CN114717511A - Preparation method of Al film on surface of sintered neodymium-iron-boron magnet - Google Patents

Abstract

The invention belongs to the field of surface protection of rare earth permanent magnet materials, in particular to a preparation method of an Al film on the surface of a sintered NdFeB magnet. First, a laser cleaning method is used to pretreat the sintered NdFeB magnet, and an inert gas is used to remove the contamination in time. The material is blown off the surface of the magnet, and then a layer of Al film is deposited on the surface of the pretreated magnet by vacuum evaporation method, and finally the Al film is treated by laser remelting technology, and finally a high bonding force and high densification are prepared on the surface of the magnet. , High corrosion-resistant Al film, which can effectively remove various pollutants adsorbed on the surface of the magnet, and use inert gas to blow the laser-cleaned dirt away from the surface of the magnet in time to avoid re-contamination and oxidation of the cleaned surface, and laser remelting can be achieved. The metallurgical bond between the Al thin film and the substrate changes the columnar structure of the Al thin film, which significantly improves the density of the Al thin film and greatly improves the corrosion resistance of the Al thin film.

Description

A kind of preparation method of Al film on the surface of sintered NdFeB magnet

technical field

The invention belongs to the field of surface protection of rare earth permanent magnet materials, in particular to a preparation method of an Al film on the surface of a sintered NdFeB magnet.

Background technique

Since its introduction in 1983, sintered NdFeB magnets have greatly promoted the rapid development of permanent magnet materials and related fields by virtue of their excellent comprehensive magnetic properties and abundant resource reserves. However, the sintered NdFeB magnets prepared by the powder metallurgy process have a multiphase structure, and the potential difference between the phases is quite different, especially the rare earth rich phase at the grain boundary has the highest electrochemical activity, which is very easy to be in the electrochemical environment. Corrosion occurs, and a small amount of rare earth-rich phase at the grain boundary acts as an anode to bear a large amount of current density, forming the corrosion characteristics of a large cathode and a small anode. The grains become isolated particles, which eventually lead to the powdering of the magnet, which severely limits the expansion of its application field. Therefore, improving the corrosion resistance of sintered NdFeB magnets has become an urgent problem.

At present, the alloying element method and the surface protection method are mainly used to improve the corrosion resistance of sintered NdFeB magnets. Among them, the alloying element method refers to adding trace elements such as Cu, Al, Co and so on in the alloy preparation to improve the corrosion resistance of the magnet itself, but this method will reduce the magnetic properties of the magnet to a certain extent, and cannot fundamentally solve the problem of the magnet Poor corrosion resistance. The surface protection method means that without affecting the magnetic properties of NdFeB magnets, a layer of corrosion-resistant coating/plating is applied to the surface of the NdFeB substrate, so as to isolate the direct contact between the external corrosive medium and the substrate. Significantly improve the poor corrosion resistance of sintered NdFeB magnets.

Commonly used surface protection methods for sintered NdFeB magnets include electroplating, electroless plating, cathodic electrophoresis, spraying and physical vapor deposition. Among them, physical vapor deposition, as an environmentally friendly surface protection technology, has gradually attracted people's attention, and vacuum evaporation of Al film has been applied to the surface protection of sintered NdFeB magnets. However, the bonding force between the prepared Al film and the NdFeB matrix is poor, and the Al film grows in a columnar crystal structure, and there are obvious gaps between the crystals that penetrate the film. The corrosion channel will eventually lead to the corrosion of the Al film on the surface of the magnet and lose its protective effect.

Publication No. CN105671503B A preparation method of a high corrosion-resistant composite coating on the surface of a sintered NdFeB magnet, the magnetron sputtering deposition Zn film and the vacuum evaporation Al film are alternately deposited on the surface of the magnet, and the deposited Zn film is used to interrupt the Al film. The columnar crystal structure blocks the rapid corrosion channel from the penetration of the corrosion solution to the substrate and improves the corrosion resistance of the Al film. The Chinese patent CN201911230623.7 discloses a densified Al coating on the surface of a sintered NdFeB magnet and a preparation method thereof. The gaps between the columnar crystals of Al during the evaporation process improve the corrosion resistance and surface hardness of the evaporated Al coating.

Based on the revelation on improving the density of the Al film by vacuum evaporation disclosed in the above patent, the present invention adopts the laser remelting technology to process the Al film by vacuum evaporation on the surface of the sintered NdFeB magnet, so as to obtain an Al film with high binding force and high densification. film.

To this end, the present invention provides a preparation method of the Al thin film on the surface of a sintered NdFeB magnet.

SUMMARY OF THE INVENTION

In order to make up for the deficiencies of the prior art, at least one technical problem proposed in the background art is solved.

The technical solution adopted by the present invention to solve the technical problem is as follows: a method for preparing the Al thin film on the surface of a sintered NdFeB magnet according to the present invention includes the following steps:

S1: Magnet pretreatment: The surface pretreatment of the sintered NdFeB magnet is carried out by laser cleaning method, and the dirt is blown away from the surface of the magnet with inert gas in time;

S2: Preparation of Al film by vacuum evaporation: in the vacuum evaporation device, a layer of Al film is deposited on the surface of the pretreated magnet by using a vacuum evaporation process;

S3: Laser remelting treatment: The Al film deposited on the surface of the magnet is modified by laser remelting technology to improve the density of the Al film and the bonding force with the substrate.

Preferably, in the pretreatment of the magnet in S1, the surface of the sintered NdFeB magnet is pretreated by a laser cleaning method to remove the oil stain and oxide scale on the surface of the magnet. The process parameters of the laser cleaning include: the laser power is 100~ 2500W, the laser beam wavelength is 1064nm, the pulse width is 50-300ns, the laser scanning speed is 5-150mm/s, and the laser incident angle is 20-90°; the magnet in S1 is pretreated, and the laser is cleaned in time with inert gas. The dirt is blown away from the surface of the magnet to avoid re-contamination and oxidation of the cleaned surface, and the inert gas is one of argon and helium.

Preferably, in the preparation of the S2 vacuum evaporation Al film, a vacuum evaporation process is used to deposit an Al film on the surface of the pretreated magnet, and the process parameters of the vacuum evaporation include a vacuum degree of 1 × 10 ^-3 ~ 5×10 ^-3 Pa, the evaporation current is 2000～2900A, and the vacuum evaporation time is 50～80min.

Preferably, in the S3 laser remelting treatment, laser remelting technology is used to modify the Al film deposited on the surface of the magnet, so as to improve the density of the Al film and the bonding force with the substrate; the laser remelting process The parameters include: the laser power is 1000-3000W, the scanning speed is 5-15mm/s, the spot size is 2-5mm, the overlap coefficient is 5%-20%, and an inert gas is filled as a protective gas, and the inert gas is One of Argon or Helium.

Preferably, the vacuum evaporation device includes a casing, a crucible and an adjustment fixture; a crucible is fixedly connected to the inside of the casing near the bottom surface of the casing, and the inside of the crucible is used for placing evaporation materials; the inside of the casing is connected to the crucible The top position of the casing is provided with an adjustment clamp; the adjustment clamp includes a push rod, a motor and a rotating pressure block; the inner side of the casing is provided with a first hydraulic groove, and the number of the first hydraulic groove is four; the four said A push rod is slidably connected to the inside of the first hydraulic groove; a motor is fixedly connected to the interior of any two adjacent push rods; the surfaces of the four push rods are rotatably connected with a rotating pressure block; , By controlling the internal hydraulic pressure of the two opposite first hydraulic grooves, the pair of push rods are controlled to be ejected, and the push rods will drive the corresponding rotating pressing blocks to squeeze the sintered NdFeB magnets, fix the sintered NdFeB magnets, and then pass the Control the rotation of the corresponding motor, the motor will drive the corresponding rotating pressure block to rotate, and the rotating pressure block will drive the sintered NdFeB magnet to rotate, so that the four sides of the sintered NdFeB magnet are adjusted to the downward direction in turn, which is convenient for the sintered NdFeB magnet. The four sides of the magnet are subjected to vacuum evaporation. After the vacuum evaporation of the four sides is completed, the other two push rods are controlled to lead out the first hydraulic tank, and the two push rods will drive the corresponding rotating pressing blocks to squeeze and sinter. NdFeB magnets, and then retract the original two push rods. At this time, the motor is controlled to rotate, and the motor will drive the rotating pressure block to rotate, so that the sintered NdFeB magnets rotate and control the two surfaces that have not been vacuum-evaporated to switch to Downward, the surface of the sintered NdFeB magnet is completely evaporated.

Preferably, the inner surface of the casing is provided with second hydraulic grooves at the top and bottom positions of the adjusting fixture; the inside of the second hydraulic grooves are slidably connected with sealing plates; the top of the sealing plate at the bottom position There are evenly arranged air inlet holes on the surface; the bottom surface of the sealing plate at the top position is provided with evenly arranged air outlet holes; when working, by setting two sealing plates, the corresponding second hydraulic pressure is derived by controlling the two sealing plates. The two sealing plates will make the sintered NdFeB magnets in a completely sealed space, and then control the air intake holes to guide the cooling gas. The cooling of the sintered NdFeB magnet and the subsequent replacement of the clamping of the sintered NdFeB magnet can avoid damage to the Al film that has been vacuum-evaporated.

Preferably, a control block is slidably connected to the inside of the air outlet; a spring is fixedly connected to the top of the control block; during operation, by setting the control block, and the control block is subjected to the pre-tightening pressure of the spring, when due to the The interior is in a vacuum state. In the initial state, the control block will automatically block the air outlet. With the continuous introduction of gas into the air inlet, the pressure between the two sealing plates increases, and then the control block slides and squeezes the spring, so that the The air outlet is automatically opened to ensure that a large amount of cooling gas stays around the sintered NdFeB magnet to achieve rapid cooling.

Preferably, cooling grooves are provided in the interior of the sealing plate near the air outlet, and the cooling grooves are connected to a cooling air source through pipes; elastic plates are slidably connected to the interior of the cooling grooves, and the elastic plates are connected to corresponding control blocks. The bottom surface of the sealing plate is fixedly connected; the elastic plate is fixedly connected with the bottom surface of the corresponding cooling tank; the surface of the sealing plate is provided with inclined holes near the air outlet; the bottom opening of the air outlet The first heating plate is fixedly connected; the bottom surface of the control block is fixedly connected with the second heating plate; during operation, by setting the elastic plate and the elastic sheet, when the control block moves upward, the control block will squeeze the spring, and at the same time The corresponding elastic plate will be pulled, so that the elastic plate will lead out of the corresponding cooling tank. Since the cooling gas source is externally connected to the inside of the cooling tank, the exported elastic plate will be in a cooling state. When the pressure between the two sealing plates increases, the gas will pass through. The inclined hole is introduced into the inside of the air outlet, and the solid particles in the gas are adsorbed by the elastic plate to realize the preliminary purification of the exhaust gas. At the same time, the exhaust gas is finally completely purified by cotton, and the cooling of the sintered NdFeB magnet is completed. The block is reset. Under the action of the elastic sheet, the elastic plate is recovered into the corresponding cooling tank, and during the recovery process, the adsorbed particles on the surface of the elastic plate will be scraped off and accumulated on the surface of the first heating plate, passing through the first heating plate. With the heating of the second heating plate, the evaporating material can be re-vaporized, and part of the evaporating material will be returned through the inclined hole and used.

Preferably, the inside of the air outlet hole is fixedly connected with a material guide elastic piece at the position of the inclined hole; the inside of the air outlet hole is fixedly connected with a guide tube at the top position of the material guide elastic piece, and the guide pipe and the corresponding inclined hole are connected with each other; When working, by setting the material guide shrapnel, when the attached crops on the surface of the elastic plate are scraped off, they will first fall into the surface of the material guide shrapnel. , the gas introduced by the inclined hole is directly introduced into the upper position of the guide shrapnel, and the flow of the gas can make the guide shrapnel vibrate, promote the impurities to fall on the surface of the first heating plate through the guide shrapnel, and complete the scraped impurities. Collection of attachments.

Preferably, a connecting rope is fixedly connected to the inside of the inclined hole; a vibration ball is fixedly connected to the end face of the connecting rope close to the material guide shrapnel; during operation, a connecting rope is arranged inside the inclined hole to connect The end of the rope is connected with a vibrating ball. When the gas passes through the inclined hole, the gas will blow the vibrating ball, so that the vibrating ball continuously shakes at the bottom of the guide shrapnel, which promotes the vibration effect on the guide shrapnel.

The beneficial effects of the present invention are as follows:

1. The present invention uses a laser cleaning method to pretreat the sintered NdFeB magnets to remove oil stains and oxide skin on the surface of the magnets, and use an inert gas to blow the laser-cleaned dirt away from the surface of the magnets in time to avoid re-contamination and oxidation. The traditional pretreatment process of sintered NdFeB magnets includes alkali washing to remove oil and acid to remove rust. During the pretreatment process, the surface magnetism of the magnet will be affected, and a small amount of hydrogen ions will adhere to the surface of the magnet, which will affect the quality of the coating. The process generates a large amount of waste liquid. Laser cleaning is a green and environmentally friendly surface cleaning method, which does not require organic solvents, does not discharge waste liquid, has less residue, does not cause environmental pollution, and can effectively remove various pollutants adsorbed on the surface of the magnet. Laser cleaning has high flexibility, good controllability, easy selection and positioning to achieve precise cleaning, and it is easy to remotely clean difficult or dangerous places. Therefore, laser cleaning can effectively avoid the surface magnetic drop caused by traditional magnet surface pretreatment, the adsorption of other cleaning products such as hydrogen ions on the substrate and the environmental pollution caused by waste liquid. It is the most ideal alternative to traditional sintered NdFeB magnet surface pretreatment. choose.

2. The present invention uses laser remelting technology to modify the Al thin film deposited on the surface of the magnet, which can realize the metallurgical bonding between the Al thin film and the substrate, and change the columnar structure of the Al thin film to significantly improve the density of the Al thin film. The corrosion resistance of the Al thin film is greatly improved. Compared with vacuum evaporation Al thin film, laser remelting technology can change the growth of columnar crystal structure of Al thin film, improve its microstructure, make its distribution more uniform, reduce or even eliminate the stress between the thin film and the substrate, and realize Al thin film and Al thin film. Metallurgical bonding between substrates. Laser remelting can remove impurities and gases, and at the same time, the structure obtained by quenching and recrystallization has high hardness, wear resistance and corrosion resistance. . Therefore, the use of laser remelting to process the vacuum-evaporated Al thin film can significantly improve the density of the Al thin film and the bonding force between the Al thin film and the substrate, and the Al thin film after laser remelting treatment has better corrosion resistance.

3. The present invention adopts a vacuum evaporation device. The vacuum evaporation device is provided with a casing, a crucible and an adjustment fixture, and by controlling the rotation of the motor, the motor will drive the rotating compact to rotate, so that the sintered NdFeB magnet rotates and controls the vacuum evaporation. The plated surface is switched to the downward direction, and the surface of the sintered NdFeB magnet is completely evaporated, and the two sealing plates will make the sintered NdFeB magnet in a completely sealed space, and then control the air intake hole to guide the air into the sintered NdFeB magnet. Cooling gas, the cooling gas will pass through the surface of the sintered NdFeB magnet and be led out through the air outlet to realize the cooling of the sintered NdFeB magnet. When replacing the clamping of the sintered NdFeB magnet later, avoid the vacuum evaporation process. damage to the Al thin film.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the method flow chart of the present invention;

Fig. 2 is the perspective view of the vacuum evaporation device used in the present invention;

Fig. 3 is the first sectional view of the vacuum evaporation device used in the present invention;

4 is a second cross-sectional view of the vacuum evaporation device used in the present invention;

Fig. 5 is the sectional view of the sealing plate of the present invention;

Fig. 6 is a partial enlarged view at A in Fig. 5;

Fig. 7 is a partial enlarged view at B in Fig. 6;

In the figure: shell 1, crucible 2, adjusting fixture 3, push rod 4, motor 5, rotary pressing block 6, first hydraulic groove 7, second hydraulic groove 8, sealing plate 9, air inlet 10, air outlet 11, Control block 12, spring 13, cooling groove 14, elastic plate 15, elastic sheet 16, inclined hole 17, first heating plate 18, second heating plate 19, material guide shrapnel 20, conduit 21, connecting rope 22, vibration ball 23 .

Detailed ways

In order to make it easy to understand the technical means, creation features, achieved goals and effects of the present invention, the present invention will be further described below with reference to the specific embodiments.

Example 1

As shown in Figure 1, (1) magnet pretreatment:

A commercial sintered NdFeB magnet (brand: 42SH, state: unmagnetized) with a specification of 20×15×4 mm was selected for the test. The surface of the sintered NdFeB magnet is pretreated by a laser cleaning method to remove the oil stain and oxide scale on the surface of the magnet. The process parameters of the laser cleaning include: the laser power is 100W, the laser beam wavelength is 1064nm, the pulse width is 50ns, The laser scanning speed is 5mm/s, and the laser incident angle is 20°. Use an inert gas to blow the laser-cleaned dirt away from the surface of the magnet in time to avoid re-contamination and oxidation of the cleaned surface, and the inert gas is argon.

(2) Preparation of Al thin film by vacuum evaporation:

A layer of Al film is deposited on the pretreated magnet surface by vacuum evaporation process. The process parameters of vacuum evaporation include vacuum degree of 1×10-3Pa, evaporation current of 2000A, and vacuum evaporation time of 50min.

(3) Laser remelting treatment:

The Al thin film deposited on the surface of the magnet is modified by laser remelting technology to improve the density of the Al thin film and the bonding force between the Al thin film and the substrate. The process parameters of the laser remelting include: the laser power is 1000W, the scanning speed is 5mm/s, the spot size is 2mm, the overlap coefficient is 5%, and an inert gas is filled as a protective gas, and the inert gas is argon gas .

Comparative Example 1

For comparison, Al thin films were deposited on the surface of sintered NdFeB magnets according to steps (1) and (2) in Example 1, without laser remelting treatment.

Example 2

(1) Magnet pretreatment:

A commercial sintered NdFeB magnet (brand: 42SH, state: unmagnetized) with a specification of 20×15×4 mm was selected for the test. The surface of the sintered NdFeB magnet is pretreated by a laser cleaning method to remove the oil and oxide scale on the surface of the magnet. The process parameters of the laser cleaning include: the laser power is 1300W, the laser beam wavelength is 1064nm, the pulse width is 175ns, The laser scanning speed is 80mm/s, and the laser incident angle is 60°. Use an inert gas to blow the laser-cleaned dirt away from the surface of the magnet in time to avoid re-contamination and oxidation of the cleaned surface, and the inert gas is helium.

(2) Preparation of Al thin film by vacuum evaporation:

A layer of Al thin film was deposited on the pretreated magnet surface by vacuum evaporation process. The process parameters of vacuum evaporation included vacuum degree of 3×10-3Pa, evaporation current of 2450A, and vacuum evaporation time of 65min.

(3) Laser remelting treatment:

The Al thin film deposited on the surface of the magnet is modified by laser remelting technology to improve the density of the Al thin film and the bonding force between the Al thin film and the substrate. The process parameters of the laser remelting include: the laser power is 2000W, the scanning speed is 10mm/s, the spot size is 3.5mm, the overlap coefficient is 12.5%, and an inert gas is filled as a protective gas, and the inert gas is helium gas.

Comparative Example 2

For comparison, Al thin films were deposited on the surface of sintered NdFeB magnets according to steps (1) and (2) in Example 1, without laser remelting treatment.

Example 3

(1) Magnet pretreatment:

A commercial sintered NdFeB magnet (brand: 42SH, state: unmagnetized) with a specification of 20×15×4 mm was selected for the test. The surface of the sintered NdFeB magnet is pretreated by a laser cleaning method to remove the oil and oxide scale on the surface of the magnet. The process parameters of the laser cleaning include: the laser power is 2500W, the laser beam wavelength is 1064nm, the pulse width is 300ns, The laser scanning speed is 150mm/s, and the laser incident angle is 90°. Use an inert gas to blow the laser-cleaned dirt away from the surface of the magnet in time to avoid re-contamination and oxidation of the cleaned surface, and the inert gas is helium.

(2) Preparation of Al thin film by vacuum evaporation:

A layer of Al thin film was deposited on the pretreated magnet surface by vacuum evaporation process. The process parameters of vacuum evaporation included vacuum degree of 5×10-3Pa, evaporation current of 2900A, and vacuum evaporation time of 80min.

(3) Laser remelting treatment:

The Al thin film deposited on the surface of the magnet is modified by laser remelting technology to improve the density of the Al thin film and the bonding force between the Al thin film and the substrate. The process parameters of the laser remelting include: the laser power is 3000W, the scanning speed is 15mm/s, the spot size is 5mm, the overlap coefficient is 20%, and an inert gas is filled as a protective gas, and the inert gas is helium .

Comparative Example 3

For comparison, an Al thin film was deposited on the surface of the sintered NdFeB magnet according to steps (1) and (2) in Example 3, without laser remelting treatment.

The samples prepared in Examples 1, 2, and 3 and the samples prepared in Comparative Examples 1, 2, and 3 were respectively subjected to a neutral salt spray test (the conditions of the salt spray test were: the temperature of the test chamber was 36 ± 2 °C, and the concentration of the brine was 5wt. %, using the test method of continuous spraying) and the adhesion of the coating are tested, and the specific results are shown in Table 1 below.

Table 1 Sample salt spray test and binding force test results

sample Bonding force (MPa) Salt spray test (h) Example 1 48.7 289 Example 2 50.2 291 Example 3 49.6 288 Comparative Example 1 12.9 96 Comparative Example 2 13.1 98 Comparative Example 3 12.6 96

As can be seen from Table 1, compared with Comparative Examples 1, 2, and 3, the binding force and salt spray resistance of the samples in Examples 1, 2, and 3 were significantly improved, indicating that the laser cleaning method was used to pretreat the magnets. , and use inert gas to blow the dirt away from the surface of the magnet in time, and then use the laser remelting technology to treat the Al film on the surface of the magnet, which can significantly improve the density of the Al film on the surface of the magnet and the bonding force between the substrate, thereby greatly improving the Improve the corrosion resistance of magnets.

Example 4

As shown in FIG. 2-FIG. 7, in Comparative Example 1, another embodiment of the present invention is: the vacuum evaporation device includes a casing 1, a crucible 2 and an adjustment fixture 3; the inside of the casing 1 is close to The crucible 2 is fixedly connected to the bottom surface of the casing 1, and the inside of the crucible 2 is used to place the evaporation material; the inside of the casing 1 is provided with an adjusting fixture 3 at the top position of the crucible 2; the adjusting fixture 3 includes a push rod 4 , a motor 5 and a rotating pressure block 6; the inner side of the casing 1 is provided with a first hydraulic groove 7, and the number of the first hydraulic groove 7 is four; the interior of the four first hydraulic grooves 7 are slidably connected with Push rods 4; wherein the interior of any two adjacent push rods 4 are fixedly connected with a motor 5; the surfaces of the four push rods 4 are rotatably connected with rotating pressure blocks 6; during operation, by controlling the relative The internal hydraulic pressure of the two first hydraulic grooves 7 controls the pair of push rods 4 to be pushed out, and the push rods 4 will drive the corresponding rotating pressing blocks 6 to squeeze the sintered NdFeB magnets, fix the sintered NdFeB magnets, and then control the Corresponding to the rotation of the motor 5, the motor 5 will drive the corresponding rotating pressure block 6 to rotate, and the rotating pressure block 6 will drive the sintered NdFeB magnet to rotate, so that the four sides of the sintered NdFeB magnet are adjusted to the downward direction in turn, which is convenient for the sintered NdFeB magnet. The four surfaces of the NdFeB magnet are subjected to vacuum evaporation. After the vacuum evaporation of the four surfaces is completed, the other two push rods 4 are controlled to lead out the first hydraulic tank 7, and the two push rods 4 will drive the corresponding rotation. The pressing block 6 squeezes and fixes the sintered NdFeB magnet, and then retracts the original two push rods 4. At this time, the motor 5 is controlled to rotate, and the motor 5 will drive the rotating pressing block 6 to rotate, so that the sintered NdFeB magnet rotates. The two surfaces that are not vacuum-evaporated are controlled to be switched downward, and the surface of the sintered NdFeB magnet is completely evaporated.

The inner surface of the housing 1 is provided with a second hydraulic groove 8 at the top and bottom positions of the adjusting fixture 3; the interior of the second hydraulic groove 8 is slidably connected with a sealing plate 9; the sealing plate at the bottom position The top surface of 9 is provided with evenly arranged air inlet holes 10; the bottom surface of the sealing plate 9 at the top position is provided with evenly arranged air outlet holes 11; during operation, by setting two sealing plates 9, by controlling the two sealing plates 9 The second hydraulic groove 8 is corresponding to the outlet of the plate 9. The two sealing plates 9 will make the sintered NdFeB magnet in a completely sealed space, and then control the air inlet 10 to introduce the cooling gas, and the cooling gas will pass through the sintered NdFeB magnet. The surface of the magnet is led out through the air outlet 11 to realize the cooling of the sintered NdFeB magnet, and the subsequent replacement of the clamping of the sintered NdFeB magnet can avoid damage to the Al film that has been vacuum-evaporated.

A control block 12 is slidably connected to the inside of the air outlet 11 ; a spring 13 is fixedly connected to the top of the control block 12 ; When the inside of the casing 1 is in a vacuum state, the control block 12 will automatically block the air outlet 11 in the initial state. The control block 12 slides and squeezes the spring 13, so that the air outlet 11 is automatically opened, which ensures that a large amount of cooling gas stays around the sintered NdFeB magnet to achieve rapid cooling.

Cooling grooves 14 are provided in the interior of the sealing plate 9 near the air outlet 11, and the cooling grooves 14 are externally connected to a cooling air source through pipes; the interiors of the cooling grooves 14 are slidably connected with elastic plates 15, and the elastic plates 15 are all slidably connected. It is fixedly connected with the bottom surface of the corresponding control block 12; the elastic sheet 16 is fixedly connected between the elastic plate 15 and the bottom surface of the corresponding cooling groove 14; the surface of the sealing plate 9 is close to the air outlet 11. Holes 17; first heating plates 18 are fixedly connected to the bottom openings of the air outlet holes 11; second heating plates 19 are fixed to the bottom surface of the control block 12; 16. When the control block 12 moves upward, the control block 12 will squeeze the spring 13, and at the same time will pull the corresponding elastic plate 15, so that the elastic plate 15 leads out the corresponding cooling tank 14. Since the cooling tank 14 is externally connected with a cooling air source, the The derived elastic plate 15 is in a cooling state. When the pressure between the two sealing plates 9 rises, the gas will be introduced into the inside of the air outlet 11 through the inclined hole 17, and the solid particles in the gas will be adsorbed by the elastic plate 15, so as to realize the anti-aircraft pressure. Preliminary purification of the exhaust gas, and at the same time, the exhaust gas is finally completely purified by cotton. After the cooling of the sintered NdFeB magnet is completed, the control block 12 is reset. Under the action of the elastic sheet 16, the elastic plate 15 is recovered into the corresponding cooling tank 14 , and during the recovery process, the adsorbed particulate matter on the surface of the elastic plate 15 will be scraped off and collected on the surface of the first heating plate 18. The heating of the first heating plate 18 and the second heating plate 19 can make the evaporation material regenerated. When vaporized, part of the vaporized material will be led back through the inclined hole 17 and used.

The inside of the air outlet hole 11 is fixed with a material guide elastic piece 20 at the position of the inclined hole 17 ; the inside of the air outlet hole 11 is fixed with a guide pipe 21 at the top position of the material guide elastic piece 20 , and the guide pipe 21 and the corresponding inclined hole 17 are connected with each other. They are all connected to each other; when working, by setting the material guide shrapnel 20, when the attached crops on the surface of the elastic plate 15 are scraped off, they will first fall into the surface of the material guide shrapnel 20, and the material guide shrapnel 20 can avoid scraping off the attached crops. It directly falls into the inclined hole 17, and at the same time, through the conduit 21, the gas introduced by the inclined hole 17 is directly introduced into the upper position of the material guide shrapnel 20, and the flow of the gas can make the material guide shrapnel 20 vibrate and promote impurities to pass through the material guide shrapnel 20. It falls into the surface of the first heating plate 18 to complete the collection of scraped-off impurities.

A connecting rope 22 is fixedly connected to the inside of the inclined hole 17; a vibration ball 23 is fixedly connected to the end face of the connecting rope 22 close to the material guide shrapnel 20; The rope 22 and the end of the rope 22 are connected with a vibrating ball 23. When the gas passes through the inclined hole 17, the gas will blow the vibrating ball 23, so that the vibrating ball 23 continuously shakes at the bottom position of the guide shrapnel 20, which promotes the guide The vibration effect of the shrapnel 20.

When working, by controlling the internal hydraulic pressure of the two opposite first hydraulic grooves 7, the pair of push rods 4 are controlled to be pushed out, and the push rods 4 will drive the corresponding rotating pressing blocks 6 to squeeze the sintered NdFeB magnets. The magnet is fixed, and then by controlling the corresponding motor 5 to rotate, the motor 5 will drive the corresponding rotating pressure block 6 to rotate, and the rotating pressure block 6 will drive the sintered NdFeB magnet to rotate, so that the four surfaces of the sintered NdFeB magnet are adjusted in turn as The downward direction is convenient for vacuum evaporation of the four surfaces of the sintered NdFeB magnet. After the vacuum evaporation of the four surfaces is completed, the other two push rods 4 are controlled to lead out the first hydraulic tank 7, and the two The push rod 4 will drive the corresponding rotating pressure block 6 to squeeze and fix the sintered NdFeB magnet, and then retract the original two push rods 4. At this time, the motor 5 is controlled to rotate, and the motor 5 will drive the rotating pressure block 6 to rotate, so that the The sintered NdFeB magnet is rotated, and the two surfaces that have not been vacuum-evaporated are controlled to switch downward, so that the surface of the sintered NdFeB magnet can be completely evaporated. By setting two sealing plates 9, by controlling the two sealing plates 9. Lead out the corresponding second hydraulic groove 8. The two sealing plates 9 will make the sintered NdFeB magnet in a completely sealed space, and then control the air inlet 10 to guide the cooling gas, and the cooling gas will pass through the sintered NdFeB magnet. The surface of the sintered NdFeB magnet can be cooled down through the air outlet 11, and the subsequent replacement of the clamping of the sintered NdFeB magnet can avoid damage to the Al film that has been vacuum-evaporated; by setting the control block 12 , and the control block 12 is preloaded by the spring 13. When the interior of the casing 1 is in a vacuum state, the control block 12 will automatically block the air outlet 11 in the initial state. The pressure between the two sealing plates 9 increases, and then the control block 12 slides and squeezes the spring 13, so that the air outlet 11 is automatically opened, ensuring that a large amount of cooling gas stays around the sintered NdFeB magnets to achieve rapid cooling; By arranging the elastic plate 15 and the elastic sheet 16, when the control block 12 moves upward, the control block 12 will squeeze the spring 13, and at the same time will pull the corresponding elastic plate 15, so that the elastic plate 15 leads out the corresponding cooling slot 14. A cooling air source is externally connected to the inside, so that the exported elastic plate 15 is in a cooling state. When the pressure between the two sealing plates 9 increases, the gas will be introduced into the inside of the air outlet 11 through the inclined hole 17 and adsorbed through the elastic plate 15. The solid particles in the gas realize the preliminary purification of the exhaust gas, and at the same time, the exhaust gas is finally completely purified by cotton, and after the cooling of the sintered NdFeB magnet is completed, the control block 12 is reset, and under the action of the elastic sheet 16, the elastic The plate 15 is recovered into the corresponding cooling tank 14, and during the recovery process, the adsorbed particles on the surface of the elastic plate 15 will be scraped off and collected on the surface of the first heating plate 18, passing through the first heating plate 18 and the second heating plate 19 The heating can make the evaporating material re-vaporize, and part of the evaporating material will be guided back through the inclined hole 17 and used; by setting the material guide shrapnel 20, when the attached crops on the surface of the elastic plate 15 are scraped off, they will first fall into the guide shrapnel 2 0 surface, the material guide shrapnel 20 can prevent the scraped off attachments from directly falling into the inclined hole 17, and at the same time, through the conduit 21, the gas introduced from the inclined hole 17 is directly introduced into the upper position of the material guide shrapnel 20, and the flow of the gas can make The vibration of the material guide shrapnel 20 promotes the impurities to fall into the surface of the first heating plate 18 through the material guide shrapnel 20 to complete the collection of scraped impurities attachments; The end of 22 is connected with a vibrating ball 23. When the gas passes through the inclined hole 17, the gas will blow the vibrating ball 23, so that the vibrating ball 23 continuously shakes at the bottom of the guide shrapnel 20, which promotes the vibration of the guide shrapnel 20. Effect.

The above-mentioned front, back, left, right, top and bottom are all based on Figure 1 in the accompanying drawings of the description, and according to the observation angle of the person as a standard, the side of the device facing the observer is defined as the front, and the left side of the observer is defined as the left, And so on.

In the description of the present invention, it should be understood that the terms "center", "portrait", "horizontal", "front", "rear", "left", "right", "vertical", "horizontal", The orientation or positional relationship indicated by "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that The device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the scope of protection of the present invention.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. a preparation method of sintered NdFeB magnet surface Al thin film, is characterized in that: may further comprise the steps: S1: Magnet pretreatment: The surface pretreatment of the sintered NdFeB magnet is carried out by laser cleaning method, and the dirt is blown away from the surface of the magnet with inert gas in time; S2: Preparation of Al film by vacuum evaporation: in the vacuum evaporation device, a layer of Al film is deposited on the surface of the pretreated magnet by using a vacuum evaporation process; S3: Laser remelting treatment: The Al film deposited on the surface of the magnet is modified by laser remelting technology to improve the density of the Al film and the bonding force with the substrate. 2. the preparation method of a kind of sintered NdFeB magnet surface Al thin film according to claim 1 is characterized in that: the magnet pretreatment in described S1, adopts laser cleaning method to carry out pretreatment to the sintered NdFeB magnet surface, In order to remove the oil stain and oxide skin on the surface of the magnet, the process parameters of the laser cleaning include: the laser power is 100-2500W, the laser beam wavelength is 1064nm, the pulse width is 50-300ns, the laser scanning speed is 5-150mm/s, and the laser scanning speed is 5-150mm/s. The incident angle is 20-90°; in the magnet pretreatment in S1, use an inert gas to blow the laser-cleaned dirt off the surface of the magnet in time to avoid re-contamination and oxidation of the cleaned surface, and the inert gas is argon, helium one of the. 3. the preparation method of a kind of sintered NdFeB magnet surface Al thin film according to claim 1, is characterized in that: the preparation of described S2 vacuum evaporation Al thin film, adopts vacuum evaporation process on the magnet surface after pretreatment A layer of Al thin film is deposited, and the process parameters of the vacuum evaporation include a vacuum degree of 1×10 ⁻³ to 5×10 ⁻³ Pa, an evaporation current of 2000 to 2900 A, and a vacuum evaporation time of 50 to 80 minutes. 4. the preparation method of a kind of sintered NdFeB magnet surface Al thin film according to claim 1, is characterized in that: described S3 laser remelting treatment, adopts laser remelting technology to modify the Al thin film deposited on the magnet surface treatment to improve the density of the Al film and the bonding force with the substrate; the process parameters of the laser remelting include: the laser power is 1000-3000W, the scanning speed is 5-15mm/s, the spot size is 2-5mm, The overlap coefficient is 5% to 20%, and an inert gas is filled as a protective gas, and the inert gas is one of argon gas or helium gas. 5. The preparation method of a sintered NdFeB magnet surface Al thin film according to claim 1, wherein the vacuum evaporation device comprises a casing (1), a crucible (2) and an adjustment fixture (3) A crucible (2) is fixedly attached to the inside of the casing (1) close to the bottom surface of the casing (1), and the inside of the crucible (2) is used to place evaporation materials; the inside of the casing (1) is connected to the crucible (2). ) is provided with an adjusting fixture (3) at the top position of the ); the adjusting fixture (3) includes a push rod (4), a motor (5) and a rotating pressure block (6); the inner side of the casing (1) is provided with a The first hydraulic grooves (7), and the number of the first hydraulic grooves (7) is four; the interiors of the four first hydraulic grooves (7) are all slidably connected with push rods (4); A motor (5) is fixedly connected to the inside of each of the push rods (4); and a rotating pressing block (6) is connected to the surfaces of the four push rods (4) in rotation. 6. the preparation method of a kind of sintered NdFeB magnet surface Al thin film according to claim 5, is characterized in that: the inner surface of described shell (1) is provided with the top and bottom positions of adjusting fixture (3) The second hydraulic groove (8); the interior of the second hydraulic groove (8) is slidably connected with a sealing plate (9); the top surface of the sealing plate (9) at the bottom position is provided with evenly arranged air intakes A hole (10); the bottom surface of the sealing plate (9) at the top position is provided with evenly arranged air outlet holes (11). 7. The method for preparing a sintered NdFeB magnet surface Al thin film according to claim 6, characterized in that: a control block (12) is slidably connected to the inside of the air outlet hole (11); the control block The tops of (12) are all fixed with springs (13). 8. The preparation method of a sintered NdFeB magnet surface Al thin film according to claim 7, characterized in that: the inside of the sealing plate (9) is provided with a cooling groove (14) near the air outlet (11) position ), and the cooling tank (14) is connected to an external cooling air source through a pipeline; the interior of the cooling tank (14) is slidably connected with an elastic plate (15), and the elastic plate (15) is connected to the bottom surface of the corresponding control block (12). between the elastic plates (15) and the bottom surface of the corresponding cooling groove (14) are fixedly connected with elastic sheets (16); the surface of the sealing plate (9) is close to the air outlet (11) A first heating plate (18) is fixedly connected to the bottom opening positions of the air outlet holes (11); and a second heating plate (19) is fixedly connected to the bottom surface of the control block (12). ). 9. The preparation method of a sintered NdFeB magnet surface Al thin film according to claim 8, characterized in that: the inside of the air outlet hole (11) is fixedly connected with a material guide shrapnel ( 20); the inside of the air outlet hole (11) is fixedly connected with a conduit (21) at the top position of the material guide elastic sheet (20), and the conduit (21) and the corresponding inclined hole (17) are connected with each other. 10 . The preparation method of the Al film on the surface of a sintered NdFeB magnet according to claim 9 , characterized in that: a connecting rope ( 22 ) is fixedly connected inside the inclined hole ( 17 ); the connecting rope (22) A vibrating ball (23) is fixedly connected to one end face of the material guide shrapnel (20).

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