JP2017011283A - METHOD FOR MANUFACTURING α-Fe/R2TM14B NANOCOMPOSITE MAGNET - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide B(boron)-rich nanocomposite magnet which enables a thin band to be cut to a predetermined length or to be punched out in an arbitrary shape, is unstable in magnetism because of small coercive force, and there is no way but forming a bond magnet of arbitrary shape together with resin after powderization since only thin piece of several millimeters in length is available with a composition of 6-8 atom % of B(boron) quantity near NdTMB stoichiometric composition.SOLUTION: A crystallized thin band of coercive force 600 kA/m or larger with a content of thin piece of less than 10 mm in length being less than 20% is formed into a composite thin band mixed with resin, which is cut to a predetermined length, bent, or punched out into an arbitrary shape, thereby providing α-Fe/RTMB nanocomposite magnet in predetermined shape. Further preferably, a crystallized thin band of average thickness 40-45 μm is used which is available by forming a molten metal alloy paddle of 1300°C or higher in the vertical direction (apex) of Cu roll having a diameter of 500 mm or longer which is moved at 14-15 m/sec, and quench-solidifying with roll surface contact distance 10-15 mm, being collected with a flat shooter.SELECTED DRAWING: Figure 2

Description

The present invention is a relatively long crystallized α-Fe / R ₂ TM ₁₄ B-based ribbon with excellent magnetic stability, directly or as a resin composite ribbon, cut and bent to a predetermined length, Alternatively, the present invention relates to a method for producing a nanocomposite magnet that is punched into an arbitrary shape.

With respect to a nanocomposite magnet ribbon that can cut a relatively long ribbon directly or as a resin-composite rare earth-iron-based ribbon into a predetermined length or stamping into an arbitrary shape, for example, Patent Document 1 In the alloy composition formula Fe _100-xy RxAy (where R is one or more of Pr, Nd, Dy and Tb, A is one or two of C (carbon) or B (boron), 1 ≦ x <6 atomic%, 15 ≦ y ≦ 30 atomic%) B (boron) -rich molten alloy with a thickness of 10-100 μm and 90% or more amorphous under specific rapid solidification conditions Using the excellent toughness and elastic deformability as a ribbon, the ribbon is directly or directly cut into a predetermined length or punched into an arbitrary shape. ₃ B phase and Nd ₂ Fe ₁₄ B phase mixed, with an average crystal grain size of 10 to 50 nm and a fine crystal structure, heat treatment at 550 to 750 ° C, coercive force of 160 kA / m or more, residual magnetization of 0.8 T or later A method for pulverizing a thin ribbon or flakes and making a bonded magnet by laminating two or more crystallized ribbons, laminating two or more of them, and bonding and integrating the crystallized ribbons laminated with an epoxy resin The manufacturing technique of the nanocomposite magnet which has arbitrary thickness or a desired shape is disclosed, without using.

Further, in Patent Document 2, a B (boron) -rich molten alloy as described above is rapidly solidified, and a surface of a thin ribbon having a thickness of 10 to 100 μm and having an amorphous structure of 90% or more is applied to 200 to 550. A metal having a melting point of ° C. is plated or vapor-deposited, and this rapidly cooled ribbon is laminated directly or after being processed into a predetermined shape, and further laminated from an amorphous structure, Fe ₃ B phase, α-Fe phase, Nd ₂ Manufacture of nanocomposite magnets with a mixture of Fe ₁₄ B phases and a fine crystal structure with an average crystal grain size of 10 to 50 nm, heat treatment at 550 to 750 ° C, and simultaneously melting and integrating the surface metal layer The technology is disclosed.

Furthermore, in Patent Document 3, Fe _100-yz Co ₁₀ RyBz or Fe _100-yz Co _9.5 TM ₂ RyBz (where TM is V, Ti, Cr, Mn, Cu, Nb, Mo, W, Ta, Hf, Or one or more elements selected from Zr, R is one or more elements selected from rare earth elements, B is boron, y indicating composition ratio, z is atomic% And 2.5 <y <4.0, 19 <z <25), and ΔTx = Tx−Tg (where Tx is the crystallization start temperature and Tg is the glass transition temperature). The temperature interval ΔTx is 35 ° C or more, the converted vitrification temperature expressed by the formula of Tg / Tm (where Tm is the melting temperature of the alloy) is 0.55 or more, and the thickness 200 obtained by the single roll rapid solidification method An alloy obtained by heat-treating a metallic glass alloy with an amorphous phase volume ratio of 90% or more and having an average particle size of 50 nm consisting of R ₂ Fe ₁₄ B, Fe ₃ B, α-Fe phase and residual amorphous phase It has the following structure and remanent magnetization Disclosed is a technology for producing a ribbon-shaped nanocomposite magnet with Mr of 1T or more, a coercive force of 150 kA / m or more, and a thickness of 200 to 300 μm.

JP-A-11-026272 JP-A-11-016715 JP 2001-254159 A JP 2003-277892 A

D. Goll, I. Kleinschroth, H. Kronmuller, Proc. 17th Int. Workshop on rare-earth magnets and their applications, Vol.2, pp.641-657 (2000). F. Yamashita, K. Takasugi, H. Yamamoto, H. Fukunaga, Transaction on Magn. Soc. Japan, Vol.2, No.2, pp.32-35 (2002). Zhongmin Chena, Y.Q.Wub, M.J.Kramer, Benjamin R. Smitha, Bao-Min Maa, Mei-Qing Huang, Journal of Magnetism and Magnetic Materials Vol.268.pp.105-113 (2004).

The amount of B (boron) in Patent Document 1 and Patent Document 2 is 15 ≦ B ≦ 30 atomic%, and the amount of B (boron) in Patent Document 3 is 19 <B <25 atomic%. The reason for such B (boron) -rich is that it is necessary to form 90% or more of amorphous, and B (boron) is about 2.5 times or more than R ₂ TM ₁₄ B stoichiometric composition, or By making the amount about 3 times or more, production of a long amorphous ribbon can be facilitated. Therefore, the ribbon-shaped nanocomposite magnet can be cut directly or directly into a predetermined length, or can be punched into an arbitrary shape.

However, PrxFe _83-x Co ₈ V ₁ Nb ₁ B ₇ (X = 2 to 7) in which the amount of B (boron) is 6 to 8 atomic% in the vicinity of the R ₂ TM ₁₄ B stoichiometric composition, For example, when a molten alloy of about 1400 ° C. is rapidly solidified, the ribbon shape (ribbon shape) has a width and length of about several mm and a thickness of about several tens of μm ([Patent Document 4] ]reference). As described above, when the amount of B (boron) is set to the vicinity of the R ₂ TM ₁₄ B stoichiometric composition, a ribbon having a length of about several millimeters can be obtained. Therefore, a quenched ribbon or flake made from such an alloy composition is formed into an arbitrary thickness or a desired shape by using a bond magnetization method in which it is pulverized and solidified with a resin. .

On the other hand, the coercive force range of B (boron) -rich nanocomposite magnets shown in Patent Document 1 and Patent Document 2 for a long amorphous ribbon is 160 to 568 kA / m, and similar patents. In Reference 3, it is 171 to 284 kA / m. The reason why the coercive force is so low is that all of Patent Document 1, Patent Document 2, and Patent Document 3 show that when the amorphous phase is crystallized, at least Fe ₃ B phase, α-Fe phase, Nd ₂ Although it has a fine crystal structure in which three phases of Fe ₁₄ B phase are mixed, the upper limit of the rare earth element R forming the hard phase is 6 atomic%, which is about 1/2 or less of the R ₂ TM ₁₄ B stoichiometric composition ( [Patent Document 1] and [Patent Document 2]), or the upper limit of the rare earth element R is limited to 4 atomic%, which is about 1/3 or less of the R ₂ TM ₁₄ B stoichiometric composition ([Patent Document 3] ]reference). In this way, nanocomposite magnets with an alloy composition of rare earth elements of 7 atomic% or less and B (boron) -rich improve the residual magnetization by increasing the soft phase content, but maintain a high retention of over 600 kA / m. Magnetic force cannot be obtained.

  By the way, in the motors, actuators, sensors, etc. that utilize the magnetic torque of B (boron) -rich nanocomposite magnets disclosed in Patent Document 1, Patent Document 2, and Patent Document 3, the level of coercive force causes the external There is a lack of magnetic stability such as linearity of torque with respect to a magnetic field, distortion of a torque curve, or initial irreversible demagnetization due to heat. Therefore, such magnetic stability may have a significant effect on the operation and reliability of the motor, actuator, sensor, etc.

For example, using a high remanence type B (boron) -rich nanocomposite magnet having a remanent magnetization of 1 T or more as disclosed in Patent Document 1, Patent Document 2, and Patent Document 3, The obtained motor can obtain a higher torque than a bonded magnet motor made from a crystallized ribbon near the R ₂ TM ₁₄ B stoichiometric composition. However, from the viewpoint of so-called magnetic stability such as linearity in current (external magnetic field such as rotating magnetic field) versus torque, position control (servo motor) where a sinusoidal torque curve is required, or initial irreversible demagnetization at high temperature exposure. There is a problem from. Further, in applications where a high permeance magnetic circuit is structurally difficult, it is difficult to take advantage of the high remanent magnetization type B (boron) -rich nanocomposite magnet.

An object of the present invention is to make an α-Fe / R ₂ TM ₁₄ B thin ribbon having excellent magnetic stability and a relatively long length as it is or directly as a composite thin ribbon with a resin, which has a predetermined length. It is intended to provide a method for producing a nanocomposite magnet that is cut, bent, or punched into an arbitrary shape, thereby increasing the torque of a motor, actuator, sensor, or the like, or improving its reliability.

(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

(1) α-Fe / R ₂ TM ₁₄ B (R is 9 atomic% or more and less than R ₂ TM ₁₄ B stoichiometric composition Nd or Pr, TM is Fe or Fe part of 20 atomic% or less Co substituted, B is 6-8 atom%) based nanocomposite magnet manufacturing method, and alloy of alloy of PrFeCoBVNb (V is 0-4 atom%, Nb is 0-3 atom%) α A relatively long coercive force of 600 kA containing less than 20% of flakes of less than 10 mm in length, rapidly cooled to below the crystallization temperature of Fe and R ₂ TM ₁₄ B and crystallized without heat treatment of α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnets by compounding a crystallized ribbon with a thickness of at least 10 m / m and a resin composition and cutting, bending, or punching into a desired length A method (claim 1).

The invention described in this section rapidly solidifies a molten alloy having B (boron) -rich as compared to R ₂ TM ₁₄ B stoichiometric composition, such as Patent Document 1, Patent Document 2, and Patent Document 3, A thin ribbon with an amorphous phase of 90% or more is cut, and the thin ribbon is appropriately cut as necessary, mechanically processed into a predetermined shape, and laminated to obtain a desired magnet. Rather than using 6 to 8 atomic% B (boron) and 9 atomic% or more R less than R ₂ TM ₁₄ B stoichiometric composition, the coercive force is 600 kA / m or more. The α-Fe / R ₂ TM ₁₄ B-based crystallized ribbon with excellent properties and a relatively long length is cut into a predetermined length, bent, or formed into any shape as a composite ribbon with resin. This is a method for producing an α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet that is stamped and laminated.
Here, the magnetic stability according to the invention described in this section is basically based on a coercive force of 600 kA / m or more. Such magnetic stability is rapidly cooled to a temperature below the crystallization temperature of α-Fe and R ₂ TM ₁₄ B for a molten alloy with an alloy composition of PrFeCoBVNb (V is 0-4 atom%, Nb is 0-3 atom%). This is realized by using a crystallized ribbon that has been crystallized without heat treatment. In addition, the relatively long ribbon according to the invention described in this section is a thin ribbon combined with the resin composition, which can be cut, bent or punched into an arbitrary shape to a predetermined length. This means an easy ribbon with a length of 10 mm or more, specifically, an α-Fe / R ₂ TM ₁₄ B-based crystal containing less than 20% of a slice with a length of less than 10 mm in the production of the ribbon. It is a thin ribbon. In addition, the processing waste and the flakes generated at the time of manufacture can be used as a raw material for the bond magnet that is pulverized and hardened together with the resin.

(2) A method for producing an α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet according to (1) above, wherein the average thickness of the crystallized ribbon is 35-50 μm.
The invention described in this section aims to stabilize the magnetic properties and facilitate the processing by setting the average thickness of the crystallized ribbon to 35 to 50 μm.

(3) In the above paragraphs (1) and (2), the vertical direction of the single roll made of Cu having a diameter of 500 mm or more in which the crystallized ribbon moves on the surface at an ambient speed of 14 to 15 m / sec in an argon gas atmosphere of 50 to 90 kPa. Α-Fe / R ₂ TM ₁₄ B produced by rapid solidification at a roll surface contact distance of 10 to 15 mm from a paddle of R-TM-B molten alloy at 1300 ° C or higher formed at (vertex) Method for producing a nanocomposite magnet (claim 3).
In the invention described in this section, a liquid rapid solidification apparatus is used to produce an α-Fe / R ₂ TM ₁₄ B crystallization ribbon having excellent magnetic stability and a relatively long length. More preferably, an R-TM-B-based molten alloy at 1300 ° C or higher in the vertical direction (vertex) of a single roll made of Cu having a diameter of 500 mm or more rotating at an argon gas atmosphere of 50 to 90 kPa and a peripheral speed of 14 to 15 m / sec. The paddle is formed so as to be in a steady state, and further, the roll surface contact distance L _{cnt of the} ribbon is adjusted so as to rapidly cool and solidify within a range of 10 to 15 mm.

(4) In the above item (3), the angle formed by the circumferential tangent that contacts the roll at the center of the paddle and the chord of the contact arc drawn by the ribbon from the paddle to the peeling point is α − or less. A method for producing an Fe / R ₂ TM ₁₄ B-based nanocomposite magnet (Claim 4).
In the invention described in this section, when the angle formed by the circumferential tangent that contacts the roll at the center of the formed paddle and the chord of the ribbon contact arc drawn from the paddle to the peeling point is θ, θ is 1.7 degrees or less. And As a result, the coercive force is 600 kA / m or more and the average thickness is 40 to 45 μm, the main phase being the α-Fe phase transformed from γ-Fe having an average crystal grain size of 10 to 50 nm and the R ₂ TM ₁₄ B phase. And a relatively long crystallized ribbon.

(5) In the above items (1) to (4), the distortion factor of the magnetic torque curve at an external magnetic field of 40 kA / m of the crystallized ribbon disk magnetized in the in-plane direction at 2.4 MA / m or more, A method for producing an α-Fe / R ₂ TM ₁₄ B nanocomposite magnet that is 1.2% or less (claim 5).
In the invention described in this section, an isotropic disk sample magnetized in the in-plane direction at 2.4 MA / m or more has a torque curve distortion rate of 1.2% or less at an external magnetic field of 40 kA / m, which is like a rotating magnetic field. This ensures the reversibility and linearity of torque with respect to an external magnetic field. As a result, although it is an α-Fe / R ₂ TM ₁₄ B nanocomposite magnet, the initial irreversible demagnetization due to heat is caused by pulverizing the crystallized ribbon or flake near the R ₂ TM ₁₄ B stoichiometric composition. Excellent magnetic stability in actual use, such as almost the same level as the bonded magnets hardened with

(6) A method for producing an α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet, wherein the flying crystallized ribbon is collected by a flat plate shooter according to the above items (3) to (5). Item 6).
In the invention described in this section, the crystallization ribbon that flies when peeling from the roll of the liquid rapid solidification apparatus is collected by a flat shooter.

Since the present invention is configured as described above, an α-Fe / R ₂ TM ₁₄ B thin ribbon having excellent magnetic stability and a relatively long length is used as it is or directly as a composite thin ribbon with a resin. Provided is a method for producing a nanocomposite magnet that is cut, bent or punched into a predetermined length, thereby increasing the torque of a motor, actuator, sensor, etc., or improving its reliability. It becomes possible.

(A) is an R-Fe-B system pseudo binary phase diagram along the R / B = 2 tie line, and (b) is a perspective view of a main part in rapid solidification. (A) is a characteristic view showing the distribution of the length of the ribbon, and (b) is a characteristic diagram showing the relationship between the roll diameter and the ribbon rotation angle. (A) is a characteristic diagram showing the relationship between the coercive force and the film thickness, and (b) is a characteristic diagram showing the relationship between the heat treatment temperature and the coercive force. (A) is a characteristic figure which shows the external magnetic field dependence of a torque, (b) is a characteristic figure which shows the external magnetic field dependence of a torque curve distortion. It is a characteristic view which shows the coercive force dependence of a torque curve distortion rate and an initial irreversible demagnetization factor.

The relatively long ribbon according to the present invention is a magnetically isotropic film in which the crystal grain size range of the main phase composed of α-Fe phase and R ₂ TM ₁₄ B phase is controlled to about 10 to 50 nm. An α-Fe / R ₂ TM ₁₄ B-based crystallized ribbon is desirable. Such ribbons have increased remanence due to remanence enhancement (residual magnetization promoting effect). For example, D. Goll et al. Rapidly solidified a molten alloy having an alloy composition of Pr ₈ Fe ₈₇ B ₅ with an α-Fe phase grain size of approximately 15 nm and a Pr ₂ Fe ₁₄ B phase grain size of 20 to 30 nm. Then, sufficient magnetic coupling occurs at the contact interface between the α-Fe phase and the Pr ₂ Fe ₁₄ B phase, and a residual magnetization of 1.17 T, a coercive force of 470 kA / m, and (BH) _{max of} 180.7 kJ / m ³ can be obtained. (Refer to [Non-Patent Document 1]).

  By the way, the initial irreversible demagnetization due to the deterioration of the demagnetization curve at high temperature of the nanocomposite magnet as described above can be generally suppressed if the coercive force is 600 kA / m or more. The initial irreversible demagnetization is governed by the level of coercive force and the temperature coefficient ΔHcJ / ΔT (% / ° C) of the coercive force. For example, in an environment up to 120 ° C, it is mounted on a motor or the like. As a magnet, practical magnetic stability is ensured (see [Non-Patent Document 2]).

However, even if Pr is 8 atomic% (Pr ₈ Fe ₈₇ B ₅ ), the coercive force is 470 kA / m (see [Non-patent Document 1]), and Pr is 6 atomic% (Pr ₆ Fe _86-xyz Co ₈ In V _x Nb _y B _z , x = 0 to 4, y = 0 to 3, z = 6 to 9), it stops at 365 kA / m. Therefore, in the present invention, the coercive force is set to 600 kA / m or more by setting R to 9 atomic% or more and 6 to 8 atomic% B (boron). However, since the present invention is a nanocomposite magnet with an α-Fe phase, the upper limit of R needs to be less than 11.76 atomic% in the R ₂ TM ₁₄ B stoichiometric composition. Further, Fe can be substituted with 20 atomic% or less of Co. Co substitution of Fe can increase the Curie temperature by approximately 10 ° C per atomic% and adjust the temperature coefficient of remanent magnetization. Further, in order to improve the coercivity temperature coefficient ΔHcJ / ΔT (% / ° C.) as well as the coercive force value that affects the initial demagnetization, or to improve the remanence by remanence enhancement, as in Non-Patent Document 2. Nb (see [Non-patent Document 3]), or Nb and V (see [Patent Document 4]) as the fourth element (grain boundary) that suppresses grain growth during rapid solidification, which requires refinement of the main phase. In general, a technique of adding about 1 atomic% is effective.

In addition, when the coercive force level is as described above, the linearity of the magnetic torque of the disk-shaped sample magnetized in the in-plane direction to two poles at an external magnetic field of 240 kA / m or less at room temperature is 0.9999 as a correlation coefficient R. The distortion rate of the torque curve at 40 kA / m is 1.15% or less. In order to set the coercive force of the α-Fe / R ₂ Fe ₁₄ B nanocomposite magnet according to the present invention to 600 kA / m or more, R of 6 atomic% or more and less than R ₂ TM ₁₄ B stoichiometric composition, 6 ˜8 atomic% B (boron) is essential.

Next, a preferred method for producing an α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet according to the present invention will be described with reference to FIGS. 1 (a) and 1 (b). Fig. 1 (a) shows an R-TM-B system pseudo binary phase diagram along the tie line with R / B (ratio of Nd or Pr to B) of 2, and Fig. 1 (b) shows rapid solidification. FIG. However, in FIG. 1 (a), the amount of Co substitution in part of Fe is constant. In FIG. 1B, 1 is a molten alloy, 11 is a nozzle (orifice), 2 is a roll surface, 3 is a paddle, 4 is a ribbon, and A is a peeling point of the ribbon 4 from the roll surface 2. Is a coil.

From the R-TM-B system pseudo binary phase diagram along the R / B = 2 tie line in Fig. 1 (a), the molten alloy 1 is set to 1300 ° C or higher. In such rapid solidification of the molten alloy 1, it is presumed that the liquid phase + γ-Fe region first passes through the γ-Fe + R ₂ Fe ₁₄ B region. Note that γ-Fe undergoes phase transformation to α-Fe in the process of being cooled to room temperature, and becomes a rapidly solidified ribbon with the α-Fe phase and the R ₂ Fe ₁₄ B phase as main phases.

Rapid solidification is performed at 1300 ° C. in the vertical direction (vertex) of a single roll surface 2 made of Cu having a diameter of 500 mm or more and moving at a speed of 14 to 15 m / sec in an argon gas atmosphere of 50 to 90 kPa (not shown), for example. The paddle (water pool) 3 of the R-TM-B molten metal alloy 1 is formed. Then, the ribbon 4 rapidly solidified by the paddle 3 is removed from the roll surface 2 up to the peeling point A. The ribbon 4 separated from the roll surface 2 at the peeling point A is further cooled in an argon gas atmosphere, and a γ-Fe phase (phase transformation to α-Fe) having an average crystal grain size of 10 to 50 nm, And the crystallization quenching ribbon 4 having a coercive force of 600 kA / m or more and having a R ₂ TM ₁₄ B phase as a main phase.

  In order to stably perform the rapid solidification according to the present invention as described above, the paddle 3 of the molten alloy 1 is provided between the nozzle 11 which is a supply source of the molten alloy 1 and the moving Cu roll surface 2. Must be formed stably. Such a paddle 3 of the molten alloy 1 is made of a molten alloy at a pressure within a certain range, for example, 30 to 50 kPa, through a nozzle (orifice) 11 heated to a melting point or higher by means such as applying a high-frequency current to the coil 5. If 1 is plugged and supplied, it can be formed. In other words, the melted alloy 1 is rapidly solidified to form the ribbon 4, and by supplying the molten alloy 1 corresponding to the amount carried away by the movement of the roll, stabilization of the paddle 3 is achieved.

If the size of the paddle 3 exceeds a certain range, the generation of the paddle 3 becomes unstable and the steady state cannot be maintained. Furthermore, it is important for the stable maintenance of the paddle 3 that the cooling capability of the cooling roll is not impaired.

The solidification interface moving speed V _sld of the stable paddle 3 as described above varies depending on the heat transfer coefficient between the molten alloy 1 and the roll surface 2. For example, a paddle of Pr ₉ Fe ₇₃ Co ₉ B ₇ V ₁ Nb ₁ molten alloy 1 above 1300 ° C in the vertical direction (vertex) of a single roll surface 2 made of Cu having a diameter of 500 mm moving at a speed of 14.5 m / sec When 3 was formed and rapidly solidified, the average thickness of the ribbon 4 was 42 μm. Further, the distance from the paddle 3 to the peeling point A of the thin ribbon 4, that is, the contact distance L _cnt between the thin ribbon 4 and the roll surface 2 was approximately 12.0 to 12.5 mm. Therefore, the solidification interface moving speed V _sld was 50 mm / sec, and the contact time of the ribbon 4 with the roll surface 2 was 0.84 msec. Furthermore, if the temperature when the molten alloy 1 of 1300 ° C. leaves the roll surface 2 as the ribbon 4 is 700 to 800 ° C., the cooling rate in the rapid solidification is approximately 7 × 10 ^{5 to} 6 × 10 ⁵ ° C / sec. It becomes.

Furthermore, in order to make the relatively long ribbon 4 according to the present invention, it is necessary to reduce the arc-shaped locus of the ribbon 4 at the contact distance L _cnt . For example, if the angle formed by the circumferential tangent of the paddle 3 and the arc chord drawn by the ribbon 4 starting from the paddle 3 and ending at the peeling point A is θ, the smaller the angle θ is, The linearity of the ribbon 4 in contact is increased. The present invention has found that when θ is about 1.4 ° or less, the position of the peeling point A is also stabilized, and a relatively long ribbon 4 can be easily obtained.

The ribbon 4 that has passed the peeling point A flies in an argon gas atmosphere of 50 to 90 kPa, and is below R ₂ TM ₁₄ B (crystallization temperature about 590 ° C.) and α-Fe (crystallization temperature about 420 ° C.). Quick cooling. Then, the ribbon 4 is collected preferably by a flat shooter (slide). In addition, although the thin ribbon of the alloy composition of B (boron) -rich like patent document 1, patent document 2, and patent document 3 turns into the continuous continuous ribbon 4, normally a twist and curvature generate | occur | produce. The reason why the ribbon 4 is collected by the flat shooter is that the ribbon 4 according to the present invention that flies linearly suppresses the generation of twisting and warping that occurs when the ribbon 4 collides with the wall surface, or the generation of flakes to be crushed. This is to increase the yield of a relatively long and linear ribbon. In this way, by suppressing twisting and warping of the ribbon, the ribbon is directly or as a ribbon combined with the resin composition, cut to a predetermined length, bent, or punched into an arbitrary shape. Processing can be facilitated.

Next, mechanical processing of the α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet according to the present invention will be described. As the mechanical processing of the ribbon according to the present invention, ultrasonic processing, microblast processing and the like can be applied. Further, punching using a precision punching die such as a fine blanking method and a shaving method is preferable, and a precision punching method using an opposing die method is more preferable.

The production method of the α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet according to the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

(Length and roll diameter)
20 mm of molten metal alloy (alloy composition Pr ₉ Fe ₇₃ Co ₉ B ₇ V ₁ Nb ₁ ) at 1350 ° C is 500 mm in diameter moving at 14.5 m / sec through an orifice of 0.8 mm in an argon gas atmosphere at 60 kPa Paddles were formed in the vertical direction (vertex) on the surface of the Cu roll and rapidly solidified. The rapidly solidified ribbon with a width of about 2 mm was collected with a plate-like shooter. In addition, as a comparative example, a ribbon of the comparative example was produced under the same conditions except that the diameter of the Cu roll was 200 mm.

FIG. 2 (a) shows the length distribution of a quenched ribbon produced with a 500 mm diameter Cu roll according to the present invention, together with a comparative example (200 mm diameter Cu roll). As is apparent from the figure, in the comparative example, the strip-shaped ribbon having a length of less than 10 mm was 75%, and the ratio of the strip-shaped strip having a length of less than 30 mm was 99%. That is, only a length of about several mm can be obtained (see [Patent Document 4]). On the other hand, the strip according to the present invention is a strip-shaped strip having a length of less than 10 mm, which is about 17%, and can be said to be a relatively long strip. Such a relatively long ribbon is compounded with a resin composition, cut to a predetermined length, bent, or punched into an arbitrary shape, and an α-Fe / R ₂ TM ₁₄ B system having a predetermined shape It can be a nanocomposite magnet.

Note that the contact distance L _cnt between the paddle 3 and the roll surface 2 did not depend on the roll diameter in this example, and was 12.0 to 12.5 mm in this alloy system. In order to stably obtain the relatively long ribbon 4 according to the present invention, it is necessary to reduce the arc-shaped locus of the ribbon 4 at the contact distance L _cnt . For example, if θ is an angle formed by the roll circumferential tangent XX ′ of the paddle 3 in FIG. 2B and the arc string drawn by the ribbon 4 in the section between the paddle 3 and the peeling point A, θ The smaller the value of, the greater the linearity of the ribbon 4 in contact with the roll surface 2. From the result of FIG. 2A, when the angle θ is about 1.4 degrees, the position of the peeling point A is stabilized along with the formation of the paddle 3, and the linearity of the ribbon 4 in contact with the roll surface 2 is increased. For example, when the roll diameter is 500 mm and the contact distance L _cnt is 15 mm at the maximum, the angle θ is 1.7 degrees. Compared with the comparative example, the linearity of the ribbon 4 on the roll surface 2 is 2.5 times. This is the reason why a relatively long ribbon 4 can be easily obtained.

(Coercivity and thickness)
10.0 ° C molten alloy (alloy composition Pr ₉ Fe ₇₃ Co ₉ B ₇ V ₁ Nb ₁ ) 20 g in an argon gas atmosphere of 60 kPa, through a 0.8 mm diameter orifice, 10.0, 14.0, 14.5, 15.0, 20.0, 30.0 Rapid solidification was performed on the surface of a roll made of Cu having a diameter of 500 mm where the roll surface moves at m / sec. The quenched ribbon with a width of about 2 mm was collected with a flat plate shooter.

Fig. 3 (a) shows the relationship between the moving speed of the 500 mm diameter Cu roll surface, the coercive force of the ribbon, and the film thickness. Fig. 3 (b) shows the moving speed of the Cu roll surface at 20 and 30 m / sec. 5 is a characteristic diagram showing the relationship between the heat treatment temperature and the coercive force HcJ of the ribbon manufactured as described above. However, the coercive force is a value at room temperature measured with an external magnetic field ± 2.4 MA / m VSM (vibrating sample magnetometer), and the heat treatment is about 10 ° C./sec in an argon gas flow (1.5 L / min). The temperature was raised to the set temperature at, and cooled to 100 ° C. or lower in the gas flow without holding time.

Like the example of this invention of Fig.3 (a), this invention can optimize the moving speed of the Cu roll surface in rapid solidification from a coercive force value. In addition, if the moving speed of the Cu roll surface is around 14-15 m / sec, the average coercive force is 686 kA / m, and the coercive force hardly changes even when heat-treated at 570-600 ° C. Rather, there is a decrease in magnetic properties due to the coarsening of the α-Fe phase and the R ₂ TM ₁₄ B phase.

In addition, in order to obtain an amorphous quenching thin ribbon like patent document 1, patent document 2, and patent document 3 by this alloy type, it is necessary to set the moving speed of the surface made from Cu to 40 m / sec or more. . When the moving speed of the Cu roll surface is 20 and 30 m / sec, crystallization occurs, but the coercive force is only a few kA / m, and the crystallization is performed as shown in FIG. Heat treatment is required. However, the coercive force of the ribbon heat-treated in the temperature range of 570 to 600 ° C. does not reach the coercivity 686 kA / m of the non-heat-treated ribbon with the moving speed of the Cu roll surface of 14 to 15 m / sec. According to the present invention, typical magnetic characteristics after 4.8 MA / m pulse magnetization in an in-plane direction with a side of about 2 mm are a residual magnetization of 0.95 T, a coercive force of 652 kA / m, and (BH) _max 140 kJ. / m ³ .

By the way, the thickness t of the _ribbon is _regulated by t = T _cnt × V _sld . Further, there is a relationship of T _cnt = L _cnt / V _roll . Where T _cnt is the contact time with the roll surface of the _ribbon , V _sld is the solidification interface moving speed, V _roll is the moving speed of the roll surface, and L _cnt is the contact distance between the ribbon and the roll surface. L _cnt was 12.0 to 12.5 mm, t was 41 to 43 μm, and V _sld was 50 mm / sec when the moving speed V _roll on the roll surface according to the present invention was 14.5 m / sec. Therefore, in order to obtain an amorphous quenching ribbon of 90% or more as in Patent Document 1, Patent Document 2, and Patent Document 3 with the alloy composition as in this example, the moving speed V _roll of the roll surface is set to In this case, the thickness t is about 16 μm. At such a thickness, the ribbon becomes extremely mechanically fragile, and even when collected with a shooter, the length is several mm or less, and the intended relatively long ribbon cannot be obtained. Therefore, even if the ribbon is directly or combined with a resin, it cannot be cut, bent, or punched into a desired shape.

(Torque and torque curve distortion)
In the in-plane direction with one side of about 2 mm according to the present invention obtained in Example 1, typical magnetic characteristics after 4.8 MA / m pulse magnetization are residual magnetization 0.95 T, coercive force 652 kA / m, ( BH) _max 140 kJ / m ³ . This sample was punched into a disk shape with a diameter of 1.6 mm by the facing die method, and further magnetized in the in-plane direction with a 4 MA / m pulsed magnetic field.

As a comparative example, the alloy composition formula Fe _100-xy RxAy described in Patent Document 1 (where R is one or more of Pr, Nd, Dy, and Tb, A is C (carbon), or B (boron) 1) or 2 types, 1 ≦ x <6 atomic%, 15 ≦ y ≦ 30 atomic%) B (boron) -rich alloy composition Nd _4.5 Fe ₇₀ Co ₅ B _18.5 Cr ₂ master alloy , The paddle is formed in the vertical direction (vertex) of a 500 mm diameter Cu roll whose surface moves at 30 m / sec through an orifice with a diameter of 0.8 mm at 1200 ° C., and rapidly solidified. An amorphous ribbon having a thickness of about 45 μm was obtained. A thin film shooter was used to collect the ribbon. The obtained amorphous ribbon is substantially continuous in the length direction, but has a large twist and warp because it flies at a speed of 30 m / sec.

The ribbon was heated to 560 ° C. at about 10 ° C./sec in an argon gas flow and crystallized. X-ray diffraction is a nanocomposite magnet composed of three phases, Fe ₃ B phase, α-Fe phase, and Nd ₂ Fe ₁₄ B phase, and the residual magnetization at room temperature measured by VSM with external magnetic field ± 2.4 MA / m is 1.1. T, coercive force was 330 kA / m, and (BH) _max was 95 kJ / m ³ . This sample was punched into a disk shape with a diameter of 1.6 mm by the facing die method, and further magnetized in the in-plane direction with a 4 MA / m pulsed magnetic field.

  4A is a magnetic torque with respect to the external magnetic field of the sample (pole pair number 2), and FIG. 4B is a characteristic diagram showing a change in distortion rate of the magnetic torque curve. However, the magnetic torque is expressed by volume magnetic torque divided by each volume because the sample has the same diameter but different thickness. The distortion rate of the magnetic torque curve is obtained by Fourier-decomposing the magnetic torque curve and dividing the harmonic component by the fundamental wave component.

  By the way, it is assumed that a sample magnetized with a pole pair number of 1 in the in-plane direction is exposed to a uniform rotating external magnetic field. Here, it is assumed that the counterclockwise direction of the rotation direction of the external magnetic field (magnetic torque generation direction) is positive, and that the S pole center of the external magnetic field rotates counterclockwise from directly above the N pole of the sample. Then, when the south pole center of the external magnetic field is directly above the north pole of the sample, the torque is zero, and when the south pole center of the external magnetic field rotates counterclockwise, the magnetic torque gradually increases and rotates 90 degrees. Maximum magnetic torque at the position. With further rotation, the magnetic torque gradually decreases again and becomes zero at 180 degrees. That is, the measured value with the magnetic torque meter is equivalent to the torque of a DC motor having a pole pair number of 1. When the external magnetic field is changed, the torque gradient dT / dHex with respect to the external magnetic field Hex corresponds to a torque constant in the DC motor.

  In the sample according to the present invention shown in FIG. 4A, the correlation coefficient in the linear approximation between the external magnetic field of 8 to 240 kA / m (corresponding to the current value of the motor) and the torque is 0.9999. The correlation coefficient of the comparative example (corresponding to [Patent Document 1]) was 0.9363. In addition, it is apparent that the slope corresponding to the torque constant in the DC motor is also large for the sample according to the present invention. Furthermore, it is clear that the magnetic torque curve distortion rate of FIG. 4 (b) is significantly smaller and more stable in the example of the present invention than in the comparative example in a wide range of external magnetic field of 8 to 240 kA / m. The distortion rate at an external magnetic field of 40 kA / m was 0.94% in the inventive example and 3.84% in the comparative example.

(Initial irreversible demagnetization)
FIG. 5 shows the relationship between the coercive force of the present invention example shown in Example 3 and the comparative example and the magnetic torque curve distortion rate at an external magnetic field of 40 kA / m, and the α-Fe phase and the Nd ₂ TM ₁₄ B phase. Characteristic diagram showing the relationship between the coercive force and initial irreversible demagnetization of a bonded magnet that is made by pulverizing a quenched ribbon with the main phase and a quenched ribbon with the Nd ₂ Fe ₁₄ B phase as the main phase and solidifying it with resin It is. However, the initial irreversible demagnetization rate is an induced voltage reduction rate before and after a stepping motor having a rotor made of a magnet magnetized with 8 poles on the outer periphery of a cylindrical magnet having a diameter of 4.1 mm is exposed to an atmosphere of 120 ° C. for 1 hour.

As is apparent from the figure, when the distortion rate of the magnetic torque curve exceeds 1.2%, the initial irreversible demagnetization rate tends to increase rapidly. Thus, both the distortion rate of the magnetic torque curve and the initial irreversible demagnetization at high temperature exposure are derived from magnetization reversal, and the examples of the present invention are alloy compositions Nd ₁₂ Fe ₇₇ Co ₅ B ₆ , that is, R ₂ TM _It has the same magnetic stability as a bonded magnet obtained by crushing a quenched ribbon with a length of several μm near the ₁₄ B stoichiometric composition and solidifying it with a resin. Furthermore, according to the example of the present invention, it is possible to obtain a relatively long ribbon, so that the ribbon is combined with a resin, as in the comparative example (corresponding to [Patent Document 1]). It is possible to make an α-Fe / Nd ₂ TM ₁₄ B-based nanocomposite magnet that is a thin ribbon, cut to a predetermined length, or stamped into an arbitrary shape.

  1: Molten alloy, 2: Roll surface, 3: Paddle, 4: Strip, 5: Coil, 11: Nozzle (orifice), A: Strip point of roll 4 with roll surface 2, X-X ′: Paddle 3 is the angle formed between the paddle 3 and the arc string drawn by the ribbon 4 in the section of the peeling point A.

Claims (6)

α-Fe / R ₂ TM ₁₄ B (R is 9 atomic% or more and less than R ₂ TM ₁₄ B stoichiometric composition Nd or Pr, TM is part of Fe or Fe is replaced by 20 atomic% or less Co And B is a method for producing a nanocomposite magnet).
Rapidly cool molten alloy with alloy composition PrFeCoBVNb (V is 0-4 atom%, Nb is 0-3 atom%) to below crystallization temperature of α-Fe and R ₂ TM ₁₄ B, and crystallize without heat treatment A relatively long crystallized ribbon with a coercive force of 600 kA / m and a resin composition containing less than 20% flakes with a length of less than 10 mm and a resin composition are combined and cut into a predetermined length. A method for producing an α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet, characterized by bending or stamping into an arbitrary shape. The method for producing an α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet according to claim 1, wherein an average film thickness of the crystallized ribbon is 35 to 50 µm. The crystallized ribbon is formed in the vertical direction (vertex) of a single roll made of Cu having a diameter of 500 mm or more and moving at a peripheral speed of 14 to 15 m / sec in an argon gas atmosphere of 50 to 90 kPa. The α-Fe / R ₂ TM ₁₄ B system according to claim 1 or 2, wherein the α-Fe / R ₂ TM ₁₄ B system is produced by rapid solidification at a roll surface contact distance of 10 to 15 mm from a paddle of a molten TM-B alloy A method for producing a nanocomposite magnet. The α- of claim 3, wherein an angle formed by a circumferential tangent that is in contact with the roll at the center of the paddle and a chord of a contact arc drawn by a ribbon from the paddle to a peeling point is 1.7 degrees or less. A method for producing a Fe / R ₂ TM ₁₄ B nanocomposite magnet. The magnetic torque curve distortion rate at an external magnetic field of 40 kA / m of the crystallized ribbon disk magnetized in the in-plane direction at 2.4 MA / m or more is 1.2% or less. 5. A method for producing an α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet according to any one of 4 above. 6. The production of an α-Fe / R ₂ TM ₁₄ B-based nanocomposite magnet according to claim 3, wherein the flying crystallized ribbon is collected by a flat shooter. Method.