CN112053824B - Sintered NdFeB permanent magnet and preparation method thereof - Google Patents
Sintered NdFeB permanent magnet and preparation method thereof Download PDFInfo
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- CN112053824B CN112053824B CN201910484815.4A CN201910484815A CN112053824B CN 112053824 B CN112053824 B CN 112053824B CN 201910484815 A CN201910484815 A CN 201910484815A CN 112053824 B CN112053824 B CN 112053824B
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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
- H01F1/0577—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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- 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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- 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
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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
- H01F41/0293—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
Abstract
The application provides a preparation method of a sintered NdFeB permanent magnet, which comprises the steps of batching, smelting, hydrogen crushing, air flow grinding, forming, sintering, machining, coating, heat treatment and the like, and also provides a sintered NdFeB permanent magnet prepared by the method, and the preparation method comprises the following steps: 29 to 33wt% of R,5 to 20wt% of Co,0.8 to 1.0wt% of B, more than 0 and less than or equal to 2wt% of M, and the balance of Fe and unavoidable impurities; wherein R consists of a second rare earth element and a first rare earth element, and M is one or more elements selected from Cu, al, zr, nb, ti and Ga. The application has high cobalt content and Curie temperature, and the coercive force and the remanence are balanced, thereby reducing the heavy rare earth content and lowering the production cost.
Description
Technical Field
The application relates to the technical field of magnetic materials, in particular to a sintered NdFeB permanent magnet and a preparation method thereof.
Background
The sintered NdFeB permanent magnet material has the excellent characteristics of high remanence, high magnetic energy product and high coercivity, is the permanent magnet with the strongest magnetism at present, and is known as the king in the permanent magnet material. As a new generation rare earth permanent magnet material, the neodymium iron boron magnet has wide application in the fields of computer technology, automobile industry, aerospace military industry, automation technology, instrument technology, microwave communication technology, wind power generation and the like. The neodymium-iron-boron magnet has high cost performance and good mechanical properties; however, the temperature characteristic is poor, the Curie temperature is only about 320 ℃, and the temperature characteristic is poor, and the temperature characteristic can only work at the temperature below 150 ℃ generally, so that the application of the neodymium-iron-boron permanent magnet material in the high-temperature field is limited.
In order to increase the curie temperature Tc and improve the use in a high-temperature environment, the addition amount of cobalt Co in the sintered neodymium-iron-boron permanent magnet material generally needs to be regulated, but as the Co content increases, the intrinsic coercivity Hcj of the permanent magnet material also rapidly deteriorates along with the increase of the addition amount of Co element, and the application of the neodymium-iron-boron permanent magnet material in the high-temperature field is limited by the lower intrinsic coercivity. Therefore, in the existing commercial sintered NdFeB permanent magnet, the mass percentage of Co elementThe specific content is often controlled below 5wt%, and in order to prevent the problem that the intrinsic coercivity Hcj is greatly reduced due to Co element addition, expensive rare earth metal elements Dy and Tb with mass percent of more than 4wt% are often required to be added to improve the intrinsic coercivity Hcj, but the Curie temperature of the magnet is only about 340 ℃; the addition of large amounts of expensive heavy rare earth elements Dy and Tb not only increases the production cost of enterprises, but also forms a large amount of main phase grains Dy2Fe14B or Tb2Fe14B due to the fact that heavy rare earth Dy or Tb is generally added in smelting, resulting in residual magnetism Br and maximum magnetic energy product (BH) max Greatly reduced, and is also limited to the application in the fields of industrial motors, rail transit, aerospace and other high-end markets.
Disclosure of Invention
The technical problem solved by the application is to provide a preparation method of the sintered NdFeB permanent magnet, and the sintered NdFeB permanent magnet prepared by the method has better comprehensive performance.
In view of the above, the application provides a preparation method of a sintered NdFeB permanent magnet, comprising the following steps:
a) The sintered NdFeB permanent magnet comprises the following components in percentage by weight: the content of R is 29-33 wt%, the content of Co is 5-20 wt%, the content of B is 0.8-1.0 wt%, the content of M is more than 0 and less than or equal to 2wt%, and the balance is Fe, wherein R consists of a first rare earth element and a second rare earth element, the first rare earth element is one or more of Ce, pr, nd, gd, ho and Y, the second rare earth element is one or two of Dy and Tb, and the content of the second rare earth element is more than 0 and less than or equal to 2wt%; m is selected from one or more of Cu, al, zr, nb, ti and Ga;
b) Smelting the proportioned raw materials to obtain a rapid hardening sheet alloy;
c) Carrying out air current grinding after hydrogen crushing on the rapid hardening sheet alloy to obtain alloy fine powder;
d) Sequentially molding, sintering and machining the alloy fine powder to obtain a neodymium iron boron semi-finished product;
e) And coating slurry containing the second rare earth element and M on the surface of the neodymium-iron-boron semi-finished product, and performing heat treatment to obtain the sintered neodymium-iron-boron permanent magnet.
Preferably, in step B), the smelting raw material includes a second rare earth element and M, or the raw material does not include the second rare earth element but includes M, or the raw material does not include the rare earth element and M.
Preferably, the average particle size of the hydrogen crushed powder is 10-30 μm, and the average particle size of the air-milled powder is 1.8-3 μm.
Preferably, the grain size of the NdFeB semi-finished product is 3-8 mu m.
Preferably, the slurry further comprises a solvent, the mass ratio of the powder formed by the second rare earth element to the solvent is 1:1, and the solvent is one or more selected from alcohol solvents and lipid solvents.
Preferably, the heat treatment comprises high-temperature treatment and low-temperature treatment which are sequentially carried out, wherein the temperature of the high-temperature treatment is 700-900 ℃, the heat preservation time is 6-10 h, the temperature of the low-temperature treatment is 480-580 ℃, and the heat preservation time is 4-10 h.
Preferably, the sintering process specifically comprises the following steps:
sintering the formed green body for 6-16 h at 1000-1090 ℃ under vacuum condition, tempering to 850-950 ℃ and preserving heat for 1.5-3 h, preserving heat for 1.5-5 h at 400-600 ℃ and cooling.
Preferably, in the smelting process, the thickness of the rapid hardening sheet alloy is 1.5-4 mm, and the casting temperature is 1350-1450 ℃.
The application also provides a sintered NdFeB permanent magnet prepared by the preparation method, which comprises the following steps:
r consists of a second rare earth element and a first rare earth element, wherein the first rare earth element is one or more selected from Ce, pr, nd, gd, ho and Y, the second rare earth element is one or two selected from Dy and Tb, and the content of the second rare earth element is more than 0 and less than or equal to 2wt%; m is selected from one or more of Cu, al, zr, nb, ti and Ga.
Preferably, the content of the second rare earth element is 0.8-2 wt%; the content of R is 29.5-32.5 wt%.
The application provides a preparation method of a sintered NdFeB permanent magnet, which comprises the preparation steps of batching, smelting, hydrogen crushing, air flow grinding, forming, sintering, machining, coating and heat treatment, wherein in the preparation process, one or two of second rare earth elements Dy and Tb are coated on the surface of a high-Co magnet in a coating manner, and then the heat treatment is carried out, so that one or two of the second rare earth elements Dy and Tb are diffused into the magnet, thereby improving the coercive force of the high-Co magnet, hardly reducing residual magnetism Br, and finally enabling the comprehensive performance of the sintered NdFeB permanent magnet to be high.
Detailed Description
For a further understanding of the present application, preferred embodiments of the application are described below in conjunction with the examples, but it should be understood that these descriptions are merely intended to illustrate further features and advantages of the application, and are not limiting of the claims of the application.
In view of the fact that the balance of intrinsic coercivity and remanence is difficult to achieve in the neodymium-iron-boron permanent magnet with high Co content in the prior art, the application provides the preparation method of the sintered neodymium-iron-boron permanent magnet, and the preparation method still obtains better balance of intrinsic coercivity and remanence and has higher comprehensive performance under the condition of high Co content. Specifically, the embodiment of the application discloses a preparation method of a sintered NdFeB permanent magnet, which comprises the following steps:
a) The sintered NdFeB permanent magnet comprises the following components in percentage by weight: the content of R is 29-33 wt%, the content of Co is 5-20 wt%, the content of B is 0.8-1.0 wt%, the content of M is more than 0 and less than or equal to 2wt%, and the balance is Fe, wherein R consists of a second rare earth element and a first rare earth element, the first rare earth element is one or more of Ce, pr, nd, gd, ho and Y, the second rare earth element is one or two of Dy and Tb, and the content of the second rare earth element is more than 0 and less than or equal to 2wt%; m is selected from one or more of Cu, al, zr, nb, ti and Ga;
b) Smelting the proportioned raw materials to obtain a rapid hardening sheet alloy;
c) Carrying out air current grinding after hydrogen crushing on the rapid hardening sheet alloy to obtain alloy fine powder;
d) Sequentially molding, sintering and machining the alloy fine powder to obtain a neodymium iron boron semi-finished product;
e) And coating slurry containing the second rare earth element and M on the surface of the neodymium-iron-boron semi-finished product, and performing heat treatment to obtain the sintered neodymium-iron-boron permanent magnet.
In the process of preparing the sintered NdFeB permanent magnet, the application firstly carries out batching according to the components and the content of the sintered NdFeB permanent magnet, and the raw materials are selected according to the raw material modes known by the person skilled in the art, so that the final components are only required to meet the component requirements of the sintered NdFeB permanent magnet.
After the proportioning, smelting the proportioned raw materials to obtain the rapid hardening sheet alloy with the thickness of 1.5-4 mm; in the smelting process, the raw materials to be smelted can be raw materials comprising second rare earth elements, first rare earth elements, co, B, M and Fe, and can also be raw materials comprising first rare earth elements, co, B, M and Fe; the material can also be formed by the first rare earth element, co, B and Fe; the material can also be formed by a first rare earth element, a second rare earth element, co, B and Fe; the smelting is performed in a smelting furnace, the casting temperature of the smelting is 1350-1450 ℃, and the specific operation process of the smelting is performed in a manner well known to those skilled in the art, and the present application is not particularly limited.
According to the application, after the rapid hardening sheet alloy is obtained, hydrogen crushing is carried out on the rapid hardening sheet alloy, and then air flow grinding is carried out on the rapid hardening sheet alloy to obtain alloy fine powder, wherein the average particle size of the hydrogen crushed powder is 10-30 mu m, and the average particle size of the alloy fine powder is 1.8-3 mu m. The hydrogen crushing and the jet mill are all technical means well known to those skilled in the art, and the present application is not particularly limited with respect to the specific operation mode thereof.
The application sequentially carries out molding, sintering and machining on the alloy fine powder to obtain a neodymium iron boron semi-finished product. The forming is specifically that the alloy fine powder is mixed for 0.5 to 5 hours in a mixer, and is pressed into a green body by a die in a constant magnetic field environment under the protection of inert gas. In the sintering process, the application is preferably carried out under vacuum condition, and the specific sintering process is as follows: sintering the formed green body for 6-16 h at 1000-1090 ℃ under vacuum condition, tempering to 850-950 ℃ and preserving heat for 1.5-3 h, preserving heat for 1.5-5 h at 400-600 ℃ and cooling. After sintering, the obtained blank is cut to obtain a semi-finished product. The grain size of the sintered blank in the present application is 3 to 8 μm, which affects the coercive force of the magnet. The dimension of the semi-finished product in the thickness direction is less than or equal to 8mm.
According to the application, after the semi-finished product is obtained, the slurry containing the second rare earth element and M is coated on the surface of the neodymium iron boron semi-finished product, so that a coating film is coated on the surface of the neodymium iron boron semi-finished product. Also included in the above slurry are solvents well known to those skilled in the art, which may be specifically selected from one or more of alcoholic solvents and lipid solvents, more specifically selected from ethanol, ethylene glycol or epoxy resins. The mass ratio of the powder formed by the second rare earth element to the solvent is 1:1. In the slurry, when the second rare earth element and the M element are contained, the two raw materials are added in the form of alloy powder. The second rare earth element and the raw material of M can be added in the smelting process besides being added in the coating process, but the content of the second rare earth element and the raw material of M in the final sintered NdFeB permanent magnet is required to be ensured to be consistent with the content of the element components of the application.
The semi-finished product with the surface coated with the film is subjected to heat treatment, wherein the heat treatment is preferably carried out in a sintering furnace, argon is preferably filled in the sintering furnace, the argon pressure is 0.01-0.8 MPa, high-temperature treatment is carried out in the heat treatment process, then low-temperature treatment is carried out, the temperature of the high-temperature treatment is 700-900 ℃, the heat preservation time is 6-10 h, the temperature of the low-temperature treatment is 480-580 ℃, and the heat preservation time is 4-10 h. In the heat treatment process, one or two of Dy and Tb are distributed at the grain boundaries, and Dy2Fe14B or Tb2Fe14B which is a main phase grain and greatly reduces remanence Br is not formed, so that the comprehensive performance is ensured.
The application also provides a sintered NdFeB magnet prepared by the preparation method, which comprises the following steps:
r consists of a second rare earth element and a first rare earth element, wherein the first rare earth element is one or more selected from Ce, pr, nd, gd, ho and Y, the second rare earth element is one or two selected from Dy and Tb, and the content of the second rare earth element is more than 0 and less than or equal to 2wt%; m is selected from one or more of Cu, al, zr, nb, ti and Ga.
In the sintered NdFeB magnet, the content of R is 29.5-32.5 wt%, the content of Co is 8-18 wt%, the content of M is 0.6-1.5 wt%, and the content of the second rare earth element is 0.8-2 wt%.
According to the application, through improvement of the sintered NdFeB permanent magnet and the manufacturing method thereof, the NdFeB permanent magnet with high performance is obtained, the cobalt content is high, the Curie temperature is high, the problem of low Curie temperature of the existing sintered NdFeB permanent magnet material is effectively solved, the heavy rare earth content is reduced, and the production cost is reduced.
The application greatly improves the chemical components and weight percentage content of the sintered NdFeB permanent magnet, improves the content of Co, greatly improves the Curie temperature of the sintered NdFeB permanent magnet, thereby enabling the sintered NdFeB permanent magnet to be applied to high-temperature environment and expanding the application range thereof. In the manufacturing process, a coating method is adopted, and a coating material formed by mixing heavy rare earth alloy and a solvent is adopted, so that the coercive force of the magnet can be effectively improved, the high-Co permanent magnet is ensured to have higher performance, and the application environment is wider.
In order to further understand the present application, the following examples are provided to illustrate the sintered nd-fe-b permanent magnet and the preparation method thereof in detail, and the scope of protection of the present application is not limited by the following examples.
Example 1
The manufacturing method of the high-performance sintered NdFeB permanent magnet comprises the following steps:
1) And (3) batching: preparing a neodymium-iron-boron magnetic material according to chemical components and weight percentage content in the high-performance sintered neodymium-iron-boron permanent magnet, and weighing the components and weight percentage of the neodymium-iron-boron magnetic material for later use;
the weight percent test results of the main chemical components in the high-performance sintered neodymium-iron-boron permanent magnet of the embodiment are shown in the example 1 column in the table 1, wherein R is Ce, pr, nd, tb, dy and Y, M is Cu, al, zr and Ga, and the balance is Fe and unavoidable impurities;
2) Smelting: firstly, putting a sintered NdFeB magnetic material into a smelting furnace for smelting to obtain a rapid hardening sheet alloy with the thickness of 1.5-4 mm, wherein the casting temperature is 1380 ℃;
3) Hydrogen crushing: placing the rapid hardening sheet alloy into a hydrogen crushing device, and performing hydrogen crushing treatment on the rapid hardening sheet alloy to obtain coarse powder, wherein the average granularity of the coarse powder is 20.8 mu m;
4) Pulverizing: grinding the hydrogen crushed coarse powder into fine powder by airflow grinding, wherein the average granularity of the fine powder is 1.86 mu m;
5) And (3) forming: mixing the fine powder in a mixer for 1h, and pressing the mixture into a green body in a constant magnetic field environment by using a die under the protection of inert gas;
7) Sintering: sintering the green body for 16 hours at the high temperature of 1000 ℃ under vacuum condition, tempering to 900 ℃ for 1.5 hours, preserving heat for 4 hours, cooling, and discharging to obtain a blank, wherein the grain size of the blank is 6.5 mu m;
8) Machining: cutting the blank into semi-finished products with certain sizes, wherein the thickness direction of the semi-finished products is 6.01mm;
9) Coating: the semi-finished product is pretreated by degreasing and the like to obtain a permanent magnet semi-finished product with no impurity on the surface, a layer of coating film is uniformly coated on the surface of the permanent magnet semi-finished product, the permanent magnet semi-finished product is dried in the air, the coating is a mixture of TbDyAl alloy powder and solvent ethanol, and the weight ratio of the TbDyAl alloy powder to the solvent is 1:1;
10 Heat treatment: placing the coated permanent magnet semi-finished product into a sintering box, placing the sintering box with the permanent magnet semi-finished product into a sintering furnace, and vacuumizing to 10 -2 And (3) filling argon under Pa, performing high-temperature treatment at the pressure of 0.02Mpa, and performing low-temperature treatment at 880 ℃ for 10 hours, and performing low-temperature treatment at 500 ℃ for 4 hours.
Example 2
The results of the weight percent testing of the main chemical components in the high performance sintered neodymium-iron-boron permanent magnet of this example are shown in example 2 column of table 1, wherein R is Pr, nd, gd, ho, tb, M is Cu, al and Nb, and the balance is Fe and unavoidable impurities.
The process steps of the method for manufacturing the high-performance sintered NdFeB permanent magnet of the embodiment are similar to those of the embodiment 1, and specific process parameters different from those of the embodiment 1 are shown in the list of the embodiment 2 in the table 2.
Example 3
The results of the weight percent testing of the main chemical components in the high performance sintered neodymium-iron-boron permanent magnet of this example are shown in example 3 column in table 1, wherein R is Pr, nd, tb, M is Cu, ti, al, and the balance is Fe and unavoidable impurities.
The process steps of the method for manufacturing the high-performance sintered NdFeB permanent magnet of the embodiment are similar to those of the embodiment 1, and specific process parameters different from those of the embodiment 1 are shown in the column of the embodiment 3 in the table 2.
Example 4
The results of the weight percent testing of the main chemical components in the high performance sintered neodymium-iron-boron permanent magnet of this example are shown in table 1, column 4 of example, where R is Pr, nd, dy, tb, M is Cu, zr, al, ga, and the balance is Fe and unavoidable impurities.
The process steps of the method for manufacturing the high-performance sintered NdFeB permanent magnet of the embodiment are similar to those of the embodiment 1, and specific process parameters different from those of the embodiment 1 are shown in the column of the embodiment 4 in the table 2.
Example 5
The results of the weight percent testing of the main chemical components in the high performance sintered neodymium-iron-boron permanent magnet of this example are shown in example 5 column in table 1, where R is Pr, nd, dy, tb, M is Al, cu, zr, ga, and the remainder are Fe and unavoidable impurities.
The process steps of the method for manufacturing the high-performance sintered NdFeB permanent magnet of the embodiment are similar to those of the embodiment 1, and specific process parameters different from those of the embodiment 1 are shown in the column of the embodiment 5 in the table 2.
Example 6
The results of the weight percent testing of the main chemical components in the high performance sintered neodymium-iron-boron permanent magnet of this example are shown in table 1, column 6 of example, where R is Pr, nd, ho, tb, M is Nb, cu, zr, ga, al, and the balance is Fe and unavoidable impurities.
The process steps of the method for manufacturing the high-performance sintered NdFeB permanent magnet of the embodiment are similar to those of the embodiment 1, and specific process parameters different from the embodiment 1 are shown in the column of the embodiment 6 in the table 2.
Example 7
The results of the weight percent testing of the main chemical components in the high performance sintered neodymium-iron-boron permanent magnet of this example are shown in the example 7 column of table 1, wherein R is Pr, nd, tb, M is Ga, al, cu, ti, and the balance is Fe and unavoidable impurities.
The process steps of the method for manufacturing the high-performance sintered NdFeB permanent magnet of the embodiment are similar to those of the embodiment 1, and specific process parameters different from those of the embodiment 1 are shown in the column of the embodiment 7 in the table 2.
Example 8
The results of the weight percent testing of the main chemical components in the high performance sintered neodymium-iron-boron permanent magnet of this example are shown in example 8 column of table 1, wherein R is Nd, tb, dy, M is Ti, al, cu, and the balance is Fe and unavoidable impurities.
The process steps of the method for manufacturing the high-performance sintered NdFeB permanent magnet of the embodiment are similar to those of the embodiment 1, and specific process parameters different from those of the embodiment 1 are shown in the column of the embodiment 8 in the table 2.
The properties of the sintered NdFeB permanent magnets prepared in examples 1 to 8 were examined, and the examination results are shown in Table 3.
Table 1 examples 1 to 8 main chemical components and weight percentage comparison table of high performance sintered nd-fe-b permanent magnet
Table 2 examples 1 to 8 parameter comparison table of high performance sintered nd-fe-b permanent magnet manufacturing method
Table 3 examples 1-8 high performance sintered nd-fe-b permanent magnet performance parameter comparison table
The above description of the embodiments is only for aiding in the understanding of the method of the present application and its core ideas. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the application can be made without departing from the principles of the application and these modifications and adaptations are intended to be within the scope of the application as defined in the following claims.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. The preparation method of the sintered NdFeB permanent magnet comprises the following steps:
a) The sintered NdFeB permanent magnet comprises the following components in percentage by weight: the content of R is 29.5-33 wt%, the content of Co is 10-20 wt%, the content of B is 0.88-1.0 wt%, the content of M is 0.65-2 wt%, and the balance is Fe, R consists of a first rare earth element and a second rare earth element, wherein the first rare earth element is one or more of Ce, pr, nd, gd, ho and Y, the second rare earth element is one or two of Dy and Tb, and the content of the second rare earth element is more than 0 and less than or equal to 2wt%; m is selected from one or more of Cu, al, zr, nb, ti and Ga;
b) Smelting the proportioned raw materials to obtain a rapid hardening sheet alloy; the thickness of the rapid hardening sheet alloy is 1.5-4 mm;
c) Carrying out air current grinding after hydrogen crushing on the rapid hardening sheet alloy to obtain alloy fine powder; the average granularity of the powder after the air flow grinding is 1.8-3 mu m;
d) Sequentially molding, sintering and machining the alloy fine powder to obtain a neodymium iron boron semi-finished product;
e) Coating slurry containing the second rare earth element and M on the surface of the neodymium-iron-boron semi-finished product, and performing heat treatment to obtain a sintered neodymium-iron-boron permanent magnet;
the heat treatment comprises high-temperature treatment and low-temperature treatment which are sequentially carried out, wherein the temperature of the high-temperature treatment is 700-900 ℃, the heat preservation time is 6-10 h, the temperature of the low-temperature treatment is 480-580 ℃, and the heat preservation time is 4-10 h.
2. The production method according to claim 1, wherein in step B), the raw material subjected to smelting includes a second rare earth element and M, or the raw material does not include the second rare earth element but includes M, or the raw material does not include the rare earth element and M.
3. The method according to claim 1, wherein the average particle size of the hydrogen pulverized powder is 10 to 30 μm and the average particle size of the air-milled powder is 1.8 to 3 μm.
4. The method according to claim 1, wherein the grain size of the neodymium iron boron semi-finished product is 3-8 μm.
5. The method according to claim 1, wherein the slurry further comprises a solvent, the mass ratio of the powder of the second rare earth element to the solvent is 1:1, and the solvent is one or more selected from the group consisting of an alcohol solvent and a lipid solvent.
6. The method according to claim 1, wherein the sintering process is specifically:
sintering the formed green body for 6-16 h at 1000-1090 ℃ under vacuum condition, tempering to 850-950 ℃ and preserving heat for 1.5-3 h, preserving heat for 1.5-5 h at 400-600 ℃ and cooling.
7. The method according to claim 1, wherein the thickness of the rapid hardening sheet alloy is 1.5-4 mm and the casting temperature is 1350-1450 ℃ during the smelting process.
8. The sintered neodymium-iron-boron permanent magnet prepared by the preparation method of any one of claims 1 to 7, comprising:
the balance being Fe;
r consists of a second rare earth element and a first rare earth element, wherein the first rare earth element is one or more selected from Ce, pr, nd, gd, ho and Y, the second rare earth element is one or two selected from Dy and Tb, and the content of the second rare earth element is more than 0 and less than or equal to 2wt%; m is selected from one or more of Cu, al, zr, nb, ti and Ga.
9. The sintered neodymium-iron-boron permanent magnet according to claim 8, wherein the content of the second rare earth element is 0.8-2 wt%.
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| JP2009170796A (en) * | 2008-01-18 | 2009-07-30 | Ulvac Japan Ltd | Permanent magnet, and manufacturing method of permanent magnet |
| CN103189943A (en) * | 2010-10-25 | 2013-07-03 | 丰田自动车株式会社 | Production method of rare earth magnet |
| CN107871581A (en) * | 2016-09-26 | 2018-04-03 | 信越化学工业株式会社 | The method for preparing R Fe B sintered magnets |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2009170796A (en) * | 2008-01-18 | 2009-07-30 | Ulvac Japan Ltd | Permanent magnet, and manufacturing method of permanent magnet |
| CN103189943A (en) * | 2010-10-25 | 2013-07-03 | 丰田自动车株式会社 | Production method of rare earth magnet |
| CN107871581A (en) * | 2016-09-26 | 2018-04-03 | 信越化学工业株式会社 | The method for preparing R Fe B sintered magnets |
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