably 1 nm or more and 200 nm or less, and more preferably 20 nm or more and 150 nm or less. Also, the average crystal grain size G _{soft of} a soft magnetic phase such as a ferromagnetic iron-based boride phase or α-Fe phase is 1
The thickness is preferably not less than 200 nm and not more than 200 nm. If the soft magnetic phase becomes too large, the exchange interaction that acts between the constituent phases weakens and the squareness of the demagnetization curve deteriorates.
H) _max decreases. Average grain size G of soft magnetic phase
_{The soft} is preferably 1 nm or more and 100 nm or less, more preferably 1 nm or more and 50 nm or less. The average crystal grain size G _hard of the soft magnetic phase and the average crystal grain size G _soft of the hard magnetic phase preferably satisfy the relationship of 0.5 ≦ G _hard / G _soft ≦ 10.

In this embodiment, the volume ratio of the Nd ₂ Fe ₁₄ B type compound phase is in the range of 30% or more and 70% or less of the whole.

The ribbon of the quenched alloy may be roughly cut or crushed before the heat treatment. After the heat treatment, the obtained magnet is finely pulverized to produce magnet powder (magnetic powder), so that various bonded magnets can be produced from the magnetic powder by a known process. When producing a bonded magnet, the iron-based rare earth alloy magnetic powder is mixed with an epoxy resin or a nylon resin and molded into a desired shape. At this time, other kinds of magnetic powder, for example, Sm-Fe-N-based magnetic powder or hard ferrite magnetic powder may be mixed with the nanocomposite magnetic powder.

Various rotary machines such as motors and actuators can be manufactured using the above-mentioned bond magnet.

When the magnet magnetic powder obtained by the method of the present invention is used for an injection-molded bonded magnet, the average particle size is 200 μm.
It is preferable to pulverize so as to have a particle diameter of m or less, and more preferable average particle diameter of the powder is 30 μm or more and 150 μm or less. When used for a compression-molded bonded magnet, it is preferable to grind so that the particle size is 300 μm or less, and more preferable average particle size is 30 μm or more and 250
μm or less. A more preferable range is 50 μm or more 20
It is 0 μm or less.

The average ratio (aspect ratio) of the minor axis size to the major axis size of the powder particles thus obtained is 0.3.
It is about 1.0. Since the thickness of the quenched alloy produced in this embodiment is sufficiently thicker than the powder particle size, it is easy to obtain powder particles having a shape close to an equiaxed shape. On the other hand, the thickness of the quenched alloy produced by normal melt spinning is 2
Since it is as thin as about 0 to 40 μm, flaky powder particles having a small aspect ratio can be obtained under the same grinding conditions as in the present embodiment. Since the powder obtained in this embodiment has an aspect ratio close to 1, it has excellent filling properties and fluidity, and is suitable for a bonded magnet.

The coercive force H _{cJ of the} magnetic powder thus obtained
Can show a value of 600 kA / m or more.

[0095]

[Example] Sample No. in Table 1 1-5 (Example) and sample No. Nd, B, C, Fe, Ti, Nb, Z having a purity of 99.5% or more so as to have an alloy composition of 6 to 8.
The materials of r, Al, and Ga were weighed so that the total amount was 15 g, and put into a quartz crucible. Since the quartz crucible has an orifice with a diameter of 0.8 mm at the bottom, the above raw material is melted in the quartz crucible and then becomes an alloy melt and drops downward from the orifice. For the dissolution of the raw material, the pressure is 1.33 to 47.92 kPa.
Was performed using a high frequency heating method under an argon atmosphere. In this example, the melt temperature was set to 1350 ° C. By pressing the molten metal surface of the molten alloy with an argon gas of 39.9 kPa, the molten metal was ejected onto the outer peripheral surface of the copper roll located at a position about 0.7 mm below the orifice. The roll rotates at high speed while the inside is cooled so that the temperature of the outer peripheral surface is maintained at about room temperature. For this reason, the molten alloy that dripped from the orifice comes into contact with the peripheral surface of the roll to remove heat, and is blown in the circumferential velocity direction. Since the molten alloy is continuously dripped on the peripheral surface of the roll through the orifice, the alloy solidified by the rapid cooling is a ribbon elongated in a ribbon shape (width: 2 to 3 mm, thickness: 30).
˜80 μm). The roll peripheral speed was 5 m / sec to 20 m / sec.

In the case of the rotating roll method (single roll method) employed in this embodiment, the cooling rate is defined by the roll peripheral speed and the molten metal flow rate per unit time. This molten metal flow-down amount depends on the orifice diameter (cross-sectional area) and the molten metal pressure. In this embodiment, the flow rate is about 0.4 to 0.8 kg.
/ Min.

Next, the above quenched alloy was heat-treated in argon gas. Specifically, the quenched alloy was held at 600 to 800 ° C. for 6 to 8 minutes and then cooled to room temperature. Thereafter, a sample having a width of 2 mm to 3 mm, a thickness of 30 μm to 80 μm, and a length of 3 mm to 5 mm was prepared, and the magnetic characteristics of each sample were measured using a vibration type magnetometer. The measurement results are shown in Table 2.

[0098]

[Table 1]

[0099]

[Table 2]

The values of sample No. 7 shown in Table 2 are low values below the measurement limit. No. 7 was in a state where it could not be said that the magnet characteristics were exhibited. As can be seen from Table 2, higher magnetization and maximum magnetic energy product were obtained in the example than in the comparative example.

[0101]

According to the present invention, by adding an appropriate amount of Ti to an iron-based alloy containing a small amount of rare earth element R and a relatively large amount of boron (carbon), a sufficient coercive force and magnetization can be obtained. It is possible to mass-produce nanocomposite magnets that exhibit excellent magnetic properties.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a strip casting apparatus that is preferably used in the present invention.

FIG. 2 is a view showing the structure of a nanocomposite magnet manufactured according to the present invention.

[Explanation of symbols]

1 melting furnace 3 molten alloy 5 Shoots (Means for guiding molten metal) 6 Paddle of molten alloy 7 cooling rolls 8 Quenched alloy 9 scraper gas ejector

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C22C 38/00 303 H01F 1/08 A H01F 1/08 1/04 H (72) Inventor Satoshi Hirosawa Osaka Prefecture 2-15-17 Egawa, Shimamoto-cho, Mishima-gun F-term in Sumitomo Special Metals Yamazaki Works (reference) 4K017 AA01 BA06 BB01 BB02 BB04 BB05 BB06 BB07 BB08 BB09 BB12 BB16 BB18 CA07 DA04 EA03 EC02 ED01 ED08 FA21 4K01 GA04 BAA27 BA27 BA04 KA46 5E040 AA04 CA01 HB19 NN01 NN06 NN18

Claims (11)

[Claims] 1. The composition formula is (Fe_1-mT_m)
_100-xyzn(B_1-pC_p)_xR_yTi_zM _n(T is Co and
And one or more elements selected from the group consisting of Ni and R are
Selected from the group consisting of Y (yttrium) and rare earth elements
One or more selected elements, M is Al, Si, Sn,
V, Cr, Mn, Cu, Zn, Ga, Zr, Nb, M
o, Ag, Hf, Ta, W, Pt, Au, and Pb
Represented by one or more elements selected from the group consisting of
Composition ratio (atomic ratio) x, y, z, m, n, and p
But each 15 <x ≦ 25 atomic%, 4 ≦ y <9 atomic%, 3 ≦ z ≦ 14 atomic%, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 10 atomic%, Satisfies 0 ≦ p ≦ 0.4 and 0.2 ≦ z / x ≦ 0.7
And A hard magnetic phase magnetically coupled by exchange interactions and
A nanocomposite magnet containing a soft magnetic phase, The average crystal grain size of the hard magnetic phase is G_hard, Of the soft magnetic phase
The average crystal grain size is G_softAnd when 1nm ≦ G_hard≤200 nm, 1nm ≦ G_soft≦ 200 nm, and 0.5 ≦ G_hard/
G_softA nanocomposite magnet satisfying the relationship of ≦ 10. 2. Containing C (carbon) as an essential element,
The nanocomposite magnet according to claim 1, wherein 0.01 ≦ p ≦ 0.4 is satisfied. 3. The soft magnetic phase contains a ferromagnetic boride, and the boride has a volume ratio of 5 to the entire soft magnetic phase.
The nanocomposite magnet according to claim 1 or 2, which occupies 0% or more. 4. The volume ratio of the hard magnetic phase is 30% or more and 70% or less of the whole magnet, and the volume ratio of the soft magnetic phase is 20% or more and 70% of the whole magnet.
The nanocomposite magnet according to any one of claims 1 to 3, wherein the total volume ratio of the hard magnetic phase and the soft magnetic phase is 90% by volume or more of the entire magnet. 5. The nanocomposite magnet according to claim 1, wherein the hard magnetic phase is composed of crystals of an R ₂ Fe ₁₄ B type compound. 6. The nanocomposite magnet according to claim 1, wherein the soft magnetic phase contains an iron-based boride. 7. The composition formula is (Fe_1-mT_m)
_100-xyzn(B_1-pC_p)_xR_yTi_zM _n(T is Co and
And one or more elements selected from the group consisting of Ni and R are
Selected from the group consisting of Y (yttrium) and rare earth elements
One or more selected elements, M is Al, Si, Sn,
V, Cr, Mn, Cu, Zn, Ga, Zr, Nb, M
o, Ag, Hf, Ta, W, Pt, Au, and Pb
Represented by one or more elements selected from the group consisting of
Composition ratio (atomic ratio) x, y, z, m, n, and p
But each 15 <x ≦ 25 atomic%, 4 ≦ y <9 atomic%, 3 ≦ z ≦ 14 atomic%, 0 ≦ m ≦ 0.5, 0 ≦ n ≦ 10 atomic%, Satisfies 0 ≦ p ≦ 0.4 and 0.2 ≦ z / x ≦ 0.7
A step of preparing a molten iron-based rare earth raw material alloy, Quenching the melt of the alloy to produce a quenched alloy; To manufacture quenched alloys for nanocomposite magnets containing
Law. 8. A step of preparing a quenched alloy produced by the manufacturing method according to claim 7, and a hard magnetic phase and a soft magnetic phase magnetically coupled by exchange interaction by heating the quenched alloy. And a step of producing a nanocomposite structure containing, wherein the nanocomposite structure has an average crystal grain size of the hard magnetic phase as G _hard and an average crystal grain size of the _soft magnetic phase as G _soft. , 1 nm ≦ G _hard ≦ 200 nm, 1 nm ≦ G _soft ≦ 200 nm, and 0.5 ≦ G _hard /
A method for producing a nanocomposite magnet, which satisfies the relationship of G _soft ≦ 10. 9. The crystallization heat treatment is performed on the quenched alloy to 50%.
The method for producing a nanocomposite magnet according to claim 8, comprising holding at a temperature of 0 ° C to 850 ° C for 30 seconds or more. 10. The method for producing a nanocomposite magnet according to claim 9, further comprising a step of crushing the quenched alloy before the crystallization heat treatment. 11. A bond magnet comprising: a step of preparing a powder of a nanocomposite magnet manufactured by the method according to claim 8; and a step of manufacturing a bond magnet using the powder. Production method.