JPH04368101A - Rare earth permanent magnet - Google Patents

Abstract

PURPOSE:To prevent deformation and cracks and realize excellent magnetization and magnetic characteristics, by adjusting to the optimum component and performing the most suitable heat treatment, concerning an Sm2(Co1-x-y-eFexCuyZr)17 based permanent magnet of a single body having a weight of 300g or heavier. CONSTITUTION:The composition of a rate earth permanent magnet of a single body having a weight of 300g or heavier is R(Co1-x-y-cFexCuyMc)z, where (z) value is 7.0-7.8, (x) value is 0.18-0.29, (y) value is less than 0.03-0.15, and (c) value is 0.005-0.05. The cooling after solid solution treatment is performed at a speed of 0.3-1.3 deg.C/min. Thereby, concerning a rare earth permanent magnet of large weight whose heat treatment is difficult, deformation, cracks, etc., in the course of heat treatment are prevented and magnetization is improved.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is directed to the use of Sm2(Co1 -x-y-cFexC
uyZrc) 17 series permanent magnet.

0002

[Prior Art] For example, in order to increase the capacity of electron accelerators, wigglers, etc., larger permanent magnets are required, and the conventional method for achieving this is to bond multiple block magnets with adhesive to form large permanent magnets. The method used was to use it as a However, in that case, the adhesive is interposed between the block magnets and forms a magnetic gap, which reduces the magnetic flux density and makes the magnetic properties non-uniform as a whole. There was a problem that the performance of Furthermore, when large anisotropic permanent magnets are incorporated into free electron lasers, etc., they are placed in an environment of high vacuum and ultraviolet rays, so the resin adhesive used to bond multiple block magnets has a high temperature. There is also the problem that the molecular structure is often destroyed by photochemical reactions caused by ultraviolet rays, resulting in deterioration.Furthermore, the work of joining multiple block magnets with adhesive is itself complicated, which poses problems in terms of time and cost. However, there is a problem in that it is difficult to supply products of uniform quality.

[0003]With the aim of solving such conventional problems, the present inventor has filed an earlier application (Japanese Patent Laid-Open No. 2-21410).
No. 5), we proposed a large-weight anisotropic permanent magnet that is integrally molded and does not create a magnetic gap. Since this permanent magnet is formed into a large single piece with a weight of over 300g, the magnetic properties are uniform throughout, and when used in free electron laser insertion devices (wigglers and/or undulators), etc. It has the extremely excellent advantage of being able to obtain good performance and solving the problems that occur when using adhesives.

0004

[Problems to be Solved by the Invention] However, the large-weight anisotropic permanent magnet proposed by the present inventors has room for further improvement as described below. That is, Sm2Co
When producing 17 series permanent magnets, 11
Solution treatment is generally performed in which the material is held at a high temperature of about 00° C. to 1200° C. for a certain period of time, and then rapidly cooled or controlled cooling is performed.

Regarding such controlled cooling after solution treatment, the present applicant has developed the energy product (BH) max of a small magnet.
This has already been disclosed in Japanese Patent Application Laid-Open No. 2-263937 for the purpose of improving the performance. On the other hand, when such solution treatment is performed using large-sized permanent magnets, an excessive difference occurs between the surface temperature and the internal temperature during cooling, and cracks may occur due to internal stress caused by the difference in the amount of shrinkage caused by cooling. There is an inherent problem that deformation occurs. In order to prevent the occurrence of cracks and deformation during cooling, it is necessary to perform slow cooling at a cooling rate that does not create an excessive difference between the surface temperature and the internal temperature. However, when slow cooling is performed in this way, it is not possible to cool down to a predetermined temperature while maintaining the homogeneous structure obtained by solution treatment, and during the cooling process, two-phase separation occurs in which SmCo5 precipitates from Sm2Co17 as a base. I have no choice but to tolerate it. In this case, when SmCo5 is precipitated in a cellular shape, the coercive force is increased by the cellular SmCo5, but there is a problem in that the residual magnetic flux density (Br) is lowered and the magnetizability is further deteriorated.

[0006] This problem of magnetization is caused by Sm
This does not occur with Co5 permanent magnets or Nd-Fe-B permanent magnets, but it becomes a serious problem with respect to marketability in Sm2Co17-based magnets, which have poor magnetization. Further, although this problem of magnetization does not occur with magnets of normal size, it becomes a serious problem with permanent magnets having a size of 300 g or more, which were previously proposed by the present inventor. In other words, in order to magnetize a magnet of this size and with poor magnetization properties, an extremely large current must be passed through the magnetizing coil for a long period of time, and it is difficult to withstand supplying such a large current for a long period of time. Magnetizing equipment is not something that general permanent magnet users have, and supplying current for such a long time is extremely disadvantageous in terms of power cost and time cost. Furthermore, even if it is attempted to supply a magnetized permanent magnet to a user, such a large magnet that has already been magnetized poses an extremely large risk during transportation, which is impractical.

That is, the present invention provides a general formula R(Co1
-x-y-cFexCuyMc)z, for example, Sm2(Co1-x-y-cFexCuyZrc)17
By solving the above-mentioned conventional problems with permanent magnets, adjusting the composition to the optimum composition, and applying the optimum heat treatment,
It is an object of the present invention to provide a rare earth permanent magnet that is free from deformation or cracking, has a magnetization property that is not difficult to use in actual use, and has good magnetic properties.

[0008]

[Means for Solving the Problems] That is, according to the present invention, a single body has a weight of 300 g or more and has a general formula R(Co1-x-y-cFexCuyMc)z (where R is at least one of rare earth elements or two In a rare earth permanent magnet having a composition represented by a combination of at least one species, where M is at least one of Ti, Zr, Hf, and Nb,
The z value is 7.0 to 7.8, and the x value is 0.18 to 7.8.
0.29, y value 0.03 to less than 0.15, c value 0.00
5 to 0.05 is provided.

[0009] Furthermore, according to the present invention, a single body weighs 300g.
or more, and has the general formula R(Co1-x-y
-cFexCuyMc)z In a rare earth permanent magnet having a composition shown by z, cooling after solution treatment is performed by 0.3 to 2
．． A rare earth permanent magnet is provided which is obtained by performing at a rate of 0° C./min. Further, according to the present invention, it has a weight of 300 g or more as a single unit, and has the general formula R (
In a rare earth permanent magnet having a composition represented by Co1-x-y-cFexCuyMc)z, the z value is 7.0.
~7.8, the x value is 0.18 to 0.29, the y value is 0.03 to less than 0.15, the c value is 0.005 to 0.05, and further cooling after solution treatment is performed. ,0.3~1.3℃
A rare earth permanent magnet obtained by performing the process at a speed of /min is provided.

[0010] The contents of the present invention will be explained in more detail below. In particular, the rare earth permanent magnet of this invention has three
It is characterized by having a weight of 00g or more. Here, being a single body excludes the case where a plurality of magnets are bonded together with an adhesive to form a single body. The reason why the weight is set at 300 g or more is that if the weight is less than 300 g, the quenching treatment used in the conventional solution treatment can be performed to some extent without causing cracks.

[0011] The rare earth permanent magnet that is the object of this invention is:
It is a Sm2Co17-based permanent magnet having a composition represented by the general formula R(Co1-x-y-cFexCuyMc)z. This is because this Sm2Co17-based permanent magnet is used in environments where radiation is present, for example, and there is less concern about a decrease in magnetic flux density due to radiation exposure, and in order to stabilize the amount of magnetic flux, the temperature is 50°C to 120°C after magnetization. While this Sm2Co17-based permanent magnet has the advantage of having a small irreversible demagnetization rate and a high Curie temperature when heated and cooled at a certain temperature, it has the problem of poor magnetization. This is not a serious problem with small magnets or normal size magnets as shown in JP-A No. 2-263937, but with a permanent magnet that weighs more than 300 g alone, such as the permanent magnet of the present invention, This is because it becomes an extremely serious problem.

Now, since the rare earth permanent magnet of the present invention has a weight of 300 g or more as a single piece as described above,
In order to overcome the problem of preventing cracking during the heat treatment process and to achieve the goals of achieving good magnetization and other magnetic properties, specific component adjustment and heat treatment are required. From this point of view, the general formula R (Co1-x-y-cFexC
z, x, y, c, etc. in uyMc)z are determined as follows. z indicating the ratio of the total amount of other elements to the total amount of rare earth element R
The value is adjusted to 7.0-7.8 in this invention. 7.
If it is less than 0, the coercive force of the obtained permanent magnet is not sufficient,
Similarly, if it exceeds 7.8, the coercive force will be insufficient. However, preferably the Z value is between 7.2 and 7.6, most preferably between 7.30 and 7.55. In other words, if it is less than 7.2 or more than 7.6, it does not satisfy the magnetic properties required for use in magnets such as wigglers, and if it is less than 7.30 or more than 7.5.
If it exceeds 5, when cooling is performed during heat treatment to prevent cracking, the control of two-phase separation accompanying the slow cooling treatment adopted during the previous solution treatment will be insufficient. In the structure, the 1/5 phase and 2/17 cell structures become nonuniform, and as a result, good magnetization cannot be obtained.

[0013] In the rare earth permanent magnet of the present invention, Fe
has the effect of increasing the energy product ((BH)max) by increasing the saturation magnetization and residual magnetic flux density Br. This F
In this invention, the x value indicating the component ratio of e is 0.18 to 0.2.
Adjusted to 9. If the x value is less than 0.18, the energy product ((BH)max) will be low, whereas if the x value exceeds 0.29, it will become extremely difficult to control the coercive force during heat treatment, which is not preferable. However, in this invention, the x value is preferably 0.20 to 0.27, most preferably 0.21 to 0.26. If the x value is less than 0.20, the energy product ((BH)max) is insufficient, and if the x value exceeds 0.27, it will be difficult to control the coercive force. Furthermore, if the x value is less than 0.21, the structure will become non-uniform during the slow cooling process to prevent cracking and deformation during heat treatment of a single unit weighing 300 g or more. Good magnetization cannot be obtained, and conversely, if the x value exceeds 0.26, it will be difficult to control the coercive force.

[0014] In the rare earth permanent magnet of the present invention, Cu
is an element necessary to cause a two-phase separation reaction,
It has the effect of increasing iHc. It is preferable that y, which indicates the component ratio of Cu, be 0.03 or more and less than 0.15. If y is less than 0.03, the precipitation of SmCo5 cells in the structure will be insufficient, and sufficient iHc for a practical permanent magnet will not be obtained, and if y exceeds 0.15, the saturation magnetization will decrease and Br will decrease. This causes deterioration in the magnetizability of the algae.

In this invention, M includes Ti, Zr, Hf,
By adding at least one type of Nb, the coercive force i
Hc can be increased. c, which indicates the amount of M, is
It is preferable to set it to 0.005 or more and less than 0.05. c is 0.
If it is less than 0.05, the effect of improving the coercive force iHc is insufficient, and if it exceeds 0.05, the magnetizability deteriorates, which is not preferable.

Furthermore, in the present invention, cooling after solution treatment during the manufacturing process is controlled, thereby obtaining a sufficient coercive force (iHc) as a practical permanent magnet, and a large weight permanent magnet of 300 g or more. It also provides magnetizability that allows easy magnetization. FIG. 19 shows a general manufacturing process for R2Co17 magnets.

That is, the rare earth R
, Co, Cu, Fe, and Zr are mixed, and then this mixture is melted to obtain an ingot. This ingot is coarsely crushed and finely crushed to obtain raw material powder. This raw material powder is 5~
Press molding is performed in a magnetic field of approximately 15 kOe, and the molded product is
Sintering is performed at a temperature of 50 to 1230°C for about 1 to 2 hours. After that, 1
Solution treatment is performed at 100 to 1200° C. for 1 hour or more, and then cooled.

[0018] The rare earth permanent magnet of the present invention has a magnet size of 30
Since it has a weight of 0 g or more, the cooling rate during cooling after the solution treatment in the manufacturing process shown in FIG. 18 becomes a problem. In other words, if the cooling rate is too high, cracks and deformation will occur during the cooling process, while if cooling is not performed at an appropriate cooling rate, practical magnetic properties such as coercive force and magnetizability will not be obtained. . In view of the above, in this invention, the cooling rate after solution treatment is set at 0.3 to 2.0°C/
Controlled cooling is performed in seconds.

[0019] If the cooling rate is less than 0.3°C, the structure of the Sm2Co17-based permanent magnet that is obtained with an excessively slow cooling rate is due to excessive SmCo in the Sm2Co17 base structure.
5 cells are precipitated, and the resulting heavy permanent magnet has poor magnetization and is extremely impractical. Conversely, if the cooling rate exceeds 2.0℃,
The risk of permanent magnets breaking and cracking during the heat treatment process increases.

[0020]

[Function] As described above, according to the rare earth permanent magnet of the present invention, the amount of each component in the composition of a SmCo permanent magnet having a large weight of 300 g or more can be adjusted optimally, and the cooling rate after solutionization can be controlled. Optimal adjustment promotes the precipitation of SmCo5 cells in the Sm2Co17 base structure to the extent that it can provide a practically sufficient coercive force, and also improves magnetization, which is a particularly important issue in heavy permanent magnets. to a sufficiently practical degree, Sm
Precipitation of SmCo5 cells into the 2Co17 matrix structure is suppressed. In this way, SmCo to the Sm2Co17 base tissue
By controlling the precipitation of 5 cells to an optimum degree, the present invention can obtain good coercive force and magnetizability for a heavy permanent magnet of 300 g or more.

[0021]

[Embodiment] Next, an embodiment of the present invention will be described. Example 1 As shown in Composition Tables 1 to 3, the component ratio x of Fe is 0.20 to
The Cu component ratio y was changed by 0.01 up to 0.25, and the Cu component ratio y was 0.055, 0.060, and 0.065 for each.
and the z value for each of them is 6.8.
Alternatively, calculations were made to obtain a composition of 8.0, and the fine powder was weighed to obtain samples ranging from 1A and 1B to 15A and 15B. These samples were stirred for 10 minutes using a mixer to blend the composition. The composition was blended by finely pulverizing A and B from 1 to 15, and then blending them so that the z value was varied in 0.1 increments from 6.8 to 8.0.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025] Molding and sintering Using the samples of each compounding ratio obtained above, 100t
50 x 50 x 60 mm by compression molding with a press
A test piece molded body was obtained. The molding was performed in a magnetic field of 10 kOe to impart anisotropy to the molded product. Next, the obtained molded body was sintered in a vacuum at 1195° C. using a Lindberg furnace to obtain a sintered body.

Solution treatment The solution treatment and heat treatment were carried out in the pattern shown in FIG. 1, respectively. The solution treatment was maintained at 1175°C/h for 4.0 hours, and then slowly cooled at 1.1°C/sec. In addition, in the heat treatment after the solution treatment, after heating at 175 ° C / min,
It was held at 818°C for 1.5 hours, once cooled to 300°C, and then held at 813°C for 10 hours, and then slowly cooled.

Results and Discussion of Results The Fe component ratio x was set to 0.20, 0.21, 0.22, 0.20, 0.21, 0.22, 0.
In each case, the z value was changed to 23, 0.24, and 0.25, and the Cu component ratio y was changed to 0.055, 0.060, and 0.0 in each case.
The magnetic properties were measured when each composition was adjusted to 65. The results are shown in Figures 2-17. As shown in each figure, low Fe
The magnetic flux density Br increases as it moves from the high Fe side to the high Fe side. In addition, as the amount of Cu increases, the coercive force iHc increases and reaches a peak in the region of z = 7.2 to 7.5, and further increases at higher z
When it comes to the side, it decreases again.

FIG. 18 shows (BH
) max is shown as a matrix. The values of (BH)max shown in FIG. 18 all satisfy the conditions of Br≧10.4 kG and bHc≧8.5 kOe, which are necessary for a wiggler magnet. As shown in FIG. 18, (BH)max generally tends to increase with some exceptions as it moves from the low Fe side to the high Fe side. Furthermore, it can be said that the dependence of the amount of Cu on (BH)max is lower than that of the amount of Fe.

Example 2 The shaping and sintering process was carried out in the same manner as in Example 1, with x=0.20,
z = 7.0, and cooling after solution treatment was 1.2°C/s.
A permanent magnet according to the present invention was manufactured as an ec, and its magnetic properties were measured. Example 3 The shaping and sintering process was carried out in the same manner as in Example 1, with x=0.20,
z=7.8 and cooling after solution treatment at 0.8℃/se
A permanent magnet according to the present invention was prepared as part c, and its magnetic properties were measured. As a comparative example, the other conditions were the same as in each example, the Fe component ratio x was 0.17, the z values were 6.9 and 7.9, and the cooling after solution treatment was 1. Magnetic properties were measured for the samples that were cooled at a cooling rate of 4° C./sec. Table 4 shows a comparison of the measurement results of the magnetic properties of Examples and Comparative Examples. Furthermore, in particular, Table 5 shows the evaluation results regarding the quality of magnetization when the residual magnetic flux density was fixed at around 11000 KG in the example and the coercive force was varied in each case. In Table 5, Bs indicates extrapolated saturation magnetization.

[0032]

[Table 4]

[0033]

[Table 5]

As shown in Table 4, when the z value is 7.0, (BH)max=25.9MGOe can be secured by heat treatment even when cooling after solution treatment is slow cooling. When the z value is 6.9, (BH)m with iHc
ax also drops rapidly. Since it has such an optimal z value, it can be seen that the example is superior in both coercive force and energy product. In addition, when the z value is 7.8, (BH)max is 26.5MG by controlling the solution treatment and heat treatment.
While Oe is maintained, when the z value reaches 7.9, both the coercive force and the energy product decrease, and it can be seen that the example is superior from these viewpoints.

Further, as shown in Table 5, all of the examples were magnetized with a commonly used magnetizing magnetic field of 25 KOe, while the comparative examples were magnetized with a normally used magnetizing magnetic field of 25 KOe. It is difficult to obtain a magnetization state close to saturation, and special large-scale magnetization equipment with a high output of 70 KOe is required to obtain a magnetization rate of 90% or more. Therefore,
The examples in which iHc was controlled to the optimum condition clearly showed good magnetization.

[0036]

Effects of the Invention As described above, the rare earth permanent magnet of the present invention has a weight of 300 g or more as a single body, and has the general formula R(Co1-x-y-cFexCuyMc)z
z of a Sm2Co17-based permanent magnet having the composition shown by
By setting the value to 7.0 to 7.8 and the x value to 0.18 to 0.29, it is possible to prevent deformation, cracking, etc. during the heat treatment process for heavy rare earth permanent magnets that are difficult to heat treat. hand,
Moreover, the excellent effect of being able to obtain good magnetic properties with an energy product of 28.9 MGOe, which has not been achieved in the past, is achieved. In particular, according to the rare earth permanent magnet of the present invention, in addition to the above, cooling after solution treatment is 0.3 to 2.
Since the formation is performed at a speed of 0°C/sec, it not only prevents deformation and cracking during the heat treatment process, but also provides good magnetization, which is an extremely important product performance for large-weight rare earth permanent magnets. This produces an excellent effect.

[Brief explanation of drawings]

[Figure 1] Sm(CoBalFexCuyZr0.025
) is a diagram showing a heat treatment pattern of z.

[Figure 2] Sm(CoBalFe0.20Cu0.055
It is a figure which shows the change of the magnetic characteristic when Z value of Zr0.025)z is changed.

[Figure 3] Sm(CoBalFe0.20Cu0.060
It is a figure which shows the change of the magnetic characteristic when Z value of Zr0.025)z is changed.

[Figure 4] Sm(CoBalFe0.20Cu0.065
It is a figure which shows the change of the magnetic characteristic when Z value of Zr0.025)z is changed.

[Figure 5] Sm(CoBalFe0.21Cu0.055
It is a figure which shows the change of the magnetic characteristic when Z value of Zr0.025)z is changed.

[Fig. 6] Sm(CoBalFe0.21Cu0.060
It is a figure which shows the change of the magnetic characteristic when Z value of Zr0.025)z is changed.

[Figure 7] Sm(CoBalFe0.21Cu0.065
It is a figure which shows the change of the magnetic characteristic when Z value of Zr0.025)z is changed.

FIG. 8 Sm(CoBalFe0.22Cu0.055
It is a figure which shows the change of the magnetic characteristic when Z value of Zr0.025)z is changed.

FIG. 9 Sm(CoBalFe0.22Cu0.060
It is a figure which shows the change of the magnetic characteristic when Z value of Zr0.025)z is changed.

FIG. 10 Sm(CoBalFe0.22Cu0.06
5Zr0.025) is a diagram showing changes in magnetic properties when the Z value of z is changed.

FIG. 11: Sm(CoBalFe0.23Cu0.05
5Zr0.025) is a diagram showing changes in magnetic properties when the Z value of z is changed.

FIG. 12: Sm(CoBalFe0.23Cu0.06
0Zr0.025) is a diagram showing changes in magnetic properties when the Z value of z is changed.

FIG. 13: Sm(CoBalFe0.23Cu0.06
5Zr0.025) is a diagram showing changes in magnetic properties when the Z value of z is changed.

FIG. 14: Sm(CoBalFe0.24Cu0.05
5Zr0.025) is a diagram showing changes in magnetic properties when the Z value of z is changed.

FIG. 15: Sm(CoBalFe0.24Cu0.06
0Zr0.025) is a diagram showing changes in magnetic properties when the Z value of z is changed.

FIG. 16 Sm(CoBalFe0.24Cu0.06
5Zr0.025) is a diagram showing changes in magnetic properties when the Z value of z is changed.

FIG. 17: Sm(CoBalFe0.25Cu0.06
5Zr0.025) is a diagram showing changes in magnetic properties when the Z value of z is changed.

FIG. 18 is a diagram showing changes in energy product (BH) max when the amounts of Fe and Cu are changed.

FIG. 19 is a diagram showing a general heat treatment process for rare earth permanent magnets.

Claims (3)

[Claims] Claim 1: A single substance having a weight of 300 g or more and having the general formula R (Co1-x-y-cFexCuyM
c) In a rare earth permanent magnet having a composition represented by z (where R is at least one rare earth element or a combination of two or more, M is at least one of Ti, Zr, Hf, and Nb), the z value is 7.0. ~7.8, the x value is 0.18 to 0.29, the y value is 0.03 to less than 0.15,
A rare earth permanent magnet characterized by having a c value of 0.005 to 0.05. 2. It has a weight of 300 g or more as a single body and has the general formula R (Co1-x-y-cFexCuyM
c) A rare earth permanent magnet having a composition represented by z, which is obtained by cooling after solution treatment at a rate of 0.3 to 2.0° C./min. 3. A single substance having a weight of 300 g or more and having the general formula R (Co1-x-y-cFexCuyM
c) In a rare earth permanent magnet having a composition represented by z, the z value is 7.0 to 7.8, and the x value is 0.1.
8 to 0.29, y value 0.03 to less than 0.15, c value 0.
005 to 0.05, and further cooling after solution treatment,
A rare earth permanent magnet characterized in that it is obtained by performing the magnetization at a rate of 0.3 to 1.3°C/min.