CN108022707B - Thermal treatment process for thermal deformation or reverse extrusion of Nd-Fe-B magnet - Google Patents
Thermal treatment process for thermal deformation or reverse extrusion of Nd-Fe-B magnet Download PDFInfo
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- CN108022707B CN108022707B CN201610962511.0A CN201610962511A CN108022707B CN 108022707 B CN108022707 B CN 108022707B CN 201610962511 A CN201610962511 A CN 201610962511A CN 108022707 B CN108022707 B CN 108022707B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- 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
- H01F1/0576—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 pressed, e.g. hot working
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
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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
- H01F41/0266—Moulding; Pressing
Abstract
The invention relates to a heat treatment process for thermally deforming or reversely extruding an Nd-Fe-B magnet, which comprises the following steps of: (1) preparing magnet powder into an isotropic Nd-Fe-B magnet with fine grains by using a hot-pressing sintering method; (2) preparing an Nd-Fe-B magnet with anisotropy by using a thermal deformation technology or a reverse extrusion molding technology; (3) Nd-Fe-B magnets having anisotropy are subjected to high-temperature-short-time heat treatment. Compared with the prior art, the method adopts different heat treatment temperature and time combinations, can independently improve the remanent magnetization of the magnet, can also independently improve the coercive force of the magnet, and can simultaneously realize the improvement of the remanent magnetization and the coercive force. After the invention is adopted, on one hand, the magnetic performance of the hot-deformed or reversely extruded magnet can be effectively improved, and on the other hand, the adopted high-temperature-short-time heat treatment process is simple to operate and short in process time, and the production efficiency can be greatly improved.
Description
Technical Field
The invention belongs to the field of magnetic materials, and relates to a heat treatment process of anisotropic nanocrystalline Nd-Fe-B, in particular to a heat treatment process of a thermally deformed or reversely extruded Nd-Fe-B magnet.
Background
The rare earth iron-based permanent magnetic material has undergone great development since the coming of the last century, and has been developed into a third-generation permanent magnetic material represented by neodymium iron boron, which has a series of advantages of high magnetic performance, wide application, rapid development and the like.
The neodymium iron boron permanent magnet mainly comprises a sintered neodymium iron boron magnet, a bonded neodymium iron boron magnet and a thermal deformation or reverse extrusion neodymium iron boron magnet. The bonded neodymium iron boron magnet has low rare earth content, and has the outstanding advantages of high dimensional precision, no deformation, no need of secondary processing and convenient mass production. The disadvantage is that the low rare earth content leads to low magnetic performance and is difficult to apply at higher temperature. The sintered Nd-Fe-B magnet has excellent magnetic performance because of containing a certain amount of heavy rare earth elements, and is the permanent magnet with the highest yield and the widest application so far. However, with the rising price of rare earth elements in recent years, especially the price of heavy rare earth elements dysprosium (Dy) and terbium (Tb) reaches ten thousand yuan per kilogram, which directly leads to the increase of the cost of sintered magnets. The heat-deformed or reversely extruded Nd-Fe-B magnet can still keep higher coercive force without dysprosium (Dy) and terbium (Tb), and has lower price compared with a sintered magnet. In addition, the thermal deformation magnet and the reverse extrusion magnet have a nanocrystalline structure, the refinement of crystal grains is beneficial to the reduction of forming pressure and the improvement of coercive force, and near-net forming can be realized.
For a long time, the same international and domestic common belief is that nanocrystalline Nd-Fe-B magnets have fine crystal grains, and the crystal grains are easily induced to grow by heat treatment at a certain temperature, so that the performance of the magnets is reduced, and the heat treatment process at a low temperature hardly has any influence on the performance of the deformed magnets, so that the research on improving the performance of the heat deformed magnets or reversely extruding the magnets by the heat treatment process has not been effectively improved. With the expansion of the application field and demand of the hot-deformed or reverse-extruded magnet in the market in recent years, the magnet is required to have more excellent magnetic properties such as coercive force and residual magnetization in terms of performance. In recent years, grain boundary diffusion has become an important method for improving the coercive force of a hot-pressed or hot-deformed magnet, however, the residual magnetization of the deformed magnet is often seriously reduced due to the large amount of penetration of a non-magnetic grain boundary phase, and meanwhile, the grain boundary diffusion process has certain complexity in the actual operation process, so that the grain boundary diffusion process is difficult to be widely applied in the actual production.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a heat treatment process for thermally deforming or reversely extruding an Nd-Fe-B magnet, which has high efficiency, stable process and reliable quality. The invention utilizes a high-temperature-short-time heat treatment process to improve the coercive force and residual magnetization intensity of the Nd-Fe-B magnet through thermal deformation or reverse extrusion.
The purpose of the invention can be realized by the following technical scheme:
a heat treatment process for thermally deforming or back-extruding an Nd-Fe-B magnet, comprising the steps of:
(1) preparing magnet powder into an isotropic Nd-Fe-B magnet with fine grains by using a hot-pressing sintering method;
(2) preparing an Nd-Fe-B magnet with anisotropy by using a thermal deformation technology or a reverse extrusion molding technology;
(3) Nd-Fe-B magnets having anisotropy are subjected to high-temperature-short-time heat treatment.
Preferably, the powder used in the preparation of the isotropic Nd-Fe-B magnet having fine grains in step (1) above may be Nd-Fe-B quenched powder alone or a mixture of Nd-Fe-B and another alloy.
The mass fraction of other alloys in the powder mixed by Nd-Fe-B and other alloys is 2-30%,
the other alloys comprise Nd-Cu, Nd-Cu-X1, Nd-Zn, Nd-Zn-X2, Nd-Dy, Nd-Dy-X3, Nd-Al, Nd-Al-X4, Pr-Cu, Pr-Zn, Ce-Cu, Ce-Al or Ce-Pr-X5 alloys;
x1 ═ Ga, Al, Co, Pr or Zn, X2 ═ Ga, Al, Co or Pr, X3 ═ Ga, Al, Co, Cu, Pr or Zn, X4 ═ Pr, Cu, Co, Ga or Zn, X5 ═ Ga, Al, Co, Pr or Zn.
Preferably, the melting point of the Nd-Fe-B powder in step (1) or the powder after mixing Nd-Fe-B with other alloys should be higher than the heat distortion temperature in step (2), but should be lower than the heat treatment temperature in step (3).
Preferably, when the hot-pressing sintering method in the step (1) is used for sintering, the temperature is 600-750 ℃, the hot-pressing pressure is 50-350MPa, and the vacuum degree is 10-1-10-4Pa, and the sintering time is 3-30 min.
Preferably, the operating conditions of the hot deformation technique in step (2) are: the temperature is 650-850 ℃, and the thermal deformation speed is 10-1-10mm/min, vacuum degree 10-1-10-4Pa, heat distortion degree 55-80%.
Preferably, the operating conditions of the backward extrusion technique in step (2) are: the Nd-Fe-B magnet is hot-pressed at the temperature of 600-750 ℃ and reversely extruded at the temperature of 750-900 ℃ so as to obtain the annular magnet, the deformation mechanism of the annular magnet is consistent with that of a thermal deformation magnet, the annular magnet is widely applied to industrial production, and the thermal deformation technology is forward deformation and is mainly researched and used in a laboratory.
Preferably, the high temperature in step (3) above is generally between 750 ℃ and 900 ℃ and the short time is mainly between 2 minutes and 150 minutes.
The preferred range of heat treatment temperature is related to the heat distortion temperature, and is usually 25 to 250 ℃ higher than the heat distortion temperature, and the time is preferably 3 to 60 minutes.
Preferably, the high temperature-short time heat treatment temperature in the above step (3) is higher than the heat distortion temperature in the step (2).
Preferably, the sample in the step (3) may be heated with the furnace, or the whole device such as a tube furnace containing the sample may be placed in the furnace chamber after the temperature reaches the set temperature.
Preferably, the high-temperature short-time heat treatment process described in the above step (3) can be cooled with a furnace after completion, and can also be rapidly cooled under the protection of high vacuum or rare gas or other non-oxidizing atmosphere.
Preferably, the high-temperature short-time heat treatment process described in the above step (3) is mainly carried out under the protection of high vacuum or rare gas or other non-oxidizing atmosphere, and the vacuum degree is usually 10-1Pa-10-5Pa is between Pa.
Compared with the prior art, the high-temperature short-time heat treatment process adopted by the invention under certain conditions can effectively improve the magnetic property of the magnet. The residual magnetization intensity of the magnet can be independently improved by adopting different heat treatment temperature and time combinations, the coercive force of the magnet can also be independently improved, and the improvement of the residual magnetization intensity and the coercive force can also be simultaneously realized. After the invention is adopted, on one hand, the magnetic performance of the hot-deformed or reversely extruded magnet can be effectively improved, and on the other hand, the adopted high-temperature-short-time heat treatment process is simple to operate and short in process time, and the production efficiency can be greatly improved. In addition, the process method can be implemented by adopting the original equipment or the common heat treatment equipment such as a vacuum tube furnace, does not need to add new equipment, and hardly increases the heat treatment cost.
Detailed Description
The present invention will be described in detail with reference to specific examples.
Example 1
7.7g of MQU-F Nd-Fe-B powder (a commercial powder suitable for hot pressing sintering thermal deformation manufactured by Tianjin Meggekun magnetic Co., Ltd.) was weighed, had a good microstructure, and was suitable for the preparation of a thermally deformable or reverse-extruded Nd-Fe-B magnet. The preservation of the raw materials is usually vacuum packaging.
Adding the powder into a hard alloy die with an inner diameter of 10mm and a height of 50mm, wherein the diameters and the lengths of an upper pressure head and a lower pressure head are respectively 9.8mm and 40mm, placing the assembled female die, the pressure heads and a base in a vacuum hot-pressing furnace, and when the vacuum degree in the furnace chamber reaches 10-3Pa, and when the temperature reaches 600 ℃, carrying out hot-pressing sintering on the powder, wherein the loading pressure is 300MPa,the sintering time was 20 minutes. And after the hot-pressing sintering is finished, cooling the sample along with the furnace, and demoulding and taking out the sintered sample after the sample is cooled to room temperature. A hot-pressed sample with a height of 14mm and a diameter of 9.8mm was obtained.
And placing the hot-pressed sample in a female die with the inner diameter of 25mm and the height of 30mm, wherein the diameter and the length of an upper pressure lever and a lower pressure lever which are matched with the female die for use are both 24.8mm and 35 mm. Placing the assembled mould in a vacuum hot-pressing furnace until the vacuum degree reaches 10-3And Pa, performing thermal deformation on the hot-pressed sample after the temperature reaches 675 ℃, wherein the thermal deformation speed is 0.1 mm/min. And finishing the thermal deformation work after the height of the sample is reduced to 72%. And taking out the sample after the furnace temperature is cooled to room temperature.
After the surface of the sample is cleaned, a plurality of blocks 2 x 3.5mm are cut off from the same concentric circle part of the sample by adopting a wire cutting technology3And (3) sampling. The cutting at the same concentric circle part is mainly adopted to ensure the consistency of the sample performance. And respectively placing the cut samples into a tube furnace for vacuum heat treatment, wherein the heat treatment temperature is 750 ℃, 800 ℃, 850 ℃ and 900 ℃, and the heat treatment time is 15 minutes. And (4) after the heat treatment is finished, placing the tube furnace in the air for rapid cooling, taking out the sample after the tube furnace is cooled to the room temperature, and polishing the surface.
And (3) completing magnetic property test on the sample with the heat-altered shape and the sample subjected to heat treatment at different temperatures on a comprehensive physical property measuring instrument (PPMS). The test result shows that compared with the performance of a thermal deformation state sample, the coercive force of the magnet is improved by 0.2T after the treatment at 750 ℃, the residual magnetization intensity is also improved by a small extent, the coercive force and the residual magnetization intensity of the sample are improved after the treatment at 800 ℃, wherein the residual magnetization intensity is improved by 0.04T, the coercive force is improved by 0.2T, the maximum magnetic energy product is improved by 20kJ/m3, the residual magnetization intensity of the sample is greatly improved by 0.07T after the treatment at 900 ℃, but the coercive force is reduced seriously due to the growth of crystal grain size.
Example 2
A heat treatment process for thermally deforming or back-extruding an Nd-Fe-B magnet, comprising the steps of:
(1) preparing single Nd-Fe-B rapid quenching powder into fine powder by using a hot pressing sintering methodAn isotropic Nd-Fe-B magnet of crystal grains; when the hot-pressing sintering method is used for sintering, the temperature is 600 ℃, the hot-pressing pressure is 50MPa, and the vacuum degree is 10-1Pa, and the sintering time is 30 min.
(2) Preparing an Nd-Fe-B magnet with anisotropy by using a thermal deformation technology; the operating conditions of the hot deformation technique are: temperature 650 ℃ and thermal deformation rate 10-1mm/min, vacuum degree 10-1Pa, degree of thermal deformation 55%.
(3) The Nd-Fe-B magnet having anisotropy was heat-treated at 750 ℃ for 3 min. The sample can be heated along with the furnace, or the device such as a tube furnace and the like which is provided with the sample can be integrally placed in the furnace chamber after the temperature reaches the set temperature. The high temperature-short time heat treatment process can be cooled along with the furnace after being finished, and can also be rapidly cooled under the protection of high vacuum or rare gas or other non-oxidizing atmosphere. When carried out under high vacuum or under the protection of noble gases or other non-oxidizing atmospheres, the vacuum is generally 10 degrees-1Pa-10-5Pa is between Pa.
Example 3
A heat treatment process for thermally deforming or back-extruding an Nd-Fe-B magnet, comprising the steps of:
(1) preparing single Nd-Fe-B quick quenching powder into an isotropic Nd-Fe-B magnet with fine grains by using a hot-pressing sintering method; when the sintering is carried out by a hot-pressing sintering method, the temperature is 700 ℃, the hot-pressing pressure is 150MPa, and the vacuum degree is 10- 2Pa, and the sintering time is 10 min.
(2) Preparing an Nd-Fe-B magnet with anisotropy by using a thermal deformation technology; the operating conditions of the hot deformation technique are: the temperature is 650 ℃, the thermal deformation speed is 1mm/min, and the vacuum degree is 10-2Pa, degree of thermal deformation 70%.
(3) The Nd-Fe-B magnet having anisotropy was heat-treated at 790 ℃ for 10 min. The sample can be heated along with the furnace, or the device such as a tube furnace and the like which is provided with the sample can be integrally placed in the furnace chamber after the temperature reaches the set temperature. The high temperature-short time heat treatment process can be cooled along with the furnace after being finished, and can also be rapidly cooled under the protection of high vacuum or rare gas or other non-oxidizing atmosphere. When the method is carried out under the protection of high vacuum or rare gas or other non-oxidizing atmosphere,the vacuum degree is usually 10-1Pa-10-5Pa is between Pa.
Example 4
A heat treatment process for thermally deforming or back-extruding an Nd-Fe-B magnet, comprising the steps of:
(1) preparing single Nd-Fe-B quick quenching powder into an isotropic Nd-Fe-B magnet with fine grains by using a hot-pressing sintering method; when the hot-pressing sintering method is used for sintering, the temperature is 750 ℃, the hot-pressing pressure is 350MPa, and the vacuum degree is 10- 4Pa, and the sintering time is 30 min.
(2) Preparing an Nd-Fe-B magnet with anisotropy by using a thermal deformation technology; the operating conditions of the hot deformation technique are: the temperature is 700 ℃, the thermal deformation speed is 10mm/min, and the vacuum degree is 10-4Pa, degree of thermal deformation 80%.
(3) Nd-Fe-B magnets having anisotropy were heat-treated at 900 ℃ for 3 min. The sample can be heated along with the furnace, or the device such as a tube furnace and the like which is provided with the sample can be integrally placed in the furnace chamber after the temperature reaches the set temperature. The high temperature-short time heat treatment process can be cooled along with the furnace after being finished, and can also be rapidly cooled under the protection of high vacuum or rare gas or other non-oxidizing atmosphere. When carried out under high vacuum or under the protection of noble gases or other non-oxidizing atmospheres, the vacuum is generally 10 degrees-1Pa-10-5Pa is between Pa.
Example 5
A heat treatment process for thermally deforming or back-extruding an Nd-Fe-B magnet, comprising the steps of:
(1) powder obtained by mixing Nd-Fe-B and other alloys is prepared into an isotropic Nd-Fe-B magnet with fine grains by a hot-pressing sintering method; when the hot-pressing sintering method is used for sintering, the temperature is 600 ℃, the hot-pressing pressure is 50MPa, and the vacuum degree is 10-1Pa, and the sintering time is 30 min.
(2) Preparing an Nd-Fe-B magnet with anisotropy by using a reverse extrusion molding technology; the operating conditions of the backward extrusion technique were: the Nd-Fe-B magnet was hot-pressed at 650 ℃ and reverse-extruded at 750 ℃ to obtain a ring magnet.
(3) Heat-treating an Nd-Fe-B magnet having anisotropy at 750 deg.C for 3min. The sample can be heated along with the furnace, or the device such as a tube furnace and the like which is provided with the sample can be integrally placed in the furnace chamber after the temperature reaches the set temperature. The high temperature-short time heat treatment process can be cooled along with the furnace after being finished, and can also be rapidly cooled under the protection of high vacuum or rare gas or other non-oxidizing atmosphere. When carried out under high vacuum or under the protection of noble gases or other non-oxidizing atmospheres, the vacuum is generally 10 degrees-1Pa-10-5Pa is between Pa.
In the powder mixed with Nd-Fe-B and other alloys, the mass fraction of the other alloys is 2 percent, and the other alloys comprise Nd-Cu, Nd-Cu-X1, Nd-Zn, Nd-Zn-X2, Nd-Dy, Nd-Dy-X3, Nd-Al, Nd-Al-X4, Pr-Cu, Pr-Zn, Ce-Cu, Ce-Al or Ce-Pr-X5 alloys; x1 ═ Ga, Al, Co, Pr or Zn, X2 ═ Ga, Al, Co or Pr, X3 ═ Ga, Al, Co, Cu, Pr or Zn, X4 ═ Pr, Cu, Co, Ga or Zn, X5 ═ Ga, Al, Co, Pr or Zn.
Example 6
A heat treatment process for thermally deforming or back-extruding an Nd-Fe-B magnet, comprising the steps of:
(1) powder obtained by mixing Nd-Fe-B and other alloys is prepared into an isotropic Nd-Fe-B magnet with fine grains by a hot-pressing sintering method; when the sintering is carried out by a hot-pressing sintering method, the temperature is 700 ℃, the hot-pressing pressure is 150MPa, and the vacuum degree is 10-2Pa, and the sintering time is 10 min.
(2) Preparing an Nd-Fe-B magnet with anisotropy by using a reverse extrusion molding technology; the operating conditions of the backward extrusion technique were: the Nd-Fe-B magnet was hot-pressed at 700 ℃ and reverse-extruded at 800 ℃ to obtain a ring magnet.
(3) The Nd-Fe-B magnet having anisotropy was heat-treated at 790 ℃ for 10 min. The sample can be heated along with the furnace, or the device such as a tube furnace and the like which is provided with the sample can be integrally placed in the furnace chamber after the temperature reaches the set temperature. The high temperature-short time heat treatment process can be cooled along with the furnace after being finished, and can also be rapidly cooled under the protection of high vacuum or rare gas or other non-oxidizing atmosphere. When carried out under high vacuum or under the protection of noble gases or other non-oxidizing atmospheres, the vacuum is generally 10 degrees-1Pa-10-5Pa is between Pa.
In the powder mixed with Nd-Fe-B and other alloys, the mass fraction of the other alloys is 10 percent, and the other alloys comprise Nd-Cu, Nd-Cu-X1, Nd-Zn, Nd-Zn-X2, Nd-Dy, Nd-Dy-X3, Nd-Al, Nd-Al-X4, Pr-Cu, Pr-Zn, Ce-Cu, Ce-Al or Ce-Pr-X5 alloys; x1 ═ Ga, Al, Co, Pr or Zn, X2 ═ Ga, Al, Co or Pr, X3 ═ Ga, Al, Co, Cu, Pr or Zn, X4 ═ Pr, Cu, Co, Ga or Zn, X5 ═ Ga, Al, Co, Pr or Zn.
Example 7
A heat treatment process for thermally deforming or back-extruding an Nd-Fe-B magnet, comprising the steps of:
(1) powder obtained by mixing Nd-Fe-B and other alloys is prepared into an isotropic Nd-Fe-B magnet with fine grains by a hot-pressing sintering method; when the hot-pressing sintering method is used for sintering, the temperature is 750 ℃, the hot-pressing pressure is 350MPa, and the vacuum degree is 10-4Pa, and the sintering time is 30 min.
(2) Preparing an Nd-Fe-B magnet with anisotropy by using a reverse extrusion molding technology; the operating conditions of the backward extrusion technique were: the Nd-Fe-B magnet was hot-pressed at 750 ℃ and reverse-extruded at 900 ℃ to obtain a ring magnet.
(3) Nd-Fe-B magnets having anisotropy were heat-treated at 900 ℃ for 3 min. The sample can be heated along with the furnace, or the device such as a tube furnace and the like which is provided with the sample can be integrally placed in the furnace chamber after the temperature reaches the set temperature. The high temperature-short time heat treatment process can be cooled along with the furnace after being finished, and can also be rapidly cooled under the protection of high vacuum or rare gas or other non-oxidizing atmosphere. When carried out under high vacuum or under the protection of noble gases or other non-oxidizing atmospheres, the vacuum is generally 10 degrees-1Pa-10-5Pa is between Pa.
In the powder mixed with other alloys, the mass fraction of other alloys is 30 percent, and the other alloys comprise Nd-Cu, Nd-Cu-X1, Nd-Zn, Nd-Zn-X2, Nd-Dy, Nd-Dy-X3, Nd-Al, Nd-Al-X4, Pr-Cu, Pr-Zn, Ce-Cu, Ce-Al or Ce-Pr-X5 alloy; x1 ═ Ga, Al, Co, Pr or Zn, X2 ═ Ga, Al, Co or Pr, X3 ═ Ga, Al, Co, Cu, Pr or Zn, X4 ═ Pr, Cu, Co, Ga or Zn, X5 ═ Ga, Al, Co, Pr or Zn.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.
Claims (7)
1. A heat treatment process for thermally deforming or reversely extruding an Nd-Fe-B magnet is characterized by comprising the following steps of:
(1) preparing magnet powder into an isotropic Nd-Fe-B magnet with fine grains by using a hot-pressing sintering method;
(2) preparing an Nd-Fe-B magnet with anisotropy by using a thermal deformation technology or a reverse extrusion molding technology;
(3) performing high-temperature short-time heat treatment on the Nd-Fe-B magnet with anisotropy;
the magnet powder in the step (1) comprises rapidly quenched Nd-Fe-B powder or powder obtained by mixing Nd-Fe-B with other alloys;
the mass fraction of other alloys in the powder mixed by Nd-Fe-B and other alloys is 2-30%,
the other alloys comprise Nd-Cu, Nd-Cu-X1, Nd-Zn, Nd-Zn-X2, Nd-Dy, Nd-Dy-X3, Nd-Al, Nd-Al-X4, Pr-Cu, Pr-Zn, Ce-Cu, Ce-Al or Ce-Pr-X5 alloys;
x1 ═ Ga, Al, Co, Pr or Zn, X2 ═ Ga, Al, Co or Pr, X3 ═ Ga, Al, Co, Cu, Pr or Zn, X4 ═ Pr, Cu, Co, Ga or Zn, X5 ═ Ga, Al, Co, Pr or Zn;
the high-temperature short-time heat treatment conditions in the step (3) are as follows: the heat treatment is carried out at a temperature between 750 ℃ and 900 ℃ for 2 minutes to 15 minutes.
2. A heat treatment process for a thermally deformed or reverse-extruded Nd-Fe-B magnet according to claim 1, wherein the hot press sintering in step (1) is carried out at a temperature of 600 ℃ to 750 ℃, a hot press pressure of 50 to 350MPa, and a degree of vacuum of 10-1-10-4Pa, and the sintering time is 3-30 min.
3. A heat treatment process for thermally deforming or reverse-extruding an Nd-Fe-B magnet according to claim 1, wherein the thermal deformation technique in the step (2) is operated under the conditions of: the temperature is 650-850 ℃, and the thermal deformation speed is 10-1-10mm/min, vacuum degree 10-1-10-4Pa, heat distortion degree 55-80%.
4. A heat treatment process for thermally deforming or back-extruding an Nd-Fe-B magnet according to claim 1, wherein the back-extrusion technique in the step (2) is operated under the conditions of: Nd-Fe-B magnet is hot pressed at 600-750 ℃ and reversely extruded at 750-900 ℃.
5. A heat-treatment process for a thermally deformed or reversely extruded Nd-Fe-B magnet according to claim 1, wherein the sample of the Nd-Fe-B magnet having anisotropy is heated in the furnace at the time of the high-temperature-short-time heat treatment in step (3), or the whole of the apparatus containing the sample is placed in the furnace chamber after the temperature reaches a set temperature.
6. A heat-treatment process for a thermally deformed or reverse-extruded Nd-Fe-B magnet according to claim 1, wherein the high-temperature-short-time heat-treatment process described in step (3) is furnace-cooled after completion, or rapidly cooled under high vacuum or under protection of a noble gas or other non-oxidizing atmosphere.
7. A heat-treatment process for a thermally deformed or reverse-extruded Nd-Fe-B magnet according to claim 6, wherein the high-temperature short-time heat-treatment process in step (3) is carried out under a high vacuum or under a rare gas or other non-oxidizing atmosphere for rapid cooling, and the degree of vacuum is 10-1Pa-10-5Pa is between Pa.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610962511.0A CN108022707B (en) | 2016-11-04 | 2016-11-04 | Thermal treatment process for thermal deformation or reverse extrusion of Nd-Fe-B magnet |
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| CN201610962511.0A CN108022707B (en) | 2016-11-04 | 2016-11-04 | Thermal treatment process for thermal deformation or reverse extrusion of Nd-Fe-B magnet |
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| CN108022707A CN108022707A (en) | 2018-05-11 |
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| CN108666127A (en) * | 2018-06-04 | 2018-10-16 | 安徽天宇磁业股份有限公司 | Based on energy-saving and environment-friendly permanent magnet processing technology |
| CN111292912B (en) * | 2020-02-25 | 2021-07-27 | 江西理工大学 | High-performance rare earth double-alloy magnet and preparation method thereof |
| CN111326336B (en) * | 2020-02-28 | 2021-06-22 | 大连理工大学 | Preparation method of oscillation type thermal deformation and permeation integrated high-coercivity rare earth permanent magnet |
| CN113035557A (en) * | 2021-03-12 | 2021-06-25 | 清华大学 | Neodymium-iron-boron magnet and preparation method thereof |
| CN113620701B (en) * | 2021-09-29 | 2023-04-18 | 海安南京大学高新技术研究院 | Preparation method of superfine-crystal high-temperature-resistant high-frequency manganese-zinc ferrite |
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| JPH06151219A (en) * | 1992-11-11 | 1994-05-31 | Seiko Epson Corp | Manufacture of permanent magnet |
| US6136100A (en) * | 1999-09-29 | 2000-10-24 | Magnequench International, Inc. | Rare-earth alloy powders for magnets and process for making magnets from rare-earth alloy powders |
| CN102473515A (en) * | 2009-07-15 | 2012-05-23 | 日立金属株式会社 | Process for production of r-t-b based sintered magnets and r-t-b based sintered magnets |
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| CN102436890B (en) * | 2011-11-30 | 2015-06-10 | 中国科学院宁波材料技术与工程研究所 | Method for improving performance of nano-crystalline neodymium-iron-boron permanent magnet material |
| CN103894607B (en) * | 2014-04-23 | 2015-12-30 | 上海交通大学 | The forming method of anisotropy toroidal magnet and mould thereof |
| CN105321646A (en) * | 2015-11-25 | 2016-02-10 | 中国科学院宁波材料技术与工程研究所 | Nanocrystalline thermal deformation rare-earth permanent magnet with high coercivity and preparation method of nanocrystalline thermal deformation rare-earth permanent magnet |
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| JPH06151219A (en) * | 1992-11-11 | 1994-05-31 | Seiko Epson Corp | Manufacture of permanent magnet |
| US6136100A (en) * | 1999-09-29 | 2000-10-24 | Magnequench International, Inc. | Rare-earth alloy powders for magnets and process for making magnets from rare-earth alloy powders |
| CN102473515A (en) * | 2009-07-15 | 2012-05-23 | 日立金属株式会社 | Process for production of r-t-b based sintered magnets and r-t-b based sintered magnets |
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