JPH04323802A - Rare-earth magnet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new rare earth magnet, particularly a rare earth-iron-nitrogen-carbon (hereinafter referred to as "R--Fe--N--C") rare earth magnet.

0002

[Prior Art] Conventionally, permanent magnets have been made of Co.
Representative examples include alnico magnets containing 30% by weight, hard ferrite magnets containing Fe oxide as a main component, and rare earth cobalt magnets containing 50 to 65% by weight Co and Sm as the rare earth element (R). ing.

However, the raw material situation for Co used in alnico magnets and rare earth cobalt magnets has become unstable, and Sm used in rare earth cobalt magnets has a low content in rare earth minerals and is extremely expensive. , hard ferrite magnets are the mainstream of permanent magnets.

However, rare earth cobalt magnets have much higher magnetic properties than other magnets, and are considered to be essential magnets mainly for small, high-value-added magnetic circuits.

[0005] Therefore, there is an urgent need to develop rare earth magnets that do not contain Co or Sm, and research has been carried out on various rare earth magnets.

[0006] Under these circumstances, the development of rare earth magnets has progressed, and recently, rare earth magnets that do not contain Co or Sm, such as Nd, Pr, Dy,
At least one of the rare earth elements Ho, Tb 8-3
A rare earth permanent magnet of a magnetically anisotropic sintered body consisting of 0 at%, B2 to 28 at%, and the balance substantially Fe, and N
At least one of the rare earth elements d, Pr, Dy, Ho, and Tb, and La, Ce, Pm, Sm, Eu, Gd,
A total of 8 to 30 at% of at least one of the rare earth elements Er, Tm, Yb, Lu, and Y, and B2 to 28 at%
A rare earth permanent magnet of a magnetically anisotropic sintered body consisting of 1000 yen and the remainder substantially Fe was proposed (Japanese Patent Publication No. 61-34242).

[0007] Furthermore, a method for manufacturing permanent magnets with high magnetic properties using a liquid quenching method has been proposed (Japanese Patent Application Laid-Open No.
No. 9-64739).

[0008]

[Problem to be solved by the invention] The above-mentioned R-Fe-B
The system magnet has high magnetic properties at room temperature. However, since the Curie temperature is approximately 300° C., the temperature characteristics are poor.

Thus, an object of the present invention is to provide a rare earth magnet that does not contain Co or contains only a small amount of Co, but has a high Curie temperature and high magnetic properties.

0010

[Means for Solving the Problems] In order to achieve the above object, the rare earth magnet according to the present invention contains 4 to 20 at% of R (wherein R is one or more rare earth elements including Y), 2
~25 at% N, 1-15 at% C, 0.1-20
α of at% (however, α is one or more of Be, B, Si, P, S), T of 0.1 to 18 at% (however, T is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo,
one or more of W, Mn, Ni, Cu),
The remainder consists of Fe. Furthermore, in the present invention,
Also provided is one in which Fe is partially replaced with Co in the range of 0<Co/Fe≦1.

Rare earth magnet R-Fe-N-C according to the present invention
In the system magnet, high magnetic properties occur in the above-mentioned composition range.

[0012] In order to ensure such an effect, it is necessary to keep the content of each component within the above-mentioned range. The range is 20at%. i.e. at least 4
However, if the R content becomes too large, the residual magnetic flux density (Br) and the maximum energy product ((B
H)max) decreases, it is important to keep the R content to 20 at% or less, and the preferable R content is 7 to 17 at%.
It is.

Furthermore, if the content of nitrogen N becomes too low, the coercive force (iHc), Br, and (BH)max decrease. On the other hand, if the N content becomes too large, iHc decreases, so N needs to be 2 to 25 at%. Preferably it is 5 to 20 at%.

Furthermore, if the content of carbon C becomes too low, iHc, (BH)max becomes small, and if the content of C becomes too large, Br, (BH)max becomes small. Therefore, C needs to be 1 to 20 at%. Preferably it is 3 to 17 at%.

By the way, if a magnetically soft phase exists in the alloy, it is difficult to form a magnet. Therefore, it is necessary to suppress the soft phase in the alloy. Therefore, Ti, Zr
, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Ni
, Cu, which is a soft phase, by containing T representing one or more transition elements selected from Cu.
The precipitation of can be suppressed. Therefore, due to the inclusion of T, i
It seems that Hc is improved.

[0016] If the T content becomes too low, iHc becomes small. Also, if the T content becomes too large, Br, (B
H) max becomes smaller. Therefore, the content of T is 0.1
It is necessary to set it to 18 at%. Preferably 0.5-1
It is 5at%.

[0017] Also, α represents one or more metalloid or nonmetallic elements selected from Be, B, Si, P, and S.
iHc is expressed by containing. In order to develop iHc, the magnetocrystalline anisotropy of the phase that controls magnetism must be large. It is thought that by containing α, the crystal magnetic anisotropy of the phase that controls magnetism increases, and iHc is expressed.

[0018] If the content of α becomes too small, iHc becomes small. Also, if the content of α becomes too large, Br, (B
H) max becomes smaller. Therefore, the content of α is 0.1
It is necessary to set it to 15at%. Preferably 0.6-1
It is 2at%.

In principle, the rare earth magnet of the present invention does not contain cobalt, which is not a good raw material, but since high magnetic properties can be obtained by containing cobalt, a small amount of cobalt can be added by replacing a part of Fe with Co. It is also possible to contain. In this case, as the amount of Co substitution increases, the Curie temperature increases, but if the amount of Co substitution increases too much, iHc decreases. Therefore, when partially replacing Fe with cobalt, it is necessary to perform the replacement within the range of 0<Co/Fe≦1.

[0020] In producing a rare earth magnet with such components, first components other than nitrogen, namely R, C, α, T,
A mixture is prepared by mixing each component of Fe or Co in a predetermined ratio, heated to a high temperature in an arc melting furnace or the like to melt it, cooled, and then pulverized.

The obtained powder is then heated to a high temperature in a nitrogen gas stream and treated with nitrogen. A certain amount of an organic binder such as an epoxy resin is kneaded into the nitrogen-containing powder obtained here, compression molded by applying a magnetic field, and then cured and bonded magnetized to produce a product.

[0022]

[Examples] Examples of rare earth magnets according to the present invention are given below. However, the invention should not be construed as being limited by this example. In this example, the manufacturing method of each magnet is also shown, and the magnetic properties are measured and shown when the content of one of the components or the Co/Fe ratio is changed. It is clear from this that good magnetic properties cannot be obtained outside the specified content of each component or the above-mentioned Co/Fe ratio.

[Example 1] The following first step (pre-step):
Through the second step (nitrogen treatment step) and third step (bond magnetization step), Sm was varied in the range of 3 to 21 at% as shown in Table 1, N: 10 at%, C: 5 at%.
%, W: 3 at%, Co: 15 at%, Si: 5 at%
, Fe: R-Fe-N according to the present invention having the remainder composition
-C-based rare earth magnet was prepared.

First step (pre-step) Required alloying elements (Sm, Fe, C, W, Co, Si
) is melted in an arc melting furnace, and 950
Solution treatment was performed at ~1020°C for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was treated with nitrogen at 570° C. for 1 to 4 hours depending on the Sm content in N2 gas at 3 atm.

Third step (bonded magnetization step) 3 wt % epoxy resin is kneaded into the N-containing powder obtained in the second step, compression molded at a molding pressure of 5 ton/cm2 in a magnetic field of 20 KOe, and then Cure treatment was performed.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are shown in Table 1 in comparison with the Sm content.

As is clear from Table 1, iHc, Br, (BH)max are small when the Sm content is less than 4 at%, and Br, (BH)max are small when the Sm content exceeds 20 at%.

[Example 2] The following first step (pre-step):
Through the second step (nitrogen treatment step) and third step (bond magnetization step), N was varied in the range of 1 to 28 at% as shown in Table 2, Sm: 13 at%, C: 3 at%.
%, Mo: 5 at%, P: 5 at%, and Fe: the balance.

1st step (pre-step) The required alloying elements (Sm, Fe, C, P, Mo) are melted in an arc melting furnace to a melting point of 950 to 100, depending on the alloy composition.
Solution treatment was performed at 0°C for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was heated to 550° C. in 5 atm N2 gas according to the N content.
．． Nitrogen treatment was performed for 5 to 12 hours.

Third step (bonded magnetization step) Same as Example 1.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are compared with the N content in Table 2.
As is clear from Table 2 shown in Table 2, when the N content is less than 2 at%, iHc, Br, and (BH)max are small, and when the N content exceeds 25 at%, iHc is small.

[Example 3] The following first step (pre-step):
Through the second step (nitrogen treatment step) and third step (bond magnetization step), C was varied in the range of 0 to 22 at% as shown in Table 3, Sm: 13 at%, N: 5 at%.
%, Co: 15at%, Be: 3at%, Cr: 5at%
%, Fe: R-Fe- according to the present invention having the remainder composition
An NC-based rare earth magnet was prepared.

First step (pre-step) Required alloying elements (Sm, Fe, Co, Be, C, C
r) is melted in an arc melting furnace, and depending on the C content, 930
Solution treatment was performed at ~980°C for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was treated at 570° C. in 1 atm N2 gas according to the C content.
Nitrogen treatment was performed for ~4 hours.

Third step (bond magnetization step) Same as Example 1.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are compared with the C content in Table 3.
As is clear from Table 3 shown in Table 3, when the C content is less than 1 at%, iHc, Br, and (BH)max are low, and when the C content exceeds 20 at%, Br and (BH)max are small. .

[Example 4] The following first step (pre-step):
After the second step (nitrogen treatment step) and third step (bond magnetization step), Sm is 7 to 13 at% and Ce is 0 to 6 a.
t% (however, Sm+Ce=13at%) as shown in Table 4, N: 13at%, C: 5at%.
%, P: 7 at%, Hf: 5 at%, and Fe: the balance.

First step (pre-step) Necessary alloying elements (Sm, Ce, C, Hf, Fe, P
) is melted in an arc melting furnace, and 950% is melted according to the Ce content.
Solution treatment was performed at ~1000°C for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was treated with nitrogen at 500° C. for 3 to 4 hours depending on the Ce content in N2 gas at 3 atm.

Third step (bond magnetization step) Same as Example 1.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are shown in Table 4 in comparison with the Ce content.

As is clear from Table 4, the magnetic properties change depending on the Ce content of Sm, but it can be seen that practically sufficient magnetic properties can be obtained. This means that R other than Sm (including Y)
This clearly indicates that it is valid even if

[Example 5] The following first step (pre-step):
After the second step (nitrogen treatment step) and third step (bond magnetization step), the T shown in Table 5 was used, and Sm:
9at%, N: 10at%, C: 3at%, T: 7at
%, Co: 15 at%, Si: 5 at%, and Fe: the balance.

First step (pre-step) Required alloying elements (Sm, Fe, Co, C, T, Si
) is melted in an arc melting furnace to a temperature of 980 to 100 depending on T.
Solution treatment was performed at 0°C for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was treated with nitrogen at 500° C. for 1 to 2 hours depending on T in 2 atm N 2 gas.

Third step (bond magnetization step) Same as Example 1.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are shown in Table 5 in comparison with T.

As is clear from Table 5, the magnetic properties change as the type of T changes, but it can be seen that practically sufficient magnetic properties can be obtained with any type of T.

[Example 6] The following first step (pre-step):
Through the second step (nitrogen treatment step) and third step (bond magnetization step), Nb was varied in the range of 0 to 20 at% as shown in Table 6, Sm: 15 at%, N: 10a.
t%, Be: 3at%, Co: 10at%, C: 7at
%, Fe: R-Fe- according to the present invention having the remainder composition
An NC-based rare earth magnet was prepared.

First step (pre-step) Required alloying elements (Sm, Fe, Co, Be, Nb,
C) is melted in an arc melting furnace, and 96% is obtained depending on the Nb content.
Solution treatment was performed at 0 to 1020°C for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was treated with nitrogen at 570° C. in 1 atm N2 gas for 3 to 8 hours depending on the Nb content.

Third step (bonded magnetization step) Same as Example 1.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are shown in Table 6 in comparison with the Nb content.

As is clear from Table 6, when the Nb content is 0.1a
If it is less than t%, iHc is low and the Nb content is 18 at%.
If it exceeds Br, (BH)max will become small.

[Example 7] The following first step (pre-step):
After the second step (nitrogen treatment step) and third step (bond magnetization step), the α shown in Table 7 was used, and Sm:
12at%, N: 13at%, C: 3at%, α: 10
An R-Fe-N-C rare earth magnet according to the present invention was prepared having a composition of Co: 5 at%, V: 5 at%, and Fe: the balance.

First step (pre-step) Required alloying elements (Sm, Fe, Co, C, α, V)
is melted in an arc melting furnace and heated to 950-970℃ depending on α.
Solution treatment was carried out for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was treated with nitrogen at 530° C. for 1 to 2 hours depending on α in 2 atmospheres of N2 gas.

Third step (bonded magnetization step) Same as Example 1.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are shown in Table 7 in comparison with α.

As is clear from Table 7, the magnetic properties change as the type of α changes, but it can be seen that practically sufficient magnetic properties can be obtained regardless of the type of α.

[Example 8] The following first step (pre-step):
Through the second step (nitrogen treatment step) and third step (bond magnetization step), P was varied in the range of 0 to 17 at% as shown in Table 8, Sm: 13 at%, N: 8 at%.
, C: 4 at%, W: 7 at%, and Fe: the balance. An R-Fe-N-C rare earth magnet according to the present invention was prepared.

1st step (pre-step) The required alloying elements (Sm, Fe, P, C, W) are melted in an arc melting furnace, and the melting point is 940 to 1000 depending on the P content.
Solution treatment was performed at ℃ for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was heated at 500° C. in 1 atm N2 gas according to the P content.
Nitrogen treatment was performed for ~6 hours.

Third step (bond magnetization step) Same as Example 1.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are compared with the P content in Table 8.
As is clear from Table 8 shown in Table 8, the P content is 0.1 at%
If the P content is less than 15 at%, iHc will be small, and if the P content exceeds 15 at%, Br, (BH)max will be small.

[Example 9] The following first step (pre-step):
Through the second step (nitrogen treatment step) and third step (bond magnetization step), Co/Fe was varied in the range of 0 to 1.1 as shown in Table 9, Sm: 13 at%, N: 12
at%, C: 4at%, S: 3at%, Cr: 5at%
, the balance is Fe and Co according to the present invention
-N-C rare earth magnet was prepared.

First step (pre-step) Required alloying elements (Sm, Fe, Co, C, S, Cr
) is melted in an arc melting furnace to give 960% depending on Co/Fe.
Solution treatment was performed at ~980°C for 24 hours. Thereafter, it was ground to an average particle size of about 3 μm using a grinder.

Second step (nitrogen treatment step) The powder obtained in the first step was treated with nitrogen at 550° C. for 4 to 5 hours depending on Co/Fe in 1 atm N 2 gas.

Third step (bonded magnetization step) Same as Example 1.

R according to the present invention obtained as described above
-iHc, Br, (BH) of Fe-N-C rare earth magnet
max was measured and the results are shown in Table 9 in comparison with Co/Fe. Also include the Curie temperature.

As is clear from Table 9, as Co/Fe increases, the Curie temperature increases, but when Co/Fe exceeds 1.0, iHc decreases.

R-Fe-N-C rare earth magnet of the present invention (
The Curie temperature of Co/Fe=0) is the same as that of conventional R-Fe-B.
It is approximately 150°C higher than the Curie temperature of rare earth magnets.

[0075]

Effects of the Invention As detailed above, R-
According to the Fe--N--C rare earth magnet, high magnetic properties can be ensured without containing a large amount of Co unlike conventional magnets. Furthermore, it exhibits a high Curie temperature.

Claims (2)

[Claims] Claim 1: 4 to 20 at% R (wherein R is one or more rare earth elements including Y), 2 to 25 at% N
, 1 to 20 at% C, 0.1 to 15 at% α (however, α is one or more of Be, B, Si, P, and S), 0.1 to 18 at% T (however, T is Ti, Zr,
Hf, V, Nb, Ta, Cr, Mo, W, Mn, Ni,
A rare earth magnet characterized by comprising one or more of Cu) and the balance Fe. 2. The Fe is C in the range of 0<Co/Fe≦1.
2. The rare earth magnet according to claim 1, wherein the rare earth magnet is replaced with o.