KR900006533B1 - Anisotropic magnetic materials and magnets made with it and making method for it - Google Patents

Abstract

Anisotropic magnetic powder having 1-100 micron particle size is produced from R-TM-B-Ga alloy, where R is one or more rare earth elements including Y, an TM is Fe being replaced with Co. Addition of Ga or combination of Ga and Co provides rare earthiron-boron permanent magnets with high coercive force together with high curie temperature and thus highly improved thermal stability compared with known magnets in the rare earth-iron-boron system.

Description

Anisotropic magnetic powder, its magnet and manufacturing method thereof

1 is a graph showing the change of irreversible loss of magnetic flux according to the heating temperature of magnets (a), (b) and (c) manufactured by different manufacturing methods.

2 shows anisotropic resin-bonded magnets (a), anisotropic sintered Sm ₂ Co ₁₇ magnets (b) and anisotropic sintered magnets (c) having a composition of Nd ₁₃ DyFe _76.8 Co _2.2 B ₆ Ga _0.9 Ta _0.1 . Is a graph comparing thermal stability.

The present invention relates to magnetic anisotropic magnetic powders composed of rare earth element-iron-boron-gallium alloy powders, and permanent magnets in which such alloy powders are dispersed in a resin. More particularly, the present invention relates to fine and magnetically anisotropic crystal grains. The thermal stability in which the rare earth element-iron-boron-gallium permanent magnet powder is dispersed in the resin relates to an acid resin-bonded permanent magnet having excellent thermal stability.

Typical rare earth element permanent magnets are SmCo ₅ permanent magnets and Sm ₂ Co ₁₇ permanent magnets. These samarium-cobalt magnets are made from ingots produced by melting samarium and cobalt in vacuum or in an inert gas atmosphere. These ingots are powdered and then the resulting powder is extruded in a magnetic field to form a green mold, which is then sintered and then heat treated to produce a permanent magnet.

Samarium-cobalt magnets obtain magnetic anisotropy by compressing them in a magnetic field as mentioned above. Magnetic anisotropy greatly increases the magnetic properties of the magnet. On the other hand, magnetically anisotropic resin-bonded samarium cobalt permanent magnets are obtained by injection molding a mixture of a samarium cobalt magnet and a resin produced from a sintered magnet having anisotropy in a magnetic field, or the mixture is obtained by compression molding in a die).

Thus, resin-bonded samarium cobalt magnets are obtained by producing sintered magnets having anisotropy, then pulverizing them, and then mixing them with the resin as a binder.

In recent years, neodymium-iron-boron magnets have been proposed as a new rare earth magnet that overcomes the disadvantages of samarium cobalt magnets containing samarium, which is expensive and unstable in supply. Japanese Patent Laid-Open Nos. 59-46008 and 59-64733 form ingots of neodymium-iron-boron alloys, and then powder them into fine powders, which are then compressed in a magnetic field to produce green shapes. Next, the permanent magnet obtained by sintering and heat-processing it like a samarium. Cobalt magnet is described. This manufacturing method is called powder metallurgy. It has also been reported to obtain a resin-bonded magnet having magnetic anisotropy by pulverizing the ingot to 0.5 to 2 탆 and then solidifying it with wax [Appl. . Phys. Lett. 48 (10), Mar 1986, pp 670-672].

Regarding the Nd-Fe-B permanent magnet, General Motors has proposed one method different from the powder metallurgy method mentioned above.

This method melts a mixture of neodymium, iron and boron, and then quenches the melt by a method such as melt spinning to produce fine flakes of amorphous alloys, followed by heat treatment of the flake amorphous alloys to form Nd. _It is a method for producing a ₂ Fe ₁₄ B intermetallic compound. The fine flakes of this quenched alloy solidify with the resin binder [see. Japanese Patent Laid-Open No. 59-211549]. However, the magnetic alloy thus prepared is magnetically isotropic. Japanese Laid-Open Patent Publication No. 60-100402 describes a method of compressing such an isotropic alloy at high temperature and then applying a high temperature and a high pressure thereto to cause partial plastic flow in the alloy to impart magnetic anisotropy.

However, conventional Nd-Fe-B permanent magnets have the following problems.

First, although the powder pension method can impart magnetic properties of magnetic anisotropy and maximum (BH) = 35-45 MGO _e , the produced magnets have a low Curie temperature, large crystal grain size, and thermal stability. This is good. Therefore, they cannot be used suitably for a motor or the like that is easy to be used in a high temperature environment.

Second, although the quenched powder can be molded relatively easily by compression molding when mixed with a resin, the resulting alloy is isotropic and therefore its magnetic properties are inevitably low. For example, magnetic properties is a (BH) maximum = 3-5MGO _e if obtained by injection molding, if obtained by compression molding (BH) and the maximum value _e = 8-10MGO, also magnetic properties It varies widely depending on the strength of the magnetic field magnetizing the silver alloy. In order to achieve the (BH) maximum of 8 MGO _e, the magnetic field should be around 50 KO _e and it is difficult to magnetize the alloy after assembling for various applications.

In addition, when the quenched alloy powder is compressed at high temperature, the density of the alloy is increased, and processing is removed from the compressed alloy powder to improve its weathering characteristics. However, since the produced alloy is isotropic, the permanently prepared alloy mixed with the quenched alloy powder with resin Like magnets are disadvantageous. The (BH) maximum of the resulting alloy is improved in proportion to the increase in density and can reach up to around 12 MGO _e . However, it is still impossible to magnetize after assembly.

According to the method of quenching the quenched alloy powder at high temperature and then causing plastic flow therein, anisotropy can be obtained in the same manner as the powder pension method, except that (BH) has a maximum value of 34-40 MGO _e , and is a cyclic magnet, for example Magnet rings having an outer diameter of 30 mm, an inner diameter of 25 mm and a thickness of 20 mm can be easily formed because die upsetting must be used to provide anisotropy.

Finally, in magnets made by pulverizing the ingots and then solidifying them with waxes, the powders used are so fine that they tend to burn and cannot be handled in the atmosphere. In addition, the magnet exhibits a low squareness ratio in the magnetization curve and thus cannot have high magnetic properties.

In addition, the inventors have attempted to produce anisotropic resin-bonded magnets by pulverizing the sintered anisotropic magnets produced by the powder pension method, then mixing the powdered particles with the resin, and then molding them with a DC magnetic field applied. However, high magnetic properties could not be obtained.

Accordingly, an object of the present invention is to solve the problems inherent in the above-described conventional techniques, and to provide a resin-bonded anisotropic magnet which can be easily magnetized after assembly, having excellent thermal stability, a magnetic powder that can be used therein, and a method for producing the same. It is to provide.

In order to achieve the above object, the present invention includes the following technical means.

That is, an object of the present invention is to firstly R-Fe-B-Ga alloy (wherein R is one or more rare earth elements containing Y, Fe is partially substituted by Co, R-Fe-Co-B-Ga Alloys may be included; one or more additional elements (M) selected from Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C, and Zn, including R-Fe-B-Ga- M- and R-Fe-Co-B-Ga-M alloys can be included), thereby forming magnetic anisotropic magnetic powder having a mean size of 0.01 to 0.5 탆, thereby forming a compacted powder magnet therefrom. And by forming a resin-bonded magnet from the above alloy powder having a third particle size of 1 to 1000 μm.

The present invention is thermally stable and anisotropic resin from magnetic powder having an average particle size of 1 to 1000 μm prepared by powdering a magnetic anisotropic R-Fe-B-Ga alloy having an average size of crystal grains of 0.01 to 0.5 μm- It is based on the inventors' invention that a bonded magnet can be obtained. Gallium (Ga) has been found to be extremely effective in improving the thermal stability of magnets.

Therefore, the magnetic anisotropic magnetic powder according to the present invention has an average particle size of 1 to 1000 μm, which is a magnetic anisotropic R-TM-B-Ga alloy having an average size of crystal grains of 0.01 to 0.5 μm [where R is At least one rare earth element comprising Y; TM is Fe, which may be partially substituted by Co, B (boron) and Ga (gallium).

The method for producing magnetic anisotropic magnetic powder according to the present invention is an R-TM-B-Ga alloy, wherein R is at least one rare earth element comprising Y; TM is Fe, which may be partially substituted by Co, B (boron) and GA (gallium)] to quench the melt to form flakes of the R-TM-B-Ga alloy in amorphous or partially crystallized form. These flakes were then compressed to produce a denser compacted powder, which was then plastically deformed while heating to produce a magnetic anisotropic R-TM-B-Ga alloy having an average size of 0.01-0.5 μm crystal grains. And then heat-treat it to increase its coercive force and then powder it.

The method for producing magnetic anisotropic magnetic powder according to the present invention is an R-TM-B-Ga alloy, wherein R is at least one rare earth element comprising Y; TM is Fe, which may be partly substituted by Co, B (boron) and Ga (gallium)] to quench the melt to form flakes of the R-TM-B-Ga alloy in amorphous or partially crystallized form. Next, these flakes were compressed to prepare a compact powder having a higher density, and then plastically deformed while heating them to form magnetically anisotropic R-TM-B-Ga alloys having an average size of 0.01 to 0.5 탆 on the crystal grains. Then, it consists of a step of powdering it without heat treatment.

The magnetically anisotropic compressed powder magnet according to the present invention is a magnetic anisotropic R-TM-B-Ga alloy having an average size of crystal grains of 0.01 to 0.5 μm, wherein R is one or more rare earth elements containing Y ; TM is Fe, which can be partially substituted by Co, B (boron) and Ga (gallium)], and magnetic anisotropic R-TM-B-Ga alloys have easy magnetization axes aligned in the same direction It is.

The magnetically anisotropic resin-bonded magnet according to the present invention is an R-TM-B-Ga alloy having 15 to 40% by volume of the resin binder and an average size of the crystal grains of 0.01 to 0.5 μm, wherein R is Y And at least one rare earth element comprising: TM is Fe, which may be partially substituted by Co, B (boron) and Ga (gallium)], where the residual anisotropic R-TM-B- Ga alloys have easy magnetization axes aligned in the same direction.

The magnetic anisotropic magnetic powder according to the present invention has an average particle size of 1 to 1000 μm, which is an R-TM-B-Ga-M alloy powder having an average size of crystal grains of 0.01 to 0.5 μm [where R is Y. Rare earth elements containing; TM is partially defined by Co, B (boron), Ga (gallium) and M (Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn) Fe may be substituted by.

The method for producing the magnetic anisotropic magnetic powder according to the invention is an R-TM-B-Ga-M alloy, wherein R is at least one rare earth element comprising Y; TM is partially defined by Co, B (boron), Ga (gallium) and M (Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn) Quenched melt to form flakes made of R-TM-B-Ga-M alloy in amorphous or partially crystallized form, and then compressed to obtain higher density A powder was prepared, and then plastically deformed while heating to form a magnetic anisotropic R-TM-B-Ga-M alloy having an average size of crystal grains of 0.01 to 0.5 μm, and then heat-treated to increase its coercive force and And then powdering them.

The method for producing the magnetic anisotropic magnetic powder according to the invention is an R-TM-B-Ga-M alloy, wherein R is at least one rare earth element comprising Y; TM can be partially substituted by Co, B (boron), Ga (gallium) and M (one or more elements selected from Nb, W, V, Ta, Si, Al, Zr, Hf, P, C and Zn) Can be quenched to form flakes of the R-TM-B-Ga-M alloy in amorphous or partially crystallized form, and then the flakes are compressed to produce a compacted powder of higher density. Then, it is plastically changed while heating to form a magnetic anisotropic R-TM-B-Ga-M alloy having an average size of the crystal grains of 0.01 to 0.5 μm, and then powdered without heat treatment.

Magnetically anisotropic compressed powder magnet according to the present invention is a magnetic anisotropic R-TM-B-Ga-M alloy having an average size of 0.01 to 0.5 μm of crystal grains, wherein R comprises Y One or more rare earth elements; TM is partially defined by Co, B (boron), Ga (gallium) and M (one or more elements selected from Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn) Is Fe, which may be substituted, wherein the magnetic anisotropic R-TM-B-Ga-M alloys have easy magnetization axes aligned in the same direction.

The magnetically anisotropic resin-bonded magnet according to the present invention is a R-TM-B-Ga-M alloy powder having a resin binder of 15 to 40% by volume, and an average size of crystal grains of 0.01 to 0.5 µm. R is one or more rare earth elements comprising Y; TM is partially defined by Co, B (boron), Ga (gallium) and M (at least one element selected from Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn) Fe, which may be substituted], where the magnetic anisotropic R-TM-B-Ga-M alloy is aligned in the same direction with easy magnetization axes.

1 is a graph showing the change of irreversible loss of magnetic flux according to the heating temperature of magnets (a), (b) and (c). (A) is manufactured by quenching, heat treatment and resin penetration. Magnet; (b) is a magnet manufactured by quenching, heat treatment and high temperature compression; (c) is a magnet manufactured by quenching, HIP and die upsetting.

2 shows the anisotropic resin-bonded source magnet (a) of Example 8, the anisotropic sintered Sm ₂ Co ₁₇ magnet (b) and the anisotropic sintered sintered composition of Nd ₁₃ DyFe _76.8 Co _2.2 B ₆ Ga _0.9 Ta _0.1 This is a graph comparing the magnet (c) in terms of thermal stability.

The composition of the alloy is preferably 11 to 18 atomic% R, 5 atomic% or less Ga, 4 to 11 atomic% B, 30 atomic% or less Co, and the remaining Fe and inevitable impurities, and 11 to 18 atomic% More preferred are R, 0.01 to 3 atomic% Ga, 4 to 11 atomic% B, 30 atomic% or less Co and residual Fe and unavoidable impurities. This alloy may contain one or more additional elements M selected from Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn. The amount of additional element M is 3 atomic% or less, more preferably 0.001 to 3 atomic%. Mixing and adding additional elements M and Ga is effective in further improving the coercive force of the alloy. Of course, in some cases it is effective to add only Ga.

The R-Fe-B alloy is an alloy containing R ₂ Fe ₁₄ B or R ₂ (Fe, Co) ₁₄ B as the main phase. The range of preferred compositions for permanent magnets is as follows: If R (one or more circuit elements comprising Y) is less than 11 atomic percent, sufficient iHc cannot be obtained and if R is greater than 18 atomic percent Br This decreases. Therefore, the amount of R is 11-18 atomic%.

When B is less than 4 atomic%, the main phase of the magnet, R ₂ Fe ₁₄ B phase is not completely formed, Br and iHc is lowered. On the other hand, when B exceeds 11 atomic%, an undesirable phase appears in the magnetic properties, resulting in lower Br. Therefore, the amount of B is 4 to 11 atomic%.

If the amount of Co exceeds 30 atomic%, the Curie temperature increases but the anisotropy constant of the main phase decreases, making it impossible to obtain a high iHc. Therefore, the amount of Co is 30 atomic% or less.

When the amount of Ga exceeds 5 atomic%, the saturation magnetization 4πIs and the Curie temperature Tc are extremely reduced. As for Ga, 0.01-3 atomic% is preferable, and 0.05-2 atomic% is more preferable.

The addition of one or more additional elements selected from Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn is effective in further increasing the coercive force of the alloy, but the amount is three atoms. If it exceeds%, an undesirable decrease in 4πIs and Tc occurs. The amount of additional elements is preferably 0.001 to 3 atomic%.

In addition, the alloy of the present invention may contain Al contained as an impurity in boron iron, and may also contain a reducing substance and impurities mixed in the reduction of rare earths.

In the present invention, when the average crystal grain size of the R-Fe-B-Ga alloy exceeds 0.5 μm, its iHc is reduced, and irreversible loss of magnetic flux occurs at 160 ° C. or more, resulting in thermal stability. Will be reduced dramatically. On the other hand, when the average crystal grain size is less than 0.01 mu m, the resin-bonded magnets formed have a low iHc, and thus a desirable permanent magnet cannot be obtained. Therefore, the average grain size is limited to 0.01 to 0.5 μm.

The average ratio of the average grain size (c) present perpendicular to the c axis of the crystal grains to the average grain size (a) of the grains present in parallel to the c axis of the grains is preferably 2 or more.

In order to produce anisotropic resin-bonded magnets having high magnetic properties, the R-Fe-B-Ga alloy to be powdered needs to have a residual magnetic flux density of 8 KG or more in a specific direction, that is, an anisotropic direction.

The flakes obtained by the quenching method are compressed or compressed by hot isostatic pressing (HIP) or hot pressing, and then plastic deformation of the resulting compressive agent is carried out by R-TM-B-Ga or R-TM- Anisotropy is imparted to the B-Ga-M alloy. One method for plastic deformation is die upsetting at high temperatures.

In the present specification, the magnetic anisotropic R-TM-B-Ga or R-TM-B-Ga-M alloy has R- showing anisotropic magnetic properties in which the shape of the 4πI-H curve changes in the magnetization direction in the second quadrant. TM-B-Ga or R-TM-B-Ga-M alloy. Compressed powders prepared by hot isostatic pressing of flakes usually have a residual magnetic flux density of 7.5 kg or less, but R-TM-B-Ga or R-TM-B-Ga having a residual magnetic flux density of 8 kg or more. Using -M alloys, the resulting resin-bonded magnets have higher magnetic properties such as residual magnetic flux density and energy products than isotropic resin-bonded magnets.

The method for producing the anisotropic magnetic particles and the anisotropic powder or resin-bonded magnet is as follows.

In the present invention, the alloy flakes are powdered to about 100 to 200 μm. The coarse powder produced by pulverization is molded at room temperature to give a green body. The green shapes are hot isostatic pressed or hot pressed at 600 to 750 ° C. to form compacted blocks with relatively small crystal grain sizes. The block is again subjected to plastic processing such as die upsetting at 600 to 800 ° C. to produce an anisotropic flat plate. This is referred to herein as an anisotropic compressed powder magnet. Depending on the application, it may be used without further treatment or processing. Although heat treatment may be performed, iHc may sufficiently increase in some cases when Ga is added, so that heat treatment may be omitted by adding Ga.

As further processing, the resulting alloys have increasingly higher anisotropy. In some cases, the flat plate may be heat treated at 600 to 800 ° C. to improve its iHc. This flat glass can be powdered to produce coarse powder for anisotropic resin-bonded magnets.

Upon plastic working, the anisotropic R-Fe-B-Ga alloy contains crystal grains planarized in the c direction. The crystal grains are formed of the average grain size (c) perpendicular to the crystal grain c-axis with respect to the grain size average (a) of the grains parallel to the c-axis of the grains such that the magnet has a residual magnetic flux density of 8KG or more. It is preferable that average ratio is two or more. In addition, the average size of the crystal grains is defined herein as a value obtained by averaging the diameters of 30 or more crystal grains converted into spheres of the same volume.

When the plastic working is a die upsetting performed with heat treatment, particularly high magnetic properties can be obtained.

The coercive force can be increased by heat-treating the R-Fe-B magnet given anisotropy by plasticity processing. At temperatures below 600 ° C., the coercive force cannot be increased, and at temperatures higher than 900 ° C., the coercive force decreases rather than before heat treatment, so the heat treatment temperature is preferably 600 to 900 ° C.

The heat treatment is carried out for a period of time necessary to keep the sample at a uniform temperature. Considering the output, it is 240 minutes or less.

The cooling rate should be at least 1 ° C / sec. If the cooling rate is less than 1 ° C / sec, the coercive force decreases before heat treatment. In addition, the term "cooling rate" herein means an average cooling rate at the heat treatment temperature (° C) to (heat treatment temperature + room temperature) / 2 (° C). However, the addition of Ga makes the heat treatment unnecessary in some cases. In this case, the heat treatment is not necessary, and large magnets used in the voice coil motor and the like hardly crack or oxidize.

In the present invention, the average particle size of the powdered powder is 1 to 1000 μm for the following reasons.

If it is less than 1 μm, the powder is easily burned, so it is difficult to handle in air, and if it exceeds 1000 μm, a thin resin-bonded magnet having a thickness of 1 to 2 mm cannot be manufactured, which is also unsuitable for injection molding. It can be carried out in a conventional manner using powdered circular mills, brown mills, attritors, ball mills, vibration mills, jet mills, and the like. have.

The coarse powder may be mixed with a thermosetting resin binder, followed by compression molding in a magnetic field, followed by thermosetting it to produce an anisotropic resin-bonded magnet of compression molding. The coarse powder may also be mixed with a thermoplastic binder. Injection molding in a magnetic field may also be used to produce anisotropic resin-bonded magnets in injection molding form.

As a material that can be used as the binder, thermosetting resin is intended to be used first in the case of compression molding. Thermally stable polyamides, polyimides, polyesters, phenolic resins, fluorine resins, silicone resins, epoxy resins and the like can be used. Moreover, Al, Sn, Pb, and various low melting solder alloys can also be used. In the case of injection molding, thermoplastic resins such as ethylene-vinyl acetate resin, nylon and the like can be used.

Example 1

An Nd ₁₅ Fe ₇₇ B ₇ Ga ₁ alloy is prepared by arc melting, and the alloy is then sliced by a single roll method under an argon atmosphere. The peripheral speed of the roll is 30 m / sec and the resulting flakes have an irregular shape with a thickness of about 30 μm. X-ray diffraction measurements showed that these flakes consisted of a mixture of amorphous and crystalline phases. These flakes are powdered to 32 mesh or less and then compacted by a die at ⁶ tons / cm ² without applying a magnetic field. The resulting compacted product has a density of 5.8 g / cc. The compacted product is hot pressed at a temperature of 750 ° C. and 2 tons / cm 2. The alloy after high temperature compression has a density of 7.30 g / cc. Therefore, a sufficiently high density is imparted by high temperature compression. The bulk product or higher density compacted powder is die upset at 750 ° C. Adjust the height of the sample so that the compression ratio before and after upsetting is 3.8. That is, ho = h = 3.8 (where ho is the height before upsetting and h is the height after upsetting).

The upset sample is heated in an Ar atmosphere for 60 minutes at a temperature of 750 ° C. and then cooled with water at a cooling rate of 7 ° C./sec. Magnetic properties before and after the heat treatment are shown in Table 1.

TABLE 1

The heat treated sample is powdered to make the particle size in the range of 250 μm to 500 μm. The resulting magnetic powder is mixed with 16 vol% of epoxy resin in a dry state, and then the resulting powder is molded in a magnetic field of 10 KOe perpendicular to the compression direction. Then, it was thermosetted at a temperature of 120 ° C. for 3 hours to obtain an anisotropic resin-bonded magnet.

The resulting anisotropic resin-bonded magnet has a magnetic property at 25 KOe magnetization strength of Br = 7.6KG, bHc = 6.8KOe, iHc = 19.0KOe and (BH) maximum = 13.5MGOe.

For comparison, a quenched bakfun with a composition of Nd ₁₇ Fe ₇₃ B ₈ Ga ₂ was heat-treated in vacuo at a temperature of 600 ° C. for 1 hour and then powdered to 250 to 500 μm, followed by resin-bonding in the same manner as above. In addition, this resin-bonded magnet is isotropic so that no magnetic field is applied in the compression molding step. The magnetic properties were measured at the magnetization intensity of 25 KOe, where Br = 6.3 KOe, bHc = 5.2 KOe, iHc = 22.1 KOe, and (BH) maximum = 6.8 MGOe (Comparative Example 1).

It can be seen from the above that the anisotropic resin-bonded magnet according to the present invention has better magnetization properties and higher magnetism than isotropic resin-bonded magnets.

For comparison, an ingot having a composition of Nd ₁₅ Fe ₇₇ B ₇ Ga ₁ is powdered in the same manner as in the above example, then mixed with a binder, and then molded in a magnetic field, followed by thermosetting. Magnetization strength of 25 KOe When the magnetic properties are measured, Br = 3.8 KOe and bHc = 0.3 KOe (Comparative Example 2).

Therefore, anisotropic resin-bonded magnets made from ingots cannot be used as practical quality because high iHc cannot be obtained. The results of Example 1 and Comparative Examples are summarized in Table 2 below.

TABLE 2

Note: * Made from ingot

Example 2

Next, the effect of the compression ratio on die upsetting on the final anisotropic resin-bonded magnet is shown. This embodiment is the same as in Example 1 in terms of composition and quenching, high temperature compression, molding in a magnetic field perpendicular to the compression direction, heat treatment and curing.

The results are shown in Table 3. The magnetic properties reported in Table 3 are the values obtained at the magnetization strength of 25 KOe. As reported in Table 3, increasing the compression ratio increases the magnetic properties of the resulting anisotropic resin-bonded magnet.

Incidentally, when the compression ratio ho / h is 5.6 or more, overheating occurs around the sample after die upsetting, but there is no effect on the final anisotropic resin-bonded magnet in compression-molded form.

TABLE 3

Example 3

Magnetic powder is prepared from Nd ₁₄ Fe ₇₉ B ₆ Ga ₁ alloy in the same manner as in Example 1. The magnetic powder is mixed with 33% by volume of EVA to form a mullet. The mallet is injection molded at 150 ° C. Test specimens produced by injection molding were 20 mm in diameter and 10 mm thick, and the magnetic field applied during injection molding was 8 KOe. The magnetic properties of the test piece were measured at a magnetization strength of 25 KOe, and Br was about 7.1KG, bHc was 5.8KOe, iHc was about 18.5KOe, and the maximum value (BH) was about 10.5MGOe.

Example 4

An anisotropic resin-bonded magnet having a composition as shown in Table 4 was prepared by the same compression molding method as in Example 1. The measured magnetic properties are as described in Table 4.

Samples 1-5 show the effect of Nd, samples 6-10 show the effect of B, and samples 11-19 show the effect of Ga. 20 to 23, 24 to 27, 28 to 31, 32 to 35, 36 to 39, 40 to 43, 44 to 47, 48 to 51, 52 to 55, 56 to 59, Samples 60-63 and 64-67 show the effects of additional elements W, V, Ta, Mo, Si, Al, Zr, Hf, P, C, Zn and Nb, respectively.

It is understood from this table that Nb is preferably from 11 to 18 atom%, boron is from 4 to 11 atom%, Ga is preferably at most 5 atom 9%, and each additional element is preferably at most 3 atom%. have.

Incidentally, the same effect of Ga and the additional element M is shown in the so-called sintering method.

TABLE 4

Note: * Comparative Example

Example 5

An alloy having a composition of Nd _14.3 Fe _70.7 Co _5.1 B _6.9 Ga _1.7 W _1.3 was prepared by arc melting and then quenched by a single roll method. The resulting flake shaped sample was bulky in three ways: To form.

(a) After heat treatment at 500 to 700 DEG C, epoxy resin is poured, followed by die molding.

(b) heat-treated at 500 to 700 ° C., followed by high temperature compression.

(c) Hot isostatic pressing followed by die upsetting to produce a flat product. The magnetic properties of the resulting sample are as shown in Table 5.

TABLE 5

After each sample is heated for 30 minutes at various temperatures, the thermal stability of each sample is examined by measuring the change in open flux. Incidentally, the measured sample is processed to obtain a penetration coefficient Pc = -2. The result is as shown in FIG. The flat upset product (c) appears to have a low average particle size and a good maximum (BH).

Example 6

An alloy having a composition of Nd _15.1 Fe _73.0 Co _3.4 B _6.9 Ga _1.7 W _0.9 was prepared by arc welding and then quenched by a single roll method. The resulting flaky sample was compressed by HIP and then upset by a die to flatten it. Prepare the product. The resulting bulky sample is powdered to 80 μm or less, then injected with epoxy resin and then molded in a magnetic field. The magnets produced have magnetic properties of Br = 7.1KG, iHc = 22.0KOe and (BH) maximum = 11.1 MGOe.

Example 7

Magnetic powder was prepared by treating Nd ₁₅ Fe _72.7 Co _3.2 B ₇ Ga _1.8 Nb _0.3 alloy in the same manner as in Example 1. The magnetic powder is mixed with an EVA binder to form a pallet, and then injection molded to produce a magnet having an inner diameter of 12 mm, an outer diameter of 16 mm, and a height of 25 mm. This magnet is anisotropic in radial direction and cut samples of 15 mm x 1.5 mm x 1.5 mm to evaluate its magnetic properties. Magnetic properties are Br = 6.5KG, bHc = 5.8KOe, iHc = 24.2KOe and (BH) maximum = 8.5MGOe.

Example 8

Anisotropic resin-bonded magnets in a compression-molded form having a composition of Nd ₁₃ DyFe _76.8 Co _2.2 B ₆ Ga _0.9 Ta _0.1 were prepared in the same manner as in Example 1. The magnetic properties of the magnet are Br = about 6.6 KG, bHc = about 6.2 KOe, iHc = about 21.0 KOe and (BH) maximum = about 10.2 MGOe. The crystal grain size of the magnet is 0.11 μm. The magnet is machined to a diameter of 10 mm x thickness 7 mm, and then tested for thermal stability. The results are shown in FIG. 2. For comparison, sintered anisotropic Sm ₂ Co ₁₇ magnets of the same composition and sintered anisotropic R-Fe-B magnets were tested.

The anisotropic resin-bonded magnet according to the present invention has better thermal stability than the sintered anisotropic magnet tested as a comparative material.

Example 9

Example 1 was repeated but the particle size of the magnetic powder was changed to prepare an anisotropic resin-bonded magnet of Nd ₁₄ Fe ₇₉ B ₆ Ga ₁ . For comparison, the change of the coercive force according to the particle size is investigated using a sintered anisotropic magnet of Nd ₁₃ Dy ₂ Fe ₇₈ B ₇ . The results are shown in Table 6.

Although the sintered compact cannot be used as a material for a resin-bonded magnet because its coercive force is reduced by powdering, the magnet according to the present invention hardly reduces coercive force by powdering.

TABLE 6

Example 10

Repeating Example 1, but changing the size of the crystal grains by changing the upsetting temperature to produce an anisotropic resin-bound magnet. The results are shown in Table 7. It is shown that excellent magnetic properties can be obtained at an average size of crystal grains of 0.01 to 0.5 µm.

TABLE 7

Example 11

Example 1 was repeated, but the heat treatment time was flashed to prepare an upset sample of R-Fe-B-Ga. The results are shown in Table 8. Magnetic properties with heating time at 750 ° C. within 240 minutes. Don't thrive.

TABLE 8

Example 12

Example 1 was repeated, but an upset sample of Nd-Fe-B-Ga was prepared by changing the heat treatment temperature for a heating time of 10 minutes. The results are shown in Table 9. It is shown that excellent magnetic properties can be obtained at heat treatment temperatures of 600 to 900 ° C.

TABLE 9

Example 13

Example 1 was repeated but the upset sample of Nd-Fe-B-Ga was prepared by changing a cooling method with respect to 10 minutes of heating time. The results are shown in Table 10. It is shown that good results are obtained at a cooling rate of 1 ° C / sec.

TABLE 10

As described in detail above, the magnetic powder for the Ga-containing anisotropic resin-bonded magnet according to the present invention has excellent magnetization capability and low irreversible loss of magnetic flux even in a relatively high temperature environment. It is useful for anisotropic resin-bonded magnets that can later be magnetized.

Claims (38)

Anisotropic R-TM-B-Ga alloys having an average crystallite size of 0.01 to 0.5 μm, wherein R is one or more rare earth elements comprising Y, TM is Fe, which may be partially substituted by Co, B is boron, Ga is gallium] and magnetically anisotropic magnetic powder, characterized in that the average particle size is 1 to 1000μm. 2. The R-TM-B-Ga alloy powder according to claim 1, wherein the R-TM-B-Ga alloy powder is essentially 11 to 18 atomic% rare earth elements, 4 to 11 atomic% boron, 5 atomic% or less Ga, 30 atomic% or less Co, and residual amount. Magnetic anisotropic powder composed of Fe and inevitable impurities. The magnetic anisotropic magnetic powder according to claim 2, wherein the magnetic flux density in the axial direction of the magnetic powder, which can be easily magnetized, is 8 KG or more. The method of claim 1, wherein the anisotropic R-TM-B-Ga alloy powder compresses the flakes obtained by supercooling from a melt having a composition of R-TM-B-Ga to provide a compacted magnet, which is subjected to plastic deformation. Magnetically anisotropic magnetic powder produced by imparting anisotropy and then grinding it. The magnetic anisotropic magnetic powder according to claim 4, wherein the magnetic anisotropy powder is imparted by die upsetting while heating. The magnetic anisotropic magnetic powder according to claim 1, wherein an average ratio of the average size (c) of the crystal grains perpendicular to the C axis of the crystal grains to the average size (a) of the crystal grains parallel to the C axis of the grains is 2 or more. . Melt of an R-TM-B-Ga alloy, where R is one or more rare earth elements comprising Y, TM is Fe, which may be partially substituted by Co, B is boron, and Ga is gallium Was supercooled to form flakes of amorphous or partially crystallized R-TM-B-Gq, alloy, and the flakes were compressed to give a denser compacted powder, and plastically deformed by heating the powder to average The magnetic anisotropic magnetic powder is prepared by forming a magnetic anisotropic R-TM-B-Ga alloy having a crystal grain size of 0.01 to 0.5 μm, heat treating the alloy to increase the coercive force of the alloy, and pulverizing the alloy. How to. The method of claim 7, wherein the anisotropic R-TM-B-Ga alloy is heated at a temperature of 600 to 900 ° C., maintained within 240 minutes at this temperature and then cooled at a rate of 1 ° C./sec or more. Melt of an R-TM-B-Ga alloy, where R is one or more rare earth elements comprising Y, TM is Fe, which may be partially substituted by Co, B is boron, and Ga is gallium Was supercooled to form flakes of amorphous or partially crystallized R-TM-B-Ga alloy, and the flakes were compressed to obtain a denser compacted powder, which was plastically deformed while heating the powder to average crystallization. A method of producing a magnetic anisotropic magnetic powder, characterized in that it comprises a magnetic anisotropic R-TM-B-Ga alloy having a particle size of 0.01 to 0.5μm, and pulverizing the alloy without heat treatment. 10. The method according to claim 7 or 9, wherein the R-TM-B-Ga alloy is essentially 11 to 18 atomic% rare earth elements, 4 to 11 atomic% boron, 30 atomic% or less Co, 5 atomic% or less A method consisting of Ca and residual amounts of Fe and inevitable impurities. Magnetic anisotropic R-TM-B-Ga alloys in which the average crystal grain size is 0.01 to 0.5 μm and the axes that can be easily magnetized are aligned in the same direction, wherein R is at least one rare earth element comprising Y, TM is Fe, which may be partially substituted by Co, B is boron, and Ga is gallium. 12. The alloy of claim 11, wherein the R-TM-B-Ga alloy consists essentially of 11 to 18 atomic percent of rare earth elements, 4 to 11 atomic percent of boron, 30 atomic percent or less of Co, 5 atomic percent or less of Ga, and residual amounts of Magnetically anisotropic compressed powder magnet composed of Fe and unavoidable impurities. 12. The method of claim 11, wherein the anisotropic R-TM-B-Ga alloy powder compresses the flakes obtained by supercooling from a melt of composition R-TM-B-Ga to provide a compacted magnet, which is subjected to plastic deformation. Magnetically anisotropic compressed powder magnet produced by imparting anisotropy and then grinding it. The magnetic anisotropic compressed powder magnet according to claim 13, wherein the magnetic anisotropy is imparted by die upsetting while heating. 15 to 40% by volume resin binder, and a residual amount of magnetic anisotropic R-TM-B-Ga alloy powder in which the average crystal grain size is 0.01 to 0.5 μm and the axes are easily aligned in the same direction, where R Is at least one rare earth element comprising Y, TM is Fe, which may be partially substituted by Co, B is boron, and Ga is gallium. The R-TM-B-Ga alloy of claim 15, wherein the R-TM-B-Ga alloy consists essentially of 11 to 18 atomic percent of rare earth elements, 4 to 11 atomic percent of boron, 30 atomic percent or less of Co, 5 atomic percent or less of Ga, and residual amounts of Magnetically anisotropic resin-bonded magnet composed of Fe and unavoidable impurities. 16. The anisotropic R-TM-B-Ga alloy powder according to claim 15, wherein the anisotropic R-TM-B-Ga alloy powder is supercooled to melt the melt having a composition of R-TM-B-Ga to compress the flakes and then calcined to give anisotropy, which is then ground. Magnetically anisotropic resin-bonded magnet produced by. 18. Magnetotropic resin-bonded magnet according to claim 17, wherein the anisotropy is imparted by die upsetting while heating. R-TM-B-Ga-M alloy powder having an average crystal grain size of 0.01 to 0.5 μm, wherein R is one or more rare earth elements comprising Y, and TM may be partially substituted by Co Fe, B is boron, Ga is gallium, M is at least one element selected from the group consisting of Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn. A magnetic anisotropic magnetic powder having a mean particle size of 1 to 1000 μm. 20. The alloy of claim 19, wherein the R-TM-B-Ga-M alloy consists essentially of 11 to 18 atomic percent rare earth elements, 4 to 11 atomic percent boron, 30 atomic percent or less Co, 5 atomic percent or less Ga, Magnetically anisotropic magnetic powder consisting of up to 3 atomic% of additional elements and residual amounts of Fe and unavoidable impurities. The magnetic anisotropic magnetic powder according to claim 20, wherein the magnetic flux density in the axial direction, which can be easily magnetized, is 8KG or more. 20. The method of claim 19, wherein the anisotropic R-TM-B-Ga-M alloy powder supercools the melt of composition R-TM-B-Ga-M to form flakes, compresses them, and then plastically deforms them. Magnetically anisotropic magnetic powder produced by imparting anisotropy by crushing and pulverizing. 23. The magnetic anisotropic magnetic powder according to claim 22, wherein the magnetic anisotropy powder is imparted by die upsetting while heating. The magnetic anisotropic magnetic powder according to claim 19, wherein an average ratio of the average size (c) of the crystal grains perpendicular to the C axis of the crystal grains to the average size (a) of the crystal grains parallel to the C axis of the grains is 2 or more. . 25. The method of claim 24 wherein the R-TM-B-Ga-M alloy powder consists essentially of 11 to 18 atomic percent rare earth elements, 4 to 11 atomic percent boron, 5 atomic percent or less Ga, 30 atomic percent or less Co. , Magnetically anisotropic magnetic powder consisting of up to 3 atomic% of additional elements and residual amounts of Fe and unavoidable impurities. The magnetic anisotropic magnetic powder according to claim 25, wherein the magnetic flux density in the axial direction, which can be easily magnetized, is 8KG or more. The magnetic anisotropic magnetic powder according to claim 19, wherein the magnetic anisotropy powder is imparted by die upsetting while heating. R-TM-B-Ga-M alloy, where R is one or more rare earth elements comprising Y, TM is Fe, which may be partially substituted by Co, B is boron, Ga is gallium, M is at least one element selected from the group consisting of Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn]. Forming flakes of the TM-B-Ga-M alloy, compressing the flakes to provide a compact powder having a higher density, and plastically deforming with heating the powder to cause magnetic anisotropy with an average crystal grain size of 0.01 to 0.5 탆. Forming an R-TM-B-Ga-M alloy, heat treating the alloy to increase the coercive force of the alloy, and pulverizing the alloy. The method of claim 28, wherein the anisotropic R-TM-B-Ga-M alloy is heated at a temperature of 600 to 900 ° C., maintained at 240 minutes at this temperature, and then cooled at a rate of 1 ° C./sec or more. R-TM-B-Ga-M alloy, where R is one or more rare earth elements comprising Y, TM is Fe, which may be partially substituted by Co, B is boron, Ga is gallium, M is at least one element selected from the group consisting of Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C, and Zn]. Forming flakes of a -B-Ga-M alloy, compressing the flakes to give a compact powder having a higher density, and plastically deforming with heating the powder to produce an anisotropic R having an average crystal grain size of 0.01 to 0.5 탆. Providing a -TM-B-Ga-M alloy, and pulverizing the alloy without heat treatment. Magnetic anisotropic R-TM-B-Ga-M alloys in which the average crystal grain size is 0.01 to 0.5 μm and the axes that are easily magnetized are aligned in the same direction, wherein R is one or more rare earth elements comprising Y TM is Fe, which may be partially substituted by Co, B is boron, Ga is gallium, M is Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn is at least one element selected from the group consisting of. The R-TM-B-Ga-M alloy of claim 31, wherein the R-TM-B-Ga-M alloy consists essentially of 11 to 18 atomic percent rare earth elements, 4 to 1 atomic percent boron, 30 atomic percent or less Co, 5 atomic percent or less Ga, Magnetically anisotropic compressed powder magnet consisting of up to 3 atomic% additional elements and residual amounts of Fe and unavoidable impurities. 32. The method of claim 31, wherein the anisotropic R-TM-B-Ga-M alloy powder supercools the melt of composition R-TM-B-Ga-M to form flakes, compresses it, and then plastically deforms it. Magnetically anisotropic compressed powder magnet produced by imparting anisotropy, and pulverizing it. 34. The magnetic anisotropic compacted powder magnet according to claim 33, wherein the magnetic anisotropy is imparted by die upsetting while heating. 15 to 40% by volume resin binder, and a residual amount of magnetic anisotropy R-TM-B-Ga-M alloy powder in which the average crystal grain size is 0.01 to 0.5 mu m and the axes can be easily magnetized aligned in the same direction [here Where R is at least one rare earth element comprising Y, TM is Fe, which may be partially substituted by Co, B is boron, Ga is gallium, and M is Nb, W, V, Ta, Mo, At least one element selected from the group consisting of Si, Al, Zr, Hf, P, C, and Zn. 38. The alloy of claim 35, wherein the R-TM-B-Ga-M alloy powder consists essentially of 11 to 18 atomic percent rare earth elements, 4 to 11 atomic percent boron, 30 atomic percent or less Co, and 5 atomic percent or less Ga. , An anisotropic resin-bonded magnet consisting of up to 3 atomic% of additional elements and residual amounts of Fe and unavoidable impurities. 36. The method of claim 35, wherein the anisotropic R-TM-B-Ga-M alloy powder supercools the melt of composition R-TM-B-Ga-M to form flakes, compresses it, and then plastically deforms it. Magnetically anisotropic resin-bonded magnet produced by imparting anisotropy thereto and crushing it. 38. The magnetotropic resin-bonded magnet of claim 37, wherein the anisotropy is imparted by die upsetting while heating.

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