CN115732155A - High-coercivity neodymium-iron-boron magnetic material and preparation method thereof - Google Patents

Abstract

The application relates to the technical field of magnetic material preparation, and particularly discloses a high-coercivity neodymium-iron-boron magnetic material and a preparation method thereof. The high-coercivity neodymium-iron-boron magnetic material comprises the following raw materials: praseodymium-neodymium alloy, copper, boron, cobalt, titanium, cerium, gadolinium, zirconium, an auxiliary agent and the balance of iron and other irremovable impurities, wherein the auxiliary agent is made of Fe ₃ Pt, fePt and carbon; the preparation method comprises the following steps: smelting praseodymium-neodymium alloy, copper, boron, cobalt, titanium, cerium, gadolinium, iron, zirconium and an auxiliary agent to obtain a smelting liquid, and carrying out melt spinning on the obtained smelting liquid to obtain a melt spinning sheet; introducing inert gas for protection when the raw materials are smelted; hydrogen crushing and airflow milling are carried out on the melt-spun sheet to obtain hydrogen broken powder; crushing hydrogen powder to obtain a green body, and further pressing the green body to obtain a green magnet; sintering and tempering the green magnet, and cooling to room temperature to obtain the magnet. High coercivity neodymium iron boron magnetic material magnet of the present applicationThe sexual performance is better.

Description

A kind of high coercivity neodymium iron boron magnetic material and preparation method thereof

technical field

The present application relates to the technical field of magnetic material preparation, more specifically, it relates to a high-coercivity NdFeB magnetic material and a preparation method thereof.

Background technique

Rare earth permanent magnet materials are widely used in various fields of the national economy such as aerospace, aviation, computer, communication, information, energy, transportation, shipping, petroleum, chemical industry, textile, household appliances, etc. Indispensable cornerstone. Especially NdFeB magnetic materials are used in household appliances and so on.

NdFeB magnetic material, as the latest achievement in the development of rare earth permanent magnet materials, is known as the "Magnetic King" because of its excellent magnetic properties. NdFeB materials have been widely used in modern industry and electronic technology due to their extremely high magnetic energy product and coercive force, as well as high energy density, so that the miniaturization, Lightweight and thinner are possible.

NdFeB magnetic materials are subject to a lower Curie temperature, and their magnetic properties deteriorate sharply in a high-temperature environment. Increasing the coercive force of NdFeB magnetic materials may reduce the loss of magnetic properties of NdFeB magnetic materials at higher temperatures .

Contents of the invention

In order to facilitate the improvement of the coercive force of NdFeB magnetic materials, the present application provides a high coercive force NdFeB magnetic material and a preparation method thereof.

In the first aspect, the present application provides a high coercive force NdFeB magnetic material, adopting the following technical solution: a high coercive force NdFeB magnetic material, including the following raw materials in weight percentage: praseodymium neodymium alloy 10-20 %, copper 0.1-0.3%, boron 0.5-1.5%, cobalt 0.1-0.3%, titanium 0.2-0.5%, cerium 10-15%, gadolinium 0.5-1%, zirconium 0.1-0.2%, auxiliary agent 1-2% , the balance is iron and other non-removable impurities, and the auxiliary agent is composed of Fe ₃ Pt, FePt, and carbon according to the mass ratio (3-5):(1-2):(1-2).

By adopting the above technical scheme, the cerium element is mainly distributed at the grain boundary, which strengthens the grain boundary and may increase the coercive force; and the cerium element may make the grains tend to be uniform and regular, reducing the number of strips, quadrilaterals, Wedges and other sharp-edged, irregularly shaped grains and oversized or undersized grains are greatly reduced or even disappeared, making the grains more compact, improving the toughness at the grain boundaries, and improving the coercivity of the magnet. The cerium element may refine the grains while making the grains tend to be uniform. If the grains are too small, the intergranular exchange effect is strong, and the magnetization direction of each grain is roughly the same. When the magnetization is reversed, it will drive the adjacent grains. Synergistic reversal, rather than the individual reversal of each grain, so that the reverse magnetization of the grains may reduce the coercive force of the magnet; the addition of auxiliary agents facilitates the reduction of the interaction domain between grains, and Fe ₃ Pt and FePt in the magnet Clusters with smaller particle size are formed and distributed on the non-magnetic carbon matrix. Due to the smaller grain size, the Fe ₃ Pt soft magnetic phase and the FePt hard magnetic phase in the cluster can be completely magnetically coupled, while the inter-cluster Separated by the non-magnetic phase, each cluster can be independently magnetized, thereby improving the coercive force of the magnetic material.

Preferably, the mass ratio of the cerium to the auxiliary agent is (11-13):(1.5-1.8).

By adopting the above technical scheme, the ratio of cerium and auxiliary agent is further optimized, so that the ratio of the two components is optimal, so as to further improve the synergy between the auxiliary agent and cerium element, thereby improving the magnetic properties of the magnet .

Preferably, the cobalt is modified cobalt, and the modified cobalt uses cobalt as the core and CoPt as the shell.

Preferably, the method for preparing modified cobalt includes the following steps: mixing cobalt powder with a thermosetting resin, heating and stirring to obtain pretreated cobalt, and mixing CoPt with pretreated cobalt to obtain the obtained product.

Preferably, the mass ratio of CoPt to cobalt is (4-5):(1-2). Further preferably, the μm.

Preferably, the heating temperature is 110-120°C.

Preferably, the thermosetting resin is phenolic resin.

By adopting the above technical scheme, the outer layer of Co is wrapped with CoPt. CoPt is a hard magnetic material, and has large magnetocrystalline anisotropy and large shape anisotropy. It is wrapped in the outer layer of Co, which is convenient to increase the saturation magnetization of Co and increase the Large magnetic energy product, at the same time, based on the exchange coupling effect between soft and hard magnetic materials, the saturation magnetization of the material is increased, thereby improving the magnetic properties of the prepared NdFeB magnetic material.

Preferably, 0.2-0.5% TiC is also included.

By adopting the above technical scheme, the addition of TiC may change the microstructure of the magnet and improve the magnetic properties of the magnet. The solubility of titanium in the NdFeB phase is small. During the grain growth process, titanium is squeezed out of NdFeB phase and gather at the grain boundary, which has the effect of inhibiting the growth of grains, and titanium carbide has the effect of isolating the grains of the hard magnetic phase, which is convenient for improving the coercive force of the magnet.

In the second aspect, the present application provides a method for preparing a high-coercivity NdFeB magnetic material, which adopts the following technical scheme:

A method for preparing a high-coercivity neodymium-iron-boron magnetic material, comprising the steps of:

(1) Melting strip: smelting praseodymium-neodymium alloy, copper, boron, cobalt, titanium, cerium, gadolinium, iron, zirconium, and auxiliary agents to obtain a smelting liquid, and stripping the obtained smelting liquid to obtain a strip sheet; The raw materials are protected by passing inert gas during smelting;

(2) Hydrogen crushing grinding: after carrying out hydrogen crushing and jet milling to the strip sheet obtained in step (1), hydrogen crushing powder is obtained;

(3) Compression forming: pressing the hydrogen broken powder prepared in step (2) to obtain a green body, further pressing the green body to obtain a raw magnet;

(4) Sintering: sintering and tempering the raw magnet prepared in step (3), and cooling down to room temperature.

Preferably, the sintering temperature in the step (4) is 1000-1050°C.

Preferably, the hydrogen breaking operation in the step (2) is as follows: place the strip strip in a hydrogen atmosphere, make the strip strip absorb hydrogen for 2-3 hours to obtain a hydrogen broken product, and control the hydrogen absorption pressure to 0.7-0.9MPa , the hydrogen absorption temperature is 350-500°C; after that, the hydrogen incineration product is heated to 600-700°C for dehydrogenation treatment.

By adopting the above-mentioned technical scheme, the NdFeB magnetic material of the present application has undergone smelting, hydrogen breaking, compression molding, sintering, and tempering treatment, and the magnetic properties of the NdFeB magnetic material thus obtained are better, and the application is smelting, The way of nitrogen protection is used to reduce the oxidation of raw materials, so as to further improve the magnetic properties of NdFeB magnetic materials.

Preferably, the particle size of the hydrogen crushed powder in the step (2) is 1-2 μm.

By adopting the above technical scheme, the particle size of the hydrogen broken powder is small, which is convenient to increase the coercive force of the magnet under the condition of affecting the remanence. The suitable particle size of the fine powder can not only reduce the agglomeration of the fine powder, but also improve the quality of the fine powder. The degree of orientation after forming orientation; at the same time, it can ensure the compactness of NdFeB magnetic materials after pressing.

Preferably, in the step (2), the strip flakes are mixed with antioxidants, and hydrogen crushing and jet milling are carried out.

By adopting the above technical scheme, during the preparation process of the hydrogen powder, the hydrogen powder is fully in contact with the oxygen in the jet mill, so that the magnetic powder tends to be oxidized, and the antioxidant inhibits the formation of high melting point oxidation with oxygen in the NdFeB magnetic material material, thereby limiting the probability of holes due to the formation of high melting point oxides, making the coercive force of NdFeB magnetic materials meet the standard, improving the corrosion resistance of NdFeB magnetic materials, thereby prolonging the work of NdFeB magnetic materials life.

Preferably, the antioxidant consists of antioxidant 1010, antioxidant 1076, and zinc stearate in a mass ratio of (4-5):(1-2):(1-2).

Preferably, the antioxidant is composed of antioxidant 1010, antioxidant 1076, and zinc stearate in a mass ratio of 5:2:2.

By adopting the above technical scheme, one of the antioxidant 1076, the antioxidant 1010, and the antioxidant 1076 is used as the main antioxidant, and the other is used as the auxiliary antioxidant, and the antioxidant 1010 and the antioxidant 1076 cooperate with each other and act synergistically. Further improve the anti-oxidation effect of hydrogen crushing powder; zinc stearate has a lubricating effect, which is convenient to improve the fluidity of the obtained hydrogen crushing powder, reduce the friction between powder particles, and then reduce the phenomenon of agglomeration of powder particles. At the same time, hydrogen The rotational resistance between broken powders is reduced, and the degree of powder orientation is improved, which facilitates the improvement of the magnetic properties of the magnet.

Preferably, the hydrogen-breaking powder in the step (3) is pretreated, and the hydrogen-breaking powder pretreatment method includes the following steps: immersing the hydrogen-breaking powder in a silicone resin solution, mixing evenly, drying, Dried, that is.

Preferably, the spin-drying method is spin-dried.

Preferably, the drying voltage of the drying machine is 180V.

Preferably, the mass fraction of the organic solution of the silicone resin is 40-50%.

Preferably, the drying is firstly baked in a vacuum drying oven for 20-30 minutes at a temperature of 55-60° C., and after the solvent evaporates, baked at 110° C. for 50-60 minutes.

Preferably, the organic solution is ethanol.

Preferably, the silicone resin is commercially available.

By adopting the above technical scheme, wrapping the silicone resin layer on the outer layer of the hydrogen powder, it is convenient to improve the particle dispersion degree of the hydrogen powder, and it is possible to improve the compactness of the obtained magnet, and at the same time, further improve the oxidation resistance of the hydrogen powder, It helps to improve the oxidation resistance and corrosion resistance of the prepared magnetic material.

Preferably, in the step (4) after the raw magnet is sintered, it is tempered at a temperature of 900-950° C. and kept for 3-4 hours; the raw magnet is cooled to 600-700° C., kept for 2-3 hours, and then cooled to 300-400°C, keep warm for 2-3h, cool down to room temperature and take out the oven.

Preferably, after sintering, the raw magnet is tempered at a temperature of 900°C and kept for 4 hours; the raw magnet is cooled to 700°C, kept for 2 hours, then cooled to 350°C, kept for 2 hours, cooled to room temperature and released from the furnace.

By adopting the above technical scheme, tempering can be carried out by the temperature of the material itself during heat preservation, so that multiple tempering can be realized through one temperature rise, which greatly saves the energy consumed by temperature rise, thereby reducing production costs and realizing energy saving and emission reduction . At the same time, multiple tempering can also improve the coercive force of NdFeB magnetic materials.

In summary, the application has the following beneficial effects:

1. The high coercive force NdFeB magnetic material of this application is obtained by adding cerium and auxiliary agent. The auxiliary agent is obtained by compounding three components of Fe ₃ Pt, FePt, and carbon. The cerium and auxiliary agent cooperate with each other, and the cerium is refined by The size of the crystal grains further improves the magnetic properties of the NdFeB magnetic material, and the auxiliary agent can improve the magnetic properties of the NdFeB magnetic material by reducing the interaction domain between the grains.

2. The high coercive force NdFeB magnetic material of this application wraps CoPt in the outer layer of Co. CoPt is a hard magnetic material, and has large magnetocrystalline anisotropy and large shape anisotropy, and is wrapped in the outer layer of Co , it is convenient to increase the saturation magnetization of Co and increase the magnetic energy product. At the same time, based on the exchange coupling between soft and hard magnetic materials, the saturation magnetization of the material is increased, thereby improving the magnetic properties of the prepared NdFeB magnetic material.

3. By adding TiC to the high-coercivity NdFeB magnetic material of this application, it is possible to change the microstructure of the magnet and improve the magnetic properties of the magnet. The solubility of titanium in the NdFeB phase is small, and the grain growth process Among them, titanium is extruded from the NdFeB phase and gathers at the grain boundary, which has the effect of inhibiting grain growth, and titanium carbide has the effect of isolating the grains of the hard magnetic phase, which is convenient for improving the coercive force of the magnet.

Detailed ways

The present application will be described in further detail below in conjunction with the examples.

The praseodymium neodymium alloy of the present application is commercially available, further optional, the praseodymium neodymium alloy of the present application is purchased from Beijing Xingrongyuan Technology Co., Ltd., and is mixed with praseodymium powder and neodymium powder, and the purity of praseodymium powder and neodymium powder is both 99.99%, praseodymium accounts for 15.5wt% of the total amount of praseodymium neodymium powder.

The iron powder of this application is commercially available, and further optionally, the iron powder of this application is purchased from Shijiazhuang Hualang Mineral Products Trading Co., Ltd., and the iron content of magnet powder is 99.9%.

The auxiliary agent in this application is composed of Fe ₃ Pt, FePt, and carbon in a mass ratio of (3-5):(1-2):(1-2). Further optionally, the auxiliary agent of the present application is composed of Fe ₃ Pt, FePt, and carbon in a mass ratio of 5:2:2.

The addition amount of TiC in this application is 0.2-0.5%, further optionally, the addition amount of TiC is 0.5%.

Example

Embodiment 1: A kind of high coercive force neodymium-iron-boron magnetic material, comprises the raw material of following percentage by weight: Praseodymium neodymium alloy 10%, copper 0.1%, boron 0.5%, cobalt 0.1%, titanium 0.2%, cerium 10%, gadolinium 0.5%, zirconium 0.1%, auxiliary agent 1%, and the balance is iron and other impurities that cannot be removed. Among them, the auxiliary agent is composed of Fe ₃ Pt, FePt, and carbon in a mass ratio of 5:2:2.

The preparation method of the above-mentioned high coercive force NdFeB magnetic material comprises the following steps:

(1) Melting strip: smelting praseodymium-neodymium alloy, copper, boron, cobalt, titanium, cerium, gadolinium, iron, zirconium, and auxiliary agents to obtain a smelting liquid, and stripping the obtained smelting liquid to obtain a strip sheet; The raw materials are protected by passing inert gas during smelting;

(2) Hydrogen crushing and grinding: carry out hydrogen crushing and jet milling on the strip sheet obtained in step (1) to obtain hydrogen crushing powder; the hydrogen crushing operation is: place the strip sheet in a hydrogen atmosphere to make the strip strip tablet suction

Hydrogen for 2 hours to obtain the hydrogen decomposed product, control the hydrogen absorption pressure to 0.8MPa, and the hydrogen absorption temperature to 400°C; then raise the temperature of the hydrogen decomposed product to 650°C for dehydrogenation treatment; the particle size of the hydrogen decomposed powder is 2 μm;

(3) Compression forming: pressing the hydrogen broken powder prepared in step (2) to obtain a green body, further pressing the green body to obtain a raw magnet;

(4) Sintering: sintering and tempering the raw magnet obtained in step (3), and lowering it to room temperature; wherein, the sintering temperature is 1050°C; after sintering, the raw magnet is tempered at a temperature of 900°C, And keep it warm for 4 hours; cool the raw magnet to 700°C, keep it warm for 2 hours, then cool it down to 350°C, keep it warm for 2 hours, cool down to room temperature and leave the oven.

The raw material component distribution ratio of the high coercive force neodymium-iron-boron magnetic material of table 1 embodiment 1-5

Example 2-4: A high-coercivity NdFeB magnetic material, the distribution ratio of each component of the raw material is shown in Table 1, the difference from Example 1 is that the distribution ratio of each component of the raw material is different.

Embodiment 5: A high-coercive force NdFeB magnetic material, the distribution ratio of each component of the raw material is shown in Table 1, and the difference from Embodiment 4 is that 0.5% TiC is also added.

Embodiment 6: A kind of high coercive force neodymium-iron-boron magnetic material, the difference with embodiment 5 is: cobalt is modified cobalt, modified cobalt takes cobalt as core, takes CoPt as shell, the preparation method of modified cobalt , comprising the following steps: mixing cobalt powder with a thermosetting resin, heating and stirring to obtain pretreated cobalt, and mixing CoPt with pretreated cobalt to obtain. Among them, the mass ratio of CoPt to cobalt is 5:1, the mass ratio of thermosetting resin to cobalt powder is 3:1, the particle size of cobalt powder is 30 μm, the particle size of CoPt is 5 μm, the heating temperature is 110 °C, and the thermosetting resin is Phenolic Resin.

Embodiment 7: A kind of high coercive force NdFeB magnetic material, the difference with embodiment 6 is: the preparation method of high coercive force NdFeB magnetic material, comprises the following steps:

(1) Melting strip: smelting praseodymium-neodymium alloy, copper, boron, cobalt, titanium, cerium, gadolinium, iron, zirconium, and auxiliary agents to obtain a smelting liquid, and stripping the obtained smelting liquid to obtain a strip sheet; The raw materials are protected by passing inert gas during smelting;

(2) Hydrogen crushing and grinding: carry out hydrogen crushing and air-jet milling of the strip sheet obtained in step (1) and the antioxidant to obtain hydrogen crushing powder; the hydrogen crushing operation is: place the strip sheet in a hydrogen atmosphere, Make the strip sheet absorb hydrogen for 2 hours to obtain the hydrogen broken product, control the hydrogen absorption pressure to 0.8MPa, and the hydrogen absorption temperature to 400°C; then raise the temperature of the hydrogen broken product to 650°C for dehydrogenation treatment; the particle size of the hydrogen broken powder is 2 μm; wherein, the antioxidant is antioxidant 1010;

(3) Compression forming: pressing the hydrogen broken powder prepared in step (2) to obtain a green body, further pressing the green body to obtain a raw magnet;

(4) Sintering: sintering and tempering the raw magnet obtained in step (3), and lowering it to room temperature; wherein, the sintering temperature is 1050°C; after sintering, the raw magnet is tempered at a temperature of 900°C, And keep it warm for 4 hours; cool the raw magnet to 700°C, keep it warm for 2 hours, then cool it down to 350°C, keep it warm for 2 hours, cool down to room temperature and leave the oven.

Embodiment 8: a kind of high coercive force neodymium iron boron magnetic material, the difference with embodiment 7 is: the antioxidant in the step (2) is made of antioxidant 1010, antioxidant 1076, zinc stearate by mass ratio 5:2:2 composition.

Embodiment 9: a kind of high coercive force neodymium-iron-boron magnetic material, and the difference of embodiment 8 is: the hydrogen breaking powder in the step (3) is pretreated, and the method for hydrogen breaking powder pretreatment comprises the steps: Immerse the hydrogen breaking powder in the silicone resin solution, mix evenly, spin dry, and dry it. Spin-drying is performed by spin-coating method. The drying voltage of the drying machine is 180V. The mass fraction of the organic solution of the silicone resin is 40%, and the drying method is firstly baked in a vacuum drying oven for 25 minutes at a temperature of 60°C, and after the solvent is evaporated, baked at 110°C for 60 minutes to obtain the product. The organic solution is ethanol; the silicone resin is commercially available.

comparative example

Comparative example 1: a high-coercivity NdFeB magnetic material, the difference from Example 1 is that no cerium is added.

Comparative example 2: a high-coercivity NdFeB magnetic material, the difference from Example 1 is that no auxiliary agent is added.

Comparative example 3: a high coercivity NdFeB magnetic material, the difference from Example 1 is that the auxiliary agent is composed of Fe ₃ Pt and FePt in a mass ratio of 3:1.

Comparative example 4: a high coercivity NdFeB magnetic material, the difference from Example 1 is that the auxiliary agent is composed of Fe ₃ Pt and carbon in a mass ratio of 3:1.

Comparative example 5: a high-coercivity NdFeB magnetic material, the difference from Example 1 is that the auxiliary agent is Fe ₃ Pt.

Detection method

Magnetic performance testing: The high coercive force NdFeB magnetic material obtained in Examples 1-9 and Comparative Examples 1-5 is based on the detection method in GB/T3217-2013 "Magnetic Test Methods for Permanent Magnet (Hard Magnetic) Materials", The magnetic properties of high coercive force NdFeB magnetic materials are tested by using the NIM-10000H rare earth permanent magnet nondestructive testing system at a temperature of 20 °C in Xi'an. The test results are shown in Table 2.

The magnetic performance detection result of the high coercivity neodymium-iron-boron magnetic material that table 2 embodiment 1-9 and comparative example 1-5 make

In conjunction with Examples 1-4, and in conjunction with the data in Table 2, it can be seen that the coercive force, maximum magnetic energy product, and remanent magnetism of the high-coercive force NdFeB magnetic material obtained in Example 1-4 are relatively large, and the magnetic properties are relatively high. The performance is better. The inventors of the present application speculate that the cerium element, the auxiliary agent and other materials in the high coercive force NdFeB magnetic material cooperate with each other, and the synergistic effect of the cerium element and the auxiliary agent may further improve the high coercive force NdFeB magnetic material. Magnetic properties of boron magnetic materials.

In conjunction with Examples 4-5, and in conjunction with the data in Table 2, it can be seen that compared with Example 4, TiC is added to the high coercive force NdFeB magnetic material of Example 5, and the high coercive force NdFeB magnetic material thus prepared The coercive force, maximum magnetic energy product, and remanent magnetism of coercive NdFeB magnetic materials are large, and the magnetic properties are better. The inventors of the present application speculate that the addition of TiC may further inhibit the growth of crystal grains. Titanium in the NdFeB phase The solubility in the medium is small. During the grain growth process, the NdFeB phase is extruded and gathered at the grain boundary, which has the effect of inhibiting the grain growth. Titanium carbide has the effect of isolating the grains of the hard magnetic phase, which is convenient Improve the magnetic performance of the magnet.

Combining Examples 5-6 and the data in Table 2, it can be seen that compared with Example 5, Co is modified in Example 6, and CoPt is coated on the outer layer of cobalt, so that the high coercivity The coercivity, maximum magnetic energy product, and remanent magnetism of NdFeB magnetic materials are large, and the magnetic properties are better. The inventors of the present application speculate that the modified Co may improve the magnetic crystal of Co through the CoPt layer wrapped by the outer layer. Anisotropy and shape anisotropy help to improve the magnetic properties of the magnets produced.

In conjunction with Examples 6-7, and in conjunction with the data in Table 2, it can be seen that, compared with Example 6, in Example 7, the strip sheet is mixed with an antioxidant during the crushing process, and the thus obtained high correction Coercivity NdFeB magnetic materials have larger coercive force, maximum magnetic energy product, and remanent magnetism, and better magnetic properties. The inventors of the present application speculate that the addition of antioxidants may inhibit the high formation of oxygen elements in NdFeB magnetic materials. Melting point oxides, thereby limiting the probability of holes due to the formation of high melting point oxides, help to improve the corrosion resistance of NdFeB magnetic materials, and then improve the magnetic properties of NdFeB magnetic materials.

In conjunction with Examples 7-8, and in conjunction with the data in Table 2, it can be seen that compared with Example 7, in Example 8, the compounded antioxidant is mixed with the strip sheet during the crushing process, thus making The obtained high coercive force NdFeB magnetic material has relatively large coercive force, maximum magnetic energy product, and remanent magnetism, and better magnetic properties. The inventors of the present application speculate that the combination of antioxidant 1010 and antioxidant 1076, The synergistic effect further improves the anti-oxidation effect of the hydrogen-breaking powder; zinc stearate may reduce the agglomeration of powder particles, and at the same time, reduce the rotational resistance between the hydrogen-breaking powders, increase the degree of powder orientation, and facilitate the improvement of the magnetic properties of the magnet.

In conjunction with Examples 8-9, and in conjunction with the data in Table 2, it can be seen that compared with Example 8, the high-coercivity NdFeB magnetic material prepared in Example 9 is wrapped in the outer layer of the hydrogen-breaking powder. Oxygen-resistant layer, the high coercive force NdFeB magnetic material thus obtained has larger coercive force, maximum magnetic energy product, remanent magnetism, and better magnetic performance. The silicone resin layer is convenient to improve the particle dispersion degree of the hydrogen powder, which may improve the compactness of the obtained magnet. At the same time, it further improves the oxidation resistance of the hydrogen powder, which helps to improve the oxidation resistance of the magnetic material produced. and corrosion resistance.

In conjunction with Example 1, Comparative Example 1-2, and in conjunction with the data in Table 2, it can be seen that the difference between Comparative Example 1-2 and Example 1 is: in Example 1, cerium and auxiliary agent are added simultaneously, and the obtained high The magnetic properties of the coercivity NdFeB magnetic material are better than those of the high coercivity NdFeB magnetic material prepared in Comparative Example 1-2.

In conjunction with Example 1, Comparative Examples 3-5, and in conjunction with the data in Table 2, it can be seen that the high coercive force NdFeB magnetic material obtained in Comparative Examples 3-5 and the high coercive force NdFeB magnetic material obtained in Example 1 The difference of the NdFeB magnetic material is that the auxiliary agent in Example 1 is composed of three components of Fe ₃ Pt, FePt, and carbon, and the magnetic properties of the high coercivity NdFeB magnetic material obtained are better than those of the comparative example 3-5 The magnetic properties of the high coercivity NdFeB magnetic material prepared.

This specific embodiment is only an explanation of this application, and it is not a limitation of this application. Those skilled in the art can make modifications to this embodiment without creative contribution according to needs after reading this specification, but as long as the rights of this application All claims are protected by patent law.

Claims (10)

1. A high coercivity NdFeB magnetic material is characterized in that: comprises the following raw materials in percentage by weight: 10-20% of praseodymium-neodymium alloy, 0.1-0.3% of copper, 0.5-1.5% of boron, 0.1-0.3% of cobalt, 0.2-0.5% of titanium, 10-15% of cerium, 0.5-1% of gadolinium, 0.1-0.2% of zirconium, 1-2% of auxiliary agent and the balance of iron and other irremovable impurities, wherein the auxiliary agent is made of Fe ₃ The alloy consists of Pt, fePt and carbon according to the mass ratio of (3-5) to (1-2).

2. The high coercivity neodymium iron boron magnetic material of claim 1, wherein: the mass ratio of the cerium to the auxiliary agent is (11-13) to (1.5-1.8).

3. The high coercivity neodymium iron boron magnetic material of claim 1, wherein: the cobalt is modified cobalt, the modified cobalt takes cobalt as a core, and CoPt as a shell layer.

4. The high coercivity neodymium iron boron magnetic material of claim 1, wherein: also comprises 0.2 to 0.5 percent of TiC.

5. A method of manufacturing a high coercivity neodymium iron boron magnetic material according to any one of claims 1 to 3, characterised in that: the method comprises the following steps:

(1) Melting and melt spinning: smelting praseodymium-neodymium alloy, copper, boron, cobalt, titanium, cerium, gadolinium, iron, zirconium and an auxiliary agent to obtain a smelting liquid, and carrying out melt spinning on the obtained smelting liquid to obtain a melt spinning sheet; introducing inert gas for protection when the raw materials are smelted;

(2) Hydrogen crushing and grinding: carrying out hydrogen crushing and airflow milling on the melt-spun sheet obtained in the step (1) to obtain hydrogen broken powder;

(3) And (3) pressing and forming: crushing the hydrogen powder prepared in the step (2) to prepare a green body, and further pressing the green body to obtain a green magnet;

(4) And (3) sintering: and (4) sintering and tempering the green magnet prepared in the step (3), and cooling to room temperature to obtain the magnetic material.

6. The method for preparing the high-coercivity neodymium-iron-boron magnetic material according to claim 5, wherein the method comprises the following steps: the particle size of the hydrogen broken powder in the step (2) is 1-2 μm.

7. The method for preparing the high-coercivity neodymium-iron-boron magnetic material according to claim 5, characterized by comprising the following steps of: and (3) mixing the melt-spun sheets with an antioxidant in the step (2), and carrying out hydrogen crushing and jet milling.

8. The method for preparing the high-coercivity neodymium-iron-boron magnetic material according to claim 7, wherein the method comprises the following steps: the antioxidant comprises an antioxidant 1010, an antioxidant 1076 and zinc stearate according to the mass ratio of (4-5) to (1-2).

9. The method for preparing the high-coercivity neodymium-iron-boron magnetic material according to claim 5, characterized by comprising the following steps of: the hydrogen broken powder in the step (3) is pretreated, and the hydrogen broken powder pretreatment method comprises the following steps: soaking hydrogen powder into the organic silicon resin solution, mixing uniformly, drying by spin-drying, and drying to obtain the hydrogen-containing organic silicon resin.

10. The method for preparing the high-coercivity neodymium-iron-boron magnetic material according to claim 5, wherein the method comprises the following steps: after the green magnet in the step (4) is sintered, tempering treatment is carried out at the temperature of 900-950 ℃, and heat preservation is carried out for 3-4h; cooling the raw magnet to 600-700 ℃, preserving heat for 2-3h, cooling to 300-400 ℃, preserving heat for 2-3h, cooling to room temperature, and discharging.