Neodymium-iron-boron magnet containing hydrogen storage alloy and preparation method of neodymium-iron-boron magnet

Abstract

According to the neodymium iron boron magnet containing the hydrogen storage alloy, the neodymium iron boron magnet is an NdFeB alloy, and the NdFeB alloy comprises the following components in percentage by weight: 28 to 32 percent of PrNd alloy, 0.1 to 3 percent of light La, Ce and Y rare earth elements, 0.1 to 3 percent of Dy, 0.8 to 1.2 percent of B, 0.3 to 1 percent of Ti, 0.1 to 2 percent of Cu, 0.1 to 3 percent of Co, 0.1 to 3 percent of Al, 0.1 to 3 percent of Ga and 60.3 to 69.59 percent of Fe. According to the neodymium-iron-boron magnet containing the hydrogen storage alloy, the probability that a diffusion source and a rare earth phase are oxidized in the preparation process can be reduced, the NdOx phase is reduced through the strong reducibility of hydrogen, the content of rich Nd is increased, and the comprehensive magnetic performance of the manufactured neodymium-iron-boron magnet is improved. According to the neodymium-iron-boron magnet containing the hydrogen storage alloy and the preparation method of the neodymium-iron-boron magnet, in the process of preparing the neodymium-iron-boron magnet, when the neodymium-iron-boron alloy is subjected to hydrogen decrepitation to obtain powder, only hydrogen absorption treatment is carried out, dehydrogenation treatment is not carried out, rare earth elements in the powder and hydrogen elements form hydride, and the hydride is stable in chemical property and not prone to being oxidized.

Description

Technical Field

[0001] The present invention relates to a neodymium-iron-boron magnet containing a hydrogen storage alloy and a preparation method thereof. Background Art

[0002] Due to the high comprehensive magnetic properties of sintered NdFeB magnets, they have become an important material basis for modern science and technology, such as computer technology, aerospace technology, communication technology, transportation technology, office automation technology, home appliance technology, etc., promoting the development of the national economy and technology. Permanent magnetic materials have become one of the most widely used magnetic materials.

[0003] Currently, two commonly used industrial methods can be used to increase the coercivity by adding heavy rare earth elements such as Dy and Tb during melting and by grain boundary diffusion of sintered magnets. Both have requirements for the powder particle size of the diffusion source. Research shows that alloy powders with smaller grain particle sizes are more likely to enter the grain boundary phase and increase the diffusion depth. When adding during melting, alloy powders with smaller grain sizes play an important role in improving the continuity and wettability of the thin grain boundary. Since the contact between oxygen in the environment and the alloy diffusion source is not completely isolated, oxidation is inevitable, and the smaller the alloy powder particle size, the easier it is to be oxidized. And during the preparation of neodymium-iron-boron, NdO x phase is often formed at the grain boundary of neodymium-iron-boron, reducing the formation of the main phase and affecting the magnetic properties of the sintered magnet.

[0004] To solve the above problems, further improve the coercivity and remanence of sintered NdFeB magnets, and reduce the formation of diffusion sources and rare earth oxide phases, it is necessary to develop a new preparation process. Summary of the Invention

[0005] The present invention provides a neodymium-iron-boron magnet containing a hydrogen storage alloy and a preparation method thereof.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0007] A neodymium-iron-boron magnet containing a hydrogen storage alloy, the neodymium-iron-boron magnet being a NdFeB alloy, and the NdFeB alloy comprising: a PrNd alloy with a content of 28-32 wt%, light La, Ce, Y rare earth elements with a content of 0.1-3 wt%, Dy with a content of 0.1-3 wt%, B with a content of 0.8-1.2 wt%, Ti with a content of 0.3-1 wt%, Cu with a content of 0.1-2 wt%, Co with a content of 0.1-3 wt%, Al with a content of 0.1-3 wt%, Ga with a content of 0.1-3 wt%, and Fe with a content of 60.3-69.59 wt%.

[0008] Preferably, the mass content of the PrNd alloy in the NdFeB alloy is 30-32%, preferably 30.3%.

[0009] Preferably, the mass content of Pr in the PrNd alloy is 0-40%, preferably 30.3%.

[0010] Preferably, the mass content of B in the NdFeB alloy is 0.8-1.2%, preferably 1%; the mass content of Al in the NdFeB alloy is 0.4-0.6%, preferably 0.5%; the mass content of Cu in the NdFeB alloy is 0.4-0.6%, preferably 0.5%; the mass content of Co in the NdFeB alloy is 0.6-0.9%, preferably 0.7-0.8%.

[0011] A preparation method of a NdFeB magnet containing a hydrogen storage alloy includes the following steps:

[0012] S1. Prepare a NdFeB alloy sheet from 30.3 wt% of a praseodymium-neodymium alloy, 0.1-1 wt% of light rare earth elements, 0.1-3 wt% of dysprosium, 1 wt% of boron, 0.3-1 wt% of titanium, 0.5 wt% of copper, 0.7 wt% of cobalt, 0.5 wt% of aluminum, 0.1-3 wt% of gallium, with the balance being iron.

[0013] S2. Hydrogen crushing process: Hydrogenate the alloy strip at room temperature - 600 °C and 10^5 Pa to hydrogen crush the alloy strip, obtaining a RE2Fe 14 BH x hydrogen compound of the alloy, and introduce high-purity argon to prevent contact with oxygen.

[0014] S3. Airflow pulverization process: Pulverize the alloy hydrogen crushed powder by airflow to obtain magnetic powder.

[0015] S4. Vacuum arc melt the Dy 70 Ni 30 alloy with a mass percentage content in an argon atmosphere of high purity 99.99%. The Dy 70 Ni 30 alloy is vacuum arc melted, the surface oxide layer is removed by sandblasting, and then it is mechanically crushed into coarse particles and stored in kerosene or alcohol.

[0016] S5. Put the Dy 70 Ni 30 alloy into a hydrogen breaking furnace for hydrogen embrittlement reaction, introduce argon to cool it to room temperature, and after cooling, obtain a DyNi hydride. Then, in an inert gas atmosphere, grind the obtained hydride alloy to a fine powder of 3 microns through ball milling or jet air milling process.

[0017] S6. Mix the prepared NdFeB alloy powder with Dy 70 Ni 30 Mix them evenly by a three-dimensional mixer, with the addition ratio being 3% of the mass of the NdFeB magnetic powder. The evenly mixed powder is pressed into a green compact under static pressure in a pulsed magnetic field;

[0018] S7. Put the pressed matrix into a vacuum sintering furnace for sintering and heat treatment to prepare an NdFeB magnet containing a hydrogen storage alloy, cool it, and finally obtain an NdFeB magnet containing a hydrogen storage alloy.

[0019] Preferably, in step S1, the NdFeB alloy sheet is made by the rapid solidification strip method.

[0020] Preferably, in step S3, the hydrogen absorption time during the hydrogen crushing process is greater than or equal to 120 minutes.

[0021] Preferably, in step S5, the temperature in the hydrogen crushing furnace is 360°C - 500°C and the hydrogen pressure is above 10^3 Pa, and it is maintained for more than 120 minutes.

[0022] Preferably, in step S6, the magnetic induction intensity of the pulsed magnetic field is 2T - 4T.

[0023] Preferably, in step S7, the sintering temperature is 1070°C, the sintering time is 5 hours, the tempering temperature is 870°C, the tempering time is 3 hours, the temperature of the aging treatment is preferably 520°C, and the time of the second aging treatment is preferably 5 hours.

[0024] Compared with the prior art, the NdFeB magnet containing a hydrogen storage alloy of the present invention can reduce the probability of oxidation of the diffusion source and the rare earth phase during the preparation process, reduce NdO x phase by the strong reducibility of hydrogen, increase the content of rich Nd, and improve the comprehensive magnetic properties of the manufactured NdFeB magnet. The NdFeB magnet containing a hydrogen storage alloy and its preparation method, during the preparation of the NdFeB magnet, when the NdFeB alloy is hydrogen crushed to obtain powder, only hydrogen absorption treatment is carried out without dehydrogenation treatment. The rare earth elements in the powder will form hydrides with hydrogen elements. Since the hydrides have stable chemical properties and are not easily oxidized, the hydrogenation of the rich rare earth phase is realized. Detailed Embodiments

[0025] The following further describes the present invention in detail with reference to embodiments.

[0026] In this specification, "residual magnetism" refers to a specific magnetic parameter that corresponds to the magnetic flux density value when the magnetic field strength is zero on the saturation hysteresis loop. This value is commonly referred to as Br and is an important indicator for measuring the magnetic retention ability of materials. The unit of Br can be Tesla (T) or Gauss (Gs), where 1 Gauss is equal to 0.0001 Tesla. Understanding the value of residual magnetism Br is of great significance for evaluating the performance and applications of magnetic materials.

[0027] The "coercivity" in this specification, also known as the intrinsic coercivity, is a key magnetic parameter. It describes that when the magnet is in a saturated magnetization state, if we monotonically decrease the magnetic field until it becomes zero and then reverse and increase the magnetic field, the magnetic field strength corresponding to when the magnetization intensity decreases to zero along the saturation hysteresis loop is the coercivity. This value is usually denoted as Hcj, and the unit is Oersted (Oe), kilo-Oersted (KOe), or Ampere per meter (A / m). It should be noted that 1 Oersted is equal to 79.6 Ampere per meter. Understanding the value of coercivity is crucial for evaluating the magnetic stability and application potential of magnets.

[0028] The "maximum magnetic energy product" mentioned in this specification refers to the maximum value of the product of Br and Hcj on the demagnetization curve, usually denoted as (BH) max , which is one of the important parameters for measuring the amount of energy stored in the magnet, with the unit of MGOe.

[0029] A neodymium-iron-boron magnet containing a hydrogen storage alloy is a NdFeB alloy. The NdFeB alloy includes: PrNd alloy with a content of 28 - 32 wt%; light rare earth elements La, Ce, Y with a content of 0.1 - 3 wt%, Dy with a content of 0.1 - 3 wt%, B with a content of 0.8 - 1.2 wt%, Ti with a content of 0.3 - 1 wt%, Cu with a content of 0.1 - 2 wt%, Co with a content of 0.1 - 3 wt%, Al with a content of 0.1 - 3 wt%, Ga with a content of 0.1 - 3 wt%, and Fe with a content of 60.3 - 69.59 wt%.

[0030] The mass content of the PrNd alloy in the NdFeB alloy is 30 - 32%, preferably 30.3%;

[0031] The mass content of Pr in the PrNd alloy is 0 - 40%, preferably 30.3%;

[0032] The mass content of B in the NdFeB alloy is 0.8 - 1.2%, preferably 1%;

[0033] The mass content of Al in the NdFeB alloy is 0.4 - 0.6%, preferably 0.5%;

[0034] The mass content of Cu in the NdFeB alloy is 0.4-0.6%, preferably 0.5%;

[0035] The mass content of Co in the NdFeB alloy is 0.6-0.9%, preferably 0.7-0.8%;

[0036] The PrNd alloy, boron (B), iron (Fe), aluminum (Al), copper (Cu) and cobalt (Co) raw materials can all be purchased from the market. The usage amount of the raw materials is matched with the mass ratio of each component in the expected NdFeB alloy obtained. At the same time, the purity requirements for all materials need to reach or exceed 99.99%. The melting temperature shall not be lower than the melting point of the main phase NdFeB, and the melting process needs to be carried out in an environment of high-purity argon (Ar), and the purity of argon must be kept above 99.999%. The melting equipment selected is a vacuum induction melting furnace. During the casting process, the temperature is preferably controlled between 1300-1400 °C, and the more ideal temperature range is 1370-1400 °C. The cooling process adopts the copper roller cooling method, in which the rotation speed of the copper roller is preferably 1.2-1.4 m / s, and the most suitable speed is 1.3 m / s. Finally, the NdFeB alloy is made into a cast sheet form, and the thickness of the cast sheet is preferably 0.2-0.8 mm, and the preferred size is 1.4 mm.

[0037] The NdFeB magnet containing a hydrogen storage alloy of the present invention can reduce the probability of oxidation of the diffusion source and the rare earth phase during the preparation process, and reduce NdO x phase by the strong reducibility of hydrogen, increase the content of rich Nd, and improve the comprehensive magnetic properties of the manufactured NdFeB magnet.

[0038] A preparation method of a NdFeB magnet containing a hydrogen storage alloy includes the following steps:

[0039] Example 1:

[0040] S1. Make a NdFeB alloy sheet by the rapid solidification strip method with 30.3 wt% of PrNd alloy, 0.1-1 wt% of light rare earth elements, 0.1-3 wt% of dysprosium, 1 wt% of boron, 0.3-1 wt% of titanium, 0.5 wt% of copper, 0.7 wt% of cobalt, 0.5 wt% of aluminum, 0.1-3 wt% of gallium, and the balance being iron.

[0041] S2. Hydrogen crushing process: Hydrogenate the alloy strip at room temperature - 600 °C and 10^5 Pa to hydrogen crush the alloy strip to obtain the RE2Fe 14 BH x hydrogen compound of the alloy. The hydrogen absorption time during the hydrogen crushing process is greater than or equal to 120 minutes, and high-purity argon is introduced to prevent contact with oxygen.

[0042] S3. Gas flow pulverization process: subject the alloy hydrided powder to gas flow pulverization to obtain magnetic powder;

[0043] S4. Put Dy 70 Ni 30 alloy with the mass percentage content into a vacuum arc melting furnace, melt it in an argon atmosphere with a high purity of 99.99%. Dy 70 Ni 30 alloy is melted by vacuum arc melting, the surface oxide layer is removed by sandblasting, then it is mechanically crushed into coarse particles and stored with kerosene or alcohol.

[0044] S5. Put Dy 70 Ni 30 alloy into a hydrogen embrittlement furnace, keep it at a temperature of 360°C - 500°C and a hydrogen pressure above 10^3 Pa for more than 120 minutes to carry out the hydrogen embrittlement reaction. Then introduce argon to cool it to room temperature. After cooling, DyNi hydride is obtained. Then, in an inert gas atmosphere, the obtained hydride alloy is ground into fine powder with a size of 3 microns by ball milling or jet mill process.

[0045] S6. Mix the prepared NdFeB alloy powder with Dy 70 Ni 30 uniformly by a three-dimensional mixer, with an addition ratio of 3% of the mass of the NdFeB magnetic powder. The uniformly mixed powder is pressed into a compact under a pulsed magnetic field static pressure with a magnetic induction intensity of 2T - 4T to obtain a green compact.

[0046] S7. Put the pressed matrix into a vacuum sintering furnace for sintering and heat treatment to prepare an NdFeB magnet containing a hydrogen storage alloy. The sintering temperature is 1070°C, the sintering time is 5 hours, the tempering temperature is 870°C, and the tempering time is 3 hours. The temperature of the aging treatment is preferably 520°C. The time of the second aging treatment is preferably 5 hours. Cool it to finally obtain an NdFeB magnet containing a hydrogen storage alloy.

[0047] Example 2:

[0048] According to the same composition as in Example 1, an NdFeB alloy sheet is made by the rapid solidification strip method, and the NdFeB alloy sheet is subjected to hydrogen crushing to obtain powder. Dy 70 Ni 30 alloy is placed in a hydrogen embrittlement furnace, kept at a temperature of 360°C and a hydrogen pressure above 10^3 Pa for more than 120 minutes to carry out the hydrogen embrittlement reaction. Then it is heated to 500°C to start dehydrogenation, and the dehydrogenation time is 2 hours. After cooling by introducing high-purity argon, then in an inert gas atmosphere, the obtained hydride alloy is ground into fine powder with a size of 3 microns by ball milling or jet mill process. Then, a magnet containing a hydrogen storage alloy without dehydrogenation is prepared by the same process as in Example 1 as a comparative experiment.

[0049] Comparative Example 1:

[0050] The matrix magnet without adding alloy fine powder was prepared by the same process as in Example 1 for comparison experiment. The matrix magnet of Dy 70 Ni 30 was used as a comparative experiment.

[0051] Table 1 Comparison of magnetic properties of magnets in Example 1, Example 2 and Comparative Example 1

[0052]

[0053] The results show that adding the hydrogen storage alloy powder Dy 70 Ni 30 to the sintered magnet matrix significantly improves the coercivity compared with the case without adding alloy powder; at the same time, the decrease in the remanence intensity is relatively small. In addition, the coercivity of the magnet doped with undehydrogenated Dy 70 Ni 30 powder is significantly higher than that of the magnet using dehydrogentated Dy 70 Ni 30 powder. The hydrogen content in the powder after hydrogen crushing is proportional to the magnetic properties of the NdFeB magnet, that is, as the hydrogen content increases, the magnetic properties of the NdFeB magnet improve.

[0054] Example 3:

[0055] NdFeB alloy sheets were made by the rapid solidification strip method according to the same composition as in Example 1, and the NdFeB alloy sheets were hydrogenated and crushed to obtain powder materials. The alloy with a mass percentage content of Dy 70 Ni 30 was melted by vacuum arc melting in an argon atmosphere with a high purity of 99.99%. The alloy of Dy 70 Ni 30 was melted by vacuum arc melting, the surface oxide layer was removed by sandblasting, and then it was mechanically crushed into coarse particles and stored in kerosene or alcohol. The alloy of Dy 70 Ni 30 was placed in a hydrogenation and crushing furnace, and hydrogen embrittlement reaction was carried out at a temperature of 360 - 500 °C and a hydrogen pressure above 10^3 Pa for more than 120 minutes. Then, argon was introduced to cool down to room temperature. After cooling, DyNi hydride was obtained. Then, in an inert gas atmosphere, the obtained hydride alloy was ground into fine powder with a size of 3 microns by ball milling or jet milling. The prepared NdFeB alloy powder and Dy 70 Ni 30 were mixed evenly by a three-dimensional mixer, and the addition ratio was 0.4% of the mass of the NdFeB magnetic powder. The uniformly mixed powder was pressed into a green compact under isostatic pressure in a pulsed magnetic field with a magnetic induction intensity of 2 T - 4 T. According to the sintering temperature and time in Example 1, and aging temperature treatment, a sintered NdFeB magnet containing hydrogen storage alloy addition was obtained.

[0056] Example 4:

[0057] Add hydrogen-containing Dy 70 Ni 30 The content of the alloy powder is 0.4%, and the neodymium iron boron magnet is prepared by the same process as in Example 3 for the comparative experiment.

[0058] Example 5:

[0059] Add hydrogen-containing Dy 70 Ni 30 The content of the alloy powder is 1%, and the neodymium iron boron magnet is prepared by the same process as in Example 3 for the comparative experiment.

[0060] Example 6:

[0061] Add hydrogen-containing Dy 70 Ni 30 The content of the alloy powder is 2%, and the neodymium iron boron magnet is prepared by the same process as in Example 3 for the comparative experiment.

[0062] Example 7:

[0063] Add hydrogen-containing Dy 70 Ni 30 The content of the alloy powder is 4%, and the neodymium iron boron magnet is prepared by the same process as in Example 3 for the comparative experiment.

[0064] Table 2 Comparison of magnetic properties of magnets in Examples 3 - 7, Example 1 and Comparative Example 1

[0065]

[0066] The results show that for the sintered magnet of Comparative Example 1, adding hydrogen-containing hydrogen storage alloy Dy with different contents 70 Ni 30 powders will cause a slight decrease in the remanence intensity, but a significant increase in the coercivity. Considering the scarcity and cost of the heavy rare earth element dysprosium (Dy), and the relationship between the coercivity improvement obtained by adding 4% alloy powder and its cost, a 3% addition ratio is preferably selected.

[0067] Example 8:

[0068] Melt the alloy with the mass percentage content of Dy 70 Ni 30 by vacuum arc melting in an argon atmosphere with a high purity of 99.99%. Dy 70 Ni 30 The alloy is melted by vacuum arc melting, the surface oxide layer is removed by sandblasting, and then it is mechanically crushed into coarse particles and stored with kerosene or alcohol. Dy 70 Ni 30The alloy is placed in a hydrogen desorption furnace and maintained at a temperature of 360 - 500 °C and a hydrogen pressure above 10^3 Pa for more than 120 minutes to carry out the hydrogen embrittlement reaction. Argon is introduced to cool the temperature to room temperature. After cooling, DyNi hydride is obtained. Then, in an inert gas atmosphere, the obtained hydride alloy is ground into fine powder of 3 microns through ball milling or jet milling process. The prepared NdFeB alloy powder is mixed with Dy 70 Ni 30 is mixed evenly through a three-dimensional mixer, and the addition ratio is 3% of the mass of the NdFeB magnetic powder. The evenly mixed powder is pressed into a shape under isostatic pressure in a pulsed magnetic field with a magnetic induction intensity of 2T - 4T to obtain a green compact. The pressed matrix is placed in a vacuum sintering furnace for sintering and heat treatment to prepare an NdFeB magnet containing a hydrogen storage alloy. The sintering temperature is 1060 °C, the sintering time is 5 hours, the tempering temperature is 870 °C, and the tempering time is 3 hours. The secondary tempering temperature is 520 °C, and the time is 3 hours. After cooling, an NdFeB magnet with the addition of a hydrogen storage alloy is finally obtained.

[0069] Example 9:

[0070] The Dy 70 Ni 30 alloy with a mass percentage content is melted by vacuum arc melting in an argon atmosphere with a high purity of 99.99%. The Dy 70 Ni 30 alloy is melted by vacuum arc melting, and the surface oxide layer is removed by sandblasting, then mechanically crushed into coarse particles and stored with kerosene or alcohol. The Dy 70 Ni 30 alloy is placed in a hydrogen desorption furnace and maintained at a temperature of 360 - 500 °C and a hydrogen pressure above 10^3 Pa for more than 120 minutes to carry out the hydrogen embrittlement reaction. Argon is introduced to cool the temperature to room temperature. After cooling, DyNi hydride is obtained. Then, in an inert gas atmosphere, the obtained hydride alloy is ground into fine powder of 3 microns through ball milling or jet milling process. The prepared NdFeB alloy powder is mixed with Dy 70 Ni 30 is mixed evenly through a three-dimensional mixer, and the addition ratio is 3% of the mass of the NdFeB magnetic powder. The evenly mixed powder is pressed into a shape under isostatic pressure in a pulsed magnetic field with a magnetic induction intensity of 2T - 4T to obtain a green compact. The pressed matrix is placed in a vacuum sintering furnace for sintering and heat treatment to prepare an NdFeB magnet containing a hydrogen storage alloy. The sintering temperature is 1080 °C, the sintering time is 5 hours, the tempering temperature is 870 °C, and the tempering time is 3 hours. The secondary tempering temperature is 520 °C, and the time is 3 hours. After cooling, an NdFeB magnet with the addition of a hydrogen storage alloy is finally obtained.

[0071] Table 3 Comparison of magnetic properties of magnets in Example 7, Example 8, Example 1 and Comparative Example 1

[0072]

[0073] The above results show that for the hydrogen storage alloy powder with an addition content of 3% in Example 1, the preferred temperature is 1070 °C, and the addition of Dy 70 Ni 30 powder will cause a slight decrease in the remanence intensity, but a significant increase in the coercivity.

[0074] For the Nd-Fe-B magnet containing a hydrogen storage alloy and its preparation method of the present invention, during the preparation of the Nd-Fe-B magnet, when the Nd-Fe-B alloy is hydrogenated to obtain a powder material, only the hydrogen absorption treatment is carried out, and the dehydrogenation treatment is not carried out. The rare earth elements in the powder material will form hydrides with hydrogen elements. Since the hydrides have stable chemical properties and are not easily oxidized, the hydrogenation of the rare earth-rich phase is achieved.

[0075] Finally, it should be noted that the above embodiments only illustrate the technical solutions of the present invention and do not limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A neodymium iron boron magnet containing a hydrogen storage alloy, characterized in that, The neodymium iron boron magnet is a NdFeB alloy, and the NdFeB alloy includes: PrNd alloy with a content of 28 - 32 wt%, light rare earth elements La, Ce, Y with a content of 0.1 - 3 wt%, Dy with a content of 0.1 - 3 wt%, B with a content of 0.8 - 1.2 wt%, Ti with a content of 0.3 - 1 wt%, Cu with a content of 0.1 - 2 wt%, Co with a content of 0.1 - 3 wt%, Al with a content of 0.1 - 3 wt%, Ga with a content of 0.1 - 3 wt%, and Fe with a content of 60.3 - 69.59 wt%.

2. The neodymium iron boron magnet containing a hydrogen storage alloy according to claim 1, characterized in that, The mass content of the PrNd alloy in the NdFeB alloy is 30 - 32%, preferably 30.3%.

3. The neodymium iron boron magnet containing a hydrogen storage alloy according to claim 1, characterized in that, The mass content of Pr in the PrNd alloy is 0 - 40%, preferably 30.3%.

4. The neodymium iron boron magnet containing a hydrogen storage alloy according to claim 1, characterized in that, The mass content of B in the NdFeB alloy is 0.8 - 1.2%, preferably 1%; the mass content of Al in the NdFeB alloy is 0.4 - 0.6%, preferably 0.5%; the mass content of Cu in the NdFeB alloy is 0.4 - 0.6%, preferably 0.5%; the mass content of Co in the NdFeB alloy is 0.6 - 0.9%, preferably 0.7 - 0.8%.

5. A method for preparing a neodymium-iron-boron magnet containing a hydrogen storage alloy, characterized in that, It includes the following steps: S1. Make a neodymium iron boron alloy sheet from 30.3 wt% of praseodymium-neodymium alloy, 0.1 - 1 wt% of light rare earth elements, 0.1 - 3 wt% of dysprosium, 1 wt% of boron, 0.3 - 1 wt% of titanium, 0.5 wt% of copper, 0.7 wt% of cobalt, 0.5 wt% of aluminum, 0.1 - 3 wt% of gallium, with the balance being iron. S2. Hydrogen crushing process: The alloy strip is hydrogenated at room temperature - 600 °C and 10^5 Pa to hydrogen crush the alloy strip, obtaining RE2Fe 14 BH x hydrides of boron and hydrogen, and high-purity argon is introduced to prevent contact with oxygen; S3. Airflow pulverization process: Pulverize the alloy hydrided powder by airflow to obtain magnetic powder. S4. Add Dy 70 Ni 30 The alloy with a mass percentage content is melted by vacuum arc melting in an argon atmosphere with a high purity of 99.99%. Dy 70 Ni 30 The alloy is melted by vacuum arc melting, the surface oxide layer is removed by sandblasting, and then it is mechanically crushed into coarse particles and stored in kerosene or alcohol; S5. Put Dy 70 Ni 30 alloy into a hydrogen desorption furnace for hydrogen embrittlement reaction, introduce argon gas to cool down to room temperature, and obtain DyNi hydride after cooling. Then, under the atmosphere of inert gas, grind the obtained hydride alloy into fine powder of 3 microns through ball milling or jet milling process; S6. Mix the prepared NdFeB alloy powder with Dy 70 Ni 30 Mix them evenly through a three-dimensional mixer, with the addition ratio being 3% of the mass of the NdFeB magnetic powder. Press the evenly mixed powder into a green compact under static pressure in a pulsed magnetic field; S7. Put the pressed matrix into a vacuum sintering furnace for sintering and heat treatment to prepare a NdFeB magnet containing a hydrogen storage alloy, cool it, and finally obtain a neodymium iron boron magnet containing a hydrogen storage alloy.

6. The preparation method of the Nd-Fe-B magnet containing a hydrogen storage alloy according to claim 5, characterized in that, In step S1, the neodymium iron boron alloy sheet is made by the rapid solidification strip method.

7. The preparation method of the Nd-Fe-B magnet containing a hydrogen storage alloy according to claim 5, characterized in that, In step S3, the hydrogen absorption time during the hydrogen breaking process is greater than or equal to 120 minutes.

8. The preparation method of the Nd-Fe-B magnet containing a hydrogen storage alloy according to claim 5, characterized in that, In step S5, the temperature in the hydrogen breaking furnace is 360°C - 500°C and the hydrogen pressure is above 10^3 Pa, and it is maintained for more than 120 minutes.

9. The preparation method of the Nd-Fe-B magnet containing a hydrogen storage alloy according to claim 5, characterized in that, In step S6, the magnetic induction intensity of the pulsed magnetic field is 2T - 4T.

10. The preparation method of the Nd-Fe-B magnet containing a hydrogen storage alloy according to claim 5, characterized in that, In step S7, the sintering temperature is 1070°C, the sintering time is 5 hours, the tempering temperature is 870°C, the tempering time is 3 hours, the temperature of the aging treatment is preferably 520°C, and the time of the second aging treatment is preferably 5 hours.

Images