CN111292951A - Method for improving coercive force of sintered neodymium-iron-boron magnet - Google Patents
Method for improving coercive force of sintered neodymium-iron-boron magnet Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
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- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
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- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
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- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/0293—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets diffusion of rare earth elements, e.g. Tb, Dy or Ho, into permanent magnets
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Abstract
The invention discloses a method for improving the coercive force of a sintered neodymium-iron-boron magnet, which comprises the following steps: sequentially plating a heavy rare earth metal film layer and a metal aluminum film layer on the surface of the sintered neodymium iron boron magnet from inside to outside by adopting multi-target continuous magnetron sputtering, and then discharging to obtain a semi-finished product; and (3) placing the semi-finished product in a pre-vacuumizing environment for heat treatment, and cooling to obtain the high-coercivity sintered neodymium-iron-boron magnet, wherein the heat treatment process is continuously vacuumized. The method of the invention improves the dischargeable temperature after magnetron sputtering coating, thereby reducing the cooling time, simplifying the subsequent furnace charging operation, and having the advantages of saving energy and improving the production efficiency.
Description
Technical Field
The invention belongs to the field of rare earth permanent magnet materials, and particularly relates to a method for improving the coercive force of a sintered neodymium-iron-boron magnet.
Background
The sintered neodymium-iron-boron magnet is a magnetic material with the strongest magnetism so far, is widely applied to the fields of aerospace, automobile industry, electronic and electric appliances, medical instruments, energy-saving motors, new energy, wind power generation and the like, and is a permanent magnetic material which is fastest in development and has the best market prospect in the world at present. The sintered neodymium-iron-boron magnet has the outstanding advantages of high magnetic energy product, high coercive force, high energy density, high cost performance, good mechanical property and the like, and plays an important role in the high and new technology field. Through research and development for more than 30 years, reasonable alloy components and a mature preparation process are designed, so that the remanence and the maximum energy product of the sintered neodymium-iron-boron magnet reach more than 90% of a theoretical value, but the coercive force of the sintered neodymium-iron-boron magnet is less than 30% of the theoretical value, and how to improve the coercive force of the sintered neodymium-iron-boron magnet becomes an important problem in the magnetic material industry.
At present, the common method for preparing the high-coercivity sintered neodymium-iron-boron magnet is to add heavy rare earth elements Dy and/or Tb, and mainly comprises three modes: (1) dy and/or Tb metal is directly added during alloy smelting; (2) adding Dy and/or Tb-containing powder into the powder in a double-alloy mode; (3) dy and/or Tb are/is diffused in the sintered NdFeB magnet through the intergranular rare earth-rich phase. Among the three methods, the sintered NdFeB magnet containing Dy and/or Tb is prepared by a grain boundary diffusion method, has higher comprehensive magnetic performance, only consumes a small amount of Dy and/or Tb, and is the most studied method at present. The common grain boundary diffusion method for the sintered neodymium-iron-boron magnet at present comprises the following steps: surface coating + heat treatment, vapor deposition + heat treatment, magnetron sputtering + heat treatment and the like. The magnetron sputtering and heat treatment process has the characteristics of good coating consistency, stable process and stable and controllable product performance, is a sintered neodymium iron boron magnet grain boundary diffusion mode with the greatest industrialization prospect, and can further improve the coating efficiency by using continuous magnetron sputtering coating equipment.
However, the current method for depositing the heavy rare earth metal film layer for grain boundary diffusion by direct magnetron sputtering also has certain disadvantages, which are mainly expressed in that: (1) in the magnetron sputtering process, the magnet can generate certain temperature rise, in order to prevent the heavy rare earth metal film layer plated on the surface of the magnet from being oxidized, the magnet must be cooled to below 80 ℃ after magnetron sputtering for discharging, and in order to cool the magnet after coating to below 80 ℃, the time of more than 20 minutes is usually required, which greatly restricts the further improvement of the production efficiency of continuous coating equipment; (2) a magnet coated with a heavy rare earth film layer on the surface thereofWhen the subsequent heat treatment is carried out in the furnace, the magnets must be separated from each other, otherwise, the two magnets which are contacted with each other can be adhered, which brings great trouble to the placing of the coated magnets in the furnace; (3) the vacuum in the furnace must be sufficiently high (usually better than 1X 10) before the temperature of the heat treatment is raised-2Pa), otherwise, the residual air in the furnace can oxidize the heavy rare earth metal layer covered on the surface of the magnet in the heating process, and the diffusion effect is influenced. These deficiencies directly affect the further improvement of the production efficiency of the continuous magnetron sputtering for sintering the grain boundary diffusion of the neodymium iron boron magnet.
Disclosure of Invention
In view of the above, the present invention needs to provide a method for improving the coercivity of a sintered ndfeb magnet, in which a metal aluminum film is covered on the surface layer of a heavy rare earth metal film formed on the surface of the magnet by magnetron sputtering, and the metal aluminum film is used to protect the heavy rare earth metal film, thereby improving the dischargeable temperature after magnetron sputtering coating, reducing the cooling time, simplifying furnace entering operation, saving energy, improving production efficiency, and solving the problem of grain boundary diffusion of the sintered ndfeb magnet by current continuous magnetron sputtering.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for improving the coercive force of a sintered neodymium-iron-boron magnet comprises the following steps:
film coating: sequentially plating a heavy rare earth metal film layer and a metal aluminum film layer on the surface of the sintered neodymium iron boron magnet from inside to outside by adopting multi-target continuous magnetron sputtering, and then discharging to obtain a semi-finished product;
and (3) heat treatment: and (3) placing the semi-finished product in a pre-vacuumizing environment for heat treatment, and cooling to obtain the high-coercivity sintered neodymium-iron-boron magnet, wherein the heat treatment process is continuously vacuumized.
Further, the sintered neodymium-iron-boron magnet is prepared by a powder metallurgy process and takes an RE2Fe14B phase as a main magnetic phase, wherein RE is at least one of rare earth elements.
Further, the coating step is completed by adopting a multi-target continuous magnetron sputtering coating device, wherein the multi-target continuous magnetron sputtering coating device comprises a preparation chamber, a cleaning chamber, a coating chamber and a cooling chamber.
Preferably, N magnetron sputtering sources are sequentially arranged in the coating chamber, wherein N is more than or equal to 2, the magnetron sputtering sources from 1 st to N-1 st are configured as heavy rare earth metal targets, and the magnetron sputtering source from N is configured as a metal aluminum target.
Furthermore, the total thickness of the heavy rare earth metal film layer is 1-15 mu m, wherein the heavy rare earth metal is at least one of dysprosium and terbium, and the thickness of the metal aluminum film layer is 0.5-2 mu m.
Further, the temperature of the discharged material is 100-200 ℃.
Furthermore, the vacuum degree of the pre-vacuumizing is 1-100 Pa.
Further, the heat preservation temperature of the heat treatment is 800-900 ℃, and the heat preservation time is 5-40 h.
Further, the heat treatment step further comprises a secondary heat treatment step.
Preferably, the temperature of the secondary heat treatment is 460-600 ℃, and the time is 3-6 h.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the sintered neodymium-iron-boron magnet, the metal aluminum film is covered on the surface layer of the heavy rare earth metal film, the heavy rare earth metal film is protected by the metal aluminum film, the discharging temperature after magnetron sputtering coating is improved, the cooling time is reduced, the energy is saved, and the production efficiency is improved.
2. After discharging, the surface metal aluminum film is oxidized into an aluminum oxide film by means of the residual temperature of the magnet and the surface film layer, so that the oxidation of the terbium film layer on the surface of the magnet in the period from the coating end to the heat treatment can be effectively reduced, the mutual adhesion between the magnets in the subsequent heat treatment process is prevented, and the furnace entering operation is simplified.
3. The requirement of vacuum degree in the vacuum heat treatment temperature rise forehearth is low, the pre-vacuumizing time can be shortened, the energy is saved, and the production efficiency is improved.
Detailed Description
In order that the invention may be more fully understood, reference will now be made to the specific embodiments illustrated. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
The invention discloses a method for improving the coercive force of a sintered neodymium-iron-boron magnet, which comprises the following steps:
film coating: sequentially plating a heavy rare earth metal film layer and a metal aluminum film layer on the surface of the sintered neodymium iron boron magnet from inside to outside by adopting multi-target continuous magnetron sputtering, and then discharging to obtain a semi-finished product;
and (3) heat treatment: and (3) placing the semi-finished product in a pre-vacuumizing environment for heat treatment, and cooling to obtain the high-coercivity sintered neodymium-iron-boron magnet, wherein the heat treatment process is continuously vacuumized.
According to the invention, through multi-target continuous magnetron sputtering coating, firstly, the surface of the sintered neodymium iron boron magnet is plated with the heavy rare earth metal film layer, and then the surface of the heavy rare earth metal film layer is plated with the metal aluminum film layer, so that the metal aluminum film layer can protect the heavy rare earth metal film, thereby improving the dischargeable temperature after magnetron sputtering coating and reducing the cooling time. In addition, after discharging, with the help of the residual heat of the magnet and the surface film layer, the metal aluminum film on the surface layer can be oxidized to form an aluminum oxide film, so that the adhesion between the magnets in the subsequent heat treatment process can be prevented; furthermore, because of the surface metal aluminum film layer, the requirement on the vacuum degree before the temperature rise of the vacuum heat treatment is low, and the effects of saving energy and improving the production efficiency are obvious.
Furthermore, the sintered neodymium-iron-boron magnet is prepared by a powder metallurgy process and is prepared from RE2Fe14A magnet having a B phase as a main magnetic phase, wherein RE is at least one of rare earth elementsIt is to be understood that the rare earth metals are conventional in the art and, therefore, are not described in detail herein.
Further, the coating step is completed by adopting a multi-target continuous magnetron sputtering coating device, wherein the multi-target continuous magnetron sputtering coating device comprises a preparation chamber, a cleaning chamber, a coating chamber and a cooling chamber. During the specific operation, the neodymium iron boron magnet to be processed is sequentially sent into a preparation chamber for vacuumizing, a cleaning chamber for ion cleaning, a coating chamber for coating and a cooling chamber for cooling, and it can be understood that specific processing parameters are not limited, and a person skilled in the art can adjust the thickness of the prepared film according to the final requirement.
Furthermore, N magnetron sputtering sources are sequentially arranged in the film plating chamber, wherein N is greater than or equal to 2, the 1 st to the N-1 st magnetron sputtering sources are configured as heavy rare earth metal targets, the nth magnetron sputtering source is configured as a metal aluminum target, and it should be noted that the configuration number of the heavy rare earth metal targets is determined according to the number of layers of the heavy rare earth metal film layer formed by final sputtering, and therefore, no specific limitation is made.
The total thickness of the heavy rare earth metal film layer and the thickness of the metal aluminum film layer are mainly determined according to the thickness of the matrix magnet, and are usually 0.1-0.3% of the thickness of the magnet, so in some specific embodiments of the invention, the total thickness of the heavy rare earth metal film layer is 1-15 μm, wherein the heavy rare earth metal is selected from at least one of dysprosium and terbium, and the thickness of the metal aluminum film layer is 0.5-2 μm.
Furthermore, because the surface layer of the heavy rare earth metal film layer is plated with the metal aluminum film layer, the requirement on the vacuum degree before heat treatment is low, and in some embodiments of the invention, the vacuum degree of the pre-vacuumizing is 1-100 Pa, so that the pre-vacuumizing time is shortened, the energy is saved, and the production efficiency is improved.
Furthermore, the residual temperature of the magnet and the surface film layer is used for oxidizing the metal aluminum film on the surface to form an aluminum oxide film, so that the mutual adhesion between the magnets in the subsequent heat treatment process is prevented, and in some embodiments of the invention, the discharging temperature is 100-200 ℃.
Further, after the plating and film forming, the semi-finished product is subjected to heat treatment, so that heavy rare earth in the heavy rare earth metal film layer is diffused into the magnet, and the coercive force of the magnet is improved.
Further, the method also comprises a secondary heat treatment step after discharging.
Further, the temperature of the secondary heat treatment is 460-600 ℃, and the time is 3-6 hours.
The invention will be more clearly and completely described below with reference to specific examples.
Example 1
Using 3-target continuous magnetron sputtering equipment, a magnet I (N52, main component Nd) with the specification of 40mm multiplied by 30mm multiplied by 3mm30Fe69B1Wt.%) two 40mm x 30mm surfaces are respectively deposited with a 5 μm terbium metal film layer and a 1 μm aluminum metal film layer from inside to outside, the magnet is taken out of a magnetron sputtering device when the temperature of the magnet is 120 ℃, the surfaces of two magnets coated with the film layers are attached and then put into a high vacuum sintering furnace for high temperature heat treatment, the temperature in the furnace before the heat treatment is increased to 35 ℃, the vacuum degree is 50Pa, the temperature increasing speed is 10 ℃/min, after the temperature is maintained for 20 hours at 800 ℃, high purity argon is introduced to start cooling, the magnet is taken out when the temperature is reduced to 75 ℃, and the magnet is subjected to heat treatment for 3 hours at 500 ℃ to obtain the magnet of the example 1.
Comparative example 1
Depositing a 5-micron terbium metal film layer on the surface of the magnet I which is the same as the magnet I in the embodiment 1 by using 3-target continuous magnetron sputtering equipment, taking the magnet I out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, separating a plurality of magnets, putting the magnets into a high-vacuum sintering furnace for high-temperature heat treatment, wherein the vacuum degree in the furnace before temperature rise is better than 1 x 10-2Pa, the remaining heat treatment process was the same as in example 1, and the magnet finally obtained was labeled as comparative example 1.
Comparative example 2
The same magnetism as in example 1 was applied by using a 3-target continuous magnetron sputtering apparatusDepositing a 5-micron terbium metal film layer on the surface of the body I, taking the body I out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, putting the magnet into a high-vacuum sintering furnace for high-temperature heat treatment in the same way as in the embodiment 1, wherein the vacuum degree in the furnace before temperature rise is better than 1 multiplied by 10-2Pa, the remaining heat treatment process was the same as in example 1, and the magnet finally obtained was labeled as comparative example 2.
Comparative example 3
Depositing a 5-micron terbium metal film layer on the surface of the magnet I which is the same as the magnet I in the embodiment 1 by using 3-target continuous magnetron sputtering equipment, taking the magnet I out of the magnetron sputtering equipment when the temperature of the magnet is 120 ℃, separating a plurality of magnets, putting the magnets into a high-vacuum sintering furnace for high-temperature heat treatment, wherein the vacuum degree in the furnace before temperature rise is better than 1 x 10-2Pa, the remaining heat treatment process was the same as in example 1, and the magnet finally obtained was labeled as comparative example 3.
Comparative example 4
A 5-micron terbium metal film layer is deposited on the surface of the magnet I which is the same as that in the embodiment 1 by using 3-target continuous magnetron sputtering equipment, the magnet I is taken out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, a plurality of magnets are separated and then put into a high-vacuum sintering furnace for high-temperature heat treatment, the heat treatment process is the same as that in the embodiment 1, and the finally obtained magnet is marked as a comparative example 4.
The magnetic properties of example 1 and comparative examples 1-4 were tested by comparison at room temperature (23 + -1 ℃) using a magnetic property tester according to the requirements of GB/T3217-2013 permanent magnetic (hard magnetic) material-magnetic property test method, and are listed in attached Table 1.
Table 1 magnet-related tests obtained in example 1 and comparative examples 1 to 4
The data comparison of the attached table 1 shows that the magnet of the comparative example 1 can avoid adhesion between magnets and improve the coercive force of the magnet, the magnet of the comparative example 2 is directly attached, the discharge temperature of the comparative example 3 can influence the coercive force improvement range, and the vacuum degree of the comparative example 4 before temperature rise can influence the coercive force improvement range. The coercive force improvement range of the embodiment 1 adopting the technology of the invention is similar to that of the comparative example 1, but the discharge temperature after film coating is improved, the heat treatment placing requirement is reduced, the pre-vacuumizing time is shortened, and the production efficiency is improved.
Example 2
Using 4-target continuous magnetron sputtering equipment, a magnet II (grade 50M, main component Nd) with the specification of 35mm multiplied by 30mm multiplied by 4mm30Dy1Fe68B1Wt.%) two 35mm x 30mm surfaces are respectively deposited with 10 μm dysprosium metal film layer and 1.5 μm aluminum metal film layer from inside to outside, the magnet is taken out of the magnetron sputtering device when the temperature is 160 ℃, the film layers on the surfaces of the two magnets are directly attached and then put into a high vacuum sintering furnace for high temperature heat treatment, the temperature in the furnace before the heat treatment is increased to 35 ℃, the vacuum degree is 80Pa, the temperature increasing speed is 10 ℃/min, after the temperature is maintained at 850 ℃ for 30 hours, high-purity argon is introduced to start cooling, the magnet is taken out when the temperature is cooled to 75 ℃, and the magnet is subjected to heat treatment at 460 ℃ for 5 hours to obtain the magnet of the example 2.
Comparative example 5
Depositing a 10 mu m dysprosium metal film layer on the surface of the magnet II which is the same as the magnet II in the embodiment 2 by using 4-target continuous magnetron sputtering equipment, taking the magnet out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, separating a plurality of magnets, then putting the magnets into a high vacuum sintering furnace for high-temperature heat treatment, wherein the vacuum degree in the furnace before temperature rise is better than 5 multiplied by 10-3Pa, the remaining heat treatment process was the same as in example 2, and the magnet finally obtained was labeled as comparative example 5.
Comparative example 6
Depositing a 10 mu m dysprosium metal film layer on the surface of the magnet II which is the same as the magnet II in the embodiment 2 by using 4-target continuous magnetron sputtering equipment, taking the magnet out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, putting the magnet into a high-vacuum sintering furnace for high-temperature heat treatment in the same way as the embodiment 2, wherein the vacuum degree in the furnace before temperature rise is better than 5 multiplied by 10-3Pa, the remaining heat treatment process was the same as in example 2, and the magnet finally obtained was designated as comparative example 6.
Comparative example 7
Depositing a 10 mu m dysprosium metal film layer on the surface of the magnet II which is the same as the magnet II in the embodiment 2 by using 4-target continuous magnetron sputtering equipment, taking the magnet II out of the magnetron sputtering equipment when the temperature of the magnet is 160 ℃, separating a plurality of magnets, putting the magnets into a high vacuum sintering furnace for high-temperature heat treatment, wherein the vacuum degree in the furnace before temperature rise is better than 5 multiplied by 10-3Pa, the remaining heat treatment process was the same as in example 2, and the magnet finally obtained was designated as comparative example 7.
Comparative example 8
A 10-micron dysprosium metal film layer is deposited on the surface of the magnet II which is the same as that in the embodiment 2 by using 4-target continuous magnetron sputtering equipment, the magnet II is taken out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, a plurality of magnets are separated and then put into a high-vacuum sintering furnace for high-temperature heat treatment, the heat treatment process is the same as that in the embodiment 2, and the finally obtained magnet is marked as a comparative example 8.
The magnetic properties of the example 2 and the comparative examples 5 to 8 were compared and tested at room temperature (23 +/-1 ℃) by using a magnetic property tester according to the requirements of the GB/T3217-2013 permanent magnetic (hard magnetic) material-magnetic property test method, and are listed in the attached Table 2.
Table 2 magnet-related tests obtained in example 2 and comparative examples 5 to 8
| Sample number | Example 2 | Comparative example 5 | Comparative example 6 | Comparative example 7 | Comparative example 8 |
| Initial magnet | Ⅱ | Ⅱ | Ⅱ | Ⅱ | Ⅱ |
| Heavy rare earth metals | Dy | Dy | Dy | Dy | Dy |
| Thickness of heavy rare earth film layer | 10 | 10 | 10 | 10 | 10 |
| Thickness of aluminum metal film layer | 1.5 | 0 | 0 | 0 | 0 |
| Temperature of magnetron sputtering material | 160 | 60 | 60 | 160 | 60 |
| Heat treatment placing mode | Bonding | Separation of | Bonding | Separation of | Separation of |
| Degree of vacuum Pa before temperature rise | 80 | 5×10-3 | 5×10-3 | 5×10-3 | 80 |
| Diffusion heat treatment process at ℃xhour | 850×30 | 850×30 | 850×30 | 850×30 | 850×30 |
| Complement heat treatment process at ℃xhour | 460×5 | 460×5 | 460×5 | 460×5 | 460×5 |
| Average coercivity improvement amplitude kOe | 5.25 | 5.38 | 5.20 | 4.48 | 4.37 |
| Whether or not toAdhesion of the components | Whether or not | Whether or not | Is that | Whether or not | Whether or not |
The data comparison of the attached table 2 shows that the magnet of the comparative example 5 can avoid the adhesion between the magnets and improve the coercive force of the magnet, the magnet of the comparative example 6 is directly attached, the coercive force improving range can be influenced by the discharge temperature of the comparative example 7, and the coercive force improving range can be influenced by the vacuum degree before the temperature rise of the comparative example 8. The coercive force improvement range of the embodiment 2 adopting the technology of the invention is close to that of the comparative example 5, but the discharge temperature after film coating is improved, the heat treatment placing requirement is reduced, the pre-vacuumizing time is shortened, and the production efficiency is improved.
Example 3
Using 5-target continuous magnetron sputtering equipment, a magnet III (grade 50H, main component Nd) with the specification of 30mm multiplied by 25mm multiplied by 6mm is adopted30Tb1Fe68B1Wt.%) two 30mm × 25mm surfaces are respectively deposited with a 15 μm terbium metal film layer and a 2 μm aluminum metal film layer from inside to outside, the magnets are taken out of a magnetron sputtering device when the temperature is 200 ℃, the film layers on the surfaces of the two magnets are directly attached and then are put into a high vacuum sintering furnace for high temperature heat treatment, the temperature in the furnace before the temperature rise of the heat treatment is 35 ℃, the vacuum degree is 100Pa, the temperature rise speed is 10 ℃/min, after the temperature is kept at 880 ℃ for 40 hours, high-purity argon is introduced to start cooling, the magnets are taken out when the temperature is cooled to 75 ℃, and the magnets are subjected to heat treatment at 550 ℃ for 6 hours to obtain the magnets of the embodiment 3.
Comparative example 9
Utilizing 5-target continuous magnetron sputtering equipment, depositing a 15-micron terbium metal film layer on the surface of the magnet III which is the same as that in the embodiment 3, taking the magnet out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, separating a plurality of magnets, then placing the magnets into a high-vacuum sintering furnace for high-temperature heat treatment, wherein the vacuum degree in the furnace before temperature rise is superior to 8 multiplied by 10-3Pa, the remaining heat treatment process was the same as in example 3, and the magnet finally obtained was designated as comparative example 9.
Comparative example 10
Depositing a 15 mu m terbium metal film layer on the surface of the magnet III by using 5-target continuous magnetron sputtering equipment, taking the magnet out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, loading the magnet into a high-vacuum sintering furnace for high-temperature heat treatment in the same way as in the example 3, wherein the vacuum degree in the furnace before temperature rise is better than 8 multiplied by 10-3Pa, the remaining heat treatment process was the same as in example 3, and the magnet finally obtained was designated as comparative example 10.
Comparative example 11
Utilizing 5-target continuous magnetron sputtering equipment, depositing a 15-micron terbium metal film layer on the surface of the magnet III which is the same as that in the embodiment 3, taking the magnet out of the magnetron sputtering equipment when the temperature of the magnet is 200 ℃, separating a plurality of magnets, then putting the magnets into a high-vacuum sintering furnace for high-temperature heat treatment, wherein the vacuum degree in the furnace before temperature rise is superior to 8 multiplied by 10-3Pa, the remaining heat treatment process was the same as in example 3, and the magnet finally obtained was designated as comparative example 11.
Comparative example 12
A 15-micron terbium metal film layer was deposited on the surface of the magnet III, which was the same as in example 3, using 5-target continuous magnetron sputtering equipment, and taken out of the magnetron sputtering equipment at a magnet temperature of 60 ℃, the plurality of magnets were separated and then put into a high-vacuum sintering furnace for high-temperature heat treatment, the heat treatment process was the same as in example 3, and the magnet obtained finally was labeled as comparative example 12.
The magnetic properties of example 3 and comparative examples 9-12 were tested by comparison at room temperature (23 + -1 ℃) using a magnetic property tester according to the requirements of GB/T3217-2013 permanent magnetic (hard magnetic) material-magnetic property test method, and are listed in the attached Table 3.
Table 3 magnet-related tests obtained in example 3 and comparative examples 9 to 12
From the data comparison of the attached table 3, it can be found that the magnet coercive force can be improved by the comparative example 9 by avoiding the adhesion between the magnets, the magnet coercive force can be improved by the direct attachment of the magnet of the comparative example 10, the coercive force improvement range can be influenced by the discharge temperature of the comparative example 11, and the coercive force improvement range can be influenced by the vacuum degree before the temperature rise of the comparative example 12. The coercive force improvement range of the embodiment 3 adopting the technology of the invention is close to that of the comparative example 9, but the discharge temperature after film coating is improved, the heat treatment placing requirement is reduced, the pre-vacuumizing time is shortened, and the production efficiency is improved.
Example 4
Using 2-target continuous magnetron sputtering equipment, a magnet IV (with a mark of 48SH and a main component of (PrNd) with a specification of 12mm multiplied by 10mm multiplied by 1mm is used29Tb2Fe68B1Wt.%) two 12mm × 10mm surfaces are respectively deposited with a 1 μm terbium metal film layer and a 0.5 μm aluminum metal film layer from inside to outside, the magnet is taken out of the magnetron sputtering device when the temperature of the magnet is 100 ℃, the film layers on the surfaces of the two magnets are directly attached and then are put into a high vacuum sintering furnace for high temperature heat treatment, the temperature in the furnace before the heat treatment is increased to 35 ℃, the vacuum degree is 1Pa, the temperature increasing speed is 10 ℃/min, high-purity argon is introduced to start cooling after the heat is preserved for 5 hours at 900 ℃, the magnet is taken out when the temperature is reduced to 75 ℃, and the magnet is subjected to heat treatment for 3 hours at 600 ℃ to obtain the magnet of the example 4.
Comparative example 13
Depositing a 1 mu m terbium metal film layer on the surface of the magnet IV which is the same as the magnet IV in the embodiment 4 by using 2-target continuous magnetron sputtering equipment, taking the magnet IV out of the magnetron sputtering equipment when the temperature of the magnet is 60 ℃, separating a plurality of magnets, putting the magnets into a high-vacuum sintering furnace for high-temperature heat treatment, wherein the vacuum degree in the furnace before temperature rise is better than 8 multiplied by 10-3Pa, the remaining heat treatment process was the same as in example 4, and the magnet finally obtained was designated as comparative example 13.
Comparative example 14
A1-micron terbium metal film layer was deposited on the surface of the magnet IV, which was the same as in example 4, using a 2-target continuous magnetron sputtering apparatus, and was taken out at a magnet temperature of 60 ℃ for magnetron sputteringA sputtering apparatus was used in which the magnet was charged into a high-vacuum sintering furnace for high-temperature heat treatment in the same manner as in example 4, and the degree of vacuum in the furnace before the temperature rise was better than 8X 10-3Pa, the remaining heat treatment process was the same as in example 4, and the magnet finally obtained was designated as comparative example 14.
Comparative example 15
Depositing a 1 mu m terbium metal film layer on the surface of the magnet IV which is the same as the magnet IV in the embodiment 4 by using 2-target continuous magnetron sputtering equipment, taking the magnet IV out of the magnetron sputtering equipment when the temperature of the magnet is 100 ℃, separating a plurality of magnets, putting the magnets into a high vacuum sintering furnace for high-temperature heat treatment, wherein the vacuum degree in the furnace before temperature rise is better than 8 multiplied by 10-3Pa, the remaining heat treatment process was the same as in example 4, and the magnet finally obtained was designated as comparative example 15.
Comparative example 16
A 2-target continuous magnetron sputtering device is utilized to deposit a 1-micron terbium metal film layer on the surface of the magnet IV which is the same as that in the embodiment 4, the magnet IV is taken out of the magnetron sputtering device when the temperature of the magnet is 60 ℃, a plurality of magnets are separated and then put into a high-vacuum sintering furnace for high-temperature heat treatment, the heat treatment process is the same as that in the embodiment 4, and the finally obtained magnet is marked as a comparative example 16.
The magnetic properties of example 4 and comparative examples 13-16 were tested by comparison at room temperature (23 + -1 ℃) using a magnetic property tester according to the requirements of GB/T3217-2013 permanent magnetic (hard magnetic) material-magnetic property test method, and are listed in the attached Table 4.
From the data comparison of the attached table 4, it can be found that the magnet coercive force can be improved by the comparative example 13 by avoiding the adhesion between the magnets, the magnet coercive force can be improved by the comparative example 14 by direct bonding, the coercive force improvement range can be influenced by the discharge temperature of the comparative example 15, and the coercive force improvement range can be influenced by the vacuum degree before the temperature rise of the comparative example 16. The coercive force improvement range of the embodiment 4 adopting the technology of the invention is similar to that of the comparative example 13, but the discharge temperature after film coating is improved, the heat treatment placing requirement is reduced, the pre-vacuumizing time is shortened, and the production efficiency is improved.
Table 4 magnet-related tests obtained in example 4 and comparative examples 13 to 16
In summary, the examples and comparative examples and the test results in tables 1 to 4 show that the invention improves the discharge temperature after coating, reduces the requirement for heat treatment placement, shortens the pre-vacuum time and improves the production efficiency while ensuring the improvement of the coercive force.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A method for improving the coercive force of a sintered neodymium-iron-boron magnet is characterized by comprising the following steps:
film coating: sequentially plating a heavy rare earth metal film layer and a metal aluminum film layer on the surface of the sintered neodymium iron boron magnet from inside to outside by adopting multi-target continuous magnetron sputtering, and then discharging to obtain a semi-finished product;
and (3) heat treatment: and (3) placing the semi-finished product in a pre-vacuumizing environment for heat treatment, and cooling to obtain the high-coercivity sintered neodymium-iron-boron magnet, wherein the heat treatment process is continuously vacuumized.
2. Such asThe method for improving the coercivity of a sintered NdFeB magnet of claim 1, wherein the sintered NdFeB magnet is prepared by a powder metallurgy process and is prepared from RE2Fe14And a B phase which is a magnet of a main magnetic phase, wherein RE is at least one of rare earth elements.
3. The method for improving the coercivity of the sintered neodymium-iron-boron magnet according to claim 1, wherein the coating step is performed by using a multi-target continuous magnetron sputtering coating device, wherein the multi-target continuous magnetron sputtering coating device comprises a preparation chamber, a cleaning chamber, a coating chamber and a cooling chamber.
4. The method for improving the coercivity of the sintered NdFeB magnet according to claim 3, wherein N magnetron sputtering sources are sequentially arranged in the coating chamber, wherein N is more than or equal to 2, the 1 st to the N-1 st magnetron sputtering sources are configured as heavy rare earth metal targets, and the Nth magnetron sputtering source is configured as a metal aluminum target.
5. The method for improving the coercivity of the sintered neodymium-iron-boron magnet according to claim 1, wherein the total thickness of the heavy rare earth metal film layer is 1-15 μm, the heavy rare earth metal is at least one of dysprosium and terbium, and the thickness of the metal aluminum film layer is 0.5-2 μm.
6. The method for improving the coercivity of the sintered neodymium-iron-boron magnet according to claim 1, wherein the discharging temperature is 100-200 ℃.
7. The method for improving the coercivity of the sintered neodymium-iron-boron magnet according to claim 1, wherein the degree of vacuum of the pre-vacuum is 1-100 Pa.
8. The method for improving the coercive force of the sintered neodymium-iron-boron magnet according to claim 1, wherein the heat preservation temperature of the heat treatment is 800-900 ℃, and the heat preservation time is 5-40 h.
9. The method for improving the coercivity of a sintered neodymium-iron-boron magnet according to claim 1, wherein the heat treatment step is further followed by a secondary heat treatment step.
10. The method for improving the coercivity of the sintered neodymium-iron-boron magnet according to claim 9, wherein the temperature of the secondary heat treatment is 460-600 ℃ and the time is 3-6 hours.
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| CN112017832A (en) * | 2020-08-20 | 2020-12-01 | 合肥工业大学 | Low-heavy rare earth high-performance sintered neodymium-iron-boron magnet and preparation method thereof |
| CN112466645A (en) * | 2020-11-23 | 2021-03-09 | 北京麦戈龙科技有限公司 | Method for preparing rare earth permanent magnet |
| CN112670073A (en) * | 2020-12-23 | 2021-04-16 | 北京麦戈龙科技有限公司 | Sintered neodymium iron boron grain boundary diffusion tool and grain boundary diffusion method |
| CN112820529A (en) * | 2020-12-31 | 2021-05-18 | 宁波松科磁材有限公司 | Preparation method of high-performance sintered neodymium iron boron |
| CN112927921A (en) * | 2021-03-18 | 2021-06-08 | 昆明理工大学 | Method for preparing high-coercivity sintered neodymium-iron-boron magnet through crystal boundary diffusion |
| CN113314327A (en) * | 2021-06-02 | 2021-08-27 | 中国科学院力学研究所 | Method for grain boundary diffusion of multi-element heavy rare earth of sintered neodymium-iron-boron magnet |
| CN113838660A (en) * | 2021-11-25 | 2021-12-24 | 天津三环乐喜新材料有限公司 | Vacuum coating equipment and method for surface protection of neodymium iron boron rare earth permanent magnet device |
| CN114141522A (en) * | 2021-11-18 | 2022-03-04 | 安徽大地熊新材料股份有限公司 | Method for improving coercive force of sintered neodymium-iron-boron magnet and application |
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Denomination of invention: A method to improve the Coercivity of sintered Nd-Fe-B magnets Effective date of registration: 20230713 Granted publication date: 20220322 Pledgee: Hefei Science and Technology Rural Commercial Bank Co.,Ltd. Lujiang Branch Pledgor: EARTH-PANDA ADVANCE MAGNETIC MATERIAL Co.,Ltd. Registration number: Y2023980048226 |