JPH07107882B2 - permanent magnet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to improvement of magnetic properties of rare earth magnet materials, particularly permanent magnet alloys containing rare earth elements (hereinafter abbreviated as R), iron and boron as main components. .

[Conventional technology]

The R-Fe-B system permanent magnet material is under development as a new composition system that can obtain higher magnetic properties than the R-Co system permanent magnet material (Japanese Patent Laid-Open Nos. 59-46008, 59-64733 and 59-). 894
No. 0, M. Sggawa et al, J. Appl. Phys. 55 (6) 2083 (198)
4) “New Moterial for Permanent Magnets on a Base
of Nd and Fe "). According to this, for example Nd ₁₅ fe ₇₅ B
₁₀ [Nd (Fe _0.88 B _0.12 ) _5.7 ] alloy (BH) max ~ 35
MGOe, the magnetic properties of the _I H _{C ~10KOe} is obtained.

Also, an alloy Nd _0.85 Dy _0.15 (Fe
_0.88 B _0.12 ) _5.7 , (BH) max ~ 30MGOe, _I H _O ~ 20
The magnetic characteristics of KOe are obtained. (M. Sagawa et al, IEEE
MAG-20,1584 (1984) “Permanent Magnet Materials
Based on the Rare Earth−Iron−Boron Tetragonal Co
mpounds) These permanent magnet materials are made by powder metallurgy. That is, the steps of manufacturing an ingot by vacuum melting, crushing, forming in a magnetic field and sintering, and heat treatment are used.

[Problems to be solved by the invention]

However, the magnetic properties of R-Fe-B magnet obtained in the prior art, in particular _I H _C, in case of using the same composition and the same manufacturing process, greatly vary with between each lot, poor extremely stable Met. As mentioned above
The _I H _C of the R-Fe-B magnet varies depending on the rare earth element and composition used, but a value as high as 20 KOe is obtained, and it is clear that the _I H _C potential of this magnet is sufficiently high. is there.

That is, in the conventional manufacturing method, _I H
There was a drawback that the potential of _C could not be extracted sufficiently and stably.

The present invention solves the problems of the prior art and provides a permanent magnet having high reproducibility and stable magnetic characteristics.

[Means for solving problems]

The permanent magnet of the present invention has the general formula: R _{1-α R'α} (Fe
_1-X B _X ) _Z (where R is a combination of one or more of Nd, La, Ce and Pr, R'is a combination of one or more of Tb, Ho, Dy, 0 <α ≦ 0.4, 0.06 ≦ X ≦ 0.1
4, 4.0 ≦ z ≦ 5.0), wherein the alloy contains oxygen in a weight ratio of 3000 to 12000 PPM and nitrogen in a weight ratio of 50 to 300 PPM.

The permanent magnet of the present invention has the general formula: R _{1-α R'α} (Fe
_1-X B _X ) _Z (where R is a combination of one or more of Nd, La, Ce and Pr, R'is a combination of one or more of Tb, Ho, Dy, 0 <α ≦ 0.4, 0.06 ≦ X ≦ 0.1
4. An alloy having a composition represented by 5.0 <z ≦ 5.8) is characterized by containing oxygen in a weight ratio of 3000 to 10000 PPM and nitrogen in a weight ratio of 50 to 300 PPM.

Further, the permanent magnet of the present invention has the general formula: R _1-α R '
_α (Fe _1-X B _X ) _Z (where R is 1 of Nd, La, Ce and Pr)
Or a combination of two or more kinds, R'is one kind or a combination of two or more kinds of Tb, Ho and Dy, 0 <α ≦ 0.4, 0.06 ≦ X
An alloy having a composition represented by ≦ 0.14, 5.8 <z ≦ 6.5) is characterized by containing oxygen in a weight ratio of 3000 to 8000 PPM and nitrogen in a weight ratio of 50 to 300 PPM.

Furthermore, the permanent magnet of the present invention has the general formula: R (Fe
_1-X B _X ) _Z (wherein R is one or a combination of two or more of Nd, La, Ce and Pr, 0.06 ≦ X ≦ 0.14, 4.0 ≦ z ≦
5.0) in an alloy having a composition represented by 5.0) oxygen in a weight ratio of 3000 to 12000 PPM and nitrogen in a weight ratio of 50 to 300 PPM.
It is characterized by containing.

Furthermore, the permanent magnet of the present invention has the general formula: R (Fe
_1-X B _X ) _Z (where R is one or a combination of two or more of Nd, La, Ce and Pr, 0.06 ≦ X ≦ 0.14, 5.0 <z ≦
5.8) in an alloy having a composition represented by oxygen in a weight ratio of 3000 to 10,000 PPM and nitrogen in a weight ratio of 50 to 300 PPM.
It is characterized by containing.

Further, the permanent magnet of the present invention has the general formula: R (Fe _1-X B _X ) _Z
(However, R is one kind or a combination of two or more kinds of Nd, La, Ce and Pr, 0.06 ≤ X ≤ 0.14, 5.8 <z ≤ 6.5), and oxygen is contained in a weight ratio of 30
It is characterized by containing 00 to 8000 PPM and nitrogen in a weight ratio of 50 to 300 PPM.

As a result of various researches and tests, the present inventor has found that in the conventional manufacturing process, oxygen and nitrogen in the air are slightly mixed in each step of raw material blending → melting → coarse crushing → fine crushing → magnetic field molding → sintering. each will place come contained, stored in the permanent magnet alloy, the difference in the content is found that can be a variable factor of _I H _C.

The optimum weight ratio of oxygen and nitrogen contained depends on the z value of the above general formula. Oxygen at 4.0 ≦ z ≦ 5.0: 3000 to 120
00PPM, nitrogen 50-300PPM, oxygen at 5.0 <z ≤ 5.8: 3000-10
000PPM, nitrogen 50-300PPM, oxygen at 5.8 <z ≤ 6.5: 3000-8
It is 000PPM and nitrogen is 50 ~ 300PPM, and if this condition is not satisfied, good magnetic properties cannot be achieved.

Next, the reasons for alloy limitation will be described.

If B substitution amount x is less than 0.06, the Curie point is not increased, it can not be obtained a high _I H _C. On the other hand, if the amount of substitution of B exceeds 0.14, Br is lowered, which is not preferable for magnetic properties. z is lowered Br If there is less than 4, it reduces the phase appears _I H _C rich Fe exceeds 6.5, neither obtain good magnetic properties. Also, as the substitution amount α of heavy rare earth increases, _I H _C
Shows an increasing tendency, while Br shows a monotonous decrease. Therefore, if α exceeds 0.4, good magnetic characteristics cannot be obtained. The amount of oxygen, in each z value region, when it exceeds the upper limit, the sintering property is deteriorated, deterioration in significant _I H _C occurs.
In addition, even if the oxygen amount becomes less than the lower limit value, _I H
_C decreases. The amount of nitrogen also shows the same tendency, and _I H _C decreases for both contents less than 50 PPM and more than 300 PPM.

That is, this means that the minimum oxygen and nitrogen are essential elements in the present alloy. The optimum oxygen amount differs depending on the z value, but this is because the effective R amount remaining after oxidation differs.

Further, more preferable oxygen and nitrogen contents are as follows.

Oxygen at 4.0 ≦ z ≦ 5.0: 3000 to 7000 PPM, nitrogen 50 to 100 PPM,
When 5.0 <z ≤ 5.8, oxygen: 3000-7000PPM, nitrogen 50-100PPM,
When 5.8 <z ≦ 6.5, oxygen is 3000 to 7000 PPM and nitrogen is 50 to 100 PPM.

The present invention has been completed through the above research and examination.

Hereinafter, the present invention will be described with reference to examples.

Example 1 An alloy having a composition of Nd (Fe _0.9 B _0.1 ) _5.5 was prepared by high frequency melting. The obtained ingot was roughly pulverized with a stamp mill and a disc mill, adjusted to 32 mesh or less, and then finely pulverized with a vibration mill. Acetone was used as the grinding medium, and finely ground with a particle size of 3.5 μm (FSSS). The finely pulverized powder was subjected to transverse magnetic field wet molding in a magnetic field of 15 KOe in an undried state. The compact was degassed at room temperature for 24 hours in a cooling chamber of a vacuum sintering furnace, moved to a sintering zone, and sintered at a temperature of 1100 ° C. for 2 hours. The oxygen content and the nitrogen content were changed by introducing air or N ₂ gas and changing the time before moving to the sintering zone after degassing. In the case of nitriding treatment, heating was performed if necessary. The obtained sintered body is 800
Hold for 1 hour at a temperature of ℃, then cool at 3 ℃ at a cooling rate of 1.5 ℃ / min.
It was cooled to 00 ° C. After cooling, it was aged at 600 ° C for 1 hour and cooled at a quenching rate of about 300 ° C / min. When the magnetic properties and oxygen and nitrogen contents of the obtained magnet were measured, the results shown in Table 1 were obtained.

As is clear from Table 1, sample No. 4 showing high _I H _C
All of Nos. 7 to 7 are in the range of optimum contents of oxygen and nitrogen. However, outside the range of the optimal level, in other conditions, both _I H _C is seen to exhibit a low value. Conditions outside the optimum content range shown in Table 1 are
No. 1 to 3 and No. 8.9 have a proper amount of nitrogen but an inappropriate amount of oxygen, while No. 10.11.16.17 has a proper amount of oxygen but an inappropriate amount of nitrogen. , No.12 ~ 15 and N
O.18 to 21 are out of the optimum range for both oxygen and nitrogen contents.

Example 2 An alloy of Nd _0.85 Dy _0.15 (Fe _0.82 B _0.08 ) _5.5 was prepared by high frequency melting. The obtained ingots were obtained in the same manner as in Example 1 to obtain magnets having various oxygen contents. In this case, the nitrogen content was the optimum content of 50 to 300 PPM. Shows the relationship between oxygen content and _I H _C obtained in Figure 1.

As shown in FIG. 1, it can be seen that _I H _C decreases both when the oxygen content is less than 3000 PPM and when it exceeds 10000 PPM.

Example 3 An alloy of Nd _0.9 Tb _0.1 (Fe _0.9 B _0.1 ) z (z = 4.4,5.2,6.2) was produced by arc melting. The obtained ingot was obtained by the same method as in Example 1 to obtain magnets having various oxygen contents.
In this case, the amount of nitrogen was set to the optimum content of 50 to 300 PPM. Shows the relationship between oxygen content and _I H _C and Br obtained in Figure 2.

As is clear from FIG. 2, it can be seen that the change form of _I H _C with respect to the oxygen content greatly differs depending on the z value. That is, the optimum oxygen content in each z is 3000 to 12000PPM when z = 4.4, and 3000 to 10000PP when z = 5.2.
When M and z = 6.2, it is 3000 to 8000 PPM. Both
Below the lower limit and above the upper limit, _I H _C decreases,
The decrease amount is greater than may exceed the upper limit, and in the second view, but the difference in the absolute value of the resulting _I H _C and Br is evident, this is a general trend of the magnet Is. That is, Br increases as z value increases, is to show a tendency to the _I H _C decreases conversely. Therefore, when the selection of the composition of the present magnet is determined in consideration of the necessary Br and _I H _C.

〔The invention's effect〕

As described above, the present invention can be obtained by controlling the contents of oxygen and nitrogen contained in the permanent magnet alloy stably after sintering the high-performance permanent magnet according to the present invention, and is industrially extremely large. It has value.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between _I H _C and oxygen content.
FIG. 2, for oxygen content, which is a view showing a change in _I H _C and Br.

Claims (6)

[Claims] 1. A general formula: R _{1-α R'α} (Fe _1-X B _X ) _Z (wherein R is one or a combination of Nd, La, Ce and Pr, and R'is Tb. , Ho, Dy, one or a combination of two or more, 0 <α ≦ 0.4, 0.06 ≦ X ≦ 0.14, 4.0 ≦ z ≦
5.0) in an alloy having a composition represented by 5.0) oxygen in a weight ratio of 3000 to 12000 PPM and nitrogen in a weight ratio of 50 to 300 PPM.
A permanent magnet characterized by containing. 2. A general formula: R _{1-α R'α} (Fe _1-X B _X ) _Z (where R is one or a combination of Nd, La, Ce and Pr, and R'is Tb. , Ho, Dy, or a combination of two or more, 0 <α ≦ 0.4, 0.06 ≦ X ≦ 0.14, 5.0 <z ≦
5.8) in an alloy having a composition represented by oxygen in a weight ratio of 3000 to 10,000 PPM and nitrogen in a weight ratio of 50 to 300 PPM.
A permanent magnet characterized by containing. 3. A general formula: R _{1-α R'α} (Fe _1-X B _X ) _Z (where R is one or a combination of Nd, La, Ce and Pr, and R'is Tb. , Ho, Dy, or a combination of two or more thereof, 0 <α ≦ 0.4, 0.06 ≦ X ≦ 0.14, 5.8 <z ≦
In the alloy having the composition represented by 6.5), oxygen is 3000-8000 PPM by weight and nitrogen is 50-300 PPM by weight.
A permanent magnet characterized by containing. 4. A general formula: R (Fe _1-X B _X ) _Z (where R is one or a combination of Nd, La, Ce and Pr, 0.06 ≦ X ≦ 0.14, 4.0 ≦ z ≦ 5.0) in an alloy having a composition represented by
A permanent magnet containing 00 to 12000 PPM and nitrogen in a weight ratio of 50 to 300 PPM. 5. A general formula: R (Fe _1-X B _X ) _Z (where R is one or a combination of Nd, La, Ce and Pr, 0.06 ≦ X ≦ 0.14, 5.0 <z ≦ 5.8) in an alloy having a composition represented by
A permanent magnet characterized by containing 0 to 10000 PPM and 50 to 300 PPM of nitrogen in a weight ratio. 6. A general formula: R (Fe _1-X B _X ) _Z (where R is one or a combination of two or more of Nd, La, Ce and Pr, 0.06 ≦ X ≦ 0.14, 5.8 <z ≦ In an alloy having the composition represented by 6.5), oxygen is added in a weight ratio of 30.
A permanent magnet characterized by containing 00-8000PPM and nitrogen in a weight ratio of 50-300PPM.