JP3080275B2 - R-Fe-Co-Al-Nb-Ga-B sintered magnet excellent in corrosion resistance and heat resistance and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an R-Fe-Co-Al-Nb-Ga-B sintered magnet excellent in corrosion resistance, heat resistance and heat treatment and a method for producing the same.

[0002]

2. Description of the Related Art Nd-Fe-B sintered magnets and Nd-F
The e-Co-B based sintered magnet is SmCo₅Type sintered magnet or
Is Sm₂Co₁₇Highest energy compared to sintered type magnets
Energy (BH) max, so it can be used for various purposes.
It is supposed to be. However, Nd-Fe-B
Based magnets and Nd-Fe-Co-B based sintered magnets
Thermal stability is inferior to these Sm-Co based sintered magnets.
Various attempts have been proposed to increase the thermal stability.
You. JP-A-64-7503 discloses that heat stability is good.
The general formula: R (Fe_1-xy-x-zCo_xB_yGa_z)_A  (Where R is at least one selected from rare earth elements)
Yes, 0 ≦ x ≦ 0.7, 0.02 ≦ y ≦ 0.3, 0.0
01 ≦ z ≦ 0.15, 4.0 ≦ A ≦ 7.5), and
And R (Fe_1-xyzCo_xB_yGa_zM_u)_A  (Where R is at least one selected from rare earth elements)
And M is 1 selected from Nb, W, V, Ta and Mo
Species or two or more elements, 0 ≦ x ≦ 0.7, 0.
02 ≦ y ≦ 0.3, 0.001 ≦ z ≦ 0.15, u ≦
0.1, 4.0 ≦ A ≦ 7.5)
Is disclosed.

[0003]

However, it has high corrosion resistance, high heat resistance and good heat treatment, and at the same time has a high level of coercive force iHc and maximum energy product (BH) max.
In the case of stably producing an Nd-Fe-Co-B-based anisotropic sintered magnet having both of the above, limitation of the component composition range based on more detailed research and examination beyond the above-mentioned known technology, It was found that it was necessary to limit oxides and the like. The present invention is based on such knowledge, and particularly, is R-Fe-Co-Al-Nb-Ga-B having excellent corrosion resistance, heat resistance, and heat treatment properties.
The present invention provides a sintered sintered magnet. The present invention relates to Co, D
By effectively utilizing y and Nb, the corrosion resistance is remarkably enhanced, the Dy content and the Ga content are set in a specific range to provide high heat resistance, and the balance between the Co content and the Al content is further improved. By increasing the allowable temperature range of the secondary heat treatment, simultaneously reducing the amount of rare earth R and limiting the amount of oxygen, R-Fe-C having a large iHc and (BH) max
An object of the present invention is to provide an o-Al-Nb-Ga-B based sintered magnet and a method for manufacturing the same.

[0004]

According to the present invention, as a main component, 28 to 32 wt% of R (R is substantially composed of Nd and Dy or Nd, Dy and Pr, and 3 to 8 wt% of R is contained) Dy) 5 wt% or less of Co (not including 0),
0.1-1 wt% Al, 0.5-2 wt% B, 0.
1-2 wt% Nb, 0.05-1 wt% Ga, balance Fe, and 1000-600 as inevitable impurity components.
R-Fe-Co-Al- containing 0 ppm of oxygen
The Nb-Ga-B-based sintered body has a temperature of 800 to 1000C x 0.
Primary heat treatment for 2 to 5 hours, 540 to 640 ° C. × 0.
By sequentially performing a second heat treatment for 2-3 hours,
Corrosion resistance that gives a coercive force (iHc) of kOe or more and a maximum energy product ((BH) max) of 30 MGOe or more;
R-Fe-Co-Al-Nb with excellent heat resistance and heat treatment
This is a method for producing a Ga-B based sintered magnet. In the present invention, R is 28 to 32 wt% as a main component (substantially, R is composed of Nd and Dy or Nd, Dy and Pr, and 3 wt% or more and less than 5 wt% of R is Dy), 5 wt% %
The following Co (not including 0), 0.1 to 1 wt% Al,
0.5-2 wt% B, 0.1-2 wt% Nb, 0.
Containing 0.5 to 1 wt% of Ga, the balance of Fe, and 1000 to 6000 ppm of oxygen as an unavoidable impurity component, and having a coercive force (iHc) of 20 kOe or more and 3
Maximum energy product of 5MGOe or more ((BH) max))
R-Fe with excellent corrosion resistance, heat resistance and heat treatment properties
-Co-Al-Nb-Ga-B based sintered magnet. In the present invention, the main component is R of 28 to 32 wt% (R is substantially composed of Nd and Dy or Nd, Dy and Pr,
5 to 8 wt% of R is Dy), 5 wt% or less of Co (not including 0), 0.1 to 1 wt% of Al, 0.5
~ 2 wt% B, 0.1 ~ 2 wt% Nb, 0.05 ~
It contains 1 wt% of Ga, the balance Fe, and 1000 to 6000 ppm of oxygen as an unavoidable impurity component, and has a coercive force (iHc) of 25 kOe or more and 30M
R-Fe-Co having a maximum energy product ((BH) max) equal to or higher than GOe and excellent in corrosion resistance, heat resistance and heat treatment properties
-Al-Nb-Ga-B based sintered magnet. The reason for limiting the composition of the sintered magnet of the present invention will be described in detail below.

[0005] In the present invention, R is contained in the range of 28 to 32 wt%. As will be described later in Examples, the smaller the R content is at 32 wt% or less, the more effective it is to improve (BH) max and corrosion resistance. However, when the content is less than 28 wt%, α-Fe is easily generated in the ingot, and it is difficult to expect an increase in (BH) max. Therefore, the R amount is set to 28 to 32 wt%. Since R is mainly composed of Nd, 50 of the R components are used.
At% or more of Nd is contained. 3 in R
Contains ~ 8 wt% Dy. The inclusion of Pr is effective in improving iHc.

By including Dy as the R component, the Curie point Tc increases and the anisotropic magnetic field (H
_A ) is increased, iHc is improved, and heat resistance is significantly improved. Dy is also effective in improving corrosion resistance. In the present invention, if the content of Dy is less than 3 wt%, the object of the present invention of improving thermal stability and corrosion resistance cannot be achieved. However, if the content is more than 8 wt%,
The residual magnetic flux density Br and the maximum energy product (BH) max are significantly reduced. Therefore, the content of Dy is 3 to 8 wt.
%. When the Dy content is 5 to 8 wt%, Br and (BH) max are reduced, but i of 25 kOe or more is obtained.
Hc can be obtained. Therefore, in order to obtain higher coercive force characteristics, the Dy content is set to 5 to 8 wt%. Conversely, in order to obtain higher Br and (BH) max, the content of Dy may be set to 3 wt% or more and less than 5 wt%.

[0007] In the present invention, Co has the effect of improving the corrosion resistance of the magnet alloy itself without substantially reducing Br, and improving the corrosion resistance by improving the adhesion of Ni plating, which is a corrosion-resistant coating. Further, there is also an effect of increasing the Curie point Tc by replacing Fe in the main phase (Nd ₂ Fe ₁₄ B) with Co. However, when the substitution amount of Co is increased, coarse crystal grains are generated due to abnormal grain growth during sintering, and the squareness of iHc and hysteresis curve is reduced. Therefore, the Co content is set to 5 wt% or less (excluding 0).

In the present invention, Al is the second of the Co additives.
This has the effect of relaxing the allowable temperature conditions for the subsequent heat treatment. That is, the Nd-Fe-Co-B based sintered magnet material containing Co has large fluctuations in magnetic properties and thermal stability with respect to fluctuations in the second heat treatment temperature. When an appropriate amount of Al is added thereto, the magnetic properties and thermal stability do not change even if the temperature conditions of the second heat treatment slightly change. As a result, the production management of the permanent magnet is facilitated, and the permanent magnet with stable quality can be efficiently produced. Al content is 0.1wt
%, The above effect is insufficient. On the other hand, 1wt%
Is exceeded, the decrease of Br becomes remarkable. Therefore, Al
Is 0.1 to 1% by weight. B content is 0.5
If it is less than 2 wt%, a high coercive force cannot be obtained.
If it exceeds t%, the B-rich nonmagnetic phase increases and Br decreases. Therefore, the B content is set to 0.5 to 2 wt%. A more preferable B content is 0.8 to 1.2 wt%.

Ga has the effect of significantly improving iHc. If the Ga content is less than 0.05 wt%, the effect of improving iHc is not sufficient, and if it exceeds 1 wt%, Br is reduced and a high maximum energy product cannot be obtained. Therefore, G
The content of a is 0.05 to 1 wt%. If the Ga content is large, the squareness of the hysteresis curve is deteriorated. Therefore, a more preferable Ga content for imparting high squareness is 0.1.
Between 0.5 and 0.8 wt%. The content of Ga is more preferably 0.1 to 0.6 wt%, particularly preferably 0.1 to 0.6 wt%.
０．４0.4 wt%.

[0010] In addition to the above components, the permanent magnet of the present invention contains 0.1%
Contains 1-2 wt% Nb. Nb has the effect of suppressing the crystal grains from becoming coarse during sintering. With this effect, iHc is improved, and the squareness of the hysteresis curve is improved. Further, the fine crystal grains of the sintered body greatly contribute to good magnetism, and further provide excellent heat resistance. Therefore, Nb is an effective additive for heat resistance. When the content of Nb is less than 0.1 wt%, the effect of suppressing coarse grains is insufficient, and when it exceeds 2 wt%, a large amount of Nb or Nb-Fe nonmagnetic boride is generated, and Br and Curie are generated. The point Tc drops significantly. Therefore, the content of Nb is set to 0.1 to 2 wt%. More preferably, it is 0.1 to 1 wt%.

The oxygen content is 1000-6000 ppm
And If the amount of oxygen is less than 1000 ppm, it is difficult to produce in industrial production. On the other hand, if it is more than 6000 ppm, the amount of oxygen that reacts with the rare-earth R component to form a rare-earth oxide increases, making it difficult to obtain a magnet having a high coercive force and a high maximum energy product.

The sintered magnet of the present invention can be manufactured, for example, as follows. That is, an ingot having a fixed component composition is produced by vacuum melting, and then the ingot is roughly pulverized to obtain a coarse powder having a particle size of about 500 μm. This coarse powder was finely pulverized in an inert gas atmosphere using a jet mill to have an average particle size of 3.0 to 6.0 μm (FSS
S. ). Next, this fine powder is subjected to an orientation magnetic field of 15 kO.
e. After press molding in a magnetic field under the condition of a molding pressure of 1.5 ton / cm ² , sintering is performed in a temperature range of 1000 to 1150 ° C. The heat treatment after sintering can be performed as follows. After sintering, the compact is once cooled to room temperature. The cooling rate after sintering hardly affects the coercive force iHc of the final product. Then, it is heated to a temperature of 800 to 1000C,
Hold for 0.2-5 hours. This is the first heat treatment.
If the heating temperature is lower than 800 ° C. or higher than 1000 ° C., a sufficiently high coercive force cannot be obtained. After heating and holding.
Cool at room temperature to 600 ° C. at a cooling rate of 3-50 ° C./min. If the cooling rate exceeds 50 ° C / min,
An equilibrium phase necessary for aging cannot be obtained, and a sufficiently high coercive force cannot be obtained. On the other hand, a cooling rate of less than 0.3 ° C./minute requires time for heat treatment, and is not economical for industrial production. More preferably, a cooling rate of 0.6 to 2.0 ° C / min is selected. Although the cooling end temperature is desirably room temperature, it may be up to 600 ° C. if iHc is somewhat sacrificed, and may be rapidly cooled below that temperature. More preferably, it is cooled to a temperature from room temperature to 400 ° C. Heat treatment is further performed at a temperature of 540 to 640 ° C. for 0.2 to 3
Do time. This is a second heat treatment. Heat treatment temperature is 5
When the temperature is lower than 40 ° C. or higher than 640 ° C., the irreversible demagnetization rate is remarkably reduced even if a high coercive force is obtained. After the heat treatment, cooling is performed at a cooling rate of 0.3 to 400 ° C./min, as in the first heat treatment. Cooling can be performed in water, in silicon oil, in a stream of argon, or the like. When the cooling rate exceeds 400 ° C./min, the magnet is cracked by rapid cooling, and an industrially valuable permanent magnet material cannot be obtained. 0.3 ° C
If it is less than / min, an unfavorable phase appears in iHc during the cooling process.

[0013]

The present invention will be described in more detail with reference to the following examples. (Reference Example 1) Metal Nd, metal Dy, Fe, Co, ferro-B, f
Erro-Nb and metal Ga were weighed to a predetermined weight, and were melted in vacuum to produce an ingot weighing 10 kg. The composition of this ingot was as follows by weight. Nd27.5-Dy3.6-B1.03-Nb0.58-Ga0.18-C
o2.02-Al0.35-Febal. (wt%) After crushing this ingot with a hammer, it was further coarsely crushed in an inert gas atmosphere using a coarse crusher to obtain a particle size of 500.
A coarse powder having a size of μm or less was obtained. The coarse powder is similarly pulverized in an inert gas atmosphere using a jet mill to obtain an average particle size of 4.0.
A fine powder having a μm (FSSS) and an oxygen content of 5500 ppm was obtained. Next, using this fine powder, the orientation magnetic field strength is 15 kOe,
Molding in a magnetic field under conditions of molding pressure 1.5 ton / cm ² ,
A 30 × 20 × 15 compact was produced. This molded body is sintered at 1080 ° C. for 3 hours under substantially vacuum conditions,
The obtained sintered body was subjected to a first heat treatment at 900 ° C. × 2 hr, and then to a second heat treatment at 530 ° C. × 2 hr. The density of the obtained sintered body was 7.55 g / cc, and the oxygen content was 4800 ppm. When the room-temperature magnetic properties of the obtained sintered magnet were measured, the following values were obtained. Br = 12.6 kG bHc = 11.6 kOe iHc = 21.8 kOe (BH) max = 35.6 MGOe Further, the Curie point Tc is 120 from 340 ° C. and 23 ° C.
° C as temperature coefficients α and β of Br and iHc, respectively.
A value of 0, -0.52% / ° C was obtained. Further, the irreversible demagnetization rates at 100 ° C. of the samples having the permeance coefficients Pc = 1.0 and 2.0 are 2.1 and 1.1%, respectively, and have excellent heat resistance.

Reference Example 2 The following experimental results were obtained in the same manner as in Example 1 except that the alloy composition and the sintering conditions were changed. Composition: Nd25.5-Dy6.4-B1.04-Nb0.55-Ga0.22-Co2.00-Al0.36-Febal. (Wt%) Sintering: 1100 ° C x 2hr Primary heat treatment: 900 ° C × 2 hr Secondary heat treatment: 530 ° C. × 2 hr Room temperature magnetic properties: Br = 11.4 kG bHc = 11.0 kOe iHc = 27.8 kOe (BH) max = 31.3 MGOe Curie point: Tc = 340 ° C. Irreversible demagnetization rate 100 ° C.]: Pc = 1.0 → 1.8% Pc = 2.0 → 0.8% Br temperature coefficient (α), iHc temperature coefficient (β) [23 ° C. to 120 ° C.]: α = −0. 09% / ° C. β = −0.51% / ° C. Oxygen content in the sintered body: 5800 ppm As in Example 1, a magnet having excellent high-temperature properties as well as ordinary-temperature magnetic properties and excellent heat resistance can be obtained.

Reference Example 3 The following experimental results were obtained in the same manner as in Examples 1 and 2, except that didymium metal (Nd 70 wt% -Pr 30 wt%) was used and the alloy composition, sintering conditions, and secondary heat treatment conditions were changed. I got Composition: Nd18.9-Pr5.1-Dy7.3-B1.10-Nb0.71-Ga0.37-Co4.72-Al0.33-Febal. (Wt%) Sintering: 1080 [deg.] C. × 2 hr Primary Heat treatment: 900 ° C. × 2 hr Secondary heat treatment: 520 ° C. × 2 hr Room temperature magnetic properties: Br = 11.5 kG bHc = 10.9 kOe iHc = 30.0 kOe (BH) max = 31.2 MGOe Curie point: Tc = 375 ° C. Irreversible Demagnetization rate [at 100 ° C.]: Pc = 1.0 → 1.4% Pc = 2.0 → 0.5% Br temperature coefficient (α), iHc temperature coefficient (β) [23 ° C. to 120 ° C.]: α = −0.09% / ° C. β = −0.48% / ° C. Oxygen content in sintered body: 5400 ppm Even when using dizyme metal, it is excellent in normal temperature magnetic properties, high temperature properties and heat resistance as in Examples 1 and 2. Can be obtained.

(Example 1) Metal Nd, metal Dy, Fe, Co, ferro-B, f
Erro-Nb and metal Ga were weighed to a predetermined weight, and were melted in vacuum to produce an ingot having a weight of 10 kg.
The composition of this ingot was as follows by weight. Nda-Dyb-B1.05-Nb0.58-Ga0.20-Co0.20-Al0.33-Febal. (A + b = TRE, b = 3.7) (wt%) Each ingot was crushed with a hammer. Thereafter, coarse pulverization is further performed in an inert gas atmosphere using a coarse pulverizer to obtain a particle size of 50.
A coarse powder of 0 μm or less was obtained. This coarse powder is similarly pulverized in an inert gas atmosphere using a jet mill to obtain an average particle size of 3.
7μm (FSSS), oxygen content 1500-5000pp
m of fine powder was obtained. Next, this fine powder was molded in a magnetic field under the conditions of an orientation magnetic field strength of 15 kOe and a molding pressure of 1.5 ton / cm ² to produce a 30 × 20 × 15 compact.
This molded body is 1070 ° C. × 2 hours under a substantially vacuum condition.
Was sintered, and the obtained sintered body was subjected to a first heat treatment at 900 ° C. × 2 hr and a second heat treatment at 540 ° C. × 2 hr. The density of the obtained sintered body is 7.55 to 7.58 g.
/ Cc, and the oxygen content was 1000 to 4000 ppm. With respect to the obtained sintered magnet, how the (BH) max and the corrosion weight loss change with respect to the TRE content was measured, and the results as shown in FIG. 1 were obtained. The corrosion weight loss was obtained when the magnet was exposed to an environment at a temperature of 120 ° C., a humidity of 90%, and a pressure of 1.0 atm for 100 hours.
(BH) max can be improved by reducing the amount of TRE as shown in FIG.
If it is less than this, α-Fe is likely to be generated in the ingot, and it is difficult to expect an increase in (BH) max. Corrosion weight loss can also be reduced by reducing the amount of TRE. This is because the Nd-rich phase which is susceptible to corrosion is reduced by reducing the TRE. However, even when the TRE content is as low as 28 to 32 wt%, if the oxygen content exceeds 6000 ppm, iHc
The amount of oxygen is 1000 to 6000
ppm. FIG. 2 shows the relationship between the oxygen content in the sintered magnet according to the present invention and the magnetic properties.

Example 2 Metal Nd, metal Dy, Fe, Co, ferro-B, f
Erro-Nb and metal Ga were weighed to a predetermined weight, and were melted in vacuum to produce an ingot having a weight of 10 kg.
The composition of this ingot was as follows by weight. Nd30.5-a-Dya-B1.03-Nb0.59-Gab-Co2.10-Al0.34-Febal. (2.8≤a≤8.5, 0≤b≤1.2) (wt%) Each ingot was hammered. And then coarsely crushed in an inert gas atmosphere using a coarse crusher to obtain a particle size of 50.
A coarse powder of 0 μm or less was obtained. This coarse powder is similarly pulverized in an inert gas atmosphere using a jet mill to obtain an average particle size of 3.
8 μm (FSSS), oxygen content 5500-6400pp
m of fine powder was obtained. Next, this fine powder was molded in a magnetic field under the conditions of an orientation magnetic field strength of 15 kOe and a molding pressure of 1.5 ton / cm ² to produce a 30 × 20 × 15 compact. This molded body was sintered at 1100 ° C. × 2 hr under substantially vacuum conditions, and the obtained sintered body was subjected to the first sintering at 900 ° C. × 2 hr.
A second heat treatment was performed, followed by a second heat treatment at 580 ° C. × 2 hr. The density of the obtained sintered body is 7.55 to 7.59 g /
cc and the content of oxygen were 5000 to 5900 ppm. The room-temperature magnetic properties of the obtained sintered magnet were measured, and the results as shown in FIGS. 3, 4, and 5 were obtained. FIG.
Is a measurement result in the case of Dy = 5.0 wt%, and when the Ga content is less than 0.05 wt%, the effect is hardly exhibited,
Even if it exceeds 1.0 wt%, the decrease of (BH) max becomes remarkable, so that 0.05 to 1.0 wt% is an appropriate amount. Ga is D
Compared with y, the effect of improving the coercive force iHc without significantly lowering (BH) max is large. FIG. 4 shows the result of changing the Dy content with the Ga content being 0.20 wt%. Although the content of Dy greatly contributes to the improvement of iHc, on the other hand, (BH) max is remarkably reduced, so that the content is appropriately 3.0 to 8.0 wt%. FIG. 5 shows the results when the Ga content was changed from 0 to 0.6 wt% using the Dy content as a parameter, and the Dy content was 8.0.
If it exceeds wt%, (BH) max is significantly reduced. When the Dy content is less than 3.0 wt%, the content of 20 kO
It is difficult to obtain a high coercive force exceeding e.

Reference Example 4 Didymium metal (Nd 70 wt% -Pr 30 wt%), metal Dy, Fe, Co, ferro-B, ferro-N
b, a predetermined weight of metal Ga was weighed and melted in vacuum to produce an ingot weighing 10 kg each. The composition of this ingot was as follows by weight. (Nd + Pr) 28.1-Dy3.6-B1.03-Nb0.58-G
ab-Co2.05-Al0.35-Febal. (0 ≦ b ≦ 0.6)
(Wt%) After each ingot was crushed with a hammer, coarse crushing was further performed in an inert gas atmosphere using a coarse crusher to obtain a particle size of 50%.
A coarse powder of 0 μm or less was obtained. This coarse powder is similarly pulverized in an inert gas atmosphere using a jet mill to obtain an average particle size of 3.
A fine powder having a thickness of 7 μm (FSSS) and an oxygen content of 5600 ppm was obtained. Next, an orientation magnetic field strength of 15 kO
(e) Molding was performed in a magnetic field under the conditions of a molding pressure of 1.5 ton / cm ² to produce a molded body of 30 × 20 × 15. This molded body is sintered at 1080 ° C. × 2.5 hr under substantially vacuum conditions, and the obtained sintered body is subjected to a first heat treatment at 890 ° C. × 2 hr and then to a second heat treatment at 530 ° C. × 2 hr. Was given. The density of the obtained sintered body is 7.55 to 7.58 g / c.
c and the oxygen content was 2800 ppm. The room-temperature magnetic properties of the obtained sintered magnet were measured, and the results shown in FIG. 6 were obtained. As shown in FIG. 6, the inclusion of Ga improves iHc and Hk, which is a measure of the squareness of the hysteresis loop.
The content of not less than wt% is essential. However, if Ga exceeds 0.4 wt%, Hk decreases and the squareness of the hysteresis loop decreases, so the upper limit is 1.0 wt%, more preferably 0.8 wt%, and still more preferably 0.1 wt%.
6 wt%, particularly preferably 0.4 wt%.

Reference Example 5 Didymium metal (Nd 70 wt% -Pr 30 wt%), metal Dy, Fe, Co, ferro-B, ferro-N
b, a predetermined weight of metal Ga was weighed and melted in vacuum to produce an ingot weighing 10 kg each. The composition of this ingot was as follows by weight. (Nd + Pr) 28.0-Dy4.0-B1.03-Nbx-Ga0.
15-Co2.04-Al0.35-Febal. (0 ≦ x ≦ 1.0)
(Wt%) After each ingot was crushed with a hammer, coarse crushing was further performed in an inert gas atmosphere using a coarse crusher to obtain a particle size of 50%.
A coarse powder of 0 μm or less was obtained. This coarse powder is similarly pulverized in an inert gas atmosphere using a jet mill to obtain an average particle size of 3.
A fine powder having a thickness of 8 μm (FSSS) and an oxygen content of 4900 ppm was obtained. Next, an orientation magnetic field strength of 15 kO
(e) Molding was performed in a magnetic field under the conditions of a molding pressure of 1.5 ton / cm ² to produce a molded body of 30 × 20 × 15. This compact was sintered at 1080 ° C. for 3 hours under substantially vacuum conditions, and the obtained sintered body was subjected to a first heat treatment at 900 ° C. for 2 hours and then a second heat treatment at 530 ° C. for 2 hours. did.
The density of the obtained sintered body is 7.55 to 7.58 g / cc,
The oxygen content was 4,400 ppm. With respect to the obtained sintered magnet, the room-temperature magnetic properties and the average crystal grain size were measured, and the results shown in FIG. 7 were obtained. As shown in FIG. 7, the crystal grain growth during sintering can be suppressed by containing Nb. Also, iHc can be improved by this effect. However, when the Nb content exceeds 2.0 wt% (B
H) 0.1 to 2.0 wt% because the decrease in max becomes large
Is suitable.

Example 3 Metal Nd, metal Dy, Fe, Co, ferro-B, f
Erro-Nb and metal Ga were weighed to a predetermined weight, and were melted in vacuum to produce an ingot weighing 10 kg. The composition of this ingot was as follows by weight. Nd27.5-Dy4.0-B1.04-Nb0.59-Ga0.19-Coa-Alb-Febal. A = 0 b = 0 a = 2.02 b = 0 a = 2.10 b = 0.34 (wt%) After crushing the ingot with a hammer, the material is further coarsely crushed in an inert gas atmosphere using a coarse crusher to obtain a particle size of 500.
A coarse powder having a size of μm or less was obtained. This coarse powder is similarly pulverized in an inert gas atmosphere using a jet mill to obtain an average particle size of 3.8.
μm (FSSS), oxygen content 6000-6400ppm
Was obtained. Next, an orientation magnetic field intensity of 1
Molding was performed in a magnetic field under the conditions of 5 kOe and a molding pressure of 1.5 ton / cm ² to produce a 30 × 20 × 15 molded body. The molded body is sintered at 1100 ° C. × 2 hr under substantially vacuum conditions, and the obtained sintered body is subjected to a first heat treatment at 900 ° C. × 2 hr, and then to a second heat treatment at 500 to 600 ° C. × 2 hr. Was given. The density of the obtained sintered body is 7.56 to 7.5.
9g / cc, oxygen content is 5400-5900pp
m. The room-temperature magnetic characteristics of the obtained sintered magnet were measured, and the results as shown in FIG. 8 were obtained. As shown in FIG. 8, the (Co-added) type (Co and Al
The temperature dependence of the second heat treatment on iHc is very large as compared with the case of (no addition). That is, FIG.
In (1), (Co added) is (Co and Al free) over the entire range of the evaluated secondary heat treatment temperature.
It can be seen that the obtained iHc is small and the iHc variation is very large as compared with the case of the above. In this case, R having stable and small variation and high iHc in industrial production
-It is difficult to obtain an Fe-Co-B based anisotropic sintered magnet. On the other hand, in the case of (Co and Al addition), as shown in FIG. 8, the dependence of the second heat treatment on temperature can be reduced, and this problem can be avoided. In particular, under the condition that the second heat treatment temperature is 540 ° C. or higher, i of almost (Co added)
It can be seen that a high iHc higher than that of Hc (without addition of Co and Al) is obtained and the iHc variation is small. In the present invention, excellent heat treatment means that a material having a higher iHc and a smaller variation in iHc than that obtained with (Co added) can be obtained, as exemplified in (Co and Al added) in FIG. This means that the second heat treatment temperature has a wide allowable temperature range of 540 to 640 ° C. Next, (Co and Al
Ni plating was applied to each sintered magnet having the composition of (no addition), (Co addition), (Co and Al addition), and the adhesion was evaluated. Ni plating was performed to a film thickness of 10 μm by electrolytic plating using a Watts bath. Wash with water after plating 1
After drying at 00 ° C. for 5 minutes, a plating adhesion test was performed. The results are as follows, and the magnet () of the present invention has excellent plating adhesion. Material Adhesion strength (Kgf / cm ² ) (Co and Al not added) 180 (Co added) 680 (Co and Al added) 700

[0021]

According to the present invention, R-Fe-Co-Al is obtained which has a high iHc and a high (BH) max stably as compared with the prior art, and is excellent in heat resistance, corrosion resistance and heat treatment.
The present invention can provide an —Nb—Ga—B based anisotropic sintered magnet and a method for manufacturing the same, and is extremely practical.

[Brief description of the drawings]

FIG. 1 shows (BH) ma with respect to the total rare earth content according to the present invention.
It is a figure which shows an example of the correlation of x and corrosion weight loss.

FIG. 2 shows (BH) ma with respect to oxygen content according to the present invention.
It is a figure showing an example of correlation of x and iHc.

FIG. 3 shows a Ga content (0 to 1.2 wt.) According to the present invention.
(%) With respect to (BH) max and iHc.

FIG. 4 shows the relationship between (BH) ma and Dy content according to the present invention.
It is a figure which shows an example of the correlation of x, iHc, and corrosion weight loss.

FIG. 5 shows a Ga content (0 to 0.6 wt.) According to the present invention.
FIG. 7 is a diagram showing another example of the correlation between (BH) max and iHc with respect to the content (%) and the Dy content.

FIG. 6 shows a Ga content (0 to 0.6 wt.) According to the present invention.
FIG. 11 is a diagram showing still another example of the correlation of (BH) max and iHc with respect to (%) and an example of the correlation of squareness (Hk).

FIG. 7 is a diagram showing an example of a correlation between the average crystal grain size of a sintered body and (BH) max with respect to the Nb content according to the present invention.

FIG. 8 is a diagram showing an example of a state of relaxation of the second heat treatment temperature dependency by adding Co and Al to iHc according to the present invention.

Claims (3)

(57) [Claims] (1) As a main component, 28 to 32 wt% of R ( actual
Qualitatively, R consists of Nd and Dy or Nd, Dy and Pr.
Ri, 3~8wt% of R is Dy), not including the following Co (0 5wt%), 0.1~1wt % of Al,
0.5-2 wt% B, 0.1-2 wt% Nb, 0.
0.5 to 1 wt% of Ga, balance Fe, and unavoidable impurities
Contain oxygen 1000~6000ppm as component
R-Fe-Co-Al-Nb-Ga-B based sintered body
First heat treatment at 800-1000 ° C. × 0.2-5 hours
And a second heat treatment at 540-640 ° C. × 0.2-3 hours.
The coercive force (i) of 20 kOe or more
Hc) and the maximum energy product of 30 MGOe or more ((B
H) max) and R-Fe-Co-Al-Nb-G having excellent corrosion resistance, heat resistance and heat treatment properties.
A method for producing an a-B based sintered magnet. 2. The method according to claim 1, wherein the main component is 28 to 32 wt% of R (actual
Qualitatively, R consists of Nd and Dy or Nd, Dy and Pr.
In addition, 3 wt% or more and less than 5 wt% of R is Dy.
5% by weight or less of Co (not including 0), 0.1 to 1
wt% Al, 0.5-2 wt% B, 0.1-2 wt%
% Nb, 0.05-1 wt% Ga, balance Fe 2,
1000-6000ppm as unavoidable impurity components
And containing more than 20kOe of coercivity
Force (iHc) and maximum energy product of 35MGOe or more
((BH) max))
-Fe-Co-Al- with excellent heat resistance, heat resistance and heat treatment
Nb-Ga-B based sintered magnet. 3. The method according to claim 1, wherein the main component is 28 to 32 wt% of R (actual
Qualitatively, R consists of Nd and Dy or Nd, Dy and Pr.
5 to 8 wt% of R is Dy).
Lower Co (not including 0), 0.1-1 wt% Al,
0.5-2 wt% B, 0.1-2 wt% Nb, 0.
0.5 to 1 wt% Ga, balance Fe 2, and inevitable impurities
Containing 1000-6000 ppm of oxygen as a material component
And a coercive force (iHc) of 25 kOe or more
30MGOe or more of the maximum energy product ((BH) max)
Corrosion resistance, heat resistance, heat treatment characteristics characterized by having
Excellent R-Fe-Co-Al-Nb-Ga-B based sintering
magnet.