Sintered permanent magnet, oxygen control device prepared from sintered permanent magnet and use method

Abstract

The invention relates to the technical field of permanent magnet preparation, and discloses a sintered permanent magnet, an oxygen control device prepared from the sintered permanent magnet and a use method, the sintered permanent magnet has excellent corrosion resistance and wear resistance, the service life of the permanent magnet is effectively prolonged, a cleaner, a homogenizer and a gradient oxygen controller are sequentially assembled in an oxygenator from top to bottom, and the service life of the oxygenator is prolonged. A flow diverter is installed in the gradient oxygen controller, transfer of magnetic powder particles is completed in a whole-process closed mode during oxygen control, the cleaner forms vortex airflow, cleaning of the magnetic powder particles is completed, residual oxygen in gaps of the particles can be removed conveniently, plasma generated by the homogenizer can reduce the surfaces of the magnetic powder particles, meanwhile, electrostatic agglomeration is eliminated, and the magnetic powder particles can be cleaned. The gradient oxygen controller forms oxygen content layers of different grades, a compact aluminum oxide film is formed on the surface of the magnetic powder through oxidation, the problem of oxidation inconsistency of fine magnetic powder is solved, and the method is particularly suitable for preparing sintered neodymium iron boron.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of permanent magnet preparation, and in particular relates to a sintered permanent magnet, an oxygen control device for sintered permanent magnet preparation and a use method. BACKGROUND

[0002] Neodymium iron boron is currently the strongest rare earth permanent magnet material, which has high magnetic energy product, good coercive force and high temperature resistance. At present, a certain amount of oxygen is added during the airflow grinding process, and isolation oxygen control is carried out in the subsequent production to achieve the purpose of oxygen control. However, it is difficult to control the particle size of the coarse powder during airflow grinding, and the length of time that the coarse powder stays in the grinding chamber directly determines the amount of oxygen absorbed by the magnetic powder, which in turn affects the coercive force of the final formed neodymium iron boron permanent magnet.

[0003] The oxygen control device for neodymium iron boron permanent magnet sintering with the application number CN202211267162.2 controls the magnetic force strength of the electromagnetic suction ring to gradually reduce the magnetic force of the electromagnetic suction ring. The magnetic powder particles with high mass originally adsorbed on the electromagnetic suction ring first fall off the electromagnetic suction ring and fall onto the rolling screen. The particles with a particle size smaller than the screen aperture pass through the screen and fall into the separation fiber cluster, while the particles with a particle size larger than the screen aperture fall into the accumulation end. The magnetic powder can fall into the separation fiber cluster according to its own weight and volume without affecting each other. Finally, the magnetic powder particles that meet the size standard exist in the mutually isolated space in the separation fiber cluster and are oxidized. The magnetic powder can be separated according to its own volume and supplemented with oxygen.

[0004] However, in the actual oxygen control process, the small magnetic powder particles filtered through the screen are gathered inside the separation fiber cluster. Since the magnetic powder particles are piled together, the magnetic powder particles cannot be uniformly and fully contacted with oxygen, making it difficult to ensure the consistency of the oxidation of the magnetic powder particles. Since a unified oxygen supplement method is used, the coercive force of the magnet after forming is improved to some extent. However, due to the large difference in size and specific surface area of the magnetic powder, uniform oxygen supplement for the magnetic powder cannot guarantee the oxidation degree between the magnetic powder, thereby affecting the final oxygen supplement effect.

[0005] Therefore, the present application proposes a sintered permanent magnet, an oxygen control device for sintered permanent magnet preparation and a use method to solve the above problems. SUMMARY

[0006] The present application aims to provide a sintered permanent magnet, an oxygen control device for sintered permanent magnet preparation and a use method to solve the problems raised in the background art.

[0007] To achieve the above object, the present application provides the following technical scheme: a sintered permanent magnet, comprising a permanent magnet base body, a surface of the permanent magnet base body is provided with an epoxy grinding layer, a surface of the epoxy grinding layer is provided with a conductive resin film layer, and a surface of the conductive resin film layer is provided with an oxidation-resistant layer.

[0008] The present application provides an oxygen control device for preparing a sintered permanent magnet, comprising an oxygen supplement device, a cleaning device, a material homogenizing device and a gradient oxygen control device are sequentially arranged in the oxygen supplement device from top to bottom. The cleaning device comprises a plurality of groups of oblique jet nozzles with the same inclination, and the plurality of groups of oblique jet nozzles are combined into a gas injection ring. The material homogenizing device comprises two groups of parallel electrode plates, a dispersion disc is arranged between the two groups of electrode plates, a gas distribution ring is fixed on the inner wall of the material homogenizing device, and a corresponding flow inducer of the gradient oxygen control device is synchronously driven and mounted below the dispersion disc. The gradient oxygen control device comprises a rhombic hole oxygen control layer, a circular hole oxygen control layer and a strip-shaped hole oxygen control layer arranged in the oxygen supplement device from top to bottom, and piezoelectric microvalves are arranged in the rhombic hole oxygen control layer, the circular hole oxygen control layer and the strip-shaped hole oxygen control layer.

[0009] Preferably, a cleaning chamber, an activation chamber and a passivation chamber are sequentially arranged in the oxygen supplement device from top to bottom, a feeding hopper is arranged at the top of the oxygen supplement device, a support is fixed at the outer edge of the bottom of the oxygen supplement device, and an electric control box is arranged at the top of the oxygen supplement device.

[0010] Preferably, the cleaning device is arranged in the cleaning chamber, a vortex material guiding groove is arranged on the cleaning device, a plurality of groups of oblique jet nozzles are uniformly distributed in the vortex material guiding groove, a discharging channel is communicated between the cleaning chamber and the activation chamber, and a discharging valve is fixedly arranged in the discharging channel.

[0011] Preferably, the material homogenizing device is arranged in the activation chamber, the material homogenizing device further comprises a rotating shaft, the top end of the rotating shaft is connected with the dispersion disc, a plurality of material homogenizing holes are uniformly arranged on the dispersion disc, an arc-shaped seat is arranged at the bottom of the activation chamber, a discharging hole is communicated between the activation chamber and the passivation chamber, and a material guiding valve is arranged in the discharging hole.

[0012] Preferably, an annular receiving groove is arranged at the top of the activation chamber, an encapsulation ring matched with the annular receiving groove is integrally arranged at the top of the dispersion disc, a plurality of groups of gas storage bags are uniformly fixed on one side of the annular receiving groove away from the opening, and a pressure bearing boss is uniformly fixed on the top of the encapsulation ring.

[0013] Preferably, a discharging port is arranged at the bottom of the passivation chamber, a discharging valve is arranged in the discharging port, the flow inducer is arranged in the passivation chamber, a motor is fixedly connected with the bottom end of the rotating shaft extending into the passivation chamber, and the flow inducer is fixedly sleeved on the outer sidewall of the rotating shaft.

[0014] Preferably, the drainage device comprises a drainage cover, the outer edge of the drainage cover is hingedly installed with a plurality of sets of swing plates in a circular array, and elastic cloth is fixedly connected between adjacent two sets of swing plates and the drainage cover; protective covers are connected to the drainage cover and the swing plates correspondingly, and the protective covers and the elastic cloth are fixedly connected; and each set of swing plates and the bottom of the drainage cover are connected through driving members.

[0015] Preferably, the driving member comprises an inner guide cylinder fixed to the bottom of the swing plate and an outer guide cylinder fixed to the bottom of the drainage cover; the inner guide cylinder and the outer guide cylinder are both arranged in the shape of an arc with the hinge shaft as the center; the inner guide cylinder is slidably assembled in the inner part of the outer guide cylinder; and a driving air bag is installed between the inner part of the inner guide cylinder and the outer guide cylinder.

[0016] The application provides a use method of an oxygen control device for sintered permanent magnet preparation. S1: magnetic powder is introduced into an oxygen supplement device; the magnetic powder is first accumulated in a cleaning device, a spiral airflow field is formed in the cleaning device through airflow sprayed by a plurality of sets of oblique jet nozzles, and the magnetic powder is driven to form a vortex to quickly strip adsorbed oxygen on the surface of the magnetic powder particles; S2: after the cleaning of the magnetic powder, the magnetic powder particles enter an equalizer; an electrode plate generates uniform plasma to reduce surface oxides; a dispersion disc rotates to uniformly distribute the magnetic powder particles in the dispersion disc, mechanically breaks the agglomeration, exposes fresh surfaces of the magnetic powder, and a gas distribution ring introduces a protective gas into the equalizer to uniformly cover the surfaces of the magnetic powder particles; S3: after the activation of the surfaces of the magnetic powder, the magnetic powder is introduced into a gradient oxygen control device; under the action of a drainage device, the magnetic powder is uniformly dispersed in the gradient oxygen control device; different opening rates of a rhombic hole oxygen control layer, a circular hole oxygen control layer and a strip hole oxygen control layer form different orders of oxygen gradients from top to bottom in the gradient oxygen control device; surface passivation of the magnetic powder is completed; the oxidation resistance and magnetic properties of the magnetic powder are improved; and finally the magnetic powder is discharged.

[0017] The technical effects and advantages of the application are as follows: 1. The application completes the transfer of the magnetic powder particles in a fully closed manner during oxygen control; the cleaning device forms a vortex airflow to clean the magnetic powder particles, which is convenient for removing residual oxygen in the gaps between the particles to achieve the purpose of pretreatment oxygen control; the equalizer generates plasma to reduce the surfaces of the magnetic powder particles and eliminate electrostatic agglomeration, which is convenient for the magnetic powder particles to have good consistency during oxidation; the gradient oxygen control device forms different levels of oxygen content layers to form a dense aluminum oxide film on the surfaces of the magnetic powder particles by oxidation, thereby solving the problem of inconsistent oxidation of fine powder, and the application is especially suitable for the preparation of high-performance sintered neodymium-iron-boron.

[0018] 2、The present application is in the control oxygen operation, the material distributor cooperates the use of the flow guide, makes the swing plate reciprocating swing, thereby drives the magnetic powder particles dispersed on the flow guide cover, increases the dispersion effect of the magnetic powder in the passivation chamber, when the swing plate swings upward, can drive the magnetic powder to move upward, makes the magnetic powder and the falling magnetic powder produce impact, increases the dispersibility between the magnetic powders, prevents the particle agglomeration, enhances the particle circulation amount. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is the whole structure schematic diagram of the present application; Figure 2 It is the whole internal structure schematic diagram of the present application; Figure 3 It is the cleaning device structure schematic diagram of the present application; Figure 4 It is the material distributor structure schematic diagram of the present application; Figure 5 It is the flow guide structure schematic diagram of the present application; Figure 6 It is the oxygen supplement tank section view structure schematic diagram of the present application.

[0020] In the drawing: 10, oxygen supplement device;11, feed hopper;12, cleaning chamber;13, activation chamber;14, passivation chamber;15, support;16, electric control box;20, cleaning device;21, vortex guide chute;22, oblique jet nozzle;23, discharging channel;24, discharging valve;30, material distributor;31, electrode plate;32, rotating shaft;33, motor;34, dispersion disc;35, encapsulation ring;36, arc-shaped seat;37, material distribution hole;38, guide valve;39, annular receiving groove;310, gas storage bag;311, pressure-bearing boss;40, gradient oxygen controller;41, rhombic hole oxygen control layer;42, circular hole oxygen control layer;43, strip-shaped hole oxygen control layer;44, discharge port;45, discharge valve;50, flow guide;51, flow guide cover;52, swing plate;53, elastic cloth;54, protective cover;55, inner guide cylinder;56, outer guide cylinder. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] The embodiment discloses a sintered permanent magnet, which comprises a permanent magnet base body, a surface of the permanent magnet base body is provided with an epoxy polishing layer, a surface of the epoxy polishing layer is provided with a conductive resin film layer, and a surface of the conductive resin film layer is provided with an oxidation-resistant layer. After sintering of the permanent magnet is completed, the epoxy polishing layer can improve the loss of the permanent magnet caused by magnetic eddy current phenomenon during use of the permanent magnet, the conductive resin film layer solves the problem that the epoxy film layer has relatively large resistance and is not conducive to formation of the oxidation-resistant layer, the oxidation-resistant layer on the surface of the sintered permanent magnet has excellent corrosion resistance and wear resistance, and the service life of the permanent magnet is effectively prolonged.

[0023] As shown in Figures 1 to 6 , the embodiment provides an oxygen control device for preparation of a sintered permanent magnet, which comprises an oxygen supplement device 10, a cleaning device 20, a material uniformizing device 30 and a gradient oxygen control device 40 are sequentially arranged in the oxygen supplement device 10 from top to bottom, the transfer of magnetic powder particles is completed in a fully closed mode during oxygen control, the cleaning device 20 forms an eddy current airflow to clean the magnetic powder particles, residual oxygen in the gap between the particles is removed, the purpose of pretreatment and oxygen control is achieved, the plasma generated by the material uniformizing device 30 can reduce the surface of the magnetic powder particles and eliminate electrostatic agglomeration, so that the magnetic powder particles have good consistency when being oxidized, the gradient oxygen control device 40 forms different levels of oxygen content layers to form a dense aluminum oxide film on the surface of the magnetic powder by oxidation, and the problem of inconsistent oxidation of fine powder is solved, and the oxygen control device is especially suitable for preparation of high-performance sintered neodymium-iron-boron.

[0024] Specifically, please refer to Figure 1 and Figure 2 , the cleaning chamber 12, the activation chamber 13 and the passivation chamber 14 are sequentially arranged in the oxygen supplement device 10 from top to bottom, the top of the oxygen supplement device 10 is provided with a feeding hopper 11, the feeding hopper 11 is provided with a sealing cover, the bottom of the oxygen supplement device 10 is fixedly provided with a support 15, and the top of the oxygen supplement device 10 is provided with an electric control box 16, so that the inside of the oxygen supplement device 10 is divided into three reaction chambers, the sealing of the feeding hopper 11 is completed through the sealing cover after the magnetic powder particles enter the inside of the oxygen supplement device 10 from the feeding hopper 11, zero atmospheric exposure of the magnetic powder can be realized, the oxygen control operation of the magnetic powder particles is facilitated, and the oxygen supplement device 10 is integrally controlled by the electric control box 16.

[0025] Please refer to Figure 2 and Figure 3The cleaner 20 includes multiple groups of oblique jet nozzles 22 with the same inclination, the multiple groups of oblique jet nozzles 22 are combined into a gas jet ring, the cleaner 20 is arranged in the cleaning chamber 12, the cleaner 20 is provided with a vortex material guiding groove 21, the multiple groups of oblique jet nozzles 22 are uniformly distributed in the vortex material guiding groove 21, the cleaning chamber 12 and the activation chamber 13 are communicated through a discharging channel 23, the discharging channel 23 is fixedly provided with a discharging valve 24, the oblique jet nozzles 22 are uniformly arranged in the vortex material guiding groove 21 and form a jet ring arranged at intervals, the jet flow formed by the jet ring is a spiral flow field, so that the magnetic powder forms a vortex in the vortex material guiding groove 21, the adsorbed oxygen on the surface of the magnetic powder particle is easily stripped, and the vortex-shaped flow can prevent the magnetic powder particles from being accumulated, so that the flow can penetrate the magnetic powder particles and the pretreatment capacity of the surface of the magnetic powder particle is improved.

[0026] It should be noted that the oxygen supplement device 10 is also provided with a vacuum air extraction module matched with the vortex material guiding groove 21, before the magnetic powder particles are introduced into the cleaning chamber 12 through the feeding hopper 11, the cleaning chamber 12 is vacuumized by the vacuum air extraction module, so that the free oxygen molecules can be quickly extracted.

[0027] Please refer to Figure 2 and Figure 4 The material distributor 30 includes two groups of parallelly distributed electrode plates 31, the electrode plates 31 generate uniform plasma when working to reduce the oxides on the surface of the magnetic powder particles, the two groups of electrode plates 31 are assembled with a dispersion disc 34, the inner wall of the material distributor 30 is fixedly provided with a gas distribution ring, the gas distribution ring is a porous ceramic ring with a pore diameter of 0.5 mm, the dispersion disc 34 is synchronously driven and installed below with a flow guide 50 corresponding to the gradient oxygen controller 40, the material distributor 30 is arranged in the activation chamber 13, the material distributor 30 further includes a rotating shaft 32, the top end of the rotating shaft 32 is connected with the dispersion disc 34, the bottom end of the rotating shaft 32 extends to the passivation chamber 14 and is fixedly connected with a motor 33, the dispersion disc 34 is uniformly provided with material distribution holes 37, the bottom of the activation chamber 13 is provided with an arc-shaped seat 36, the activation chamber 13 and the passivation chamber 14 are communicated through a discharging hole, and the discharging hole is assembled with a material guiding valve 38.

[0028] In actual use, when the magnetic powder particles pass through the cleaning work of the cleaner 20, the discharge valve 24 is opened, the magnetic powder particles in the cleaner 20 are introduced into the dispersion disc 34 through the discharge channel 23, and then the discharge valve 24 is closed. At the same time, the motor 33 works to drive the dispersion disc 34 to rotate through the rotating shaft 32, uniformly disperses the magnetic powder particles in the dispersion disc 34 by the dispersion disc 34, and uniformly distributes the magnetic powder particles in the dispersion disc 34. The purpose of mechanically breaking the agglomeration of the magnetic powder particles is achieved by the friction between the dispersion disc 34 and the magnetic powder particles during rotation, which facilitates the exposure of the fresh surface of the magnetic powder, the gas distribution ring introduces the protective gas into the uniformizer 30, and ensures that the protective gas is uniformly distributed in the activation chamber 13. The protective gas is Ar / H2 mixed gas, and the proportion is 95:5%, so that the protective gas uniformly covers the surface of the magnetic powder, plays a protective role on the surface of the magnetic powder particles, can reduce the surface of the magnetic powder that has been oxidized, and prevents the surface of the magnetic powder from further oxidizing under the action of the protective gas.

[0029] Please refer to Figure 2 and Figure 6 The gradient oxygen controller 40 includes a diamond hole oxygen control layer 41, a circular hole oxygen control layer 42 and a strip hole oxygen control layer 43 arranged from top to bottom inside the oxygen supplement device 10, and the diamond hole oxygen control layer 41, the circular hole oxygen control layer 42 and the strip hole oxygen control layer 43 are all equipped with piezoelectric microvalves, and oxygen sensors are arranged at the diamond hole oxygen control layer 41, the circular hole oxygen control layer 42 and the strip hole oxygen control layer 43. The oxygen content in the passivation chamber 14 can be monitored in real time, and based on the real-time oxygen concentration feedback, the opening degree of the piezoelectric microvalve is adjusted to make the oxygen partial pressure gradient deviation <±5%.

[0030] At the same time, the passivation chamber 14 is also provided with a micro-atomizing nozzle, which can introduce Ar gas containing 0.1-0.5% silane into the passivation chamber 14, so as to facilitate the formation of a Si-O-Nd surface protection layer on the magnetic powder particles in the passivation chamber 14, and improve the oxidation resistance. The passivation chamber 14 is provided with a discharge port 44 at the bottom, and the discharge valve 45 is arranged in the discharge port 44. The flow guide 50 is arranged in the passivation chamber 14 and is fixedly sleeved on the outer sidewall of the rotating shaft 32.

[0031] After the magnetic powder particles are activated, the material guiding valve 38 is opened, and the magnetic powder falls through the uniform material holes 37 on the surface of the dispersion disc 34 while the dispersion disc 34 rotates, completing the screening of the magnetic powder particles and improving the consistency of the particle size when the magnetic powder is transferred downward. After the magnetic powder falls into the passivation chamber 14, the material guiding valve 38 is closed, and at the same time, the motor 33 drives the flow inducer 50 to rotate through the rotating shaft 32, which can guide the magnetic powder particles falling from the material guiding valve 38 and disperse the magnetic powder under the action of the rotating flow inducer 50, facilitating the uniform distribution of the magnetic powder in the passivation chamber 14 during the falling process. The different opening rates of the rhombic hole oxygen control layer 41, the circular hole oxygen control layer 42, and the strip hole oxygen control layer 43 form different orders of oxygen gradients from top to bottom in the gradient oxygen controller 40, so that the magnetic powder particles pass through different oxygen gradients in sequence to realize the oxidation operation of the magnetic powder. Moreover, the oxidation operation under different oxygen gradients can precisely control the oxidation rate of the magnetic powder through precise oxygen control, preventing the over-oxidation of the magnetic powder and breaking through the oxygen regulation bottleneck of traditional uniform multi-hole plates. The surface passivation of the magnetic powder by the gradient oxygen controller 40 can improve the oxidation resistance and magnetic properties of the magnetic powder particles. After the oxidation of the magnetic powder particles is completed, the unloading valve 45 is opened to discharge the magnetic powder from the unloading port 44.

[0032] It should be noted that, please refer to Figure 2 and Figure 4 , the top of the activation chamber 13 is provided with a ring-shaped receiving groove 39, and the top of the dispersion disc 34 is integrally provided with a packaging ring 35 matched with the ring-shaped receiving groove 39. A plurality of groups of air storage bags 310 are uniformly fixed in the ring-shaped receiving groove 39 away from the opening side, and a pressure bearing boss 311 is uniformly fixed on the top of the packaging ring 35. Please refer to Figure 4 and Figure 5 , the flow inducer 50 includes a flow cover 51, and a plurality of groups of swing plates 52 are circularly arrayed and hingedly installed on the outer edge of the flow cover 51 through a hinge shaft. Elastic cloth 53 is fixedly connected between adjacent two groups of swing plates 52 and the flow cover 51, and a protective cover 54 is connected to the flow cover 51 corresponding to the swing plate 52. The protective cover 54 and the elastic cloth 53 are fixedly connected, and each group of swing plates 52 and the bottom of the flow cover 51 are connected through a driving member. The driving member includes an inner guide cylinder 55 fixed on the bottom of the swing plate 52 and an outer guide cylinder 56 fixed on the bottom of the flow cover 51. The inner guide cylinder 55 and the outer guide cylinder 56 are both set as arc-shaped cylinders with the hinge shaft as the center, the inner guide cylinder 55 is slidingly assembled in the outer guide cylinder 56, and a driving air bag is installed between the inner guide cylinder 55 and the outer guide cylinder 56. The driving air bag is communicated with the air storage bag 310 through an air guide pipe.

[0033] In the process of guiding the magnetic powder particles from the material guide valve 38 into the passivation chamber 14, the magnetic powder particles first fall onto the surface of the flow guide cover 51. With the rotation of the flow guide cover 51, the magnetic powder is uniformly dispersed into the passivation chamber 14 by centrifugal force. Moreover, during the rotation of the dispersion disc 34, the pressure-bearing boss 311 at the top of the encapsulation ring 35 is synchronously rotated. The encapsulation ring 35 blocks the magnetic powder particles to prevent them from entering the inside of the annular receiving groove 39. The pressure-bearing bosses 311 are arranged at intervals, so that the gas storage bag 310 is extruded at intervals during the rotation of the pressure-bearing bosses 311. When the gas storage bag 310 is extruded, the gas inside the gas storage bag 310 is guided into the driving air bag through the gas guide pipe, so as to make the driving air bag expand and push the inner guide cylinder 55 to move outward from the outer guide cylinder 56. Thus, the inner guide cylinder 55 pushes the swing plate 52 to rotate upward around the hinge shaft. When the pressure-bearing boss 311 and the gas storage bag 310 are out of position, the gas inside the driving air bag flows back to the gas storage bag 310 through the gas guide pipe, and then the swing plate 52 is reset downward. With the reciprocating extrusion and misalignment of the pressure-bearing boss 311 and the gas storage bag 310, the driving force and the reset force for swinging the swing plate 52 are generated, so that the swing plate 52 swings reciprocally. Thus, the magnetic powder particles dispersed on the flow guide cover 51 are driven, the dispersion effect of the magnetic powder inside the passivation chamber 14 is increased, and when the swing plate 52 swings upward, the magnetic powder is driven to move upward, so that the magnetic powder collides with the falling magnetic powder, the dispersibility of the magnetic powder is increased, the particle agglomeration is prevented, and the particle circulation amount is enhanced.

[0034] A method for using an oxygen control device prepared by sintered permanent magnet, the steps of the method are: S1: guiding the magnetic powder into the oxygen supplement device 10, first, the magnetic powder accumulates in the cleaner 20, a spiral gas flow field is formed in the cleaner 20 by the gas flow sprayed by the multiple groups of oblique jet nozzles 22, the magnetic powder is driven to form a vortex flow, and the adsorbed oxygen on the surface of the magnetic powder particles is quickly stripped off; S2: after the cleaning of the magnetic powder, the magnetic powder particles enter the material homogenizer 30, the electrode plate 31 generates uniform plasma to reduce the surface oxide, the dispersion disc 34 rotates to uniformly distribute the magnetic powder particles in the dispersion disc 34, the mechanical breaking breaks the agglomeration, exposes the fresh surface of the magnetic powder, and the gas distribution ring guides the protective gas into the material homogenizer 30 to uniformly cover the surface of the magnetic powder; S3: after the surface activation of the magnetic powder, the magnetic powder is guided into the gradient oxygen control device 40, under the action of the flow guide 50, the magnetic powder is uniformly dispersed in the gradient oxygen control device 40, the different opening rates of the rhombic hole oxygen control layer 41, the circular hole oxygen control layer 42 and the strip hole oxygen control layer 43 form different orders of oxygen gradients from top to bottom in the gradient oxygen control device 40, the surface passivation of the magnetic powder is completed, the oxidation resistance and magnetic properties of the magnetic powder are improved, and finally the magnetic powder is discharged.

[0035] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A sintered permanent magnet, characterized in that: The invention comprises a permanent magnet substrate, wherein the surface of the permanent magnet substrate is laminated with an epoxy grinding layer, the surface of the epoxy grinding layer is laminated with a conductive resin film layer, and the surface of the conductive resin film layer is laminated with an anti-oxidation layer.

2. An oxygen control device for preparing a sintered permanent magnet according to claim 1, characterized in that: The oxygenator (10) comprises a cleaning device (20), a material homogenizer (30) and a gradient oxygen controller (40) which are sequentially installed in the oxygenator (10) from top to bottom; The washer (20) comprises a plurality of groups of oblique jet nozzles (22) with the same inclination, wherein the plurality of groups of oblique jet nozzles (22) are combined into a gas injection ring; The material distributor (30) includes two sets of parallel electrode plates (31), a dispersion plate (34) is installed between the two sets of electrode plates (31), a gas distribution ring is fixed on the inner wall of the material distributor (30), and a flow guide (50) corresponding to the gradient oxygen controller (40) is installed under the dispersion plate (34) in a synchronously driven manner; The gradient oxygen controller (40) comprises a rhombus-shaped pore oxygen control layer (41), a circular pore oxygen control layer (42), and a strip-shaped pore oxygen control layer (43) arranged from top to bottom inside the oxygen supplementer (10), and piezoelectric microvalves are installed in the rhombus-shaped pore oxygen control layer (41), the circular pore oxygen control layer (42), and the strip-shaped pore oxygen control layer (43).

3. The oxygen control device for preparing sintered permanent magnets according to claim 2, characterized in that: The interior of the oxygenator (10) is provided with a cleaning chamber (12), an activation chamber (13) and a passivation chamber (14) in sequence from top to bottom. A feed hopper (11) is provided on the top of the oxygenator (10). A support (15) is fixed to the outer edge of the bottom of the oxygenator (10). An electric control box (16) is provided on the top of the oxygenator (10).

4. The oxygen control device for preparing sintered permanent magnets according to claim 3, characterized in that: The cleaning device (20) is arranged in the cleaning chamber (12), and a vortex guide groove (21) is provided on the cleaning device (20). A plurality of groups of oblique air jet nozzles (22) are evenly distributed in the vortex guide groove (21). A discharge channel (23) is connected between the cleaning chamber (12) and the activation chamber (13), and a discharge valve (24) is fixedly provided in the discharge channel (23).

5. The oxygen control device for preparing sintered permanent magnets according to claim 3, characterized in that: The material distributor (30) is arranged in the activation chamber (13), and the material distributor (30) further includes a rotating shaft (32). The top end of the rotating shaft (32) is connected to a dispersion disk (34), and the dispersion disk (34) is evenly provided with material distribution holes (37). The bottom of the activation chamber (13) is provided with an arc seat (36). A discharge hole is connected between the activation chamber (13) and the passivation chamber (14), and a material guide valve (38) is installed in the discharge hole.

6. The oxygen control device for preparing sintered permanent magnets according to claim 5, characterized in that: An annular receiving groove (39) is provided on the top of the activation chamber (13), and a packaging ring (35) matching the annular receiving groove (39) is integrally formed on the top of the dispersion disk (34). Multiple groups of air storage bags (310) are evenly fixed on the side of the annular receiving groove (39) away from the opening, and a pressure-bearing boss (311) is evenly fixed on the top of the packaging ring (35).

7. The oxygen control device for preparing sintered permanent magnets according to claim 6, characterized in that: The passivation chamber (14) is provided with a discharge port (44) at the bottom thereof, a discharge valve (45) is installed in the discharge port (44), the flow guide (50) is arranged in the passivation chamber (14), the bottom end of the rotating shaft (32) extends to the passivation chamber (14) and is fixedly connected to the motor (33), and the flow guide (50) is fixedly sleeved on the outer wall of the rotating shaft (32).

8. The oxygen control device for preparing sintered permanent magnets according to claim 7, characterized in that: The deflector (50) comprises a deflection cover (51), wherein the outer edge of the deflection cover (51) is hingedly mounted with a plurality of swing plates (52) distributed in a circular array via a hinge shaft, and an elastic cloth (53) is fixedly connected between two adjacent sets of swing plates (52) and the deflection cover (51), and a protective cover (54) is connected to the deflection cover (51) at positions corresponding to the swing plates (52), and the protective cover (54) and the elastic cloth (53) are fixedly connected, and each set of swing plates (52) and the bottom of the deflection cover (51) are connected via a driving member.

9. The oxygen control device for preparing sintered permanent magnets according to claim 8, characterized in that: The driving member comprises an inner guide cylinder (55) fixed to the bottom of the swing plate (52) and an outer guide cylinder (56) fixed to the bottom of the drainage cover (51), and the inner guide cylinder (55) and the outer guide cylinder (56) are both configured as arc cylinders with the hinge axis as the center of the circle, and the inner guide cylinder (55) is slidably assembled inside the outer guide cylinder (56), and a driving air bag is installed between the inner guide cylinder (55) and the outer guide cylinder (56), and the driving air bag is connected to the air storage bag (310) through the air guide tube.

10. A method for using an oxygen control device for preparing a sintered permanent magnet, which is implemented using the oxygen control device for preparing a sintered permanent magnet according to claim 9, characterized in that: The steps for use are: S1: The magnetic powder is introduced into the oxygenator (10). First, the magnetic powder accumulates inside the cleaning device (20). The airflow ejected by the plurality of oblique air nozzles (22) forms a spiral airflow field in the cleaning device (20), driving the magnetic powder to form a vortex, and quickly stripping the adsorbed oxygen on the surface of the magnetic powder particles; S2: After the magnetic powder is cleaned, the magnetic powder particles enter the material distributor (30), the electrode plate (31) generates uniform plasma, reduces the surface oxides, and the dispersion disk (34) rotates, so that the magnetic powder particles are evenly distributed in the dispersion disk (34), mechanically breaking the agglomeration and exposing the fresh surface of the magnetic powder. The gas distribution ring introduces protective gas into the material distributor (30), so that the protective gas evenly covers the surface of the magnetic powder; S3: After the surface of the magnetic powder is activated, the magnetic powder is introduced into the gradient oxygen controller (40). Under the action of the flow guide (50), the magnetic powder is evenly dispersed inside the gradient oxygen controller (40). The different opening rates of the diamond-shaped pore oxygen control layer (41), the circular pore oxygen control layer (42) and the strip-shaped pore oxygen control layer (43) form oxygen gradients of different orders of magnitude from top to bottom inside the gradient oxygen controller (40), completing the surface passivation of the magnetic powder, improving the oxidation resistance and magnetic properties of the magnetic powder, and finally discharging it.

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