JP3160817B2 - Rare earth bonded magnet material, rare earth bonded magnet, and method for manufacturing rare earth bonded magnet - Google Patents

Abstract

A rare-earth bonded magnet is improved in its heat resistance by coating rare-earth magnetic powder with heat resisting addition polymerized thermosetting resin consisting mainly of triazine resin because oxidation of the rare-earth magnetic powder is prevented or retarded by triazine rings formed in the coating film of the thermosetting resin consisting mainly of the triazine resin. The heat resistance of the bonded magnet is further improved by curing the thermosetting resin in a vacuum and by adding organometallic salt in the thermosetting resin as a metallic catalyser since the coating film is formed more firmly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare-earth bonded magnet material, a rare-earth bonded magnet, and a rare-earth bonded magnet suitable for providing a rare-earth bonded magnet used in a wide variety of products such as automobiles, office equipment, home appliances, and audio equipment. The present invention relates to a method for manufacturing a bonded magnet.

[0002]

2. Description of the Related Art Conventionally, alnico magnets and ferrite magnets have been used as permanent magnets in many cases. Rare earth magnets having better magnetic properties than these magnets have been developed, and their use and usage are rapidly increasing. Is expanding.

[0003] Such a rare-earth magnet contains active metals and thus has a drawback that it is easily oxidized, thereby deteriorating corrosion resistance and temperature resistance characteristics. There is a disadvantage that.

[0004] Among the rare earth magnets, R-Fe-B
, R-Fe-N based magnets, in addition to R (rare earth),
Since (Fe) is the main component, oxidation is more remarkable than that of the Sm-Co magnet. Therefore, although R-Fe-based rare earth magnets have excellent magnetic properties, they have significant problems in terms of oxidation resistance, corrosion resistance, temperature characteristics at room temperature or higher, and heat resistance.

[0005] Among them, sintered magnets are densified by a sintering reaction. Corrosion resistance and the like can be considerably prevented by, for example, Ni plating or resin coating on the product surface in the final step of magnet production. In addition, among the bonded magnets, magnets that are injection-molded using a thermoplastic resin such as polyamide resin coat the surface of the product in the same way as a sintered magnet because the magnetic powder is completely covered around the resin. This can be prevented.

[0006]

On the other hand, among the bonded magnets, a magnet formed by compression molding using a binder such as a thermosetting resin such as an epoxy resin or a metal has many holes in addition to the magnetic material and the binder. Due to the presence, even if the magnet surface is completely coated, oxidation cannot be prevented due to vacancies inside the magnet. It is also unavoidable that the magnetic material oxidizes through the coating and through the pores inside. As a result, the time-dependent change of the magnetic properties at room temperature and the time-dependent change of the magnetic properties at and above room temperature have a disadvantage that the heat resistance is inferior. Was an issue.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and aims to prevent the rare earth magnetic material from being oxidized as much as possible and to change the magnetic characteristics with time at room temperature and the magnetic characteristics at room temperature or higher. It is an object of the present invention to provide a rare-earth bonded magnet with little change and improved heat resistance.

[0008]

According to the present invention, there is provided a rare-earth bonded magnet material comprising, on the surface of a rare-earth magnetic powder, a resin containing a cyanate group together with an epoxy resin as a binder which is a thermosetting resin as a main component. It is characterized in that it is configured to be coated with an addition polymerization type thermosetting resin.

The rare earth bonded magnet according to the present invention has a surface coated with an epoxy resin as a thermosetting resin as a binder and a high heat-resistant addition polymerization type thermosetting resin mainly composed of a resin containing a cyanate group. It is characterized in that a rare earth magnetic powder is bonded by the binder.

Further, in the method for producing a rare earth bonded magnet according to the present invention, a binder is added to the rare earth magnetic powder,
Upon producing a rare earth bonded magnet by compression molding, the rare earth magnetic powder is a high heat resistant addition polymerization type thermosetting resin mainly containing a resin containing a cyanate group together with an epoxy resin as a binder which is a thermosetting resin. At the same time as or before or after the addition of the binder, it is characterized in that the surface of the rare earth magnetic powder is coated with the high heat-resistant addition polymerization type thermosetting resin and then compression-molded. A configuration in which an organic metal salt is added as a metal catalyst together with a highly heat-resistant addition polymerization type thermosetting resin mainly containing an epoxy resin as a binder and a resin containing a cyanate group, and in the same embodiment, curing of the thermosetting resin Process in vacuum for 15 minutes
It is characterized in that the structure is performed at 0 ° C. or higher.

In the present invention, as the rare earth magnetic powder, a magnetic powder containing a rare earth such as R-Fe, R-Fe-B or R-Fe-N is used.

As a resin to be coated on the surface of such a rare earth magnetic powder, a high heat resistant resin mainly composed of a resin containing a cyanate group having an unsaturated triple bond (—RO—C≡N) is used. A polymerizable thermosetting resin is used.

The rare-earth bonded magnet material according to the present invention is characterized in that a high heat-resistant addition polymerization mainly comprising the above-mentioned resin containing a cyanate group together with an epoxy resin as a binder which is a thermosetting resin is provided on the surface of the rare-earth magnetic powder. It is formed by coating a mold-curable resin. In the coating, a solution containing a high heat-resistant addition-polymerization-type thermosetting resin whose main component is a resin containing a cyanate group (for example, using methyl ethyl ketone or the like as a solvent) A) coating a rare earth magnetic powder by immersing it in a rare earth magnetic powder, adding a thermosetting resin containing a resin containing a cyanate group as a main component to the rare earth magnetic powder, or mixing a resin containing a cyanate group as a main component. A method of evaporating the thermosetting resin and coating the surface of the rare earth magnetic powder is employed.

The rare earth bonded magnet according to the present invention is a rare earth bonded magnet whose surface is coated with a high heat resistant addition polymerization type thermosetting resin mainly composed of the resin containing a cyanate group together with an epoxy resin as a binder which is a thermosetting resin. The magnetic powder is bonded with the binder. In this case, the binder is an epoxy resin, which is also a thermosetting resin, and is molded into a predetermined shape by a molding method such as compression molding (bonding). ) Is done.

After the molding, the curing treatment of the epoxy resin as the binder, which is a thermosetting resin, and the thermosetting resin containing a resin containing a cyanate group as a main component is performed at 150 ° C. or more in a non-acidic atmosphere or vacuum. It is better to do it. In this curing treatment, the thermosetting resin is cured, but among the thermosetting resins, the resin containing a cyanate group is cured by heating to form a triazine ring, and this triazine ring is exposed to heat energy. Since it is extremely stable, it has excellent heat resistance.

In order to coat a thermosetting resin having a resin containing a cyanate group as a main component more uniformly on the individual surfaces of the rare earth magnetic powder, if the curing treatment is performed at 150 ° C. or more in a vacuum, the cyanate group Once evaporates and deposits on the surface of the rare-earth magnetic powder, which hardens, and thus adheres more uniformly.

Further, in producing the rare earth bonded magnet in this manner, together with an epoxy resin as a binder and a high heat-resistant addition polymerization type thermosetting resin mainly composed of a resin containing a cyanate group, octylic acid is used as a metal catalyst. It is also desirable to add an organic metal salt such as zinc or iron acetylacetone, if necessary.By adding an organic metal salt as a metal catalyst, a heat mainly composed of a rare earth magnetic powder and a resin containing a cyanate group can be obtained. Since the adhesiveness with the curable resin is improved and a stronger heat-resistant coating film can be obtained, it is possible to further reduce the change over time in the magnetic properties.

[0018]

The rare earth bonded magnet material according to the present invention,
In the method for manufacturing a rare earth bonded magnet and a rare earth bonded magnet, a high heat resistant addition polymerization type thermosetting resin mainly containing a resin containing a cyanate group together with an epoxy resin as a binder which is a thermosetting resin is provided on the surface of the rare earth magnetic powder. The coating and the use of this coating make it possible to avoid or slow down the oxidation of the magnetic material. The heat resistance is further improved by making the change with time of the material small.

[0019]

EXAMPLES (Example 1) 28% by weight Nd-0.9% by weight B-5.0% by weight Co-
A rare earth magnet alloy melt containing Fe as the main component
Spray onto the surface of a copper roll rotating at m / sec.
After producing a ribbon having a thickness of 0 μm, the ribbon was pulverized to a size of 200 μm or less to obtain a rare earth magnetic powder. Next, the rare earth magnetic powder was annealed at 550 ° C. for 10 minutes.

Next, an epoxy resin as a binder, which is a thermosetting resin, is added to the rare earth magnetic powder after annealing in an amount of 2% by weight, and a heat-resistant addition polymerization type thermosetting resin mainly containing a resin containing a cyanate group is used as a main component. As a conductive resin, BT2000 manufactured by Mitsubishi Gas Chemical Co., Ltd. was added and mixed in an amount shown in Table 1. Further, in some cases, zinc octylate was added as an organometallic salt to the BT2000 in an amount of 0.000.
6% by weight was added.

Next, each of the mixed powders was weighed 10 mm ×
After compression molding to a height of 7 mm, a hardening treatment was performed at 170 ° C. for 1 hour in argon.

Further, each of the compression-molded articles was magnetized in a pulse magnetic field of 50 kOe, and the open flux value was measured. After heating at 180 ° C. for 1000 hours, the open flux value was measured again at room temperature. The rate of change of the value, ie, the irreversible demagnetization rate, was determined. Table 1 shows epoxy resins and resins containing cyanate groups (BT200
The measurement results of the addition amount of 0) and the irreversible demagnetization rate after 180 hours at 180 ° C. are shown.

[0023]

[Table 1]

As shown in Table 1, the surface of the rare earth magnetic powder was not coated with BT2000. In the case of No. 1, while the irreversible demagnetization rate after 180 ° C. × 1000 hours was considerably large, BT2000 coated with BT2000 as a resin containing a cyanate group was used. In the case of Nos. 2 to 8, it was recognized that the irreversible demagnetization rate was considerably reduced when the coating amount of BT2000 was increased to some extent. However, it was recognized that it is desirable to set the content to 2% by weight or less, because if the coating amount of BT2000 is too large, the magnetic properties deteriorate. It was also found that the irreversible demagnetization rate was smaller when the organic metal salt was added.

Example 2 28% by weight Nd-0.9% by weight B-5.0% by weight Co-
A rare earth magnet alloy melt containing Fe as the main component
Spray onto the surface of a copper roll rotating at m / sec.
After producing a ribbon having a thickness of 0 μm, the ribbon was pulverized to a size of 200 μm or less to obtain a rare earth magnetic powder. Next, the rare earth magnetic powder was annealed at 550 ° C. for 10 minutes.

Next, 2% by weight of an epoxy resin as a binder, which is a thermosetting resin, is added to the annealed rare earth magnetic powder, and the BT2000, which is a high heat-resistant addition polymerization type thermosetting resin containing a cyanate group, is further added. Was added and mixed in the amounts shown in Table 2. Further, in some cases, 0.0006% by weight of zinc octylate as an organic metal salt was added to the BT2000.

Next, each of the mixed powders was 10 mm in diameter ×
After compression molding to a size of 7 mm in height, a curing treatment was performed at 170 ° C. for 1 hour in a vacuum.

Further, each of the above-mentioned compression molded articles was magnetized in a pulse magnetic field of 50 kOe, and the open flux value was measured. After heating at 180 ° C. × 1000 hours, the open flux value was measured again at room temperature, and the open flux value was measured. The rate of change of the value, ie, the irreversible demagnetization rate, was determined. Table 2 shows the amounts of epoxy resin and BT2000 added and 180 ° C.
The measurement results of the irreversible demagnetization rate after × 1000 hours are shown.

[0029]

[Table 2]

As shown in Table 2, when the curing treatment is performed in a vacuum, the resin containing a cyanate group (BT2000) is uniformly coated on the individual surfaces of the magnetic powder. It was recognized that the irreversible demagnetization rate after × 1000 hours was further reduced, and the heat resistance of the magnet was further improved.

Example 3 A rare earth magnetic powder containing 31.0% by weight of Nd-1.0% by weight of B and the balance of Fe as a main component was prepared in the same manner as in Example 1, and then the rare earth after annealing was prepared. 2.0% by weight of an epoxy resin as a binder which is a thermosetting resin in the magnetic powder;
0.3% by weight of a high heat-resistant addition polymerization type thermosetting resin (BT2000) containing a resin containing a cyanate group as a main component was added and mixed. Further, in some parts, zinc octylate was added as an organometallic salt to the BT2000 by 0.0006.
% By weight.

Next, after compression-molding each mixed powder to a size of 10 mm in diameter × 7 mm in height, one part is in the air, another part is in argon, and another part is further. Was subjected to a curing treatment at 170 ° C. for 1 hour in a vacuum.

Further, each of the above-mentioned compression molded articles was magnetized in a pulse magnetic field of 50 kOe, and the open flux value was measured. After heating at 180 ° C. × 1000 hours, the open flux value was measured again at room temperature, and the open flux value was measured. The rate of change of the value, ie, the irreversible demagnetization rate, was determined. Table 3 shows these results.

[0034]

[Table 3]

As shown in Table 3, a resin containing a cyanate group (BT2000) and Conventional Example No. 17 to 19, the irreversible demagnetization rate after 180 ° C. × 1000 hours showed a large value.
Inventive Example No. 000 to which no organic metal salt was added.
Inventive Example No. 20 to which both BT2000 and BT2000 and an organic metal salt were added 180 ° C for 23-25
The irreversible demagnetization rate after 1000 hours is considerably small, and it is recognized that the irreversible demagnetization rate is the smallest when the curing treatment is performed in a vacuum, which is effective for further improving the heat resistance. It was also found that the irreversible demagnetization rate could be further reduced when an organic metal salt was added.

Example 4 An ingot having a component of Sm2Fe17 was heated at 1100 ° C.
, And then mechanically pulverized to 120 mesh or less, and the powder was heat-treated at 550 ° C. for 5 hours in an N 2 atmosphere to perform a nitriding treatment.

Next, the powder after nitriding is pulverized by a jet mill to an average particle size of 3 μm to obtain a fine rare earth magnetic powder, and then an epoxy resin as a binder which is a thermosetting resin is added to the rare earth magnetic powder. 2% by weight, and 0.3% by weight of BT2000 as a high heat-resistant addition polymerization type thermosetting resin containing a cyanate group.
0.0015% by weight was added to T2000.

Next, each of the mixed powders was subjected to a vertical magnetic field molding in a magnetic field of 15 kOe to obtain a molded body having a diameter of 10 mm and a height of 7 mm. At 170 ° C. for 1 hour.

Subsequently, in the same manner as in Example 1, 180 ° C. ×
The irreversible demagnetization rate after 1000 hours was measured.
The results are shown in FIG.

The typical magnetic characteristics of this rare earth magnet are Br-8.0 kG, iHc = 8.5 kOe, (B
H) max = 11.8 MGOe.

[0041]

[Table 4]

As shown in Table 4, BT2000 and Conventional Example No. 180 ℃ at 26
Although the irreversible demagnetization rate after 1000 hours showed a large value, BT2000 was added and the inventive example No. Inventive Example Nos. 27 and 28 and BT2000 and an organometallic salt were both added. 29,
In the case of No. 30, the irreversible demagnetization rate after 180 ° C. × 1000 hours is considerably small, and the irreversible demagnetization rate becomes smaller when the curing treatment is performed in a vacuum, further improving the heat resistance. Is found to be effective,
It was recognized that the irreversible demagnetization rate could be further reduced when an organic metal salt was added.

[0043]

The rare earth bonded magnet material according to the present invention,
According to the rare-earth bonded magnet and the method of manufacturing the rare-earth bonded magnet, the oxidation of the rare-earth magnetic material, which is liable to be remarkably oxidized, is further prevented. A remarkably excellent effect is obtained in that the change in characteristics with time is small and a rare earth bonded magnet with improved heat resistance can be provided.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 1/06 H01F 1/08 H01F 41/02

Claims (5)

(57) [Claims] 1. A method for coating a surface of a rare earth magnetic powder with a heat-resistant addition polymerization type thermosetting resin mainly composed of a resin containing a cyanate group together with an epoxy resin as a binder which is a thermosetting resin. Rare earth bonded magnet material. 2. A rare earth magnetic powder having a surface coated with a high heat-resistant addition polymerization type thermosetting resin containing a resin containing a cyanate group as a main component together with an epoxy resin as a binder which is a thermosetting resin, is bound by the binder. Rare earth bonded magnet characterized by the following. 3. A binder is added to the rare earth magnetic powder,
Upon producing a rare earth bonded magnet by compression molding, the rare earth magnetic powder is a high heat resistant addition polymerization type thermosetting resin mainly containing a resin containing a cyanate group together with an epoxy resin as a binder which is a thermosetting resin. A method for producing a rare earth bonded magnet, characterized in that the binder is added simultaneously with or before or after the addition of the binder, and the surface of the rare earth magnetic powder is coated with the high heat resistant addition polymerization type thermosetting resin and then compression molded. 4. The method according to claim 3, wherein an organic metal salt is added as a metal catalyst together with a high heat-resistant addition polymerization type thermosetting resin mainly composed of an epoxy resin as a binder and a resin containing a cyanate group. Of manufacturing rare earth bonded magnets. 5. The method for producing a rare-earth bonded magnet according to claim 3, wherein the curing treatment of the thermosetting resin is performed in a vacuum at 150 ° C. or higher.