Preparation method of neodymium-iron-boron permanent magnet material and neodymium-iron-boron magnet

Abstract

The invention discloses a preparation method of a neodymium-iron-boron permanent magnet material and a neodymium-iron-boron magnet, and relates to the technical field of neodymium-iron-boron magnets, and the preparation method of the neodymium-iron-boron permanent magnet material comprises the following steps: providing neodymium-iron-boron powder, and cleaning the neodymium-iron-boron powder by using plasma cleaning equipment; the outer side of the cleaned neodymium-iron-boron powder is coated with a layer of protective film which does not affect neodymium-iron-boron magnetic attraction through magnetron sputtering equipment. The invention further provides a neodymium-iron-boron magnet, the neodymium-iron-boron magnet comprises the neodymium-iron-boron permanent magnet material, and the neodymium-iron-boron permanent magnet material is prepared through the preparation method of the neodymium-iron-boron permanent magnet material. Compared with a traditional method for protecting the surface of a neodymium-iron-boron product, the neodymium-iron-boron powder is plated with a protective film, the neodymium-iron-boron powder has higher corrosion resistance and wider application range of the neodymium-iron-boron product, and after the neodymium-iron-boron powder is sintered into the required product, the problems of corrosion resistance, rust resistance and over-brittleness of the neodymium-iron-boron material can be solved from the source.

Description

Technical Field

[0001] This invention relates to the field of neodymium iron boron magnetic materials technology, and particularly to a method for preparing neodymium iron boron permanent magnet materials and neodymium iron boron magnets. Background Technology

[0002] Neodymium iron boron (NdFeB) is a commonly used rare-earth permanent magnet material, known as the "King of Magnets" due to its excellent magnetic properties. It is a product of the National 863 High-Tech Program. NdFeB permanent magnets possess extremely high magnetic energy product and coercivity, and their high energy density has led to their widespread application in modern industry, electronics, and the medical field. This has made it possible to miniaturize, lighten, and thinn instruments, electroacoustic motors, magnetic separation and magnetization devices, medical equipment, and other medical devices. The advantages of NdFeB permanent magnets are their high cost-effectiveness and good mechanical properties; the disadvantages are that NdFeB is relatively brittle and easily broken by external forces; the magnetism of NdFeB decreases with increasing temperature, thus limiting its application at high temperatures; and the surface of NdFeB is susceptible to oxidation and corrosion, especially in humid environments. Currently in China, hot-dip galvanizing or vacuum deposition techniques are mainly used to form an aluminum coating on the surface of NdFeB magnets, which improves the corrosion resistance of NdFeB magnets, as well as their wear resistance and thermal stability.

[0003] Hot-dip galvanizing or vacuum deposition aluminum plating is costly; the thickness of the aluminum plating layer is difficult to control, often resulting in aluminum layers that are too thick or too thin, or uneven in thickness; the magnetic properties of neodymium iron boron are damaged due to the increased temperature during hot-dip galvanizing; aluminum plating involves chemical reactions and the treatment of waste liquids and gases, which may have an impact on the environment. Summary of the Invention

[0004] To address the above-mentioned problems, this invention proposes a method for preparing neodymium iron boron permanent magnet materials and a neodymium iron boron magnet.

[0005] The technical solution adopted in this invention is as follows:

[0006] This application provides a method for preparing neodymium iron boron permanent magnet materials, comprising the following steps:

[0007] We provide neodymium iron boron powder and use plasma cleaning equipment to clean it.

[0008] A protective film that does not affect the magnetic attraction of NdFeB is coated onto the outside of the cleaned NdFeB powder using magnetron sputtering equipment.

[0009] Coating a protective film onto NdFeB powder provides higher corrosion resistance compared to traditional surface protection on NdFeB products. It also broadens the application range of NdFeB products. Sintering NdFeB powder into the desired product can solve the problems of corrosion and rust prevention as well as brittleness of NdFeB materials from the source.

[0010] Furthermore, the outer diameter of the neodymium iron boron powder is between 2 micrometers and 10 micrometers, and the thickness of the protective film is between 0.2 micrometers and 1 micrometer.

[0011] Furthermore, the protective film is made of aluminum or nickel.

[0012] Furthermore, the plasma cleaning equipment includes:

[0013] The cavity is used for connection to the anode of the power supply;

[0014] The tray is inclinedly set in the cavity. The tray has a receiving groove. The bottom of the tray is used to connect the cathode of the power supply (which can be a resonant power supply). The receiving groove is used to place the powder to be cleaned. After being powered on, plasma can be generated between the cavity and the tray. The generated plasma is used to bombard the powder on the tray. In this application, the powder is neodymium iron boron powder.

[0015] The stirring blades are rotatably mounted on the tray and used for stirring powders;

[0016] Drive element, used to drive the stirring blades to rotate;

[0017] A rotating structure is used to drive the tray to rotate;

[0018] A vacuum pumping device, connected to the cavity, is used to create a negative pressure vacuum state inside the cavity.

[0019] This application's plasma cleaning equipment utilizes plasma for cleaning. Its working principle is as follows: the cavity acts as the anode, while the target material (i.e., the powder to be cleaned) and the tray act as the cathode, forming a complete system. The cathode typically uses a resonant power supply for mixing and modulation. By modulating the voltage applied to the object being cleaned (powder), plasma can be generated. Utilizing the chemical activity and physical bombardment of the plasma, contaminants on metal surfaces and organic substrates can be effectively removed. In this application, the tray is tilted within the cavity (the tray's axis is not 90° to the horizontal plane). During operation, the rotating structure allows the tray to rotate around its own axis. This adds the tumbling effect of gravity on the powder under the tilt angle, in addition to the mechanical tumbling of the stirring blades, resulting in a more uniform and thorough cleaning process. Compared to traditional chemical cleaning, this method of powder cleaning shortens the operation steps (eliminating the need for complex wastewater treatment), achieves more thorough cleaning, and avoids the problem of low powder recovery rates.

[0020] In this application, when using plasma cleaning equipment to clean NdFeB powder, the NdFeB powder to be cleaned is positioned as the cathode. Impurities and dirt on the NdFeB powder are deposited onto the anode target under the action of the plasma cleaning equipment, thereby achieving the effect of plasma cleaning. Compared to using traditional liquid cleaning agents as cleaning solutions for water washing, plasma cleaning facilitates the recovery of micron-sized NdFeB powder.

[0021] Furthermore, when using plasma cleaning equipment to clean NdFeB powder, the vacuum level inside the plasma cleaning equipment should not exceed 1×10⁻⁶. -1 Pa, the cleaning temperature is between 140℃ and 160℃;

[0022] Cleaning time: 1 to 5 minutes.

[0023] Furthermore, the magnetron sputtering apparatus includes:

[0024] Cavity, tray, stirring blades, drive components, rotating structure, and station switching structure;

[0025] The cavity has multiple spaced mounting positions for mounting a target material connected to the cathode;

[0026] The tray has a receiving slot, the tray is tilted inside the cavity, the bottom of the tray is used to connect the anode, and the receiving slot of the tray is used to hold the powder;

[0027] The stirring blades are located on one side of the bottom wall of the receiving tank and are used to stir the powder. The driving element is used to drive the stirring blades to rotate.

[0028] The pallet is mounted on a workstation switching structure, which is used to change the position of the pallet so that the pallet can be aligned with one of the installation positions.

[0029] The rotating structure is used to drive the tray to rotate around its own axis.

[0030] The tray is tilted within the cavity (the tray's axis is not 90° to the horizontal plane). During operation, the rotating structure allows the tray to rotate around its own axis. This adds to the powder's tumbling effect, which is amplified by gravity under the tilt angle, in addition to the mechanical tumbling caused by the stirring blades. This results in a three-dimensional mixing layer on top of planar mixing, leading to more uniform powder coating. The station switching structure allows the tray to move and align with targets at different mounting positions. This online, multi-level, continuous preparation structure with different targets enables continuous production of multiple coatings, shortening production time and improving efficiency compared to previous single-level processes.

[0031] In this embodiment, when using a magnetron sputtering device to coat a protective film on the outside of NdFeB powder, the NdFeB powder to be coated with the protective layer is the anode, and the cathode is the target material of the protective film to be coated on the NdFeB powder. In this embodiment, the protective film target material is an aluminum target material.

[0032] Furthermore, during the magnetron sputtering formation of a protective film on the outer side of the NdFeB powder, a protective gas is introduced into the magnetron sputtering equipment. The flow rate of the protective gas is set between 65 sccm and 120 sccm, and the internal pressure of the magnetron sputtering equipment is controlled at 2.5 × 10⁻⁶. -1 Pa ~ 8.5 × 10 -1 Between Pa, the magnetron sputtering current is set to 1.5A to 2.5A, the voltage is set to 400V to 650V, and the sputtering operation time is 3 minutes to 15 minutes to obtain NdFeB powder coated with a protective film.

[0033] Furthermore, when a protective film is formed by magnetron sputtering on the outer side of the NdFeB powder, the protective gas is used to prevent the NdFeB powder from oxidizing. The protective gas is at least one of helium, neon, argon, or nitrogen.

[0034] This application also provides a neodymium iron boron magnet, comprising a neodymium iron boron permanent magnet material, wherein the neodymium iron boron permanent magnet material is prepared using the above-described method for preparing a neodymium iron boron permanent magnet material.

[0035] Furthermore, the method for preparing the neodymium iron boron magnet includes: placing the neodymium iron boron permanent magnet material in a magnetic field, introducing an inert gas as a protective gas, and performing vacuum sintering treatment on the neodymium iron boron permanent magnet material to produce a neodymium iron boron magnet;

[0036] Alternatively, the method for preparing the NdFeB magnet includes: placing the NdFeB permanent magnet material and auxiliary materials in a magnetic field, introducing an inert gas as a protective gas, and performing vacuum sintering treatment on the NdFeB permanent magnet material and auxiliary materials to produce the NdFeB magnet.

[0037] Compared to existing NdFeB magnets, the NdFeB magnet provided in this application has a protective film, and the protective film is distributed both inside and outside the NdFeB magnet. Without affecting its performance, it has higher corrosion resistance, wear resistance and thermal stability.

[0038] The inert gas can be at least one of helium, neon, argon, or nitrogen.

[0039] Furthermore, neodymium iron boron permanent magnet materials with a size between 3 and 5 micrometers are preferred.

[0040] The beneficial effects of this invention are:

[0041] Coating a protective film onto NdFeB powder provides higher corrosion resistance compared to traditional surface protection on NdFeB products. It also broadens the application range of NdFeB products. Sintering NdFeB powder into the desired product can solve the problems of corrosion and rust prevention as well as brittleness of NdFeB materials from the source. Attached Figure Description

[0042] Figure 1 This is a schematic flowchart of the preparation method of neodymium iron boron permanent magnet material according to an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of a plasma cleaning equipment;

[0044] Figure 3 This is a top view of a plasma cleaning equipment;

[0045] Figure 4 This is a top view of the tray and agitator blades of a plasma cleaning equipment;

[0046] Figure 5 This is a schematic diagram of a magnetron sputtering device;

[0047] Figure 6 This is a top view of a magnetron sputtering equipment;

[0048] Figure 7 This is a top view of the tray and agitator blades of a magnetron sputtering device.

[0049] The labels for the attached figures are as follows:

[0050] 100. Powder; 1. Cavity; 101. Mounting position; 2. Tray; 21. Receiving tank; 22. Base plate; 23. Side plate; 3. Stirring blade; 4. Rotating structure; 5. Vacuum device; 51. Vacuum port; 6. Lifting structure; 7. Piping; 8. Opening and closing assembly; 81. Telescopic element; 811. Telescopic rod; 82. Sealing plate; 9. Station switching structure; 91. Moving part; 92. Switching element; 10. Target material. Detailed Implementation

[0051] The present invention will now be described in detail with reference to the accompanying drawings.

[0052] like Figure 1 As shown, this application provides a method for preparing neodymium iron boron permanent magnet materials, comprising the following steps:

[0053] S10: Provide NdFeB powder and clean it using plasma cleaning equipment;

[0054] S20: A protective film that does not affect the magnetic attraction of NdFeB is coated on the outside of the cleaned NdFeB powder using magnetron sputtering equipment.

[0055] Coating a protective film onto NdFeB powder provides higher corrosion resistance compared to traditional surface protection on NdFeB products. It also broadens the application range of NdFeB products. Sintering NdFeB powder into the desired product can solve the problems of corrosion and rust prevention as well as brittleness of NdFeB materials from the source.

[0056] In this embodiment, the outer diameter of the neodymium iron boron powder is between 2 micrometers and 10 micrometers, and the thickness of the protective film is between 0.2 micrometers and 1 micrometer.

[0057] In this embodiment, the protective film is made of aluminum, which is cheaper than nickel.

[0058] In other embodiments, the protective film may also be made of nickel.

[0059] In this embodiment, when using a plasma cleaning device to clean NdFeB powder, the vacuum level inside the plasma cleaning device is no higher than 1×10⁻⁶. -1 Pa, cleaning temperature is 150℃;

[0060] Cleaning time: 1 to 5 minutes.

[0061] In this embodiment, when a protective film is formed on the outside of the NdFeB powder by magnetron sputtering, a protective gas is introduced into the magnetron sputtering equipment. The flow rate of the protective gas is set to 100 sccm, and the internal pressure of the magnetron sputtering equipment is controlled at 5 × 10⁻⁶. - 1 Pa, the magnetron sputtering current was set to 2A, the voltage was set to 500V, and the sputtering operation time was 10 minutes to obtain NdFeB powder coated with a protective film.

[0062] In this embodiment, when a protective film is formed by magnetron sputtering on the outside of the NdFeB powder, a protective gas is used to prevent the NdFeB powder from oxidizing, and the protective gas is argon.

[0063] In other embodiments, the protective gas is at least one of helium, neon, or nitrogen.

[0064] This application also provides a neodymium iron boron magnet, comprising a neodymium iron boron permanent magnet material, which is prepared using the above-described method for preparing a neodymium iron boron permanent magnet material.

[0065] In this embodiment, the method for preparing neodymium iron boron magnets includes: placing neodymium iron boron permanent magnet material in a magnetic field, introducing an inert gas as a protective gas, and performing vacuum sintering treatment on the neodymium iron boron permanent magnet material to produce neodymium iron boron magnets.

[0066] In other embodiments, the method for preparing neodymium iron boron magnets includes: placing neodymium iron boron permanent magnet material and auxiliary material in a magnetic field, introducing an inert gas as a protective gas, and performing vacuum sintering treatment on the neodymium iron boron permanent magnet material and auxiliary material to prepare neodymium iron boron magnets.

[0067] Compared to existing NdFeB magnets, the NdFeB magnet provided in this application has a protective film, and the protective film is distributed both inside and outside the NdFeB magnet. Without affecting its performance, it has higher corrosion resistance, wear resistance and thermal stability.

[0068] In this embodiment, the protective gas is argon.

[0069] In other embodiments, the protective gas is at least one of helium, neon, or nitrogen.

[0070] In this embodiment, neodymium iron boron permanent magnet material with an outer diameter between 3 micrometers and 5 micrometers is preferably subjected to sintering treatment.

[0071] like Figure 2 , Figure 3 and Figure 4 As shown, the plasma cleaning equipment includes:

[0072] Cavity 1, cavity 1 is used to connect to the anode of the power supply;

[0073] The tray 2 is inclinedly arranged in the cavity 1. The tray 2 has a receiving groove 21. The bottom of the tray 2 is used to connect the cathode of the power supply (which can be a resonant power supply). The receiving groove 21 is used to place the powder 100 to be cleaned. After being powered on, plasma can be generated between the cavity 1 and the tray 2. The generated plasma is used to bombard the powder 100 on the tray 2. In this embodiment, the powder 100 is neodymium iron boron powder.

[0074] The stirring blade 3 is rotatably mounted on the tray 2 and is used to stir the powder 100.

[0075] The driving element (omitted in the figure) is used to drive the stirring blade 3 to rotate;

[0076] Rotating structure 4 is used to drive tray 2 to rotate;

[0077] The vacuum pumping device 5 is connected to the cavity 1 and is used to create a negative pressure vacuum state inside the cavity 1.

[0078] The shape of the tray 2 in this application can be in various forms, including but not limited to circles, triangles, etc.

[0079] This application's plasma cleaning equipment uses plasma for cleaning. The working principle is as follows: the cavity 1 acts as the anode, and the target material (i.e., the powder 100 to be cleaned) and tray 2 act as the cathode, forming a complete system. The cathode is typically mixed and modulated using a resonant power supply. By modulating the voltage applied to the object to be cleaned (powder 100), plasma can be generated. By utilizing the chemical activity and physical bombardment of the plasma, contaminants on metal surfaces and organic substrates can be effectively removed. In this application, tray 2 is tilted within the cavity 1 (the axis of tray 2 is not 90° to the horizontal plane). During operation, the rotating structure 4 allows tray 2 to rotate around its own axis. This adds the tumbling of the powder 100 under its own gravity under the tilt angle, in addition to the mechanical tumbling of the stirring blades 3, making the entire cleaning process more uniform and thorough. Compared with traditional chemical cleaning, this method of cleaning powder 100 shortens the operation steps (eliminating the need for complex wastewater treatment), achieves more thorough cleaning, and eliminates the problem of low powder 100 recovery rate.

[0080] In this embodiment, when using a plasma cleaning device to perform plasma cleaning on NdFeB powder, the NdFeB powder to be cleaned is positioned as the cathode. Impurities and dirt on the NdFeB powder are deposited onto the anode target position under the action of the plasma cleaning device, thereby achieving the effect of plasma cleaning.

[0081] In other embodiments, the tray 2 may also be horizontally disposed within the cavity 1.

[0082] Compared with traditional chemical cleaning, the method of cleaning powder 100 in this application has shorter operation steps (no need for complicated wastewater treatment), more thorough cleaning, and no problem of low recovery rate of powder 100.

[0083] In practical applications, the driving element can be a motor or a rotary cylinder, etc. The driving element can drive directly or indirectly (for example, through conventional transmission structures such as gear sets or worm gears).

[0084] In practical applications, the rotating structure 4 can be a single-axis center drive (e.g., directly driven by a motor) or a side drive that drives the main shaft to rotate (e.g., the pallet has a first gear, the motor's rotating shaft has a second gear, and the motor drives the pallet to rotate through the meshing of the first and second gears).

[0085] In practical applications, this embodiment is particularly suitable for cleaning powders such as neodymium iron boron 100.

[0086] like Figure 2 As shown, in this embodiment, the angle between the axis of tray 2 and the horizontal plane is A, and the range of A is 10° to 60°.

[0087] If angle A is too small, the tumbling effect is weak; if angle A is too large, powder 100 tends to accumulate in large quantities on the lower side, making it easy for the powder 100 to fall out of the container cavity and affecting the reliable stirring of the stirring blade 3. When the angle between the axis of tray 2 and the horizontal plane is 10° to 60°, the powder 100 can be tumbled better, and the cleaning can be more uniform and thorough.

[0088] like Figure 2 As shown, in this embodiment, a lifting structure 6 is also included. The tray 2 is installed on the lifting structure 6, and the lifting structure 6 can drive the tray 2 to move up and down.

[0089] The lifting structure 6 allows for adjustment of the position of the powder tray 2, ensuring proper positioning. Furthermore, it makes loading and unloading the powder 100 from the tray 2 more convenient and efficient; additionally, it facilitates internal maintenance and cleaning of the equipment, such as replacing the tray 2 and removing residues.

[0090] In practical applications, the lifting structure 6 can take many forms, including but not limited to: electric push rod, cylinder or hydraulic cylinder, as well as gear and rack structure, transmission belt structure or transmission chain structure, etc.

[0091] like Figure 2 and Figure 4 As shown, the tray 2 includes a base plate 22 and side plates 23 located around the base plate 22, the side plates 23 and the base plate 22 forming a receiving groove 21. In this embodiment, the base plate 22 has a circular or polygonal structure, and the side plates 23 are adapted to the base plate 22.

[0092] In practical applications, a vibration mechanism is installed below the base plate 22. The vibration mechanism enables the powder to vibrate 100, resulting in a more uniform cleaning effect.

[0093] In this embodiment, during operation, the rotation direction of the stirring blade 3 is opposite to that of the tray 2. This arrangement allows the powder 100 to tumble better, resulting in more uniform and thorough cleaning.

[0094] In this embodiment, the vacuum pumping device 5 includes a vacuum pump and a molecular pump. For example... Figure 1 As shown, the vacuum port 51 of the vacuum device 5 is connected to the cavity 1 through the pipe 7. The pipe 7 also has an opening and closing component 8 for controlling the opening and closing of the suction port of the vacuum device 5. In this embodiment, the opening and closing component 8 includes:

[0095] The telescopic element 81 is fixed on the outside of the pipe 7, and the telescopic rod 811 of the telescopic element 81 extends into the pipe 7.

[0096] The sealing disc 82 is fixed on the telescopic rod 811 of the telescopic element 81. When the telescopic rod 811 extends, it drives the sealing disc 82 to block the suction port of the vacuum device 5.

[0097] like Figure 5 , Figure 6 and Figure 7 As shown, the magnetron sputtering equipment includes a cavity 1, a tray 2, a stirring blade 3, a drive element (not shown in the figure), a rotating structure 4, and a station switching structure 9.

[0098] The cavity 1 has a plurality of spaced mounting positions 101 for mounting a target 10 connected to the cathode;

[0099] The tray 2 has a receiving groove 21. The tray 2 is inclinedly disposed in the cavity 1. The bottom of the tray 2 is used to connect the anode. The receiving groove 21 of the tray 2 is used to hold the powder 100.

[0100] The stirring blade 3 is disposed on one side of the bottom wall of the receiving tank 21 for stirring the powder 100, and the driving element is used to drive the stirring blade 3 to rotate.

[0101] The pallet 2 is installed on the workstation switching structure 9, which is used to change the position of the pallet 2 so that the pallet 2 can be aligned with one of the installation positions 101.

[0102] Rotating structure 4 is used to drive tray 2 to rotate around its own axis.

[0103] The tray 2 is tilted inside the cavity 1 (the axis of the tray 2 is not 90° to the horizontal plane). During operation, the rotating structure 4 allows the tray 2 to rotate around its own axis. This allows the powder 100 to be tumbled in the tray 2 not only by the mechanical tumbling of the stirring blades 3, but also by the tumbling caused by its own gravity under the tilt angle. This results in a three-dimensional mixing of the powder 100 on top of the planar mixing, making the powder 100 coating more uniform. The station switching structure 9 can drive the tray 2 to move, so that the tray 2 can be aligned with the target material 10 at different mounting positions 101. That is, through this online multi-level continuous preparation of different target materials 10, multiple sets of coating production can be carried out continuously. Compared with the previous single-level, it shortens the production time and improves the production efficiency.

[0104] For example, in one scenario, three different materials need to be plated. First, the three different targets 10 are installed on different mounting positions 101 (first mounting position 101, second mounting position 101, and third mounting position 101 in sequence). The station switching structure 9 is controlled to align the tray 2 with the first mounting position 101 (at this time, the target 10 and the bottom surface of the receiving tank 21 are set horizontally or at a small angle). The first coating (film coating) is performed according to the set process. After the first coating is completed, the station switching structure 9 is activated to align the tray 2 with the second mounting position 101. Then, the second coating (film coating) is performed according to the set process. After the second coating is completed, the station switching structure 9 is activated to align the tray 2 with the third mounting position 101. Then, the third coating (film coating) is performed according to the set process. In practical applications, multiple switches are provided externally, each corresponding to a cathode. When tray 2 is aligned with the corresponding mounting position 101, the cathode aligned with tray 2 is turned on, while the other cathodes are turned off. When the coating of a cathode is completed, the power supply to it can be turned off. When another cathode needs to work, the corresponding switch is turned on, thereby completing the continuous preparation of more than 100 layers of powder.

[0105] In this embodiment, a target material 10 is required, namely an aluminum target material 10.

[0106] In this embodiment, when using a magnetron sputtering device to coat the outer side of the NdFeB powder 100 with a protective film, the NdFeB powder 100 to be coated with the protective layer is the anode, and the cathode is the protective film target 10 to be coated on the NdFeB powder 100. In this embodiment, the protective film target 10 is an aluminum target 10.

[0107] In practical applications, the driving element can be a motor or a rotary cylinder, etc. The driving element can drive directly or indirectly (for example, through conventional transmission structures such as gear sets or worm gears).

[0108] In practical applications, the rotating structure 4 can be a single-axis center drive (e.g., directly driven by a motor) or a side drive that drives the main shaft to rotate (e.g., the tray 2 has a first gear, the motor's rotating shaft has a second gear, and the motor drives the tray 2 to rotate through the meshing of the first and second gears).

[0109] like Figure 5 As shown, in this embodiment, the workstation switching structure 9 includes a movable component 91 and a switching element 92. The movable component 91 is rotatably mounted on the cavity 1, and the tray 2 is mounted on the movable component 91. Each mounting position 101 is arranged at intervals around an axis. The switching element 92 is used to drive the movable component 91 to rotate, so that the tray 2 can correspond to the target material 10 at different mounting positions 101. The rotating design, combined with the tilted arrangement of the tray 2, allows for the setting of more mounting positions 101, that is, multiple mounting positions 101 can be set on the top of the entire cavity 1.

[0110] In this embodiment, the tray 2 is rotatably mounted on the movable part 91, and the rotating structure 4 has a driving component, which drives the tray 2 to rotate directly or through the transmission component.

[0111] In this embodiment, the movable component 91 has a lifting element (not shown in the figure), and the tray 2 is mounted on the lifting element. The lifting element allows adjustment of the position of the powder-filled tray 2 to ensure proper positioning. Furthermore, it makes loading and unloading the powder 100 from the tray 2 more convenient and efficient; additionally, it facilitates maintenance and cleaning of the equipment's interior, such as replacing the tray 2 and removing residues. In practical applications, the lifting element can take various forms, including but not limited to: electric push rods, cylinders, or hydraulic cylinders, as well as gear and rack structures, transmission belt structures, or transmission chains.

[0112] like Figure 5 As shown, in this embodiment, the angle between the axis of tray 2 and the horizontal plane is A, and the range of A is 10° to 60°.

[0113] If angle A is too small, the tumbling effect is weak; if angle A is too large, powder 100 tends to accumulate in large quantities on the lower side, making it easy for the powder 100 to fall out of the container cavity and affecting the reliable stirring of the stirring blade 3. When the angle between the axis of tray 2 and the horizontal plane is 10° to 60°, the powder 100 can be tumbled better, and the coating can be more uniform.

[0114] In this embodiment, during operation, the rotation direction of the stirring blade 3 is opposite to that of the tray 2. This arrangement allows the powder 100 to tumble better and be coated more evenly.

[0115] like Figure 5 and Figure 7 As shown, in this embodiment, the tray 2 includes a bottom plate 22 and a side plate 23 located around the bottom plate 22, the side plate 23 and the bottom plate 22 forming a receiving groove 21;

[0116] The base plate 22 is a circular or polygonal structure, and the side plate 23 is adapted to the base plate 22.

[0117] like Figure 5 As shown, in this embodiment, the magnetron sputtering equipment also includes a vacuum pumping device 5. The vacuum pumping port 51 of the vacuum pumping device 5 is connected to the cavity 1 through the pipeline 7. The vacuum pumping device 5 is used to make the cavity 1 a negative pressure vacuum state.

[0118] The pipeline 7 also has an opening and closing assembly 8 for controlling the opening and closing of the suction port of the vacuum device 5, the opening and closing assembly 8 including;

[0119] The telescopic element 81 is fixed on the outside of the pipe 7, and the telescopic rod 811 of the telescopic element 81 extends into the pipe 7.

[0120] The sealing disc 82 is fixed on the telescopic rod 811 of the telescopic element 81. When the telescopic rod 811 extends, it drives the sealing disc 82 to block the suction port of the vacuum device 5.

[0121] Example 2

[0122] The difference between this embodiment and Embodiment 1 lies in the tray structure of the plasma cleaning equipment. In this embodiment, both the bottom plate and side plates of the tray have fine holes, the outer diameter of which is smaller than the minimum outer diameter of the powder. The fine holes facilitate the removal of the ejected material from the powder and the tray, increasing cleaning efficiency and ensuring the cleaning effect.

[0123] The above description is merely a preferred embodiment of the present invention and does not limit the scope of patent protection of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, whether directly or indirectly applied to other related technical fields, are similarly included within the scope of protection of the present invention.

Claims

1. A method for preparing neodymium iron boron permanent magnet material, characterized in that, Includes the following steps: We provide neodymium iron boron powder and use plasma cleaning equipment to clean it. A protective film that does not affect the magnetic attraction of NdFeB is coated onto the outside of the cleaned NdFeB powder using magnetron sputtering equipment.

2. The method for preparing a neodymium iron boron permanent magnet material as described in claim 1, characterized in that, The outer diameter of the neodymium iron boron powder is between 2 micrometers and 10 micrometers, and the thickness of the protective film is between 0.2 micrometers and 1 micrometer.

3. The method for preparing a neodymium iron boron permanent magnet material as described in claim 1, characterized in that, The protective film is made of aluminum or nickel.

4. The method for preparing a neodymium iron boron permanent magnet material as described in claim 1, characterized in that, The plasma cleaning equipment includes: a cavity for connecting to the anode of a power source; A tray is inclinedly disposed in the cavity. The tray has a receiving groove. The bottom of the tray is used to connect the cathode of the power supply. The receiving groove is used to place the powder to be cleaned. When the power is turned on, plasma can be generated between the cavity and the tray. The generated plasma is used to bombard the powder on the tray. A stirring blade is rotatably mounted on the tray for stirring powder; A driving element for driving the stirring blades to rotate; A rotating structure is provided for driving the tray to rotate; A vacuum pumping device, connected to the cavity, is used to create a negative pressure vacuum state within the cavity.

5. The method for preparing a neodymium iron boron permanent magnet material as described in claim 1, characterized in that, When cleaning NdFeB powder using plasma cleaning equipment, the vacuum level inside the plasma cleaning equipment should not exceed 1×10⁻⁶. -1 Pa, the cleaning temperature is between 140℃ and 160℃.

6. The method for preparing a neodymium iron boron permanent magnet material as described in claim 1, characterized in that, The magnetron sputtering equipment includes: Cavity, tray, stirring blades, drive components, rotating structure, and station switching structure; The cavity has multiple spaced mounting positions for mounting a target material connected to the cathode. The tray has a receiving groove, the tray is inclinedly disposed in the cavity, the bottom of the tray is used to connect the anode, and the receiving groove of the tray is used to hold powder. The stirring blades are disposed on one side of the bottom wall of the receiving tank for stirring powder, and the driving element is used to drive the stirring blades to rotate. The pallet is mounted on a workstation switching structure, which is used to change the position of the pallet so that the pallet can be aligned with one of the installation positions. The rotating structure is used to drive the tray to rotate around its own axis.

7. The method for preparing a neodymium iron boron permanent magnet material as described in claim 1, characterized in that, During the magnetron sputtering formation of a protective film on the outer side of NdFeB powder, a protective gas is introduced into the magnetron sputtering equipment. The flow rate of the protective gas is set between 65 sccm and 120 sccm, and the internal pressure of the magnetron sputtering equipment is controlled at 2.5 × 10⁻⁶. -1 Pa ~ 8.5 × 10 -1 Between Pa, the magnetron sputtering current is set to 1.5A to 2.5A, the voltage is set to 400V to 650V, and the sputtering operation time is 3 minutes to 15 minutes to obtain NdFeB powder coated with a protective film.

8. The method for preparing a neodymium iron boron permanent magnet material as described in claim 7, characterized in that, When a protective film is formed on the outside of NdFeB powder by magnetron sputtering, the protective gas is used to prevent the NdFeB powder from oxidizing. The protective gas is at least one of helium, neon, argon or nitrogen.

9. A neodymium iron boron magnet, characterized in that, The material includes neodymium iron boron permanent magnets, which are prepared using a method for preparing neodymium iron boron permanent magnets as described in any one of claims 1 to 8.

10. A neodymium iron boron magnet as described in claim 9, characterized in that, The method for preparing the neodymium iron boron magnet includes: Neodymium iron boron (NdFeB) permanent magnets can be manufactured by placing NdFeB permanent magnets in a magnetic field, introducing an inert gas as a protective gas, and then vacuum sintering the NdFeB permanent magnets. Alternatively, the method for preparing the NdFeB magnet includes: placing the NdFeB permanent magnet material and auxiliary materials in a magnetic field, introducing an inert gas as a protective gas, and performing vacuum sintering treatment on the NdFeB permanent magnet material and auxiliary materials to produce the NdFeB magnet.

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