CN113936878A - Thermal deformation rare earth permanent magnetic material and preparation method thereof - Google Patents

Thermal deformation rare earth permanent magnetic material and preparation method thereof Download PDF

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Publication number
CN113936878A
CN113936878A CN202010608852.4A CN202010608852A CN113936878A CN 113936878 A CN113936878 A CN 113936878A CN 202010608852 A CN202010608852 A CN 202010608852A CN 113936878 A CN113936878 A CN 113936878A
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alloy
powder
magnetic powder
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彭海军
于敦波
白馨元
权宁涛
李天昊
闫文龙
王子龙
武凯文
朱胜杰
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Youyan Rare Earth Rongcheng Co ltd
Grirem Advanced Materials Co Ltd
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Youyan Rare Earth Rongcheng Co ltd
Grirem Advanced Materials Co Ltd
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B22D11/0611—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by a single casting wheel, e.g. for casting amorphous metal strips or wires
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
    • 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 thermal deformation rare earth permanent magnetic material and a preparation method thereof, and the raw material comprises the following chemical formula (R1) according to atomic percentage1‑cCec)xFe100‑x‑y‑zM1yBzThe main alloy magnetic powder a and the chemical formula of R2 according to the atomic percentagea(Cu1‑bM2b)100‑aAuxiliary combination ofThe gold powder comprises c which is more than or equal to 0 and less than or equal to 1, x which is more than or equal to 12 and less than or equal to 15, y which is more than or equal to 0 and less than or equal to 10, z which is more than or equal to 5 and less than or equal to 7, R1 is at least one of Nd, Pr, Dy, Tb, Ho, La and Gd, M1 is at least one of Si, Mn, Al, Co, Ga and Cu, a which is more than or equal to 60 and less than or equal to 90, b which is more than or equal to 0 and less than or equal to 1, R2 is at least one of Nd, Pr, La and Ce, and M2 is at least one of Al, Zn, Ga, Sn and In. The material not only reduces the grain boundary phase melting point of the main alloy magnetic powder, but also increases the grain boundary phase proportion by diffusing the low-melting-point auxiliary alloy into the main alloy powder, so that the hot-pressing temperature can be reduced to below 650 ℃ and the thermal deformation temperature can be reduced to below 700 ℃, thereby effectively preventing the crystal grains from growing and improving the coercive force.

Description

Thermal deformation rare earth permanent magnetic material and preparation method thereof
Technical Field
The invention relates to a thermal deformation rare earth permanent magnetic material and a preparation method thereof, belonging to the technical field of rare earth permanent magnetic materials.
Background
The rare earth permanent magnetic material is a permanent magnetic material taking an intermetallic compound formed by rare earth metal elements and transition group metal elements as a matrix. The neodymium iron boron permanent magnet is a permanent magnet material with the highest magnetism at present, is widely applied to the fields of automobiles, air conditioners, wind power generation, national defense, aerospace and the like, and is an important functional material for supporting social progress.
The prior preparation method of the fully-compact NdFeB permanent magnet mainly comprises a sintering method and a thermal deformation method. Compared with sintering method, the thermal deformation method has the advantages of low rare earth consumption, good corrosion resistance, easy near-net shaping, etc. The hot deformed Nd-Fe-B magnet consists of Nd2Fe14B as main phase and Nd rich grain boundary phase. The performance of the thermally deformed magnet depends mainly on factors such as intrinsic properties of the main phase, the shape and size of crystal grains, the degree of c-axis orientation of the crystal grains of the main phase, and the distribution of grain boundary phases. The process of manufacturing a hot deformed magnet generally includes two steps of heating to compact magnetic powder into an isotropic magnet, and reheating to hot deform the isotropic magnet into an anisotropic magnet. In the thermal deformation process, the deformation temperature is higher than the melting point of the grain boundary phase, the grain boundary phase which is melted into liquid plays roles of lubrication, mass transfer and the like in the deformation process, and the proper liquid phase is favorable for deformation of the magnet and orientation of crystal grains along the c axis. However, in the prior art, the thermal deformation temperature is usually about 800 ℃, the thermal deformation temperature is too high, and the excessive thermal deformation temperature can cause the crystal grains to grow excessively to limit the improvement of the magnetic performance of the material.
Disclosure of Invention
The invention aims to provide a thermal deformation rare earth permanent magnetic material, which comprises the following raw materials in percentage by atom (R1)1-cCec)xFe100-x-y-zM1yBzThe main alloy magnetic powder a and the chemical formula of R2 according to the atomic percentagea(Cu1-bM2b)100-aWherein c is more than or equal to 0 and less than or equal to 1, x is more than or equal to 12 and less than or equal to 15, y is more than or equal to 0 and less than or equal to 10, z is more than or equal to 5 and less than or equal to 7, R1 is at least one of Nd, Pr, Dy, Tb, Ho, La and Gd, M1 is at least one of Si, Mn, Al, Co, Ga and Cu, a is more than or equal to 60 and less than or equal to 90, b is more than or equal to 0 and less than or equal to 1, R2 is at least one of Nd, Pr, La and Ce, and M2 is at least one of Al, Zn, Ga, Sn and In. The material not only reduces the grain boundary phase melting point of the main alloy magnetic powder, but also increases the grain boundary phase proportion by diffusing the low-melting-point auxiliary alloy into the main alloy powder, so that the hot-pressing temperature can be reduced to below 650 ℃ and the thermal deformation temperature can be reduced to below 700 ℃, thereby effectively preventing the crystal grains from growing and improving the coercive force.
Optionally, the mass of the secondary alloy powder is not more than 10% of the mass of the main alloy magnetic powder a.
Optionally, the melting point of the secondary alloy powder is less than 500 ℃.
Optionally, the particle size of the main alloy magnetic powder a is 100 μm to 250 μm, and the particle size of the auxiliary alloy powder is 80 μm to 150 μm.
In the present application, the particle size refers to the median diameter of the powder.
Optionally, the thermally deformable rare earth permanent magnetic material is composed of a matrix phase and a Cu-containing grain boundary rare earth-rich phase, the matrix phase grains are of a nanoscale layered structure, the ratio of the long axis to the short axis of the layered structure is greater than 3, and the dimension of the short axis in the direction is less than 100 nm.
Optionally, the matrix phase is (Ce, R1)2(Fe,Co)14And B, wherein R1 is at least one of Nd, Pr, Dy and Tb.
In a second aspect of the present application, there is provided a method for preparing a thermally deformable rare earth permanent magnetic material, comprising at least the following steps:
(1) respectively providing a main alloy magnetic powder a and an auxiliary alloy powder;
(2) diffusing the auxiliary alloy powder into the main alloy magnetic powder a through heat treatment to obtain magnetic powder b;
(3) carrying out hot press molding on the magnetic powder b to obtain a hot-pressed magnet;
(4) and thermally deforming the hot-pressed magnet to obtain the thermal deformation rare earth permanent magnet material.
Optionally, the preparation method of the secondary alloy powder in the step (1) comprises the following steps:
weighing a metal simple substance raw material according to the metal element proportion of the auxiliary alloy powder;
smelting the weighed metal simple substance raw materials into an alloy ingot, and then crushing the alloy ingot into auxiliary alloy powder, wherein the crushing can be carried out in a mechanical crushing mode and/or a hydrogen crushing mode; or
Melting the weighed metal simple substance raw materials and then directly atomizing into auxiliary alloy powder; or
Melting the weighed metal simple substance raw materials, rapidly quenching into a belt, and mechanically crushing into required powder.
Optionally, the method for preparing the main alloy magnetic powder a in the step (1) includes:
weighing a metal simple substance raw material according to the element proportion of the main alloy magnetic powder a;
smelting the weighed metal simple substance raw materials into alloy ingots;
melting and spraying the alloy ingot on a rotating roller again to prepare a strip sheet;
and preparing the strip into main alloy magnetic powder a by a mechanical crushing mode, wherein a single magnetic powder particle consists of a plurality of crystal grains, and the size of the crystal grain is less than 50 nm.
Optionally, the mass of the secondary alloy powder is not more than 10%, preferably 1% to 5%, of the mass of the main alloy magnetic powder a.
Optionally, the melting point of the secondary alloy powder is less than 500 ℃.
Optionally, the particle size of the main alloy magnetic powder a is 100 μm to 250 μm, and the particle size of the auxiliary alloy powder is 80 μm to 150 μm.
Optionally, the thermally deformable rare earth permanent magnetic material is composed of a matrix phase and a Cu-containing grain boundary rare earth-rich phase, the matrix phase grains are of a nanoscale layered structure, the ratio of the long axis to the short axis of the layered structure is greater than 3, and the dimension of the short axis in the direction is less than 100 nm.
Optionally, the matrix phase is (Ce, R1)2(Fe,Co)14And B, wherein R1 is at least one of Nd, Pr, Dy and Tb.
Optionally, specific conditions of the heat treatment in step (2) include:
under the condition of vacuum or protective atmosphere;
the heat treatment temperature is higher than the melting point of the auxiliary alloy powder and is less than 600 ℃;
the heat treatment time is 0.5-5 h.
Optionally, the heat treatment in step (2) is performed in a heat treatment furnace capable of rotating forward and backward.
Optionally, specific conditions of the hot press forming in the step (3) include:
under the condition of vacuum or protective atmosphere;
the hot pressing temperature is 550-650 ℃;
the hot pressing pressure is 80MPa to 120 MPa;
the hot pressing time is 1-30 min.
Optionally, the hot pressing process in step (3) is: putting the magnetic powder b obtained in the step (2) into a hot-pressing mold, heating the magnetic powder to a hot-pressing temperature under the condition of vacuum or protective atmosphere, and applying hot-pressing pressure to the magnetic powder to obtain a hot-pressed magnet;
optionally, specific conditions of the thermal deformation in the step (4) include: the thermal deformation process in the step (4) is as follows: putting the hot-pressed magnet in the step (3) into a thermal deformation mold, heating the hot-pressed magnet to a thermal deformation temperature in vacuum or protective atmosphere, and applying thermal deformation pressure to the hot-pressed magnet to enable the deformation of the magnet to reach 60% -80% to obtain a thermal deformation magnet; wherein the thermal deformation temperature is 600-700 ℃.
Has the advantages that:
firstly, because the low-melting-point alloy is diffused into the main alloy powder before hot pressing and thermal deformation, the grain boundary phase melting point of the main alloy magnetic powder is reduced, the grain boundary phase proportion is increased, the hot pressing temperature is reduced to be below 650 ℃, the thermal deformation temperature is reduced to be below 700 ℃, the grain growth is effectively prevented, and the coercive force is improved.
Secondly, the low-melting-point alloy is diffused before pressing, so that the low-melting-point alloy is favorably and uniformly distributed among magnet grains, the grains are separated by a grain boundary phase, the magnetism isolating function among the grains is obviously improved, and the coercivity is favorably improved.
Thirdly, the main alloy magnetic powder contains Ce, which can reduce the melting point of the main phase, soften the main phase at a lower thermal deformation temperature, improve the deformability of the magnet, and cooperate with the low-melting-point grain boundary phase diffused to the grain boundary, thereby facilitating the thermal deformation process and reducing the pressure required by thermal deformation. In addition, the price of Ce is low, and the material cost can be reduced.
Fourthly, the size of the crystal grain of the thermally deformed magnet obtained in the present invention in the short axis direction is 100nm or less, and the long axis/short axis ratio is 3 or more.
Drawings
Fig. 1 is a transmission electron microscope image of a thermally deformable magnet prepared in example 1.
Fig. 2 is a transmission electron micrograph of the thermally deformed magnet prepared in comparative example 1.
Detailed Description
The low-temperature thermal deformation rare earth permanent magnet and the preparation method thereof provided by the invention will be further explained below.
As analyzed in the background art, the preparation of the thermal deformation rare earth permanent magnet in the prior art has high thermal deformation temperature and high requirement on equipment, and in order to solve the problem, the invention provides a low-temperature thermal deformation rare earth permanent magnet material and a preparation method thereof.
The invention provides a preparation method of a rare earth permanent magnet, which comprises the following steps:
s1, respectively providing a main alloy magnetic powder a and an auxiliary alloy powder;
s2, mixing the two powders in the S1, performing heat treatment under the condition of vacuum or protective atmosphere, and uniformly diffusing the auxiliary alloy powder into the main alloy magnetic powder a to obtain magnetic powder b;
s3, carrying out hot press molding on the magnetic powder b under the condition of vacuum or protective atmosphere to obtain a hot-pressed magnet;
and S4, thermally deforming the hot-pressed magnet under the vacuum or protective atmosphere condition to obtain the thermally deformed magnet.
Wherein the melting point of the secondary alloy powder in step S1 is less than 500 ℃. The following benefits are obtained with a melting point of the secondary alloy powder below 500 deg.c: firstly, the auxiliary alloy powder can be diffused into the main alloy magnetic powder a at a lower temperature, and the diffusion is easy and uniform; secondly, the crystal grains of the main alloy magnetic powder a can be prevented from growing up by diffusion at low temperature; and thirdly, the low-melting-point alloy is diffused into the main alloy magnetic powder, so that the temperature in the hot pressing and thermal deformation processes can be reduced, the functions of reducing the hot pressing and thermal deformation pressure to a certain extent can be achieved, and the requirement on the equipment capacity is reduced.
Further, the chemical formula of the secondary alloy powder in step S1 is R2 in atomic percenta(Cu1-bM2b)100-aWherein a is more than or equal to 60 and less than or equal to 90, b is more than or equal to 0 and less than or equal to 0.8, and R is one or more of Nd, Pr, La and CeM2 is one or more of Al, Zn, Ga, Sn and In. The light rare earth elements Nd, Pr, La and Ce adopted in the auxiliary alloy material are beneficial to controlling the melting point of the alloy and reducing the cost. The auxiliary alloy material contains a certain amount of Cu, which is beneficial to improving the wettability between the alloy material and the main alloy magnetic powder crystal grains. One or more of Al, Zn, Ga, Sn and In elements are added to further adjust the melting point of the auxiliary alloy material and improve the wettability between grain boundary phase and main phase grains.
Further, the method for preparing the secondary alloy powder in step S1 includes: preparing materials according to the element proportion of the auxiliary alloy, smelting the materials into alloy ingots, and preparing the alloy ingots into required powder in the modes of mechanical crushing, hydrogen crushing and the like; or melting the raw materials and then directly atomizing into required powder; or melting the raw materials, rapidly quenching into strips, and mechanically crushing into required powder.
The chemical formula of the main alloy magnetic powder a in the step S1 is (R1) in atomic percentage1-cCec)xFe100-x-y-zM1yBzWherein c is more than or equal to 0 and less than or equal to 1, x is more than or equal to 12 and less than or equal to 15, y is more than or equal to 0 and less than or equal to 10, z is more than or equal to 5 and less than or equal to 7, R is one or more of Nd, Pr, Dy, Tb, Ho, La and Gd, and M1 is one or more of Si, Mn, Al, Co, Ga and Cu. R is provided as magnetism in the main alloy magnetic powder2Fe14B tetragonal phase, addition of Ce to cause R2Fe14The melting points of B tetragonal phase and B grain boundary phase are reduced, so that hot-pressing thermal deformation at a lower temperature is facilitated, the c value of Ce content is not too low, otherwise the effect of reducing the melting point is not obvious, but the content of Ce is not too high, otherwise the intrinsic magnetic performance of the main phase is reduced, and the performance of the magnet is reduced, therefore, c is preferably more than or equal to 0.1 and less than or equal to 0.3.
Further, the preparation method of the main alloy magnetic powder a in the step (1) comprises the following steps: the alloy ingot is melted according to the element proportion of the main alloy, the alloy ingot is melted again and sprayed on a rotating roller to prepare a strip sheet, the strip sheet is prepared into the required main alloy magnetic powder in a mechanical crushing mode, a single magnetic powder particle is composed of a plurality of crystal grains, and the size of the crystal grain is below 50 nm.
In order to enable the auxiliary alloy magnetic powder to be fully diffused into the main alloy magnetic powder a, the granularity of the main alloy magnetic powder a in the step (1) is 100-250 microns, and the granularity of the auxiliary alloy powder is 80-150 microns.
The mass of the auxiliary alloy powder in the step (2) is not more than 10% of the mass of the main alloy magnetic powder a. Because the auxiliary alloy powder is non-magnetic, the addition amount is not suitable to be too much, otherwise the magnetism can be diluted; if too small, the grain boundary phase ratio is too small, and the low-temperature thermal deformation cannot be achieved. The addition amount of the auxiliary alloy powder is preferably 1 to 5 percent of the mass of the main alloy magnetic powder.
Further, in the step (2), the heat treatment temperature is higher than the melting point of the auxiliary alloy and lower than 600 ℃, and the heat treatment time is 0.5 to 5 hours. The heat treatment temperature is above the melting point of the auxiliary alloy, which is beneficial to the sufficient melting and diffusion of the auxiliary alloy, but the diffusion temperature is not too high, otherwise, the crystal grains of the main alloy magnetic powder are easy to grow, and the heat treatment below 600 ℃ can play a role in preventing the crystal grains from growing. Similarly, the heat treatment time should not be too short, otherwise the diffusion is not sufficient, and too long will easily cause the crystal grain growth.
Further, the heat treatment in the step (2) is performed in a heat treatment furnace which can be rotated forward and backward for uniform diffusion.
The magnetic powder b processed by the step S2 is composed of main phase grains having a size of less than 50nm and a low melting point grain boundary phase mixed with the secondary alloy component, and the grain boundary phase becomes a liquid phase in the hot-press thermal deformation process, and plays roles of lubricating the grains, transferring mass, promoting deformation and orientation of the grains, and the like, so that the temperature and pressure in the steps S3 and S4 can be adjusted according to the components and proportion of the diffused secondary alloy.
The hot pressing process in step S3 is: and (5) placing the magnetic powder b obtained in the step (S2) into a hot-pressing die, heating the magnetic powder to a hot-pressing temperature under the condition of vacuum or protective atmosphere, and applying hot-pressing pressure to the magnetic powder to obtain a hot-pressed magnet, wherein the hot-pressing temperature is 550-650 ℃, the hot-pressing pressure is 80-120 MPa, and the hot-pressing time is 1-30 min. The purpose of hot pressing is to change the magnetic powder into a compact magnet, but crystal grains are not oriented in the hot pressing process, and the temperature and the pressure are selected as low as possible on the premise of comprehensively ensuring the compactness of the magnet and the preparation efficiency.
The thermal deformation process in step S4 is: and (3) putting the hot-pressed magnet in the step (S3) into a thermal deformation mold, heating the hot-pressed magnet to a thermal deformation temperature in vacuum or protective atmosphere, and applying thermal deformation pressure to the hot-pressed magnet to enable the deformation of the magnet to reach 60% -80% to obtain the thermal deformation magnet, wherein the thermal deformation temperature is 600-700 ℃, and the thermal deformation pressure is 30-60 MPa.
The method provided by the invention can reduce the pressure during hot-pressing thermal deformation and the temperature during hot-pressing thermal deformation, compared with the pressure, the temperature is a more sensitive factor for grain growth, especially for nanocrystalline materials, and the grain size is an important factor influencing the coercive force of rare earth permanent magnets, the thermal deformation treatment can effectively prevent the excessive growth of magnet grains at low temperature, the size of the obtained thermal deformation magnet grains in the short axis direction is below 100nm, and the ratio of the long axis to the short axis is above 3.
Therefore, the invention also provides a high-coercivity nanocrystalline heat-deformable rare earth permanent magnet obtained by the preparation method, which consists of a matrix phase (Ce, R)2(Fe,Co)14B and a Cu-containing grain boundary rare earth-rich phase, wherein R is one or more of rare earth elements Nd, Pr, Dy and Tb, and the matrix phase crystal grain is in a nano-scale layered structure. Wherein the ratio of the long axis to the short axis of the layered nanocrystal is more than 3, and the dimension of the short axis direction is less than 100 nm.
In summary, the invention adopts the low-melting point alloy, and under the condition of preventing the crystal grains of the main alloy magnetic powder from growing up, the low-melting point alloy is uniformly diffused into the main alloy powder before the hot pressing and hot deformation processes are carried out, so that the magnetic powder containing a certain proportion of low-melting point grain boundary phase is obtained. Meanwhile, the main alloy magnetic powder contains a certain amount of Ce, so that the melting point of the main phase is reduced, the main phase can be softened at a lower thermal deformation temperature, the thermoplasticity of the magnet is enhanced, and the hot pressing temperature is reduced to be below 650 ℃ and the thermal deformation temperature is reduced to be below 700 ℃ under the synergistic action of the low-melting-point grain boundary phase diffused to a grain boundary. The thermal deformation temperature is below 700 deg.C, the growth of crystal grain in thermal deformation process can be effectively prevented, the size of crystal grain in short axis direction after thermal deformation can be controlled below 100nm, and the ratio of long axis/short axis of crystal grain is greater than 3 due to good thermal plasticity of magnet. The method is also beneficial to reducing the pressure during thermal deformation, not only reduces the requirement on equipment, but also ensures that more grain boundary phases can be kept among crystal grains without being extruded during thermal deformation, and improves the magnetic isolation effect among the crystal grains so as to improve the coercive force of the magnet.
The advantageous effects of the present application will be further described below with reference to examples and comparative examples.
In the following examples, the magnetic properties (remanence B) of a thermally deformed magnetrMaximum energy product (BH)maxAnd coercive force Hcj) The test was performed using a Vibrating Sample Magnetometer (VSM). The magnet grain size was observed and measured by transmission electron microscopy.
Example 1
A thermally deformable magnet was prepared as follows:
1) in terms of atomic percent (Nd)0.9Ce0.1)13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller wheel in an argon atmosphere to obtain a rapid quenching zone, wherein the roller surface speed is 33m/s, the rapid quenching temperature is 1340 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) According to atomic percent Pr68Cu32The components are mixed and then melted into master alloy ingots by an induction melting mode. And spraying the molten master alloy to the surface of a water-cooled roller wheel in an inert atmosphere to obtain an auxiliary alloy rapid quenching belt, wherein the roller surface speed is 20m/s, the rapid quenching temperature is 750 ℃, and the spraying pressure is 0.03 MPa. Mechanically crushing the auxiliary alloy rapid quenching belt into auxiliary alloy powder with the grain diameter of 80-150 microns.
3) And uniformly mixing the main alloy magnetic powder a and the auxiliary alloy powder, wherein the auxiliary alloy powder accounts for 2% of the mass of the main alloy magnetic powder a. And (3) placing the mixed powder in a vacuum heat treatment furnace with a rotatable furnace body for diffusion treatment, wherein the temperature is 530 ℃, and the heat preservation time is 1 hour. And cooling to room temperature along with the furnace to obtain magnetic powder b.
4) And (3) carrying out hot press molding on the magnetic powder b for 3min under the conditions of a vacuum environment, a temperature of 600 ℃ and a pressure of 100MPa to obtain a compact hot-pressed magnet.
5) And thermally deforming the hot-pressed magnet under the conditions that the temperature is 650 ℃ and the pressure is 50MPa in a vacuum environment, wherein the thermal deformation amount is 70 percent, and thus obtaining the thermal deformation magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1 and FIG. 1.
Example 2
A thermally deformable magnet was prepared as follows:
1) in terms of atomic percent (Nd)0.8Ce0.2)13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller in an argon atmosphere to obtain a rapid quenching zone, wherein the roller surface speed is 33m/s, the rapid quenching temperature is 1320 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) According to atomic percent Pr68Cu30Al2The components are mixed and then melted into master alloy ingots by an induction melting mode. And spraying the molten master alloy to the surface of a water-cooled roller wheel in an inert atmosphere to obtain an auxiliary alloy rapid quenching belt, wherein the roller surface speed is 20m/s, the rapid quenching temperature is 750 ℃, and the spraying pressure is 0.03 MPa. Mechanically crushing the auxiliary alloy rapid quenching belt into auxiliary alloy powder with the grain diameter of 80-150 microns.
3) And uniformly mixing the main alloy magnetic powder a and the auxiliary alloy powder, wherein the auxiliary alloy powder accounts for 1% of the mass of the main alloy magnetic powder a. And (3) placing the mixed powder into a vacuum heat treatment furnace with a rotatable furnace body for diffusion treatment, wherein the temperature is 570 ℃, and the heat preservation time is 0.5 hour. And cooling to room temperature along with the furnace to obtain magnetic powder b.
4) And carrying out hot press molding on the magnetic powder b for 5min under the conditions of vacuum environment, temperature of 640 ℃ and pressure of 100MPa to obtain the compact hot-pressed magnet.
5) And thermally deforming the hot-pressed magnet under the conditions that the temperature is 680 ℃ and the pressure is 60MPa in a vacuum environment, wherein the thermal deformation amount is 70%, so as to obtain the thermally deformed magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1.
Example 3
A thermally deformable magnet was prepared as follows:
1) in terms of atomic percent (Nd)0.8Ce0.2)13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller in an argon atmosphere to obtain a rapid quenching zone, wherein the roller surface speed is 33m/s, the rapid quenching temperature is 1320 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) According to atomic percent Pr68Cu30Ga2The components are mixed and then melted into master alloy ingots by an induction melting mode. And spraying the molten master alloy to the surface of a water-cooled roller wheel in an inert atmosphere to obtain an auxiliary alloy rapid quenching belt, wherein the roller surface speed is 20m/s, the rapid quenching temperature is 750 ℃, and the spraying pressure is 0.03 MPa. Mechanically crushing the auxiliary alloy rapid quenching belt into auxiliary alloy powder with the grain diameter of 80-150 microns.
3) And uniformly mixing the main alloy magnetic powder a and the auxiliary alloy powder, wherein the auxiliary alloy powder accounts for 2% of the mass of the main alloy magnetic powder a. And (3) placing the mixed powder in a vacuum heat treatment furnace with a rotatable furnace body for diffusion treatment, wherein the temperature is 550 ℃, and the heat preservation time is 1 hour. And cooling to room temperature along with the furnace to obtain magnetic powder b.
4) And (3) carrying out hot press molding on the magnetic powder b for 5min under the conditions of a vacuum environment, a temperature of 620 ℃ and a pressure of 100MPa to obtain a compact hot-pressed magnet.
5) And thermally deforming the hot-pressed magnet under the conditions that the temperature is 680 ℃ and the pressure is 50MPa in a vacuum environment, wherein the thermal deformation amount is 70%, so as to obtain the thermally deformed magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1.
Example 4
A thermally deformable magnet was prepared as follows:
1) in terms of atomic percent (Nd)0.8Ce0.2)13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller in an argon atmosphere to obtain a rapid quenching zone, wherein the roller surface speed is 33m/s, the rapid quenching temperature is 1320 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) According to atomic percent Pr68Cu30Ga2The components are mixed and then melted into master alloy ingots by an induction melting mode. And spraying the molten master alloy to the surface of a water-cooled roller wheel in an inert atmosphere to obtain an auxiliary alloy rapid quenching belt, wherein the roller surface speed is 20m/s, the rapid quenching temperature is 750 ℃, and the spraying pressure is 0.03 MPa. Mechanically crushing the auxiliary alloy rapid quenching belt into auxiliary alloy powder with the grain diameter of 80-150 microns.
3) And uniformly mixing the main alloy magnetic powder a and the auxiliary alloy powder, wherein the auxiliary alloy powder accounts for 5% of the mass of the main alloy magnetic powder a. And (3) placing the mixed powder in a vacuum heat treatment furnace with a rotatable furnace body for diffusion treatment, wherein the temperature is 550 ℃, and the heat preservation time is 2 hours. And cooling to room temperature along with the furnace to obtain magnetic powder b.
4) And carrying out hot press molding on the magnetic powder b for 8min under the conditions of a vacuum environment, a temperature of 620 ℃ and a pressure of 90MPa to obtain a compact hot-pressed magnet.
5) And thermally deforming the hot-pressed magnet under the conditions that the temperature is 680 ℃ and the pressure is 45MPa in a vacuum environment, wherein the thermal deformation amount is 70%, and thus obtaining the thermal deformation magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1.
Example 5
A thermally deformable magnet was prepared as follows:
1) in terms of atomic percent (Nd)0.7Ce0.3)13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller wheel in an argon atmosphere to obtain a rapid quenching belt, wherein the roller surface speed is 35m/s, the rapid quenching temperature is 1300 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) According to atomic percent Pr68Cu30Ga2The components are mixed and then melted into master alloy ingots by an induction melting mode. And spraying the molten master alloy to the surface of a water-cooled roller wheel in an inert atmosphere to obtain an auxiliary alloy rapid quenching belt, wherein the roller surface speed is 20m/s, the rapid quenching temperature is 750 ℃, and the spraying pressure is 0.03 MPa. Mechanically crushing the auxiliary alloy rapid quenching belt into auxiliary alloy powder with the grain diameter of 80-150 microns.
3) And uniformly mixing the main alloy magnetic powder a and the auxiliary alloy powder, wherein the auxiliary alloy powder accounts for 2% of the mass of the main alloy magnetic powder a. And (3) placing the mixed powder in a vacuum heat treatment furnace with a rotatable furnace body for diffusion treatment, wherein the temperature is 550 ℃, and the heat preservation time is 1 hour. And cooling to room temperature along with the furnace to obtain magnetic powder b.
4) And (3) carrying out hot press molding on the magnetic powder b for 10min under the conditions of a vacuum environment, a temperature of 620 ℃ and a pressure of 100MPa to obtain a compact hot-pressed magnet.
5) And thermally deforming the hot-pressed magnet under the conditions that the temperature is 660 ℃ and the pressure is 45MPa in a vacuum environment, wherein the thermal deformation amount is 70%, and thus obtaining the thermal deformation magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1.
Example 6
A thermally deformable magnet was prepared as follows:
1) according to atomic percent Nd13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller wheel in an argon atmosphere to obtain a rapid quenching belt, wherein the speed of the roller surface is 30m/s, the rapid quenching temperature is 1380 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) According to atomic percent Pr68Cu30Ga2The components are mixed and then melted into master alloy ingots by an induction melting mode. And spraying the molten master alloy to the surface of a water-cooled roller wheel in an inert atmosphere to obtain an auxiliary alloy rapid quenching belt, wherein the roller surface speed is 20m/s, the rapid quenching temperature is 750 ℃, and the spraying pressure is 0.03 MPa. Mechanically crushing the auxiliary alloy rapid quenching belt into auxiliary alloy powder with the grain diameter of 80-150 microns.
3) And uniformly mixing the main alloy magnetic powder a and the auxiliary alloy powder, wherein the auxiliary alloy powder accounts for 2% of the mass of the main alloy magnetic powder a. And (3) placing the mixed powder in a vacuum heat treatment furnace with a rotatable furnace body for diffusion treatment, wherein the temperature is 550 ℃, and the heat preservation time is 1 hour. And cooling to room temperature along with the furnace to obtain magnetic powder b.
4) And (3) carrying out hot press molding on the magnetic powder b for 10min under the conditions of a vacuum environment, a temperature of 620 ℃ and a pressure of 100MPa to obtain a compact hot-pressed magnet.
5) And thermally deforming the hot-pressed magnet under the conditions of 700 ℃ of temperature and 55MPa of pressure in a vacuum environment, wherein the thermal deformation amount is 70%, and thus obtaining the thermal deformation magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1.
Example 7
A thermally deformable magnet was prepared as follows:
1) in terms of atomic percent (Nd)0.74Pr0.16Ce0.1)13Fe76.9Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller wheel in an argon atmosphere to obtain a rapid quenching zone, wherein the roller surface speed is 33m/s, the rapid quenching temperature is 1340 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) According to atomic percent Nd70Cu10Zn20The components are mixed and then melted into master alloy ingots by an induction melting mode. And spraying the molten master alloy to the surface of a water-cooled roller wheel in an inert atmosphere to obtain an auxiliary alloy rapid quenching belt, wherein the roller surface speed is 20m/s, the rapid quenching temperature is 800 ℃, and the spraying pressure is 0.03 MPa. Mechanically crushing and granulating the auxiliary alloy rapid quenching beltAnd (3) auxiliary alloy powder with the diameter of 80-150 microns.
3) And uniformly mixing the main alloy magnetic powder a and the auxiliary alloy powder, wherein the auxiliary alloy powder accounts for 3% of the mass of the main alloy magnetic powder a. And (3) placing the mixed powder in a vacuum heat treatment furnace with a rotatable furnace body for diffusion treatment, wherein the temperature is 580 ℃, and the heat preservation time is 2 hours. And cooling to room temperature along with the furnace to obtain magnetic powder b.
4) And carrying out hot press molding on the magnetic powder b for 15min under the conditions of a vacuum environment, a temperature of 650 ℃ and a pressure of 110MPa to obtain a compact hot-pressed magnet.
5) And thermally deforming the hot-pressed magnet under the conditions that the temperature is 680 ℃ and the pressure is 60MPa in a vacuum environment, wherein the thermal deformation amount is 70%, so as to obtain the thermally deformed magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1.
Example 8
A thermally deformable magnet was prepared as follows:
1) according to atomic percent Nd13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller wheel in an argon atmosphere to obtain a rapid quenching belt, wherein the speed of the roller surface is 30m/s, the rapid quenching temperature is 1380 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) According to atomic percent Pr68Cu22Zn10The components are mixed and then melted into master alloy ingots by an induction melting mode. And spraying the molten master alloy to the surface of a water-cooled roller wheel in an inert atmosphere to obtain an auxiliary alloy rapid quenching belt, wherein the roller surface speed is 20m/s, the rapid quenching temperature is 750 ℃, and the spraying pressure is 0.03 MPa. The auxiliary alloy is rapidly quenched and brought intoMechanically crushing the mixture into auxiliary alloy powder with the grain size of 80-150 microns.
3) And uniformly mixing the main alloy magnetic powder a and the auxiliary alloy powder, wherein the auxiliary alloy powder accounts for 1% of the mass of the main alloy magnetic powder a. And (3) placing the mixed powder in a vacuum heat treatment furnace with a rotatable furnace body for diffusion treatment, wherein the temperature is 580 ℃, and the heat preservation time is 2 hours. And cooling to room temperature along with the furnace to obtain magnetic powder b.
4) And carrying out hot press molding on the magnetic powder b for 30min under the conditions of a vacuum environment, a temperature of 650 ℃ and a pressure of 100MPa to obtain a compact hot-pressed magnet.
5) And thermally deforming the hot-pressed magnet under the conditions that the temperature is 680 ℃ and the pressure is 60MPa in a vacuum environment, wherein the thermal deformation amount is 70%, so as to obtain the thermally deformed magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1.
Comparative example 1
A thermally deformable magnet was prepared as follows:
1) according to atomic percent Nd13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller wheel in an argon atmosphere to obtain a rapid quenching belt, wherein the speed of the roller surface is 30m/s, the rapid quenching temperature is 1380 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) And carrying out hot press molding on the main alloy magnetic powder a under the conditions of a vacuum environment, a temperature of 675 ℃ and a pressure of 100MPa to obtain a compact hot-pressed magnet.
3) And thermally deforming the hot-pressed magnet under the conditions that the temperature is 730 ℃ and the pressure is 55MPa in a vacuum environment, wherein the thermal deformation amount is 70 percent, and thus obtaining the thermal deformation magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1 and FIG. 2.
Comparative example 2
A thermally deformable magnet was prepared as follows:
1) in terms of atomic percent (Nd)0.8Ce0.2)13.8Fe76.1Co4Ga0.5B5.6The components are mixed and then melted into master alloy ingots by an induction melting mode. And (3) spraying the molten master alloy ingot to the surface of a rotating water-cooled roller in an argon atmosphere to obtain a rapid quenching zone, wherein the roller surface speed is 33m/s, the rapid quenching temperature is 1320 ℃, and the spraying pressure is 0.06 MPa. And mechanically crushing the obtained quick quenching belt into main alloy magnetic powder a with the grain size of 100-250 microns.
2) And carrying out hot press molding on the main alloy magnetic powder a under the conditions of a vacuum environment, a temperature of 650 ℃ and a pressure of 90MPa to obtain a compact hot-pressed magnet.
3) And thermally deforming the hot-pressed magnet under the conditions of 720 ℃ of temperature and 50MPa of pressure in a vacuum environment, wherein the thermal deformation amount is 70%, and thus obtaining the thermally deformed magnet.
The obtained thermally deformed magnet was processed into a sample of phi 3mm x 3mm, and magnetic property measurement was performed using VSM. The grain size was measured by transmission electron microscopy. Measurement of the resulting remanence (B)r) Coercive force (H)cj) Maximum energy product (BH)maxAnd the crystal grain size in the short axis direction of the magnet and the ratio of the long axis/short axis size are shown in Table 1.
TABLE 1 magnetic Properties of examples and comparative examples of thermally deformed magnets
Figure BDA0002560168290000141
Figure BDA0002560168290000151
As can be seen from the examples 1-8 in Table 1, the preparation method provided by the invention can effectively reduce the hot-pressing thermal deformation temperature and prevent the crystal grains from growing so as to obtain a larger coercive force. As can be seen from the examples and comparative examples, the low melting point alloy is diffused into the main alloy magnetic powder containing Ce, so that the hot-pressing heat distortion temperature and pressure are obviously reduced synergistically.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (12)

1. A thermal deformation rare earth permanent magnetic material is characterized in that the raw materials comprise (R1) according to the chemical formula by atom percentage1- cCec)xFe100-x-y-zM1yBzThe main alloy magnetic powder a and the chemical formula of R2 according to the atomic percentagea(Cu1-bM2b)100-aWherein c is more than or equal to 0 and less than or equal to 1, x is more than or equal to 12 and less than or equal to 15, y is more than or equal to 0 and less than or equal to 10, z is more than or equal to 5 and less than or equal to 7, R1 is at least one of Nd, Pr, Dy, Tb, Ho, La and Gd, M1 is at least one of Si, Mn, Al, Co, Ga and Cu, a is more than or equal to 60 and less than or equal to 90, b is more than or equal to 0 and less than or equal to 1, R2 is at least one of Nd, Pr, La and Ce, and M2 is at least one of Al, Zn, Ga, Sn and In.
2. A thermally deformable rare earth permanent magnetic material as claimed in claim 1, wherein the mass of the secondary alloy powder is not more than 10% of the mass of the primary alloy magnetic powder a.
3. A thermally deformable rare earth permanent magnetic material as claimed in claim 1, wherein the melting point of the secondary alloy powder is less than 500 ℃.
4. The material according to claim 3, wherein the particle size of the main alloy magnetic powder a is 100 to 250 μm, and the particle size of the auxiliary alloy powder is 80 to 150 μm.
5. A thermally deformable rare earth permanent magnetic material as claimed in claim 1, characterized by consisting of a matrix phase and a Cu-containing grain boundary rare earth-rich phase, said matrix phase grains being in the form of a nano-scale layered structure having a major axis/minor axis ratio of more than 3 and a minor axis direction dimension of less than 100 nm.
6. A thermally deformable rare earth permanent magnetic material as claimed in claim 5, wherein said matrix phase is (Ce, R1)2(Fe,Co)14And B, wherein R1 is at least one of Nd, Pr, Dy and Tb.
7. A method of producing a thermally deformable rare earth permanent magnetic material as claimed in any one of claims 1 to 6, comprising at least the steps of:
(1) respectively providing a main alloy magnetic powder a and an auxiliary alloy powder;
(2) diffusing the auxiliary alloy powder into the main alloy magnetic powder a through heat treatment to obtain magnetic powder b;
(3) carrying out hot press molding on the magnetic powder b to obtain a hot-pressed magnet;
(4) and thermally deforming the hot-pressed magnet to obtain the thermal deformation rare earth permanent magnet material.
8. The method according to claim 7, wherein the method of preparing the secondary alloy powder in step (1) comprises:
weighing a metal simple substance raw material according to the metal element proportion of the auxiliary alloy powder;
smelting the weighed metal simple substance raw materials into an alloy ingot, and then crushing the alloy ingot into auxiliary alloy powder; or
Melting the weighed metal simple substance raw materials and then directly atomizing into auxiliary alloy powder; or
Melting and rapidly quenching the weighed metal simple substance raw materials into strips, and mechanically crushing the strips into auxiliary alloy powder.
9. The production method according to claim 7, wherein the production method of the main alloy magnetic powder a in step (1) includes:
weighing a metal simple substance raw material according to the element proportion of the main alloy magnetic powder a;
smelting the weighed metal simple substance raw materials into alloy ingots;
melting and spraying the alloy ingot on a rotating roller again to prepare a strip sheet;
and preparing the strip into main alloy magnetic powder a in a mechanical crushing mode.
10. The production method according to claim 7, wherein the specific conditions of the heat treatment in the step (2) include:
under the condition of vacuum or protective atmosphere;
the heat treatment temperature is higher than the melting point of the auxiliary alloy powder and is less than 600 ℃;
the heat treatment time is 0.5-5 h.
11. The production method according to claim 7, wherein the specific conditions of the hot press molding in the step (3) include:
under the condition of vacuum or protective atmosphere;
the hot pressing temperature is 550-650 ℃;
the hot pressing pressure is 80MPa to 120 MPa;
the hot pressing time is 1-30 min.
12. The method of claim 7, wherein the specific conditions for hot deformation in step (4) include:
under the condition of vacuum or protective atmosphere;
the thermal deformation temperature is 600-700 ℃;
the thermal deformation pressure is 30 MPa-60 MPa;
the deformation amount is 60-80%.
CN202010608852.4A 2020-06-29 2020-06-29 Thermal deformation rare earth permanent magnetic material and preparation method thereof Pending CN113936878A (en)

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