阅读说明：本技术 一种无重稀土的高矫顽力永磁体及其制备工艺 (Heavy rare earth-free high-coercivity permanent magnet and preparation process thereof ) 是由 熊吉磊 陈敏 成丽春 刘星 周宏亮 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种无重稀土的高矫顽力永磁体及其制备工艺,属于钕铁硼永磁材料领域,所述永磁体包括钕铁硼合金和LaCo5系合金,其中,所述LaCo5系合金的含量占所述永磁体重量的0.1-25％；本发明通过往Nd-Fe-B材料中加入LaCo5的单相微粉,采用烧结工艺烧结使钕铁硼磁体具有较高的各向异性,从而获得低成本的高矫顽力钕铁硼磁体。(The invention discloses a heavy rare earth-free high-coercivity permanent magnet and a preparation process thereof, belonging to the field of neodymium iron boron permanent magnet materials, wherein the permanent magnet comprises neodymium iron boron alloy and LaCo5 series alloy, wherein the content of the LaCo5 series alloy accounts for 0.1-25% of the weight of the permanent magnet; according to the invention, the single-phase micro powder of LaCo5 is added into the Nd-Fe-B material, and the neodymium iron boron magnet is sintered by adopting a sintering process, so that the neodymium iron boron magnet with high coercivity and low cost is obtained.)

1. The heavy rare earth-free high-coercivity permanent magnet is characterized by comprising a neodymium-iron-boron alloy and a LaCo5 series alloy, wherein the LaCo5 series alloy accounts for 0.1-25% of the weight of the permanent magnet.

2. The heavy rare earth-free high-coercivity permanent magnet according to claim 1, wherein the LaCo5 series alloy is a multi-LaCo 5 series alloy obtained by jointly replacing part of Co in LaCo5 with Fe, Mo, Ag, Ga, and Zr elements.

3. The heavy rare earth-free high coercive force permanent magnet according to claim 1, wherein the multi-element LaCo 5-based alloy has a composition represented by the following formula:

La_16.7Co_{83.3-x-y-z-m-n}Fe_xMo_yAg_zGa_mZr_n，

wherein x, y, z, m and n represent atomic percent, x is more than or equal to 5 and less than or equal to 20, y is more than or equal to 1 and less than or equal to 5, z is more than or equal to 0.1 and less than or equal to 0.6, m is more than or equal to 0.1 and less than or equal to 2, and n is more than or equal to 0.1 and less than or equal to 0.3.

4. The method for producing a heavy rare earth-free high coercive force permanent magnet according to claim 1, comprising the steps of:

(1) preparing LaCo5 series alloy;

(2) respectively carrying out hydrogen explosion on the neodymium iron boron alloy and the LaCo5 series alloy to respectively prepare neodymium iron boron alloy coarse powder and LaCo5 series alloy coarse powder, and respectively preparing neodymium iron boron alloy fine powder and LaCo5 series alloy fine powder by milling powder through air flow;

(3) respectively carrying out orientation molding on the neodymium iron boron alloy fine powder and the LaCo5 series alloy fine powder in a magnetic field to prepare neodymium iron boron alloy green compacts and LaCo5 alloy green compacts, and respectively preparing neodymium iron boron blanks and LaCo5 alloy blanks after carrying out microwave vacuum sintering in the magnetic field;

(4) and adhering the LaCo5 alloy blank to the neodymium iron boron blank, and performing vacuum heat treatment in a magnetic field to obtain the neodymium iron boron alloy.

5. The method for producing a heavy rare earth-free high coercive force permanent magnet according to claim 4, wherein the method for producing the LaCo 5-based alloy is: the materials are mixed according to the designed atomic percentage, and the mixture is smelted by a vacuum smelting melt-spun furnace and cast into sheet alloy with the thickness of 0.1-0.2 mm.

6. The method for preparing the heavy rare earth-free high-coercivity permanent magnet according to claim 4, wherein the process conditions of the gas-flow milled powder are as follows: grinding under protective atmosphere, controlling oxygen content below 5ppm, grinding pressure at 0.60-0.62MPa, inlet temperature of protective gas at 5-10 deg.C, and external cooling circulating water at 5-10 deg.C.

7. The method for producing a heavy rare earth-free high coercive force permanent magnet as claimed in claim 4, wherein the magnetic field strength of the orientation molding is 2.0T, and the green compact density of the molding is 4.4 ± 0.5g/cm³。

8. The method as claimed in claim 4, wherein the magnetic field strength of the microwave vacuum sintering is 2.0-7.0T, the sintering temperature is 900-.

9. The method as claimed in claim 4, wherein the magnetic field strength of the vacuum heat treatment is 2.0-7.0T, the treatment temperature is 540-.

10. The method for preparing the heavy rare earth-free high-coercivity permanent magnet according to claim 4, wherein the LaCo5 alloy blank is plated on the neodymium iron boron blank by a magnetron sputtering method, and the content of the LaCo5 alloy is controlled by adjusting sputtering time.

Technical Field

The invention relates to the field of neodymium iron boron permanent magnet materials, in particular to a heavy rare earth-free high-coercivity permanent magnet and a preparation process thereof.

Background

Magnetic materials, especially rare earth NdFeB series permanent magnetic materials, are the best permanent magnetic materials in comprehensive performance at present, and become indispensable important material basis in modern industry and scientific technology. The sintered Nd-Fe-B permanent magnet material is rapidly industrialized due to excellent cost performance, and is widely applied to various high and new technical fields of computer hard disk drives, hard disk voice coil motors, generators, nuclear magnetic resonance instruments, sound equipment, communication equipment and the like.

The main phase Nd2Fe14B of the NdFeB permanent magnet material is a very high anisotropy field, the theoretical limit of the coercive force is as high as 70kOe, the coercive force of the sintered NdFeB magnet is only 1/5-1/3 of the theoretical value, various efforts are tried to obtain a magnet with high coercive force and high stability, at present, the most effective method is to add heavy rare earth elements such as Dy and Tb through grain boundary diffusion, however, the heavy rare earth resources are limited, the price is high, and the cost cannot be effectively reduced. Therefore, how to reduce the usage amount of expensive heavy rare earth such as Dy, Tb and the like on the premise of ensuring the coercive force and improve the cost performance of products becomes one of the key development directions of enterprises in the future.

Disclosure of Invention

Aiming at the problem of cost caused by dependence of coercive force improvement on expensive heavy rare earth, the invention provides a heavy rare earth-free high coercive force permanent magnet and a preparation process thereof.

The purpose of the invention is realized by adopting the following technical scheme:

the permanent magnet comprises a neodymium iron boron alloy and a LaCo5 series alloy, wherein the content of the LaCo5 series alloy accounts for 0.1-25% of the weight of the permanent magnet.

Preferably, the LaCo5 series alloy is a multi-element LaCo5 series alloy obtained by jointly replacing part of Co in LaCo5 with Fe, Mo, Ag, Ga and Zr elements.

Preferably, the multi-LaCo 5-based alloy has a composition represented by the following formula:

La_16.7Co_{83.3-x-y-z-m-n}Fe_xMo_yAg_zGa_mZr_n，

wherein x, y, z, m and n represent atomic percent, x is more than or equal to 5 and less than or equal to 20, y is more than or equal to 1 and less than or equal to 5, z is more than or equal to 0.1 and less than or equal to 0.6, m is more than or equal to 0.1 and less than or equal to 2, and n is more than or equal to 0.1 and less than or equal to 0.3.

Another object of the present invention is to provide a method for preparing the heavy rare earth-free high coercivity permanent magnet, which specifically comprises the following steps:

(1) preparing LaCo5 series alloy;

(2) respectively carrying out hydrogen explosion on the neodymium iron boron alloy and the LaCo5 series alloy to respectively prepare neodymium iron boron alloy coarse powder and LaCo5 series alloy coarse powder, and respectively preparing neodymium iron boron alloy fine powder and LaCo5 series alloy fine powder by milling powder through air flow;

(3) respectively carrying out orientation molding on the neodymium iron boron alloy fine powder and the LaCo5 series alloy fine powder in a magnetic field to prepare neodymium iron boron alloy green compacts and LaCo5 alloy green compacts, and respectively preparing neodymium iron boron blanks and LaCo5 alloy blanks after carrying out microwave vacuum sintering in the magnetic field;

(4) and adhering the LaCo5 alloy blank to the neodymium iron boron blank, and performing vacuum heat treatment in a magnetic field to obtain the neodymium iron boron alloy.

Preferably, the preparation method of the LaCo5 alloy comprises the following steps: the materials are mixed according to the designed atomic percentage, and the mixture is smelted by a vacuum smelting melt-spun furnace and cast into sheet alloy with the thickness of 0.1-0.2 mm.

Preferably, the process conditions of the airflow milling powder are as follows: grinding under protective atmosphere, controlling oxygen content below 5ppm, grinding pressure at 0.60-0.62MPa, inlet temperature of protective gas at 5-10 deg.C, and external cooling circulating water at 5-10 deg.C.

Preferably, the magnetic field intensity of the orientation forming is 2.0T, and the density of the formed compact is 4.4 +/-0.5 g/cm³。

Preferably, the magnetic field intensity of the microwave vacuum sintering is 2.0-7.0T, the sintering temperature is 900-1000 ℃, the sintering time is 15-40min, and the microwave power is 2.0-5.0 kW.

Preferably, the magnetic field intensity of the vacuum heat treatment is 2.0-7.0T, the treatment temperature is 540-.

Preferably, the LaCo5 alloy blank is plated on the neodymium iron boron blank by a magnetron sputtering method, and the content of the LaCo5 alloy is controlled by adjusting the sputtering time.

The invention has the beneficial effects that:

the invention provides a new neodymium iron boron permanent magnet with high coercivity prepared at low cost, so that the prepared neodymium iron boron magnet has high coercivity with good cost performance, and particularly, heavy rare earth such as Dy replaces Nd to remarkably improve the coercivity of the magnet mainly because the magnetocrystalline anisotropy field Ha (Ha about 12000KA/m) of Dy2Fe14B is about 2 times higher than the magnetocrystalline anisotropy field Ha (Ha about 5840KA/m) of Nd2Fe14B, and LaCo5 also has high magnetocrystalline anisotropy field Ha (Ha about 14000KA/m), so that the coercivity of the neodymium iron boron magnet can be theoretically greatly improved by adding LaCo5 type magnetic powder into the neodymium iron boron magnetic powder by adopting a proper process technology. The method has the advantages that the single-phase micro powder of LaCo5 is added into the Nd-Fe-B material, and the neodymium iron boron magnet has high anisotropy by adopting sintering process, so that the low-cost high-coercivity neodymium iron boron magnet is obtained.

Detailed Description

The invention is further described with reference to the following examples.

The embodiment of the invention relates to a heavy rare earth-free NdFeB/LaCo5 type permanent magnet, which comprises neodymium iron boron alloy and LaCo5 series alloy, wherein the embodiment takes commercial neodymium iron boron with the trademark of N50 as an example for illustration, and the invention can also be applied to neodymium iron boron alloy with other trademarks.

Example 1

A heavy rare earth-free NdFeB/LaCo5 type permanent magnet is prepared by the following steps:

(1) mixing, wherein the LaCo5 type powder is prepared according to the following atomic ratio: la_16.7Co_{83.3-x-y-z-m- n}Fe_xMo_yAg_zGa_mZr_nWherein x is 5, y is 1, z is 0.1, m is 0.1, and n is 0.10; the neodymium iron boron alloy adopts a commercial N50 neodymium iron boron melt-spun alloy sheet;

(2) a vacuum smelting melt-spinning furnace is adopted, smelting is started when the smelting melt-spinning furnace is pumped into an environment with the vacuum degree of less than 0.7Pa, the smelting temperature is controlled to be 1350-1390 ℃, then the rotating speed of a water-cooling copper roller is adjusted to be 45rpm, the water inlet temperature is controlled to be 10-15 ℃, casting is started to obtain a sheet alloy, and the thickness of the prepared sheet alloy is controlled to be 0.1-0.20 mm;

(3) respectively loading LaCo5 alloy sheets and N50 alloy sheets into a reaction kettle of a rotary hydrogen explosion furnace for vacuumizing treatment, filling argon to normal pressure when the vacuum degree reaches below 0.5Pa, vacuumizing to fill high-purity industrial hydrogen (the purity is 99.99%), absorbing saturated hydrogen, finishing hydrogen absorption when the pressure loss of the hydrogen absorption is less than or equal to 0.01Mpa/3min, using water cooling and using an infrared thermometer to measure the temperature in the hydrogen absorption process to ensure that the temperature in the hydrogen absorption process is controlled below 100 ℃, closing the furnace after the hydrogen absorption is finished, heating to 580 ℃ to perform dehydrogenation until the vacuum degree reaches below 30Pa, finishing dehydrogenation, finally performing water cooling treatment, reducing the temperature to below 30 ℃, discharging into a mixing tank protected by argon gas, and obtaining hydrogen explosion powder;

(4) preparing powder by adopting airflow milling powder preparing equipment, respectively putting the hydrogen explosion powder prepared in the step (3) into the airflow milling powder preparing machine, controlling the oxygen content in the milling process to be below 5ppm, operating the whole airflow mill under the protection of nitrogen, controlling the milling pressure to be between 0.60 and 0.62MPa, controlling the inlet temperature of the nitrogen to be between 5 and 10 ℃, and controlling the temperature of cooling circulating water outside a milling chamber to be between 5 and 10 ℃; obtaining a fine powder having a particle size distribution of X10 ═ 0.4 μm, X50 ═ 1.1 μm, and X90 ═ 2.4 μm;

(5) magnetic field forming: respectively placing the fine powder prepared in the step (4) into a fully-sealed magnetic field forming press with the oxygen content of less than 10ppm, and performing orientation forming to obtain green compacts, wherein the magnetic field intensity is 2.0T, and the density of the formed green compacts is 4.4 +/-0.5 g/cm³；

(6) Magnetic field microwave sintering: carrying out magnetic field microwave sintering on the green bodies prepared in the step (5), wherein the specific process comprises the steps of putting the green bodies into a furnace, vacuumizing to be below 0.7Pa, heating to 900 ℃, keeping the temperature for 40min, carrying out air cooling to be below 50 ℃ under the protection of argon after the heat preservation is finished, discharging to obtain target blanks and N50 neodymium iron boron blanks, and carrying out surface grinding and polishing and appearance processing on the formed target blanks to obtain a LaCo5 type target;

(7) plating LaCo5 type target alloy on the N50 neodymium-iron-boron blank by magnetron sputtering, and controlling the content of the LaCo5 type target alloy by controlling the sputtering time to make the weight of the LaCo5 type target alloy respectively account for 5%, 10%, 15%, 20% and 25% of the total weight to obtain a sputtered mixed neodymium-iron-boron magnet;

besides magnetron sputtering, other possible attachment means, such as coating, electrophoresis, etc., can be used by those skilled in the art;

(8) magnetic field heat treatment: and (3) putting the mixed neodymium iron boron magnet obtained in the step (7) into a vacuum magnetic field heat treatment furnace with the vacuum degree of less than 0.7Pa for magnetic field heat treatment, heating to 540 ℃, keeping the temperature for 6 hours, wherein the magnetic field intensity is 2.0T, and after the heat preservation is finished, air-cooling to below 50 ℃ under the protection of argon to obtain the high-coercivity permanent magnet product.

The permanent magnet performance of different LaCo5 type alloy contents is measured by taking a sample with 0% of LaCo5 type alloy content as a reference, and the measurement results are shown in the following table:

example 2

A heavy rare earth-free NdFeB/LaCo5 type permanent magnet is prepared by the following steps:

(1) mixing, wherein the LaCo5 type powder is prepared according to the following atomic ratio: la_16.7Co_{83.3-x-y-z-m- n}Fe_xMo_yAg_zGa_mZr_nX is 10, y is 3, z is 0.3, m is 0.8, n is 0.2; the neodymium iron boron alloy adopts a commercial N50 neodymium iron boron melt-spun alloy sheet;

(2) a vacuum smelting melt-spinning furnace is adopted, smelting is started when the smelting melt-spinning furnace is pumped into an environment with the vacuum degree of less than 0.7Pa, the smelting temperature is controlled to be 1350-1390 ℃, then the rotating speed of a water-cooling copper roller is adjusted to be 45rpm, the water inlet temperature is controlled to be 10-15 ℃, casting is started to obtain a sheet alloy, and the thickness of the prepared sheet alloy is controlled to be 0.1-0.20 mm;

(3) respectively loading LaCo5 alloy sheets and N50 alloy sheets into a reaction kettle of a rotary hydrogen explosion furnace for vacuumizing treatment, filling argon to normal pressure when the vacuum degree reaches below 0.5Pa, vacuumizing to fill high-purity industrial hydrogen (the purity is 99.99%), absorbing saturated hydrogen, finishing hydrogen absorption when the pressure loss of the hydrogen absorption is less than or equal to 0.01Mpa/3min, using water cooling and using an infrared thermometer to measure the temperature in the hydrogen absorption process to ensure that the temperature in the hydrogen absorption process is controlled below 100 ℃, closing the furnace after the hydrogen absorption is finished, heating to 580 ℃ to perform dehydrogenation until the vacuum degree reaches below 30Pa, finishing dehydrogenation, finally performing water cooling treatment, reducing the temperature to below 30 ℃, discharging into a mixing tank protected by argon gas, and obtaining hydrogen explosion powder;

(4) preparing powder by adopting airflow milling powder preparing equipment, respectively putting the hydrogen explosion powder prepared in the step (3) into the airflow milling powder preparing machine, controlling the oxygen content in the milling process to be below 5ppm, operating the whole airflow mill under the protection of nitrogen, controlling the milling pressure to be between 0.60 and 0.62MPa, controlling the inlet temperature of the nitrogen to be between 5 and 10 ℃, and controlling the temperature of cooling circulating water outside a milling chamber to be between 5 and 10 ℃; obtaining a fine powder having a particle size distribution of X10 ═ 0.5 μm, X50 ═ 1.2 μm, and X90 ═ 2.5 μm;

(5) magnetic field forming: respectively placing the fine powder prepared in the step (4) into a fully-sealed magnetic field forming press with the oxygen content of less than 10ppm, and performing orientation forming to obtain green compacts, wherein the magnetic field intensity is 2.0T, and the density of the formed green compacts is 4.4 +/-0.5 g/cm³；

(6) Magnetic field microwave sintering: carrying out magnetic field microwave sintering on the green bodies prepared in the step (5), wherein the specific process comprises the steps of putting the green bodies into a furnace, vacuumizing to below 0.7Pa, heating to 950 ℃, preserving heat for 20min, carrying out microwave power of 2.0kW and magnetic field intensity of 2.0T, carrying out air cooling to below 50 ℃ under the protection of argon after heat preservation is finished, discharging to obtain target blanks and N50 neodymium iron boron blanks, and carrying out surface polishing and appearance processing on the formed target blanks to obtain a LaCo5 type target;

(7) plating LaCo5 type target alloy on the N50 neodymium-iron-boron blank by magnetron sputtering, and controlling the content of the LaCo5 type target alloy by controlling the sputtering time to make the weight of the LaCo5 type target alloy respectively account for 5%, 10%, 15%, 20% and 25% of the total weight to obtain a sputtered mixed neodymium-iron-boron magnet;

(8) magnetic field heat treatment: and (3) putting the mixed neodymium iron boron magnet obtained in the step (7) into a vacuum magnetic field heat treatment furnace with the vacuum degree of less than 0.7Pa for magnetic field heat treatment, heating to 560 ℃, preserving heat for 4 hours, keeping the magnetic field intensity at 5.0T, and after heat preservation, carrying out air cooling to below 50 ℃ under the protection of argon to obtain the high-coercivity permanent magnet product.

The permanent magnet performance of different LaCo5 type alloy contents is measured by taking a sample with 0% of LaCo5 type alloy content as a reference, and the measurement results are shown in the following table:

example 3

A heavy rare earth-free NdFeB/LaCo5 type permanent magnet is prepared by the following steps:

(1) mixing the LaCo5 type powder according to the following atomic ratio_16.7Co_{83.3-x-y-z-m- n}Fe_xMo_yAg_zGa_mZr_nX is 20, y is 5, z is 0.6, m is 2.0, n is 0.3; the neodymium iron boron alloy adopts a commercial N50 neodymium iron boron melt-spun alloy sheet;

(2) a vacuum smelting melt-spinning furnace is adopted, smelting is started when the smelting melt-spinning furnace is pumped into an environment with the vacuum degree of less than 0.7Pa, the smelting temperature is controlled to be 1350-1390 ℃, then the rotating speed of a water-cooling copper roller is adjusted to be 45rpm, the water inlet temperature is controlled to be 10-15 ℃, casting is started to obtain a sheet alloy, and the thickness of the prepared sheet alloy is controlled to be 0.1-0.20 mm;

(3) respectively loading LaCo5 alloy sheets and N50 alloy sheets into a reaction kettle of a rotary hydrogen explosion furnace for vacuumizing treatment, filling argon to normal pressure when the vacuum degree reaches below 0.5Pa, vacuumizing to fill high-purity industrial hydrogen (the purity is 99.99%), absorbing saturated hydrogen, finishing hydrogen absorption when the pressure loss of the hydrogen absorption is less than or equal to 0.01Mpa/3min, using water cooling and using an infrared thermometer to measure the temperature in the hydrogen absorption process to ensure that the temperature in the hydrogen absorption process is controlled below 100 ℃, closing the furnace after the hydrogen absorption is finished, heating to 580 ℃ to perform dehydrogenation until the vacuum degree reaches below 30Pa, finishing dehydrogenation, finally performing water cooling treatment, reducing the temperature to below 30 ℃, discharging into a mixing tank protected by argon gas, and obtaining hydrogen explosion powder;

(4) preparing powder by adopting airflow milling powder preparing equipment, respectively putting the hydrogen explosion powder prepared in the step (3) into the airflow milling powder preparing machine, controlling the oxygen content in the milling process to be below 5ppm, operating the whole airflow mill under the protection of nitrogen, controlling the milling pressure to be between 0.60 and 0.62MPa, controlling the inlet temperature of the nitrogen to be between 5 and 10 ℃, and controlling the temperature of cooling circulating water outside a milling chamber to be between 5 and 10 ℃; obtaining a fine powder having a particle size distribution of X10 ═ 0.46 μm, X50 ═ 1.14 μm, and X90 ═ 2.43 μm;

(5) magnetic field forming: respectively placing the fine powder prepared in the step (4) into a fully-sealed magnetic field forming press with the oxygen content of less than 10ppm, and performing orientation forming to obtain green compacts, wherein the magnetic field intensity is 2.0T, and the density of the formed green compacts is 4.4 +/-0.5 g/cm³；

(6) Magnetic field microwave sintering: carrying out magnetic field microwave sintering on the green bodies prepared in the step (5), wherein the specific process comprises the steps of putting the green bodies into a furnace, vacuumizing to below 0.7Pa, heating to 1000 ℃, keeping the temperature for 15min, keeping the microwave power at 5.0kW and the magnetic field intensity at 6.0T, carrying out air cooling to below 50 ℃ under the protection of argon after heat preservation is finished, discharging, obtaining target blanks and N50 neodymium iron boron blanks, and carrying out surface grinding and polishing and appearance processing on the formed target blanks to obtain a LaCo5 type target;

(7) plating LaCo5 type target alloy on N50 neodymium iron boron blank by magnetron sputtering, and controlling the content of the LaCo5 type target alloy by controlling the sputtering time to make the weight of the LaCo5 type target alloy respectively account for 5%, 10%, 15%, 20% and 25% of the total weight to obtain a sputtered mixed neodymium iron boron magnet;

(8) magnetic field heat treatment: and (3) putting the mixed neodymium iron boron magnet obtained in the step (7) into a vacuum magnetic field heat treatment furnace with the vacuum degree of less than 0.7Pa for magnetic field heat treatment, heating to 590 ℃, preserving the heat for 3 hours, keeping the magnetic field intensity at 7.0T, and after the heat preservation is finished, air-cooling to below 50 ℃ under the protection of argon to obtain the high-coercivity permanent magnet product.

The permanent magnet performance of different LaCo5 type alloy contents is measured by taking a sample with 0% of LaCo5 type alloy content as a reference, and the measurement results are shown in the following table:

comparative example 1

A preparation process of an Nd2Fe14B/LaCo5 type permanent magnet comprises the following steps:

steps (1) to (4) are the same as in example 1;

(5) mixing powder: respectively adding 0-25% of LaCo5 type alloy fine powder into an N50 flailing fine powder tank, then mixing the powder for 60min under the protection of argon, cooling for 2h after the powder mixing is finished, and sieving the mixed fine powder by a 100-mesh sieve under the protection of argon;

(6) magnetic field forming: placing the mixed fine powder obtained in the step (5) into a fully-sealed magnetic field forming press with oxygen content less than 10ppm for magnetic field orientation forming, wherein the magnetic field intensity is 2.0T, and the formed compact density is 4.2-4.3g/cm³；

(7) Cold isostatic pressing: putting the pressed blank obtained in the step (6) into cold isostatic pressing equipment for further pressing and forming to improve the density, and obtaining a green blank under the isostatic pressing pressure of 250 MPa;

(8) and (3) vacuum sintering: putting the green body in the step (7) into a normal vacuum sintering furnace under the protection of argon gas for high-temperature sintering, wherein the specific process is that the green body is put into the sintering furnace, is vacuumized to 0.5Pa, is heated to 450 ℃ at a speed of 7 ℃/min, is subjected to heat preservation for 30min, is heated to 870 ℃ at a speed of 6 ℃/min from 450 ℃, is subjected to heat preservation for 60min, is heated to 1070 ℃ at a speed of 5 ℃/min, and is subjected to heat preservation for 180 min; after the heat preservation is finished, the furnace is discharged after the air cooling is carried out to below 30 ℃ under the protection of argon;

(9) aging heat treatment: heating the product in the step (8) to 895 ℃ at the temperature of 7 ℃/min, and keeping the temperature for 2.5 h; after the heat preservation is finished, air cooling is carried out to below 200 ℃, then the temperature is raised to 495 ℃ of the second heat treatment temperature, the heat preservation is carried out for 5 hours, after the heat preservation is finished, the air cooling is carried out to below 30 ℃ under the protection of argon, and then the Nd2Fe14B/LaCo5 type permanent magnet is obtained.

The permanent magnet performance of different LaCo5 type alloy contents is measured by taking a sample with 0% of LaCo5 type alloy content as a reference, and the measurement results are shown in the following table:

comparative example 2

A preparation process of an Nd2Fe14B/LaCo5 type permanent magnet comprises the following steps:

steps (1) to (4) are the same as in example 2; steps (5) to (9) were the same as in comparative example 1.

The permanent magnet performance of different LaCo5 type alloy contents is measured by taking a sample with 0% of LaCo5 type alloy content as a reference, and the measurement results are shown in the following table:

comparative example 3

A preparation process of an Nd2Fe14B/LaCo5 type permanent magnet comprises the following steps:

steps (1) to (4) are the same as in example 3; steps (5) to (9) were the same as in comparative example 1.

The permanent magnet performance of different LaCo5 type alloy contents is measured by taking a sample with 0% of LaCo5 type alloy content as a reference, and the measurement results are shown in the following table:

finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.