CN113593873A - High-coercivity mixed rare earth permanent magnet material and preparation method thereof - Google Patents

High-coercivity mixed rare earth permanent magnet material and preparation method thereof Download PDF

Info

Publication number
CN113593873A
CN113593873A CN202110712117.2A CN202110712117A CN113593873A CN 113593873 A CN113593873 A CN 113593873A CN 202110712117 A CN202110712117 A CN 202110712117A CN 113593873 A CN113593873 A CN 113593873A
Authority
CN
China
Prior art keywords
rare earth
permanent magnet
alloy powder
shell
coercivity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202110712117.2A
Other languages
Chinese (zh)
Inventor
姜华
史荣莹
左志军
马明国
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jingci Material Science Co ltd
Original Assignee
Jingci Material Science Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jingci Material Science Co ltd filed Critical Jingci Material Science Co ltd
Priority to CN202110712117.2A priority Critical patent/CN113593873A/en
Publication of CN113593873A publication Critical patent/CN113593873A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • 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
    • H01F1/0572—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 with a protective layer
    • 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
    • H01F1/0573—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 obtained by reduction or by hydrogen decrepitation or embrittlement
    • 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
    • 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
    • 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 discloses a high-coercivity mixed rare earth permanent magnet material and a preparation method thereof, wherein the permanent magnet material consists of main phase grains with a multi-shell-core-shell structure and a rare earth-rich grain boundary phase and is prepared by mixing rare earth-poor alloy powder (MM)aR100‑a)b(Fe，TM)100‑a‑b‑cBcAdding submicron-grade rare earth-rich alloy powder R'x(Fe，TM)100‑x‑yByThrough the orientation compression and sintering processes, a first hard magnetic shell layer is formed around the main phase crystal grains, after the first diffusion tempering treatment, an external hard magnetic shell layer with a higher magnetocrystalline anisotropy field is formed around the first hard magnetic shell layer, and then the mixed rare earth permanent magnetic material with a multi-shell-core-shell structure can be obtained through multiple diffusion processes. The multi-shell-core-shell structure can simultaneously improve the nucleation field and the pinning field of the reverse domain, thereby improving the coercive force of the magnetAnd then, the magnet is prepared by using the mixed rare earth as a raw material, so that the balanced use of rare earth resources can be promoted, and the environmental pollution caused by rare earth separation can be reduced.

Description

High-coercivity mixed rare earth permanent magnet material and preparation method thereof
Technical Field
The invention relates to the field of rare earth permanent magnetic materials. More particularly, the invention relates to a high coercivity mixed rare earth permanent magnet material and a preparation method thereof.
Background
The neodymium iron boron permanent magnet material is a third-generation rare earth permanent magnet material, has excellent comprehensive magnetic property, and is widely applied to many fields of electric automobiles, medical instruments, wind power generation, aerospace, ships and the like. With the vigorous development in the fields of new energy automobiles, intelligent equipment and industrial robots, the demand and the yield of neodymium iron boron permanent magnet materials are increased year by year. According to the statistical data of Ministry of industry and communications, the yield of the sintered neodymium iron boron blank in China in 2018 is about 15.5 ten thousand tons, and the yield is increased by 5 percent on a same scale. For a long time, Nd and Pr elements in rare earth are largely used in Nd-Fe-B permanent magnetic materials, but the mixed rare earth (MM) with higher abundance and low price is used in a small amount. The permanent magnet material is prepared by using the mixed rare earth, so that on one hand, the separation and extraction links of various rare earth elements can be saved, and the cost is greatly reduced; on the other hand, by utilizing the synergistic effect of different rare earth elements, compared with the method of directly adding La and Ce rare earth elements, the comprehensive performance of the permanent magnet material is more excellent. Therefore, the mixed rare earth is used for preparing the permanent magnet material, so that the production cost of the permanent magnet material can be greatly reduced, and the pollution of a rare earth separation link to the environment can be reduced.
Different rare earth elements have different intrinsic magnetic properties when forming the 2:14:1 primary phase, MM compared to Pr and Nd2Fe14The saturation magnetic polarization strength Js and the magnetocrystalline anisotropy field HA of B are lower, so that the addition of MM inevitably causes the performance of the permanent magnet material to be reduced. Therefore, how to ensure certain magnetic performance while reducing the cost of the permanent magnet material is an urgent problem to be solved by the large-scale popularization and application of the MM at present. From a microscopic view, the coercive force of the permanent magnetic material has strong correlation with a microstructure. In the process of the demagnetization of the permanent magnetic material, when an external directional field reaches a nucleation field, a reverse domain starts to be formed, and then the reverse magnetization is realized by rapid expansion through irreversible domain wall displacement. If the nucleation field of the reverse domain is improved and the pinning field of the irreversible domain wall is increased by optimizing the microstructure design, the material quality can be effectively improvedAnd (4) coercive force.
At present, research on low-cost rare earth permanent magnet materials mostly focuses on the aspects of preparing a high-abundance Ce magnet by a double-main-phase method, regulating and controlling magnet grain boundaries and the like. The research work of low-cost Ce-Nd-Fe-B magnets is firstly developed by the iron and steel research institute at home, and the developed double-main-phase technology (patent grant: CN 12800454B) mainly comprises the steps of respectively manufacturing (Ce, Re) -Fe-B rapid hardening sheets and Nd-Fe-B rapid hardening sheets, carrying out hydrogen breaking and jet milling, then carrying out powder mixing, pressing, low-temperature sintering and low-temperature tempering, and obtaining the sintered Ce-Nd-Fe-B magnets. When the content of Ce is not higher than 80 wt.% of the total weight of the rare earth, the coercive force of the magnet is better than that of the magnet prepared by a single alloy method with the same components. In patent CN103794323A, reference is made to the high abundance of Rare Earths (RE)100-aMMa) Although the wettability of the rare earth-rich phase relative to the main phase is improved by a method of regulating and controlling the grain boundary, the exchange coupling effect among the grains of the main phase is reduced, and the coercive force can be improved to a certain degree, the problem of magnet performance deterioration after the addition proportion of the mixed rare earth is increased is not fundamentally solved.
Disclosure of Invention
An object of the present invention is to solve at least the above problems and to provide a high coercive force mixed rare earth permanent magnetic material and a method for producing the same. By mixing in rare earth-poor alloy powder (MM)aR100-a)b(Fe，TM)100-a-b-cBcAdding submicron-grade rare earth-rich alloy powder R'x(Fe，TM)100-x-yByThrough the orientation compression and sintering processes, a first hard magnetic shell layer can be formed around the main phase grains, after one-time diffusion tempering treatment, an external hard magnetic shell layer with higher magnetocrystalline anisotropy field is formed around the first hard magnetic shell layer, and then a mixed rare earth permanent magnetic material consisting of the main phase grains with a multi-shell-core-shell structure and a rare earth-rich grain boundary phase can be obtained after multiple diffusion processes, wherein the multi-shell-core-shell structure can simultaneously improve the nucleation field and the pinning field of a reverse domain, so that the coercive force of a magnet can be improvedThe magnet prepared by the material can promote the balanced use of rare earth resources and reduce the environmental pollution caused by rare earth separation.
To achieve these objects and other advantages in accordance with the present invention, there is provided a method for preparing a high coercive force misch metal permanent magnetic material, characterized by comprising the steps of:
step 1: preparation (MM)aR100-a)b(Fe，TM)100-a-b-cBcA rare earth-poor alloy powder;
step 2: preparation of R'x(Fe，TM)100-x-yByA rare earth-rich alloy powder;
and step 3: mixing (MM) prepared in step 1aR100-a)b(Fe，TM)100-a-b-cBcRare earth-lean alloy powder and R 'prepared in step 2'x(Fe，TM)100-x-yByMixing the rare earth-rich alloy powder uniformly;
and 4, step 4: carrying out orientation molding on the alloy powder mixed in the step 3 under the protection of inert gas, carrying out isostatic pressing treatment on the alloy powder in oil, and finally sintering to obtain a sintered magnet;
and 5: preparing a diffusion source into powder, a target material, a solution or a rapid quenching strip;
step 6: attaching the diffusion source prepared in the step 5 to the surface of the sintered magnet prepared in the step 4;
and 7: and performing high-temperature diffusion and tempering treatment under the vacuum or inert gas atmosphere to obtain the high-coercivity mixed rare earth permanent magnet material consisting of main phase grains and a rare earth-rich grain boundary phase, wherein the main phase grains have a multi-shell-core-shell structure.
Preferably, the rare earth-poor alloy has the chemical formula (MM)aR100-a)b(Fe，TM)100-a-b-cBcWherein a, b and c are the mass percentages of the corresponding elements: a is more than or equal to 5 and less than or equal to 100, b is more than or equal to 26 and less than or equal to 31, c is more than or equal to 0.95 and less than or equal to 1.2, R is one or the combination of more of Pr, Nd, La, Ce and Y, MM is a mixed rare earth alloy which is directly extracted from raw ore after rough separation and takes La, Ce, Pr and Nd as main rare earth elements, TM is Al, Cu, Co, Nb, Ga, Zr, V and Ti is one or a combination of several elements;
the rare earth-rich alloy has a chemical formula R'x(Fe，TM)100-x-yByWherein x and y are the mass percentages of the corresponding elements: x is more than or equal to 34 and less than or equal to 50, y is more than or equal to 0.95 and less than or equal to 1, and R' is one or the combination of more elements of Pr, Nd, Gd, Ho, Dy and Tb.
Preferably, the MM is bayan obo associated rare earth, the total rare earth content in the MM component is more than 98%, wherein the MM component comprises 40-60% of Ce, 15-35% of La, 5-20% of Nd and 1-10% of Pr in percentage by weight, and the balance of other trace rare earth elements and inevitable impurities.
Preferably, the average particle size of the rare earth-poor alloy powder prepared in the step 1 is 3-5 μm, the rare earth-rich alloy powder prepared in the step 2 is submicron powder with the average particle size of 100 nm-1 μm, and the rare earth-poor alloy powder and the rare earth-rich alloy powder are prepared by the processes of batching, smelting, strip throwing, hydrogen breaking and air flow grinding.
Preferably, the powder mixing time in the step 3 is 5-15 h, and the mixing mass ratio of the two powders is 1: 99-99: 1.
Preferably, in the step 4, the orientation magnetic field during orientation molding is 1T-3T, the pressure during isostatic pressing is 180 MPa-250 MPa, the temperature during sintering is 1010-1100 ℃, and the sintering time is 4-10 h.
Preferably, the rare earth element in the diffusion source of step 5 is one or a combination of several selected from Pr, Nd, Gd, Ho, Dy and Tb, and the diffusion source is one or several selected from corresponding rare earth metals, alloys, fluorides, oxides and oxyfluorides.
Preferably, in the diffusion tempering treatment in the step 7, the high-temperature diffusion at 600-900 ℃ is firstly carried out, the temperature is kept for 1-10 h, and then the tempering treatment at 440-590 ℃ is carried out, the temperature is kept for 1-8 h.
Preferably, when the main phase crystal grains are required to have 3 or more shells, the method for preparing the high coercivity misch metal permanent magnet material further comprises the step 8: and repeating the step for 5-7 times to obtain the high-coercivity mixed rare earth permanent magnet material with a multi-shell-core-shell structure.
Preferably, the high-coercivity mixed rare earth permanent magnet material prepared by the method is composed of main phase grains and a rare earth-rich grain boundary phase, wherein the main phase grains have a multi-shell-core shell structure.
The invention at least comprises the following beneficial effects:
1. the invention provides a high-coercivity mixed rare earth permanent magnetic material, which aims to solve the problem of coercivity deterioration caused by adding high-abundance mixed rare earth, and provides a multi-shell-core-shell structure for simultaneously increasing a reverse magnetic domain nuclear field and an irreversible domain wall displacement pinning field from the aspect of regulating and controlling a main phase grain microstructure so as to improve the coercivity of the mixed rare earth permanent magnetic material. The mixed rare earth permanent magnet material consists of main phase grains of a multi-shell-core shell structure and a rare earth-rich grain boundary phase, wherein a magnetocrystalline anisotropy field of the main phase grains at a core position is smaller than that of a shell layer, and the magnetocrystalline anisotropy field of the main phase grains is gradually increased from an inner shell layer close to the core to an outer shell layer close to the grain boundary phase. In the process of reverse magnetization, the formation of the anti-magnetic domain of the crystal grain generally occurs on the surface layer of the crystal grain, and the magnetocrystalline anisotropy field at the surface layer is larger, so that the nucleation field of the reverse magnetization domain is improved, the interface pinning effect of different magnetocrystalline anisotropy fields among multiple shells is utilized, the pinning field of reverse domain wall displacement is improved, the nucleation and movement of the reverse magnetization domain need to overcome higher energy barrier, and the intrinsic coercivity of the material is improved.
2. The rare earth raw material MM of the invention is low-cost mixed light rare earth containing about 80% of La and Ce, the raw material can be directly extracted from the bayan obo tailings, the source is wide, the extraction process is short, and the link of extracting and separating rare earth simple substance elements can be omitted, so that the pollution to the environment can be reduced, the formula cost of the rare earth permanent magnet material can be reduced, and the sustainable development of the rare earth permanent magnet industry is facilitated.
3. The invention provides a preparation method of a high-coercivity mixed rare earth permanent magnetic material, which is characterized in that submicron-grade rare earth-rich alloy powder is added into poor rare earth alloy powder, and in a sintering stage, due to different particle sizes of the two powders, submicron-grade rare earth-rich alloy particles tend to be swallowed by poor rare earth alloy powder particles with larger sizes, and finally a rare earth-rich main phase hard magnetic shell layer is formed around the poor rare earth main phase crystal grains, wherein the hard magnetic shell layer can effectively inhibit nucleation and movement of a reverse magnetic domain, so that the coercivity of a magnet is improved, meanwhile, the rare earth-rich phase in the rare earth-rich alloy is enriched around the main phase crystal grains, so that the wettability between a crystal boundary phase and a main phase is improved, a good demagnetization coupling effect can be achieved, and the coercivity of the magnet is further improved.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
FIG. 1 is a schematic illustration of a rare earth-poor alloy powder and a rare earth-rich alloy powder after mixing;
FIG. 2 is a schematic view of a sintered magnet microstructure;
FIG. 3 is a schematic diagram of a two-layer shell-core-shell structure of a main phase grain.
Detailed Description
The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.
The invention provides a preparation method of a high-coercivity mixed rare earth permanent magnet material, which comprises the following steps:
1. preparing rare earth-poor alloy powder: prepared by the process of burdening, smelting, melt spinning, hydrogen breaking and air flow milling (MM)aR100-a)b(Fe,TM)100-a-b-cBcThe rare earth-poor alloy powder comprises 26-31% of total rare earth in the alloy, and the particle size distribution of the rare earth-poor alloy powder is controlled by controlling the rotating speed of a jet mill sorting wheel to obtain micron-sized fine powder with the average particle size of 3-5 mu m;
2. preparing rare earth-rich alloy powder: firstly, preparing R 'through a material mixing-smelting-melt-spinning process'x(Fe,TM)100-x-yByThen the strip throwing sheet is processed by hydrogen breaking and high-energy He jet milling or high-energy ball milling to obtain submicron-grade rare earth-rich alloy powder,the powder has an average particle diameter of 100nm to 1 μm, preferably 100nm to 500 nm.
3. Mixing powder: the two alloy powders are mixed according to a certain proportion and put into a charging bucket, a certain amount of antioxidant is added, and the two alloy powders are mixed in a mixer for 5-15 hours to ensure that the two alloy powders are completely and uniformly mixed, wherein the mixing mass ratio of the two alloy powders is 1: 99-99: 1.
4. Orientation forming and sintering: and (2) carrying out orientation molding on the mixed alloy powder under the protection of inert gas, wherein an orientation magnetic field is 1T-3T, then carrying out isostatic pressing treatment in oil at a pressure of 180 MPa-250 MPa, and finally sintering in a sintering furnace at a sintering temperature of 1010-1100 ℃ for 4-10 h.
5. Preparing a diffusion source: and preparing the diffusion source into a required powder, target material, solution or rapid quenching strip state. The rare earth element in the diffusion source is one or a combination of more of Pr, Nd, Gd, Ho, Dy and Tb, and the diffusion source is one or more of corresponding rare earth metal, alloy, fluoride, oxide and oxyfluoride.
6. The surface of the magnet is attached with a diffusion source: and (3) directly attaching powder, solution or rapid quenching strips on the surface of the magnet prepared in the step (4) according to different states of the diffusion source, or sputtering and depositing a diffusion target on the surface of the magnet in a magnetron sputtering mode.
7. Diffusion tempering treatment: and (3) in a sintering furnace, firstly carrying out high-temperature diffusion at 600-900 ℃ for 1-10 h, then carrying out tempering treatment at 440-590 ℃ for 1-8 h, wherein the diffusion tempering is carried out in vacuum or inert gas atmosphere.
8. And (5) performing diffusion tempering treatment for multiple times. And (3) selecting a diffusion source with high magnetic crystal anisotropy field when a 2:14:1 main phase is formed, repeating the step 5-7 for diffusion tempering treatment, repeating the step 5-7 once every time, adding a shell layer to the obtained main phase crystal grain, and repeating the step 5-7 times according to the requirement on the number of the shell layers of the main phase crystal grain to obtain the mixed rare earth permanent magnetic material with the multi-shell-core shell structure and high coercivity.
According to the rare earth permanent magnet material, the average particle sizes of the rare earth poor alloy powder and the rare earth rich alloy powder are different (as shown in figure 1), after sintering, the rare earth rich alloy main phase particles tend to be swallowed by the rare earth poor alloy main phase particles, a first hard magnetic shell layer (as shown in figure 2) is formed around the rare earth poor alloy main phase particles, then after a first diffusion tempering process is carried out, a second hard magnetic shell layer (as shown in figure 3) is formed around the first hard magnetic shell layer, and after a plurality of diffusion tempering processes, the main phase crystal grains of a multi-shell-core-shell structure are finally obtained.
Example 1:
1. preparing rare earth-poor alloy powder and rare earth-rich alloy powder:
two alloy rapid-hardening tablets were prepared: according to nominal composition (MM)0.05Nd0.95)29FebalCo0.2Nb0.12Al0.45B0.95Rare earth-poor alloy and Nd34FebalCo0.2Nb0.12Al0.45B0.95And respectively mixing the rare earth-rich alloys, putting the mixed raw materials into a crucible, filling argon gas into the crucible for smelting, and then pouring the molten raw materials onto a copper roller with the rotating speed of 3m/s to prepare the quick-setting sheet of the two alloys with the thickness of 0.1-0.6 mm.
Hydrogen breaking: and (3) respectively carrying out hydrogen crushing treatment on the two quick-setting tablets by using a rotary hydrogen crushing furnace, and coarsely crushing the quick-setting tablets into particles with the particle size of less than 500 microns.
Milling powder by airflow: inert gases such as high-pressure nitrogen and the like are used for air flow milling under the pressure of 0.5-1.0 Mpa, the rotation speed of a sorting wheel is controlled, rare earth poor alloy hydrogen is pulverized into fine powder with the average particle size of 3-5 mu m, and high-pressure helium is used for pulverizing rare earth rich alloy hydrogen into submicron fine powder with the average particle size of 100-500 nm.
2. Mixing powder: mixing the rare earth-poor alloy powder and the rare earth-rich alloy powder according to the mass ratio of 80:20, and then mixing for 5 hours on a powder mixer. After the powder mixing, the nominal composition MM of the alloy powder1.45Nd28.55FebalCo0.2Nb0.12Al0.45B1。
3. Orientation forming and sintering: carrying out orientation compression on the mixed powder under a 1.8T magnetic field, and carrying out isostatic pressing under the pressure of 220MPa to obtain a green body; and sintering the green body in a vacuum sintering furnace at the sintering temperature of 1040 ℃ for 4h to obtain the sintered magnet.
4. Preparing a diffusion source: the components are prepared by a rapid hardening process (PrNd)70Cu30A thin strip.
5. Diffusion tempering treatment: will (PrNd)70Cu30Directly covering the upper and lower surfaces of the sintered magnet with a thin strip, placing the thin strip in a material box, and vacuumizing to (3-5) x 10-3Pa, heating to 860 ℃ at the speed of 10 ℃/min, preserving heat for 5h, and then carrying out vacuum annealing heat treatment at 470 ℃ for 2h to obtain the final magnet.
As a comparative example, the nominal composition MM1.45Nd28.55FebalCo0.2Nb0.12Al0.45B1And (3) batching, obtaining a sintered magnet with the same components and the same process through strip throwing, hydrogen breaking, air flow milling, orientation forming and sintering, and then performing diffusion tempering treatment under the same conditions in the steps (4) and (5).
The two magnets were processed into a D10 x 10 sample column and the magnetic properties were measured as follows:
Figure BDA0003133324800000061
the result shows that the coercive force Hcj of the magnet of the embodiment is obviously superior to that of the comparative example, and the organization observation shows that the main phase grains form a two-layer shell-core shell structure, so that the distribution of grain boundary phases is more uniform.
Example 2:
1. nominal composition MM was prepared in the same manner as in step 1 of example 126FebalCo0.15Nb0.12Al0.55B0.95Rare earth-poor alloy powder and (Pr)0.3Nd0.7)50FebalCo0.15Nb0.12Al0.55B0.95The rare earth-rich alloy powder, wherein the rare earth-poor alloy powder has an average particle size of 5 μm, and the rare earth-rich alloy powder has an average particle size of 0.5 μm.
2. Mixing powder: uniformly mixing the lean rare earth alloy powder and the rich rare earth alloy powder according to the mass ratio of 85:15, and then mixing for 5 hours on a powder mixer. The nominal composition of the alloy powder after powder mixing is
MM22.1(Pr0.3Nd0.7)7.5FebalCo0.15Nb0.12Al0.55B0.95。
3. Orientation forming and sintering: carrying out orientation compression on the mixed powder under a 2T magnetic field, and carrying out isostatic pressing under the pressure of 180MPa to obtain a green body; and sintering the green body in a vacuum sintering furnace at the sintering temperature of 1030 ℃ for 4h to obtain the sintered magnet.
4. Diffusion and tempering treatment: using commercially available Pr77.5Zn22.5And (3) depositing a diffusion source substance on the surface of the sample by using a high-temperature magnetron sputtering technology. The sputtering temperature is 600 ℃, and the sputtering time is 3 h; and carrying out vacuum heat treatment on the sample subjected to high-temperature deposition for 2h at the tempering temperature of 500 ℃ to obtain the final magnet.
As a comparative example, the nominal composition MM22.1(Pr0.3Nd0.7)7.5FebalCo0.15Nb0.12Al0.55B0.95Proportioning, obtaining a sintered magnet with the same composition through melt spinning, hydrogen breaking, air flow milling, orientation forming and sintering, and then performing Pr on the sintered magnet under the same condition as the step 4 of the example 277.5Zn22.5And (4) performing diffusion tempering treatment on the alloy round target.
The two magnets were processed into a D10 x 10 sample column and the magnetic properties were measured as follows:
Figure BDA0003133324800000071
it can be seen that, compared with the comparative magnet with the same component, the coercive force Hcj of the embodiment is obviously improved from 5.6kOe to 6.4kOe, and it is noted that the proportion of the mixed rare earth MM in the total rare earth reaches about 74.6%, the magnetic energy product (BH) max of the magnet reaches 21.9MGOe, and the performance of the magnet can fill the gap between the permanent magnetic ferrite and the neodymium iron boron.
Example 3:
1. a nominal composition (MM) was prepared in the same manner as in step 1 of example 10.4，Nd0.6)30FebalCo0.15Nb0.12Al0.55B1Rare earth-poor alloy powder and Nd34FebalCo0.15Nb0.12Al0.55B1A rare earth-rich alloy powder.
2. Mixing powder: uniformly mixing the lean rare earth alloy powder and the rich rare earth alloy powder according to the mass ratio of 95:5, and then mixing for 5 hours on a powder mixer. The nominal composition of the mixed alloy powder is MM11.4Nd18.8FebalCo0.15Nb0.12Al0.55B1。
3. Orientation forming and sintering: carrying out orientation compression on the mixed powder under a 2T magnetic field, and carrying out isostatic pressing under the pressure of 220MPa to obtain a green body; sintering the green body in a vacuum sintering furnace at 1050 ℃ for 4h to obtain a sintered magnet with the density of 7.52g/cm3The oxygen content in the magnet was 750 ppm.
4. Diffusion and tempering treatment: the sintered magnet was Pr-treated according to the method of step 4 in example 277.5Zn22.5Carrying out magnetron sputtering deposition and tempering treatment on the alloy to obtain the magnet after primary diffusion tempering. Mixing DyF3Uniformly mixing the powder and alcohol according to the ratio of 1:1, and then carrying out ball milling and stirring on the mixed solution by using a ball mill to obtain DyF3And (3) uniformly coating the diffusion source on the surface of the magnet after the primary diffusion tempering with a mixed slurry diffusion source of alcohol, then performing diffusion treatment on the magnet for 10 hours at 900 ℃ in an argon atmosphere, and after the secondary diffusion is completed, performing tempering treatment on the magnet for 4 hours at 480 ℃ in the argon atmosphere to obtain the final magnet.
As a comparative example, the nominal composition was MM11.4Nd18.8FebalCo0.15Nb0.12Al0.55B1Mixing, and then obtaining the same-component sintering through melt spinning, hydrogen breaking, air flow grinding, orientation forming and sinteringThe process conditions of the bonded magnet, in which the average particle size of the jet-milled powder, the sintering temperature, the sintering time and the like were exactly the same as those in example 3. Subjecting the sintered magnet to Pr77.5Zn22.5After magnetron sputtering deposition and tempering treatment, DyF is carried out3The solution slurry was diffused and tempered, and the specific process was also completely the same as in example 3.
The two magnets were processed into a D10 x 10 sample column and the magnetic properties were measured as follows:
Figure BDA0003133324800000081
as can be seen from the table, compared with the comparative example magnet with the same components, the coercive force Hcj of the magnet of the embodiment is improved by 1.8kOe through the 3-shell-core structure formed by regulating and controlling the microstructure of the main phase crystal grains. In the embodiment, the mixed rare earth MM accounts for about 37.7% of the total amount of rare earth in the formula, and the performance of the magnet still reaches the standard of a commercial N38 mark (the maximum magnetic energy product is more than 35MGOe, and the coercive force is more than 12 kOe).
Compared with the prior art, the mixed rare earth permanent magnetic material prepared by optimizing the microstructure of the main phase crystal grains has higher coercive force under the condition of the same formula as the traditional process, because the main phase crystal grains have a plurality of hard magnetic shell layers, and have higher magnetocrystalline anisotropy fields at the positions of the outermost layer of the crystal grains where reverse domain nucleation and growth are easy to occur, and in addition, the magnetocrystalline anisotropy fields between the shell layers and the core are different, so that the pinning effect on the growth of the reverse domains is stronger. According to the invention, the problem of coercive force deterioration caused by adding high-abundance mixed rare earth can be effectively solved by regulating and controlling the microstructure of the main phase crystal grains, and the effect of improving coercive force by medium-heavy rare earth elements is enhanced.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims (10)

1. A preparation method of a high-coercivity mixed rare earth permanent magnet material is characterized by comprising the following steps:
step 1: preparation (MM)aR100-a)b(Fe，TM)100-a-b-cBcA rare earth-poor alloy powder;
step 2: preparation of R'x(Fe，TM)100-x-yByA rare earth-rich alloy powder;
and step 3: mixing (MM) prepared in step 1aR100-a)b(Fe，TM)100-a-b-cBcRare earth-lean alloy powder and R 'prepared in step 2'x(Fe，TM)100-x-yByMixing the rare earth-rich alloy powder uniformly;
and 4, step 4: carrying out orientation molding on the alloy powder mixed in the step 3 under the protection of inert gas, carrying out isostatic pressing treatment on the alloy powder in oil, and finally sintering to obtain a sintered magnet;
and 5: preparing a diffusion source into powder, a target material, a solution or a rapid quenching strip;
step 6: attaching the diffusion source prepared in the step 5 to the surface of the sintered magnet prepared in the step 4;
and 7: and performing high-temperature diffusion and tempering treatment under the vacuum or inert gas atmosphere to obtain the high-coercivity mixed rare earth permanent magnet material consisting of main phase grains and a rare earth-rich grain boundary phase, wherein the main phase grains have a multi-shell-core-shell structure.
2. The method of claim 1, wherein the rare earth-lean alloy is of formula (MM)aR100-a)b(Fe，TM)100-a-b-cBcWherein a, b and c are the mass percentages of the corresponding elements: a is more than or equal to 5 and less than or equal to 100, b is more than or equal to 26 and less than or equal to 31, c is more than or equal to 0.95 and less than or equal to 1.2, R is one or the combination of more of Pr, Nd, La, Ce and Y, and MM is directly extracted from crude ore after rough separationThe mixed rare earth alloy takes La, Ce, Pr and Nd as main rare earth elements, and the TM is one or the combination of more of Al, Cu, Co, Nb, Ga, Zr, V and Ti;
the rare earth-rich alloy has a chemical formula R'x(Fe，TM)100-x-yByWherein x and y are the mass percentages of the corresponding elements: x is more than or equal to 34 and less than or equal to 50, y is more than or equal to 0.95 and less than or equal to 1, and R' is one or the combination of more elements of Pr, Nd, Gd, Ho, Dy and Tb.
3. The method for preparing a high coercivity mixed rare earth permanent magnet material according to claim 2, wherein the MM is Bayan Obo associated rare earth, the total rare earth content in the MM component is more than 98%, and the MM component comprises, by weight, 40-60% of Ce, 15-35% of La, 5-20% of Nd and 1-10% of Pr, and the balance of other trace rare earth elements and inevitable impurities.
4. The method for preparing a high-coercivity mixed rare earth permanent magnet material according to claim 1, wherein the average particle size of the rare earth-poor alloy powder prepared in the step 1 is 3-5 μm, the average particle size of the rare earth-rich alloy powder prepared in the step 2 is submicron powder with the average particle size of 100 nm-1 μm, and the rare earth-poor alloy powder and the rare earth-rich alloy powder are prepared through the processes of batching, smelting, melt spinning, hydrogen breaking and air flow milling.
5. The preparation method of the high-coercivity mixed rare earth permanent magnet material according to claim 1, wherein the powder mixing time in the step 3 is 5-15 h, and the mass ratio of the two powders is 1: 99-99: 1.
6. The method for preparing a high coercivity mixed rare earth permanent magnet material according to claim 1, wherein in the step 4, the orientation magnetic field during orientation molding is 1T-3T, the pressure during isostatic pressing is 180 MPa-250 MPa, the sintering process temperature is 1010-1100 ℃, and the sintering time is 4-10 h.
7. The method of claim 1, wherein the rare earth element in the diffusion source of step 5 is selected from one or more of Pr, Nd, Gd, Ho, Dy, Tb, and the diffusion source is selected from one or more of corresponding rare earth metals, alloys, fluorides, oxides, and oxyfluorides.
8. The method for preparing a high coercivity mixed rare earth permanent magnet material according to claim 1, wherein in the diffusion tempering treatment in the step 7, high temperature diffusion at 600-900 ℃ for 1-10 h is firstly carried out, and then tempering treatment at 440-590 ℃ for 1-8 h is carried out.
9. The method for producing a high coercive force misch metal permanent magnet material according to any of claims 1 to 8, wherein when the main phase grains are required to have 3 or more shell layers, the method further comprises the steps of:
and 8: and repeating the step for 5-7 times to obtain the high-coercivity mixed rare earth permanent magnet material with a multi-shell-core-shell structure.
10. The high-coercivity mixed rare earth permanent magnet material prepared by the method according to any one of claims 1 to 9, which consists of main phase grains and a rare earth-rich grain boundary phase, wherein the main phase grains have a multi-shell-core-shell structure.
CN202110712117.2A 2021-06-25 2021-06-25 High-coercivity mixed rare earth permanent magnet material and preparation method thereof Pending CN113593873A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110712117.2A CN113593873A (en) 2021-06-25 2021-06-25 High-coercivity mixed rare earth permanent magnet material and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110712117.2A CN113593873A (en) 2021-06-25 2021-06-25 High-coercivity mixed rare earth permanent magnet material and preparation method thereof

Publications (1)

Publication Number Publication Date
CN113593873A true CN113593873A (en) 2021-11-02

Family

ID=78244628

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110712117.2A Pending CN113593873A (en) 2021-06-25 2021-06-25 High-coercivity mixed rare earth permanent magnet material and preparation method thereof

Country Status (1)

Country Link
CN (1) CN113593873A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114464443A (en) * 2022-01-17 2022-05-10 北京工业大学 Method for simultaneously improving coercivity and corrosion resistance of multi-main-phase LaCe-based sintered permanent magnet material
CN116230348A (en) * 2023-03-09 2023-06-06 钢铁研究总院有限公司 High-corrosion-resistance low-temperature-coefficient sintered Nd-Fe-B permanent magnet material and preparation method thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114464443A (en) * 2022-01-17 2022-05-10 北京工业大学 Method for simultaneously improving coercivity and corrosion resistance of multi-main-phase LaCe-based sintered permanent magnet material
CN114464443B (en) * 2022-01-17 2024-02-06 北京工业大学 Method for simultaneously improving coercivity and corrosion resistance of multi-main-phase LaCe-based sintered permanent magnet material
CN116230348A (en) * 2023-03-09 2023-06-06 钢铁研究总院有限公司 High-corrosion-resistance low-temperature-coefficient sintered Nd-Fe-B permanent magnet material and preparation method thereof
CN116230348B (en) * 2023-03-09 2024-01-02 钢铁研究总院有限公司 High-corrosion-resistance low-temperature-coefficient sintered Nd-Fe-B permanent magnet material and preparation method thereof

Similar Documents

Publication Publication Date Title
JP6366666B2 (en) Method for producing sintered Nd-Fe-B magnetic body containing no heavy rare earth element
CN103106991B (en) Based on high-coercive force high-stability neodymium iron boron magnet and the preparation method of crystal boundary reconstruct
CN102220538B (en) Sintered neodymium-iron-boron preparation method capable of improving intrinsic coercivity and anticorrosive performance
CN110853856B (en) High-coercivity cerium-containing magnet and preparation method thereof
CN111210963B (en) High-performance yttrium cerium based rare earth permanent magnet and preparation method thereof
CN110047636B (en) Preparation method of high-coercivity La/Ce-rich sintered magnet
CN102610347A (en) Rare earth permanent magnet alloy material and preparation process thereof
EP3355319B1 (en) Corrosion-resistant sintered neodymium-iron-boron magnet rich in lanthanum and cerium, and manufacturing method
JP7470804B2 (en) Neodymium iron boron magnet material, raw material composition, and manufacturing method
CN107958760B (en) Rare earth permanent magnetic material and preparation method thereof
JP2023509225A (en) Heavy rare earth alloy, neodymium iron boron permanent magnet material, raw material and manufacturing method
CN109732046B (en) Sintered neodymium-iron-boron magnet and preparation method thereof
CN109087768B (en) Neodymium iron boron permanent magnet material for magnetic suspension system and preparation method thereof
CN113593873A (en) High-coercivity mixed rare earth permanent magnet material and preparation method thereof
CN112750587A (en) Preparation method of high-performance sintered samarium-cobalt magnet
CN112086255A (en) High-coercivity and high-temperature-resistant sintered neodymium-iron-boron magnet and preparation method thereof
EP4152348B1 (en) Preparation method for heavy rare earth-free high-performance neodymium-iron-boron permanent magnet material
CN112017835B (en) Low-heavy rare earth high-coercivity sintered neodymium-iron-boron magnet and preparation method thereof
CN110033914B (en) Method for improving coercive force of sintered neodymium-iron-boron magnet
CN116612956A (en) Cerium-containing neodymium-iron-boron magnet with core-shell structure and preparation method and application thereof
CN109594023B (en) Short-process Ce-Fe-based sintered permanent magnet and preparation method thereof
JP2023177261A (en) Rare earth magnetic material and manufacturing method for the same
CN107146672A (en) A kind of superelevation magnetic property sintered Nd-Fe-B permanent magnetic material and preparation method
CN114464443B (en) Method for simultaneously improving coercivity and corrosion resistance of multi-main-phase LaCe-based sintered permanent magnet material
CN114927302A (en) Rare earth magnet and method for producing same

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination