CN116417215A - Magnet pretreatment method and magnet - Google Patents
Magnet pretreatment method and magnet Download PDFInfo
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- CN116417215A CN116417215A CN202111658948.2A CN202111658948A CN116417215A CN 116417215 A CN116417215 A CN 116417215A CN 202111658948 A CN202111658948 A CN 202111658948A CN 116417215 A CN116417215 A CN 116417215A
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- 238000002203 pretreatment Methods 0.000 title claims abstract description 9
- 230000002441 reversible effect Effects 0.000 claims abstract description 47
- 238000000034 method Methods 0.000 claims abstract description 18
- 230000005415 magnetization Effects 0.000 claims abstract description 12
- 230000035699 permeability Effects 0.000 claims description 17
- 238000011084 recovery Methods 0.000 claims description 6
- 230000005347 demagnetization Effects 0.000 description 27
- 230000002427 irreversible effect Effects 0.000 description 17
- 230000006641 stabilisation Effects 0.000 description 15
- 238000011105 stabilization Methods 0.000 description 15
- 230000032683 aging Effects 0.000 description 11
- 230000007246 mechanism Effects 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 5
- 230000004907 flux Effects 0.000 description 4
- 238000003754 machining Methods 0.000 description 4
- 238000007781 pre-processing Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- 239000002344 surface layer Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910001172 neodymium magnet Inorganic materials 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005662 electromechanics Effects 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000007885 magnetic separation Methods 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F13/00—Apparatus or processes for magnetising or demagnetising
- H01F13/006—Methods and devices for demagnetising of magnetic bodies, e.g. workpieces, sheet material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
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Abstract
The application relates to a magnet pretreatment method and a magnet. The pretreatment method of the magnet comprises the following steps: placing the magnetized magnet into a magnetizing coil; and electrifying the magnetizing coil to enable the magnetizing coil to generate a reverse magnetic field with the magnetization direction opposite to that of the magnet, so as to pretreat the magnet. According to the method, the magnets are demagnetized reversely through the magnetizing coil, the field intensity of the magnetic field of the magnetizing coil and the energizing time of the magnetizing coil can be controlled accurately, and the consistency of products is improved.
Description
Technical Field
The application relates to the field of magnet stabilization treatment, in particular to a magnet pretreatment method and a magnet.
Background
The neodymium-iron-boron permanent magnet is the permanent magnet with the strongest magnetism at present, has excellent characteristics of high magnetic energy product, high cost performance and the like, is easy to process into various sizes, and is widely applied to aviation, aerospace, microwave communication technology, electronics, electroacoustic, electromechanics, computing technology, automation technology, automobile industry, petrochemical industry, magnetic separation technology, instruments, magnetic medical technology and other devices and equipment needing permanent magnetic fields, and particularly suitable for developing various updated products with high performance, miniaturization and light weight.
In general, when the use temperature increases from room temperature to a certain high temperature, the magnet generates reversible demagnetization and irreversible demagnetization. Reversible demagnetization means that when the magnetic property of the magnet is reduced from room temperature to high temperature, the magnetic property returns to the original value of the room temperature magnetic property when the temperature is reduced to room temperature; irreversible demagnetization refers to a decrease in magnetic properties when the magnet is raised from room temperature to a high temperature, and when the temperature is lowered to room temperature, the magnetic properties cannot be restored to room temperature magnetic property original values, and the ratio of the reduced portion thereof to the room temperature magnetic property original values is called a high temperature demagnetizing rate.
One of the reasons for irreversible demagnetization of a magnet is that the magnet is manufactured by grinding, cutting and other machining of a large blank magnet, wherein crystal grains on the surface layer of the magnet are damaged in the machining process, and the surface layer is corroded by acid washing in the surface treatment process after machining, such as electroplating, so that the magnet structure is irreversibly damaged. In particular, for a small-sized magnet, since the surface layer portion of the small-sized magnet occupies a larger volume ratio, damage caused by machining has a larger influence on the magnet structure, the degree of the demagnetizing curve square of the small-sized magnet becomes poor, and the high-temperature demagnetizing rate may be higher, so that the magnet is easily demagnetized in use.
In order to solve the technical problems, the magnet is heated to 10-20 ℃ higher than the highest working temperature after being saturated and magnetized before being used, and the aging treatment of heat preservation is carried out for a certain time to eliminate the irreversible loss of the magnet. Thus, when the magnet after the aging treatment is warmed up to the maximum operating temperature, the irreversible loss is removed in the aging treatment, so that the overall magnetic performance of the magnet is less degraded. However, the plating layer on the surface of the magnet may be discolored due to the long aging treatment time. In addition, the inventors found that when small magnets are subjected to mass aging treatment, there is a problem in that the variation in the high-temperature demagnetizing rate between the magnets after the treatment is large. Further analysis has found that since the magnetized small-sized magnets are arranged in a row by attraction to each other, when the small-sized magnets arranged in the row are subjected to the aging heat treatment, the difference in Pc between the individual magnets constituting the row is large with respect to the permeabilities (Pc, the slopes of the magnet demagnetization curve load lines) of the isolated magnets in which the magnets are arranged at intervals, the magnets Pc in the central portion of the row are larger than the isolated magnets Pc, and the magnets Pc at both ends of the row are smaller. The larger Pc under the same high temperature conditions, the smaller the irreversible loss removed by the aging treatment. For the small magnets in the middle of the column, the irreversible loss removed after the aging treatment is small, so that the high-temperature demagnetizing rate is still high when the magnet is used.
CN110571042 discloses a technical scheme for replacing aging treatment, where the magnetic supply mechanism uses a permanent magnet to generate a constant magnetic field, the magnet to be treated is placed in the clamping mechanism, then the clamping mechanism is placed in the constant magnetic field, so that the magnetic field of the magnet to be treated is opposite to the constant magnetic field generated by the magnetic supply mechanism, and then the clamping mechanism is taken out in the forward direction or the reverse direction, so as to complete the treatment of the magnet. However, the inventor finds that the technical scheme can generate the problem of non-uniform magnetic field intensity at different positions of a demagnetizing field space during batch processing, thereby causing non-uniform irreversible loss of removal among the magnets after pretreatment demagnetizing. The space of the demagnetizing field area is larger when the batch processing is performed, the constant magnetic field generated by the magnetic supply mechanism is an open magnetic field, when the space of the demagnetizing field area is larger, the magnetic field intensity is easy to be different at different positions of the magnetic field area, the magnetic field intensity of the central area is large, the magnetic field intensity of the two end areas is low, so that the demagnetizing field born by the magnets at different positions is uneven, and the irreversible loss degree of removing each magnet in the same batch is different. In addition, especially for the pre-stabilization treatment of small products in batch treatment, the magnetic field area provided by the magnetic supply mechanism of the technical scheme is smaller, and the space of the clamping mechanism is smaller.
Disclosure of Invention
Based on the problems, the application provides a magnet pretreatment method and a magnet, which improve the uniformity of removing irreversible loss among magnets in batch treatment.
One embodiment of the present application provides a method for preprocessing a magnet, including: placing the magnetized magnet into a magnetizing coil; and electrifying the magnetizing coil to enable the magnetizing coil to generate a reverse magnetic field with the magnetization direction opposite to that of the magnet, so as to pretreat the magnet.
According to some embodiments of the application, the method for pre-treating a magnet further comprises: the field strength of the reverse magnetic field is determined according to the intrinsic coercive force and the recovery magnetic permeability of the magnet.
According to some embodiments of the application, the determining the field strength of the opposing magnetic field from the intrinsic coercivity and the return permeability of the magnet comprises: using the formula:
determining the field strength of the reverse magnetic field, wherein H is the field strength of the reverse magnetic field, H cJ Is intrinsic coercivity, mu r For restoring magnetic permeability, the coefficient alpha is 0.3-1.
According to some embodiments of the present application, the placing the magnet within the magnetizing coil includes: and arranging the single or a plurality of magnets into a plurality of columns and placing the columns into the magnetizing coil.
According to some embodiments of the application, the dimension of the magnet in each direction is less than or equal to 3mm.
According to some embodiments of the application, the dimension of the magnet in each direction is less than or equal to 1mm.
One embodiment of the present application provides a magnet pretreated by the pretreatment method described above.
According to some embodiments of the application, the magnet is a cuboid, cube, cylinder, sphere or ellipsoid.
According to the method, the magnets are demagnetized reversely through the magnetizing coil, the field intensity of the magnetic field of the magnetizing coil and the energizing time of the magnetizing coil can be controlled accurately, the field intensity of the reverse magnetic field at each position in the magnetizing coil is uniform and consistent, the irreversible loss generated by the reverse magnetic field to each magnet is basically the same, the irreversible loss deviation removed between the magnets after batch treatment is small, and the consistency of the magnets produced in batch is improved.
Drawings
In order to more clearly illustrate the technical solutions of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings by a person skilled in the art without departing from the scope of protection of the present application.
Fig. 1 is a schematic view of a magnet according to an embodiment of the present application placed in a magnetizing coil.
Detailed Description
The following description of the embodiments of the present application, taken in conjunction with the accompanying drawings, will clearly and fully describe the technical aspects of the present application, and it will be apparent that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
As shown in fig. 1, the magnetic supply device of the embodiment of the present application generates a magnetic field through a magnetizing coil 100. The magnetizing coil 100 is a spiral pulse coil, and can control the field strength of the generated magnetic field by setting the energizing current. The magnet 200 of this embodiment is a saturated and magnetized rare earth magnet, such as a neodymium-iron-boron magnet. The magnetic pole of the magnetic field generated by the magnetizing coil 100 is opposite to the magnetic pole of the magnet 200, and the magnetic field of the magnetizing coil 100 is used as a reverse magnetic field to apply reverse demagnetization to the magnet 200, so as to perform stabilization pretreatment on the magnet 200 and remove irreversible loss of the magnet.
The method for preprocessing the magnet provided by the embodiment comprises the following steps:
s1, placing the magnetized magnet into a magnetizing coil.
Since the magnets are magnetized, the plurality of magnets are automatically arranged in a row on the tray, and the plurality of magnets arranged in the row are placed in the magnetizing coil.
S2, electrifying a magnetizing coil and electrifying the magnetizing coil to enable the magnetizing coil to generate a reverse magnetic field with the magnetization direction opposite to that of the magnet, so that the magnet is preprocessed.
Setting the field intensity of the magnetic field of the magnetizing coil as the field intensity of a preset reverse magnetic field, and setting the charging current value of the needed magnetizing coil according to the field intensity of the reverse magnetic field. The magnetizing coil is electrified according to a preset current value, and the generated magnetic field is used as a reverse magnetic field to perform stabilization pretreatment on the magnet.
According to the embodiment, the field intensity of the magnetic field of the magnetizing coil and the power-on time of the magnetizing coil can be accurately controlled, the field intensity of the reverse magnetic field at each position in the magnetizing coil is uniform and consistent, the irreversible loss generated by the reverse magnetic field to each magnet is basically the same, the irreversible loss deviation removed between the magnets after batch processing is small, and the consistency of the magnets in batch production is improved.
According to an optional technical solution of the present application, the method further includes step S3, determining a field strength of the reverse magnetic field, including: the field strength of the reverse magnetic field is determined according to the intrinsic coercive force and the recovery permeability of the magnet.
The inventors have found that the field strength of the applied opposing magnetic field is related to the intrinsic coercivity and the return permeability of the magnet. The magnets are of the same batch, and the intrinsic coercive force and the recovery permeability of the magnets can be considered to be consistent.
Alternatively, the field strength of the opposing magnetic field is determined using the following formula:
h is the field strength of the reverse magnetic field;
H cJ is intrinsic coercivity;
μr is the recovery permeability, which is the permeability corresponding to the slope of the recovery line, which can beWith Br/H cb Values are equivalent;
the coefficient alpha is 0.3-1.
According to an optional technical solution of the present application, placing the magnet into the magnetizing coil in step S1 includes: the plurality of magnets are arranged in a single column or a plurality of columns and placed in the magnetizing coil so that the magnetizing direction of each column of magnets is the same.
A plurality of magnets are arranged into a single row or a plurality of rows by using a tray or a die and then are placed into a magnetizing coil, so that the single row or the plurality of rows of magnets can be preprocessed at the same time, and the preprocessing efficiency of the magnets is improved.
According to an optional technical scheme of the application, in step S2, the magnetizing coil is electrified, the electrified current is set according to the intensity of the reverse magnetic field, and an operator generates pulse current by clicking a control button so as to generate a required reverse magnetic field in the magnetizing coil.
The method for preprocessing the magnet is particularly suitable for magnets with the sizes less than or equal to 3mm in all directions. Is especially suitable for the magnet with the dimension less than or equal to 1mm in each direction. Compared with a magnet with a large size, the magnet with a small size has larger irreversible loss proportion to magnetic flux loss, and the aim of quick and uniform demagnetization can be fulfilled when the small magnets are pretreated in batches.
Embodiments of the present application provide a magnet that is pre-treated by the pre-treatment method described above.
According to an alternative technical scheme of the application, the magnet is cuboid, cube, cylinder, spheroid or ellipsoid.
The method for testing the high-temperature demagnetizing rate of the magnet comprises the following steps: and measuring the magnetic flux A of ase:Sub>A single magnet at room temperature, placing the magnet on an aluminum plate for specific heat preservation for 1h, baking, and measuring the magnetic flux B of the magnet after the magnet is cooled to the room temperature, wherein the high-temperature demagnetizing rate is= (B-A)/A multiplied by 100 percent.
Example 1
Commercial N40H grade 49.5×34.5×25.5mm gauge green magnet with br=13.2 kgs, H cJ =18 kOe, cut blank magnet into small magnets of 0.9×0.5×0.8 mm in size, measure small magnet demagnetizing curve with VSM to obtain H cJ Return permeability μ =17 kOe r =1.15. And ∈ represents the orientation direction.
1. Alpha is chosen to be 0.4 and the corresponding magnitude of the opposing magnetic field is 4.9kOe. 300 samples are selected, 5T magnetic fields are magnetized and then are arranged into a plurality of columns, the columns are placed in magnetizing coils, so that the magnetization direction of each column of magnets is opposite to the direction of a magnetic field generated by the magnetizing coils, and reverse magnetic field demagnetization stabilization treatment is carried out. The magnetizing coil current was controlled so that the magnetic field generated was 4.9kOe. After the reverse field demagnetization stabilization treatment, each magnet was tested individually for high temperature demagnetization rate at 120 ℃ after 1 hour. The average value of the high-temperature demagnetizing rate of 300 magnets is-5.0%, and the polar difference is 2.0%.
2. Alpha is chosen to be 0.8 and the corresponding reverse field size is 9.8kOe. 300 samples are selected, 5T magnetic fields are magnetized and then are arranged into a plurality of columns, the columns are placed in magnetizing coils, so that the magnetization direction of each column of magnets is opposite to the direction of a magnetic field generated by the magnetizing coils, and reverse magnetic field demagnetization stabilization treatment is carried out. The magnetizing coil current was controlled so that the magnetic field generated was 9.8kOe. After the reverse field demagnetization stabilization treatment, each magnet was tested individually for high temperature demagnetization rate at 120 ℃ after 1 hour. The average value of the high-temperature demagnetizing rate of 300 magnets is-1.5%, and the polar difference is 2.0%.
The magnet after the stabilization treatment of the implementation has small irreversible loss and good consistency. The larger the alpha value is, the larger the reverse magnetic field is, the lower the high-temperature demagnetizing rate after stabilization treatment is, but the lower the original magnetic flux A value after demagnetization is, the magnitude of the field intensity of the reverse magnetic field needs to be selected within the range of the reverse magnetic field obtained by the formula according to actual conditions and application requirements.
Example 2
Commercial N44H brand 49.5×34.5×25.5mm gauge green magnet was selected with br=13.5 kgs, H cJ =17.0 kOe, cut blank magnet into small magnets with dimensions of 1.5×0.4×0.8 cJ Return permeability μ =15 kOe r ＝1.3。
Alpha is chosen to be 0.5 and the corresponding reverse field size is 4.8kOe. 300 samples are selected, 5T magnetic fields are magnetized and then are arranged into a plurality of columns, the columns are placed in magnetizing coils, so that the magnetization direction of each column of magnets is opposite to the direction of a magnetic field generated by the magnetizing coils, and reverse magnetic field demagnetization stabilization treatment is carried out. The magnetizing coil current was controlled so that the magnetic field generated was 4.8kOe. After the reverse magnetic field demagnetizing and stabilizing treatment, each magnet is tested independently for high-temperature demagnetizing rate at 100 ℃ after 1 h. The average value of the high-temperature demagnetizing rate of 300 magnets is-4.0%, and the polar difference is 2.0%.
Example 3
A commercially available N42SH brand 49.5×34.5×25.5mm gauge green magnet was selected with br=13.4 kgs, h cJ =21.0 kOe, cut the blank magnet into small magnets of 3×1.5×1 ∈mm in size, measure the small magnet demagnetizing curve using VSM to obtain H cJ Return permeability μ =20 kOe r ＝1.1。
Alpha is chosen to be 0.7 and the corresponding reverse field size is 10.6kOe. 300 samples are selected, 5T magnetic fields are magnetized and then are arranged into a plurality of columns, the columns are placed in magnetizing coils, so that the magnetization direction of each column of magnets is opposite to the direction of a magnetic field generated by the magnetizing coils, and reverse magnetic field demagnetization stabilization treatment is carried out. The magnetizing coil current was controlled so that the magnetic field generated was 10.6kOe. After the reverse magnetic field demagnetizing and stabilizing treatment, each magnet is tested independently for high-temperature demagnetizing rate at 130 ℃ after 1 h. The average value of the high-temperature demagnetizing rate of 300 magnets is-2.0%, and the polar difference is 2.0%.
Example 4
Commercial N40H grade 49.5×34.5×25.5mm gauge green magnet with br=13.2 kgs, H cJ =18.0 kOe, cut the blank magnet into small magnets with dimensions 4×1.8×1.2 cJ Return permeability μ =18 kOe r ＝1.05。
Alpha is chosen to be 0.9 and the corresponding reverse field size is 13.2kOe. 300 samples are selected, 5T magnetic fields are magnetized and then are arranged into a plurality of columns, the columns are placed in magnetizing coils, so that the magnetization direction of each column of magnets is opposite to the direction of a magnetic field generated by the magnetizing coils, and reverse magnetic field demagnetization stabilization treatment is carried out. The magnetizing coil current was controlled so that the magnetic field generated was 13.2kOe. After the reverse magnetic field demagnetizing and stabilizing treatment, each magnet was tested individually for high temperature demagnetizing rate at 80 ℃ for 1 hour. The average value of the high-temperature demagnetizing rate of 300 magnets is-1.5%, and the polar difference is 2.0%.
Example 5
A commercially available 49.5×34.5×25.5mm gauge green magnet, with br=14kgs, h, trade name N48SH was selected cJ =22.5 kOe, cut the blank magnet into small magnets with a size of 2mm diameter and 1 ∈mm height, measure the small magnet demagnetizing curve with VSM to obtain H cJ Return permeability μ =22.5 kOe r ＝1.03。
Alpha is chosen to be 0.5 and the corresponding reverse field size is 9.6kOe. 300 samples are selected, 5T magnetic fields are magnetized and then are arranged into a plurality of columns, the columns are placed in magnetizing coils, so that the magnetization direction of each column of magnets is opposite to the direction of a magnetic field generated by the magnetizing coils, and reverse magnetic field demagnetization stabilization treatment is carried out. The magnetizing coil current was controlled so that the magnetic field generated was 9.6kOe. After the reverse magnetic field demagnetization stabilization treatment, each magnet was tested individually for high temperature demagnetization rate at 140 ℃ after 1 hour. The average value of the high-temperature demagnetizing rate of 300 magnets is-3.0%, and the polar difference is 2.0%.
Comparative example 1
The magnet size is 0.9x0.5x0.8 ∈ mm, 300 sample magnets are selected for saturation magnetization, then arranged in a row and placed in a heat treatment furnace for high-temperature aging treatment at 130 ℃ for 1h, after cooling, the high-temperature demagnetization test is carried out in the same way as in example 1, the average value of the high-temperature demagnetization rate is-10.1%, the extremely bad is 5.0%, and the high-temperature demagnetization rate is higher and the consistency is bad after aging treatment.
Comparative example 2
The magnet size is 0.9x0.5x0.8 ∈ mm, 300 sample magnets are selected for saturation magnetization, pretreatment is carried out through the device and the method disclosed by CN110571042, the magnetic field in the central area is 9.8kOe, then the high-temperature demagnetization test which is the same as that of the embodiment 1 is carried out, the average value of the high-temperature demagnetization rate is-6.2%, the range is 5.0%, and therefore, the high-temperature demagnetization rate is higher and the consistency is poor after the treatment by the method, and the effect is not obvious.
The embodiments of the present application are described in detail above. Specific examples are used herein to illustrate the principles and embodiments of the present application, and the description of the above examples is only used to help understand the technical solution and core ideas of the present application. Therefore, those skilled in the art will recognize that many modifications and adaptations of the present application are possible and can be accomplished with the aid of the teaching herein within the scope of the present application. In view of the foregoing, this description should not be construed as limiting the application.
Claims (8)
1. A method of pre-treating a magnet, comprising:
placing the magnetized magnet into a magnetizing coil; and
and electrifying the magnetizing coil to enable the magnetizing coil to generate a reverse magnetic field with the magnetization direction opposite to that of the magnet, so as to pretreat the magnet.
2. The method for pretreatment of a magnet according to claim 1, further comprising: the field strength of the reverse magnetic field is determined according to the intrinsic coercive force and the recovery magnetic permeability of the magnet.
3. The method of pretreatment of a magnet according to claim 2, wherein said determining the field strength of the opposing magnetic field from the intrinsic coercivity and the return permeability of the magnet comprises: using the formula:
determining the field strength of the reverse magnetic field, wherein H is the field strength of the reverse magnetic field, H cJ Is intrinsic coercivity, mu r For restoring magnetic permeability, the coefficient alpha is 0.3-1.
4. The method of pre-treating a magnet according to claim 1, wherein the placing the magnet into the magnetizing coil comprises: a plurality of magnets are arranged in a single column or a plurality of columns and placed in the magnetizing coil.
5. The method for pretreating a magnet according to claim 1, wherein the dimension of the magnet in each direction is 3mm or less.
6. The method for pretreating a magnet according to claim 5, wherein the dimension of the magnet in each direction is 1mm or less.
7. A magnet, characterized in that it is pretreated by the pretreatment method according to any one of claims 1 to 6.
8. The magnet of claim 7, wherein the magnet is a cuboid, cube, cylinder, sphere or ellipsoid.
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| CN202111658948.2A CN116417215A (en) | 2021-12-31 | 2021-12-31 | Magnet pretreatment method and magnet |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117038258A (en) * | 2023-10-08 | 2023-11-10 | 北京中科三环高技术股份有限公司 | Demagnetizing method of permanent magnet and magnet |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117038258A (en) * | 2023-10-08 | 2023-11-10 | 北京中科三环高技术股份有限公司 | Demagnetizing method of permanent magnet and magnet |
| CN117038258B (en) * | 2023-10-08 | 2023-12-26 | 北京中科三环高技术股份有限公司 | Demagnetizing method of permanent magnet and magnet |
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