A method for preparing a neodymium-iron-boron nano-coating material

Abstract

The present application relates to a kind of preparation methods of coating material, in particular to a kind of preparation methods of neodymium iron boron nano coating material.It includes the following steps: substrate pretreatment;Coating preparation: spray preparation nano coating, the binder of nano coating belongs to silicon-titanium modified polymer system, coating thickness is controlled at 20-25 μm, curing process: 50-70 ℃ surface dry 5-20 min, 160-200 ℃ baking and curing 40-60 min;Coating plasma treatment: plasma treatment 2-4 times.The present application nano gray coating can significantly improve surface tension after plasma treatment, the durability of coating surface tension treated under the condition that air is gas source is obviously superior to nitrogen, surface tension is still above 50 mN / m after room temperature is placed and naturally aged 6 months;After coating surface plasma treatment, drawing strength is also improved simultaneously.

Description

Technical Field

[0001] This invention relates to a method for preparing a coating material, and more particularly to a method for preparing a neodymium iron boron nano-coating material. Background Technology

[0002] With the development of grain boundary diffusion technology and surface corrosion protection technology, various high-grade and highly corrosion-resistant NdFeB magnets have been gradually developed and widely used in motors, new energy vehicles, magnetic levitation, and other fields. In the production of various permanent magnet motors, bonding processes are used to ensure the mechanical reliability of the rotor under high-speed rotation (12000 r / min). In recent years, with the expansion of NdFeB applications, especially the rapid development of offshore wind power, the corrosion resistance of coatings has gradually improved. Among them, nano-coatings have excellent resistance to accelerated aging tests (PCT) and salt spray, and can be used as high-corrosion-resistant coating materials for marine environments or harsher conditions. However, nano-coatings contain hydrophobic functional groups and have low surface tension, generally between 28-30 mN / m. If bonding processes are used in the application, surface treatment is required to improve the surface tension of the coating. Commonly used surface treatment methods include chemical treatment, flame treatment, corona treatment, UV irradiation, and plasma treatment. Plasma treatment, being unrestricted by material texture and not damaging the material's mechanical properties, is far superior to general chemical treatment methods and has become one of the most commonly used methods. Plasma surface treatment technology for coatings utilizes the interaction of non-polymerizing gases (such as O2, N2, Ar, etc.) with the coating surface to introduce polar groups such as -COOH, -OH, and -NH2, thereby increasing surface tension and active chemical bonds to improve adhesion.

[0003] However, the surface tension of the plasma-treated coating gradually decreases over time, posing a challenge to practical applications. In particular, some products require downstream customers to complete the adhesive bonding process after plasma treatment, which typically involves transportation and warehousing. The time from plasma treatment to final adhesive bonding is quite long, which places high demands on the durability of the coating after plasma treatment. However, there are few reports on this aspect, and the impact of ion treatment on corrosion resistance and adhesive properties has also not been reported. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems and provide a method for preparing neodymium iron boron nanocoating materials.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0006] A method for preparing a neodymium iron boron nanocoating material includes the following steps:

[0007] Substrate pretreatment;

[0008] Coating preparation: Nano-coating is prepared by spraying. The binder of the nano-coating belongs to the silicon-titanium modified polymer system. The coating thickness is controlled at 20-25μm. Curing process: Surface drying at 50-70℃ for 5-20min, baking curing at 160-200℃ for 40-60min.

[0009] Plasma treatment of coating: Plasma treatment is performed 2-4 times using a plasma device for coating treatment.

[0010] The nano-ash coating of this invention can significantly improve the surface tension of the coating after plasma treatment. The surface tension durability of the coating treated with air as the gas source is significantly better than that of nitrogen. After 6 months of natural aging at room temperature, the surface tension is still above 50 mN / m. The pull-out strength of the coating surface is also improved after plasma treatment.

[0011] Preferably, step (2) coating preparation includes: using a silicon-titanium modified polymer system as the binder for the nano-coating, using a reciprocating sprayer to spray the nano-coating, controlling the coating thickness to be 20-25μm, and curing process: surface drying at 60℃ for 10min, and baking curing at 180℃ for 50min.

[0012] Preferably, the substrate pretreatment in step (1) includes the following steps in sequence: degreasing, first ultrasonic water washing, acid washing, second ultrasonic water washing, water washing, deionized water washing, anhydrous ethanol washing, and drying.

[0013] More preferably, the degreasing includes using a degreasing agent with a mass concentration of 4-6%.

[0014] More preferably, the degreasing includes using a degreasing agent with a mass concentration of 5%.

[0015] More preferably, the pickling includes using nitric acid with a mass concentration of 4-6%.

[0016] More preferably, the pickling includes using nitric acid with a mass concentration of 3%.

[0017] Preferably, step (3) involves plasma treatment 2-4 times.

[0018] Preferably, step (3) involves plasma treatment three times.

[0019] As a preferred option, plasma treatment increases the pull-out strength by more than 45% and maintains a surface tension of ≥50mN / m for 6 months.

[0020] The effects of plasma treatment on the surface tension, corrosion resistance, aging resistance, and adhesion of NdFeB nanocoatings were compared using surface tension testing, copper accelerated acid salt spray testing (CASS), high pressure accelerated aging testing (PCT), pull-out testing, and XPS and FTIR characterization. The aim was to develop a process with better corrosion resistance, aging resistance, and adhesion in NdFeB coating production. The results showed that, under air as the gas source, the surface tension of the nano-coating reached an inflection point after two plasma treatments, increased rapidly after three treatments, and reached the target value of 60 mN / m after four treatments. Compared with nitrogen, the surface tension durability of the nano-coating treated under air was significantly better for the first eight months, and remained ≥50 mN / m for six months. After plasma treatment, the pull-out strength of the coating increased from 20.16 MPa and 21.26 MPa before treatment to 32.22 MPa and 30.23 MPa, respectively, an average increase of 45.94%, without affecting the corrosion resistance and aging resistance of the coating. The increase in surface tension of the coating was mainly due to the introduction of a large amount of O and a small amount of N elements into the coating, resulting in a large number of associated -OH groups and a small number of α-amino acid structures.

[0021] As a preferred embodiment, the plasma treatment in step (3) uses a plasma device for coating treatment, which includes a box, and the box is equipped with a plasma generator and a vacuum chamber water cooling mechanism.

[0022] A vacuum system is connected to one side of the housing. The plasma generator includes a cathode, a water jacket sleeved on the outside of the cathode, an air tube sleeved on the outside of the water jacket sleeve, a coil wound around one end of the air tube, and a power supply connected to the coil. A replaceable cathode head is provided at one end of the cathode, and the cathode head is located inside the coil. An anode is connected to the outer end of the cathode head. A discharge chamber is provided inside the anode, and an electric arc is provided on the surface of the discharge chamber. A plasma nozzle is provided at one end of the anode. A vacuum chamber water cooling mechanism is located on the side of the anode. An adjustment device for adjusting the angle of the plasma generator is provided inside the housing.

[0023] As an optional embodiment of the plasma device for coating treatment described in this invention, the vacuum chamber water cooling mechanism includes a shell, a water pipe, a rotating rod, and a first nozzle. The shell has a sliding groove and a groove body connected to it. A sealing block is slidably connected in the sliding groove. A flow groove is formed on the sealing block. A connecting rod is fixedly connected to the rotating rod. A flow limiting component is fixedly connected to the connecting rod. The rotating rod is used to adjust the position of the sealing block to connect the flow groove to the water pipe.

[0024] The current-limiting component is a rotating plate, which has a first through hole, and the connecting rod is used to make the rotating plate rotate.

[0025] As an optional embodiment of the plasma device for coating treatment described in this invention, a positioning plate is fixedly connected to the sealing block, and a second through hole is provided on the positioning plate. The connecting rod is used to connect the first through hole and the second through hole, thereby controlling the water flow rate into the tank.

[0026] As an optional embodiment of the plasma device for coating treatment described in this invention, a limiting ring is rotatably connected to the sealing block. The limiting ring is in the shape of a hollow ring and is used to ensure stability when the sealing block rotates.

[0027] As an optional embodiment of the plasma device for coating treatment described in this invention, wherein: a second nozzle is slidably connected inside the first nozzle, the second nozzle being in the shape of an inverted frustum, the first nozzle being in the shape of an inverted frustum, the radius of the first nozzle being larger than the radius of the second nozzle, a movable block being fixedly connected to the second nozzle, the movable block being used to cause the second nozzle to slide inside the first nozzle, a movable groove being formed inside the first nozzle, one end of the movable block being slidably connected to the movable groove, and the other end of the movable block being connected to the second nozzle.

[0028] As an optional embodiment of the plasma device for coating treatment described in this invention, wherein: a push rod is installed on the moving block, a limiting rod is detachably installed on the push rod, a limiting groove is formed on the first nozzle, the limiting groove is connected to the moving groove, and the limiting groove is engaged with the limiting rod.

[0029] As an optional embodiment of the plasma device for coating treatment described in this invention, wherein: a box door is provided on one side of the box body, multiple layers of protruding sealing rings are provided on the inner side of the box door, and screw rods are threaded to the four corners of the box door, one end of the screw rod is rotatably connected to the box body, and the other end of the screw rod is provided with a rotating handle.

[0030] As an alternative embodiment of the plasma device for coating treatment described in this invention, the vacuum system includes a vacuum pump installed in the housing, which is used to evacuate the housing.

[0031] As an optional embodiment of the plasma device for coating treatment described in this invention, the adjusting device includes a motor, a lead screw connected to the output end of the motor, a sliding sleeve threaded onto the lead screw, the rotation of the lead screw can drive the movement of the sliding sleeve, the plasma generator is mounted on the sliding sleeve, and a disc is coaxially arranged on the lead screw, the outer circumferential surface of the disc is provided with an anti-slip texture, and the outer circumferential surface of the disc contacts the side of the rotating rod.

[0032] In summary, the present invention has the following beneficial effects:

[0033] 1. The nano-ash coating of this invention can significantly improve the surface tension of the coating after plasma treatment. The surface tension durability of the coating treated under air as the gas source is significantly better than that under nitrogen. After 6 months of natural aging at room temperature, the surface tension is still above 50mN / m. The tensile strength of the coating surface is also improved after plasma treatment.

[0034] 2. By placing the plasma generator inside a vacuum chamber, compressed air enters the air pipe, the coil is energized, and water enters the water jacket. The water is circulated. Two electrodes are set up in the sealed chamber to form an electric field. A vacuum pump is used to achieve a certain degree of vacuum. As the gas becomes more and more rarefied, the distance between molecules and the free movement distance of molecules or ions also become longer. Under the action of the electric field, they collide to form plasma, which is then ejected through the plasma nozzle. The vacuum chamber water cooling mechanism can cool down the plasma ejected from the plasma nozzle.

[0035] When it is necessary to control the amount of water sprayed by the atomizing nozzle, the user connects the delivery pipe to the water pipe, and the water source is delivered into the water pipe. At this time, the user rotates the rotating rod, which drives the sealing block to rotate. When the sealing block rotates to a certain position, the sliding groove connects with the flow groove on the sealing block. At this time, the water in the water pipe flows into the flow groove and is delivered to the rotating plate through the flow groove. The rotating rod rotates, which drives the connecting rod to rotate, which in turn drives the rotating plate to rotate. After the rotating plate rotates to a certain position, the water flow flows through the gap connecting the first and second through holes into the tank. The water in the tank further flows into the first nozzle, at which point the first nozzle begins to spray water. The rotating rod makes it easy to adjust the amount of water sprayed by the atomizing nozzle, thereby controlling the water pressure during spraying and improving the working efficiency of the atomizing nozzle. When not in use, the user rotates the rotating rod, which drives the sealing block to seal the water pipe, meaning that the first nozzle cannot spray water. It is easy to use and adjust, and can effectively control the temperature inside the plasma generator cavity, thereby obtaining a better coating effect.

[0036] The present invention discloses a plasma device for coating treatment. When it is necessary to adjust the spraying range of the atomizing nozzle, the user pushes a push rod, which drives a moving block to slide in a moving groove. The moving block drives a second nozzle to slide. The sliding of the moving block in the moving groove helps to limit the second nozzle during sliding, preventing displacement of the second nozzle from sliding within the first nozzle. After sliding to the desired spraying position, the user fixes the push rod. The sliding of the second nozzle facilitates the adjustment of the spraying range of the first nozzle, thereby stabilizing the temperature inside the plasma generator cavity and obtaining a coating with better effect.

[0037] This invention employs surface tension testing, copper accelerated acid salt spray testing (CASS), high-pressure accelerated aging testing (PCT), pull-out testing, and XPS and FTIR characterization to compare the effects of plasma treatment on the surface tension, corrosion resistance, aging resistance, and adhesion of NdFeB nanocoatings. The aim is to develop a process with better corrosion resistance, aging resistance, and adhesion in NdFeB coating production. Results show that under air-source conditions, the surface tension of the nanocoating reaches an inflection point after two plasma treatments. After three treatments, the surface tension rapidly increases, and after four treatments, the target value of 60 mN / m is reached. Compared to nitrogen, the surface tension durability of plasma treatment under air conditions is significantly better for the first eight months, and remains ≥50 mN / m for six months. After plasma treatment, the pull-out strength of the coating increases from 20.16 MPa and 21.26 MPa before treatment to 32.22 MPa and 30.23 MPa, respectively, an average increase of 45.94%, without affecting the coating's corrosion resistance and aging resistance. Attached Figure Description

[0038] Figure 1 a is a schematic diagram of typical experimental conditions for the relationship between plasma treatment and surface tension in this invention;

[0039] Figure 1 b is a schematic diagram of the relationship between different treatment times of plasma treatment and surface tension in this invention;

[0040] Figure 2 This is a schematic diagram of the surface tension durability test curve of the coating of the present invention;

[0041] Figure 3 a is a schematic diagram of the copper coating of the present invention accelerating acidic salt spray test for 96 hours;

[0042] Figure 3 b is a schematic diagram of the copper coating of the present invention accelerating acidic salt spray test for 300 hours;

[0043] Figure 4 a is a schematic diagram of the high-pressure accelerated aging test of the coating of the present invention for 96 hours;

[0044] Figure 4b is a schematic diagram of the high-pressure accelerated aging test of the coating of the present invention for 240 hours;

[0045] Figure 5 a is a schematic diagram comparing the pull-out test of the coating before pull-out of the present invention;

[0046] Figure 5 b is a schematic diagram comparing the pull-out test results of the coating after the present invention;

[0047] Figure 6 This is a schematic diagram of the XPS test results curve of the coating of the present invention;

[0048] Figure 7 This is a schematic diagram of the FTIR test results curve of the coating of the present invention;

[0049] Figure 8 This is a three-dimensional structural schematic diagram of a plasma device for coating treatment according to the present invention;

[0050] Figure 9 This is a front view schematic diagram of a plasma device for coating treatment according to the present invention;

[0051] Figure 10 This is a schematic diagram of the internal structure of a plasma device for coating treatment according to the present invention;

[0052] Figure 11 This invention relates to a plasma device for coating treatment. Figure 10 Enlarged structural diagram at point A in the middle;

[0053] Figure 12 This is a three-dimensional structural diagram of the plasma generator of the present invention;

[0054] Figure 13 This is a schematic diagram of the plasma generator structure of the present invention;

[0055] Figure 14 This is a cross-sectional view of the plasma generator of the present invention;

[0056] Figure 15 This is a schematic diagram of the outer shell structure of a plasma device for coating treatment according to the present invention;

[0057] Figure 16 This is a schematic cross-sectional view of the outer casing of a plasma device for coating treatment according to the present invention;

[0058] Figure 17 This is a schematic diagram of the exploded structure of a plasma device for coating treatment according to the present invention;

[0059] Figure 18 For the present invention Figure 17 Enlarged view at point B in the middle;

[0060] Figure 19 This is a schematic diagram of the exploded structure of the nozzle of the present invention.

[0061] In the diagram: 1. Outer shell; 2. Water pipe; 3. Rotating rod; 4. First nozzle; 5. Slide groove; 6. Tank body; 7. Sealing block; 8. Flow groove; 9. Connecting rod; 10. Rotating plate; 11. First through hole; 12. Positioning plate; 13. Second through hole; 14. Limiting ring; 15. Second nozzle; 16. Moving block; 17. Moving groove; 18. Push rod; 19. Limiting rod; 20. Limiting groove; 21. Box body; 22. Plasma generator 23. Vacuum chamber water cooling mechanism; 24. Vacuum system; 25. Cathode; 26. Water jacket; 27. Air pipe; 28. Coil; 29. ​​Cathode head; 30. Anode; 31. Discharge chamber; 32. Electric arc; 33. Plasma nozzle; 34. Adjustment device; 35. Box door; 36. Sealing ring; 37. Lead screw; 38. Rotary handle; 39. Air pump; 40. Motor; 41. Lead screw; 42. Sliding sleeve; 43. Disc. Implementation

[0062] Please see Figure 8-14 A plasma device for coating treatment includes a housing 21, a plasma generator 22 and a vacuum chamber water cooling mechanism 23 disposed inside the housing 21.

[0063] A vacuum system 24 is connected to one side of the housing 21. The plasma generator 22 includes a cathode 25, a water jacket 26 is sleeved on the outside of the cathode 25, an air pipe 27 is sleeved on the outside of the water jacket 26, a coil 28 is wound around one end of the air pipe 27, and a power supply is connected to the coil 28. A replaceable cathode head 29 is provided at one end of the cathode 25. The cathode head 29 is located inside the coil 28. An anode 30 is connected to the outer end of the cathode head 29. A discharge chamber 31 is provided inside the anode 30, and an electric arc 32 is provided on the surface of the discharge chamber 31. A plasma nozzle 33 is provided at one end of the anode 30. A vacuum chamber water cooling mechanism 23 is provided on the side of the anode 30. An adjustment device 34 for adjusting the angle of the plasma generator 22 is provided inside the housing 21.

[0064] This device places the plasma generator 22 inside the vacuum chamber 21, with compressed air entering the air pipe 27, the coil 28 energized, and water entering the water jacket 26. The water is circulated. Two electrodes are set in the sealed chamber 21 to form an electric field. A vacuum pump is used to achieve a certain degree of vacuum. As the gas becomes increasingly rarefied, the distance between molecules and the free movement distance of molecules or ions also increases. Under the action of the electric field, they collide to form plasma, which is then ejected through the plasma nozzle 33. The vacuum chamber water cooling mechanism 23 can cool and reduce the temperature of the plasma ejected from the plasma nozzle 33. Example

[0065] Please see Figure 15-19 A plasma device for coating treatment includes a housing 1, a water pipe 2, a rotating rod 3, and a first nozzle 4. The housing 1 has a sliding groove 5 and a tank 6 connected to each other. A sealing block 7 is slidably connected in the sliding groove 5. A flow groove 8 is provided on the sealing block 7. A connecting rod 9 is fixedly connected to the rotating rod 3. A flow limiting component is fixedly connected to the connecting rod 9. The rotating rod 3 is used to adjust the position of the sealing block 7 so as to connect the flow groove 8 with the water pipe 2.

[0066] The current limiting component is a rotating plate 10, which has a first through hole 11. The connecting rod 9 is used to make the rotating plate 10 rotate.

[0067] When it is necessary to control the amount of water sprayed by the atomizing nozzle, the user connects the delivery pipe to the water pipe 2, and the water source is delivered into the water pipe 2. At this time, the user rotates the rotating rod 3, which drives the sealing block 7 to rotate. When the sealing block 7 rotates to a certain position, the sliding groove 5 connects with the flow groove 8 on the sealing block 7. At this time, the water in the water pipe 2 flows into the flow groove 8, and the water flow is transmitted to the rotating plate 10 through the flow groove 8. The rotation of the rotating rod 3 drives the connecting rod 9 to rotate, which in turn drives the rotating plate 10 to rotate. After being rotated to a certain position, the water flow rate is sent to the tank 6 through the first through hole 11. The water in the tank 6 is further sent to the first nozzle 4. At this time, the first nozzle 4 starts to spray water. The rotating rod 3 can easily adjust the size of the water flow sprayed by the atomizing nozzle, thereby controlling the water pressure during spraying and improving the working efficiency of the atomizing nozzle. When not in use, the user can rotate the rotating rod 3, and the rotating rod 3 will drive the sealing block 7 to block the water pipe 2, so that the first nozzle 4 cannot spray water. It is convenient to use and adjust, and has a simple structure. Example

[0068] This embodiment is an improvement on the basis of embodiment 1. This embodiment also includes: a positioning plate 12 is fixedly connected to the sealing block 7, and a second through hole 13 is opened on the positioning plate 12. The connecting rod 9 is used to make the first through hole 11 and the second through hole 13 connect, thereby controlling the water flow into the tank 6.

[0069] In this embodiment, when it is necessary to control the water flow into the tank 6, the user rotates the rotating rod 3, and the connecting rod 9 on the rotating rod 3 drives the rotating plate 10 to rotate. The rotation of the rotating plate 10 drives the first through hole 11 to rotate. After the rotating plate 10 rotates to a certain position, the first through hole 11 and the second through hole 13 come into contact or communicate. The water in the flow tank 8 or flows into the tank 6 through the gap between the first through hole 11 and the second through hole 13. The connecting rod 9 can easily adjust the gap between the first through hole 11 and the second through hole 13, thereby controlling the water flow and increasing the water flow required by the user for spraying, thus making it more versatile.

[0070] The other structures in this embodiment are the same as in Embodiment 1, and will not be described again here. Example

[0071] This embodiment is an improvement on embodiment 1. This embodiment also includes: a limiting ring 14 is rotatably connected to the sealing block 7. The limiting ring 14 is in the shape of a hollow ring and is used to make the sealing block 7 stable when it rotates.

[0072] In this embodiment, when the rotating rod 3 drives the sealing block 7 to rotate, the limiting ring 14 is in a hollow annular shape, which facilitates the limiting of the sealing block 7 during rotation, preventing the sealing block 7 from leaving the slide groove 5 during rotation and improving the stability of the sealing block 7 during rotation.

[0073] The other structures in this embodiment are the same as in Embodiment 1, and will not be described again here. Example

[0074] This embodiment is an improvement on embodiment 1. This embodiment also includes: a second nozzle 15 slidably connected inside the first nozzle 4, the second nozzle 15 being in the shape of an inverted frustum, the first nozzle 4 being in the shape of an inverted frustum, the radius of the first nozzle 4 being larger than the radius of the second nozzle 15, and a moving block 16 being fixedly connected to the second nozzle 15, the moving block 16 being used to cause the second nozzle 15 to slide inside the first nozzle 4.

[0075] In this embodiment, when it is necessary to adjust the spray range of the atomizing nozzle, the user pushes the second nozzle 15. At this time, the moving block 16 on the second nozzle 15 slides within the first nozzle 4. Since the radius of the first nozzle 4 is larger than the radius of the second nozzle 15, the second nozzle 15 can slide freely within the first nozzle 4. After sliding to the desired spray position, the user can fix the moving block 16. The sliding of the second nozzle 15 facilitates the adjustment of the spray range of the first nozzle 4, improving the practicality of the atomizing nozzle.

[0076] The other structures in this embodiment are the same as in Embodiment 1, and will not be described again here. Example

[0077] This embodiment is an improvement on embodiment 4. This embodiment also includes: a moving groove 17 is provided in the first nozzle 4, one end of the moving block 16 is slidably connected to the moving groove 17, and the other end of the moving block 16 is connected to the second nozzle 15.

[0078] In this embodiment, when it is necessary to adjust the spray range of the atomizing nozzle, the user pushes the second nozzle 15. At this time, the moving block 16 on the second nozzle 15 slides in the moving groove 17. Since the radius of the first nozzle 4 is larger than the radius of the second nozzle 15, the second nozzle 15 can slide freely in the first nozzle 4. The sliding of the moving block 16 in the moving groove 17 helps to limit the second nozzle 15 when it slides, avoiding displacement of the second nozzle 15 when it slides in the first nozzle 4. When it slides to the desired spray position, the user can fix the moving block 16. The sliding of the second nozzle 15 facilitates the adjustment of the spray range of the first nozzle 4, improving the practicality of the atomizing nozzle.

[0079] The other structures in this embodiment are the same as in Embodiment 1, and will not be described again here. Example

[0080] This embodiment is an improvement on embodiment 4. This embodiment also includes: a push rod 18 is installed on the moving block 16, a limit rod 19 is detachably installed on the push rod 18, a limit groove 20 is opened on the first nozzle 4, the limit groove 20 is connected to the moving groove 17, and the limit groove 20 is engaged with the limit rod 19.

[0081] In this embodiment, when the second nozzle 15 needs to be fixed after sliding to a certain position in the first nozzle 4, the user can insert the limiting rod 19 through the pushing rod 18 and into the limiting groove 20 to position the moving block 16. This ensures that the second nozzle 15 needs to be positioned after sliding, thereby increasing the specific range of the atomizing nozzle and making it more versatile in use.

[0082] The other structures in this embodiment are the same as in Embodiment 1, and will not be described again here. Example

[0083] A box door 35 is provided on one side of the box body 21. Multiple layers of protruding sealing rings 36 are provided on the inner side of the box door 35. Each of the four corners of the box door 35 is threaded with a screw rod 37. One end of the screw rod 37 is rotatably connected to the box body 21, and the other end of the screw rod 37 is provided with a rotating handle 38.

[0084] By rotating the handle 38, the lead screw 37 can be rotated, and the lead screw 37 then drives the cabinet door 35 to press towards the cabinet 21, so that the cabinet 21 is as sealed as possible.

[0085] The vacuum system 24 includes a vacuum pump 39 installed in the housing 21, which is used to evacuate the housing 21.

[0086] The adjustment device 34 includes a motor 40, a lead screw 41 connected to the output end of the motor 40, a sliding sleeve 42 threaded onto the lead screw 41, and the rotation of the lead screw 41 can drive the movement of the sliding sleeve 42. The plasma generator 22 is mounted on the sliding sleeve 42. A disc 43 is also coaxially arranged on the lead screw 41. A layer of anti-slip texture is provided on the outer circumferential surface of the disc 43, and the outer circumferential surface of the disc 43 contacts the side of the rotating rod 3.

[0087] The motor 40 is a forward and reverse motor. The motor 40 can drive the rotation of the lead screw 41. The lead screw 41 drives the sliding sleeve 42 to move, and then drives the plasma generator 22 to move. This allows the nozzle end of the plasma generator 22 to be placed on the surface of the workpiece to be processed. The additional disc 43 can drive the rotation of the rotating rod 3. The rotation of the rotating rod 3 can control the cooling water, thereby achieving linkage.

[0088] 1. Experimental Preparation

[0089] 1.1 Materials and Reagents

[0090] Neodymium iron boron (grade: N42, specifications: D18mm×18mm and D30mm×8mm): Zhejiang Xinsheng Permanent Magnet Technology Co., Ltd.; Nitric acid (industrial grade): Shanghai Jing'en Industrial Co., Ltd.; Degreasing agent (industrial grade): Jiaxing Kerong Environmental Protection Technology Co., Ltd.; Anhydrous ethanol (industrial grade, ≥99.5%): Jinan Xinshun Chemical Co., Ltd.; Deionized water (18.25MΩ): self-made.

[0091] 1.2 Substrate Pretreatment

[0092] The process flow is as follows: degreasing (5% degreasing agent) → water washing (ultrasonic) → pickling (3% nitric acid) → water washing (ultrasonic) → water washing → deionized water washing → anhydrous ethanol washing → drying.

[0093] 1.3 Coating Preparation

[0094] The binder for the nano-coating belongs to the silicon-titanium modified polymer system. The nano-coating is applied using a reciprocating sprayer produced by Shenzhen Rongde Robotics Technology Co., Ltd. The coating thickness is controlled at 20-25μm. The curing process is as follows: surface drying at 60℃ for 10min, followed by baking and curing at 180℃ for 50min.

[0095] 1.4 Plasma Treatment of Coating

[0096] The plasma device (power: 800W) of the present invention is used for coating surface treatment.

[0097] 1.5 Performance Testing

[0098] Surface testing ink manufactured by Plasmatreat GmbH, Germany, grade: 28-72mN / m; the qualification standard for nano-coating plasma treatment is: surface tension ≥60mN / m after treatment, and ≥50mN / m after 3 months at room temperature. Test method: Apply the test ink to the coating surface. If the liquid wets the surface (i.e., the liquid spreads continuously), the surface tension of the tested coating is higher than the reading of the corresponding test ink. Continue testing, using test inks with higher readings, repeating the process until the liquid no longer wets the surface (i.e., the liquid shrinks). The reading of the last test ink that wets the surface and remains unshrinked for 2 seconds is the surface tension of the tested coating. Pull-out tests were performed using a microcomputer-controlled electronic universal testing machine, model LD25.504, manufactured by Lisheng (Shanghai) Scientific Instruments Co., Ltd.

[0099] The PCT test was conducted in an EHS-211 ESPEC thermal shock test chamber at a temperature of (120±2)℃, an air pressure of 0.2MPa, and a humidity mode of supersaturation (FULL). The corrosion resistance qualification requirement was that no visible defects such as bubbles (bulges), peeling, rust, or chalking should appear on the coating surface within 96 hours. Since all samples passed after 96 hours and there was no differentiation, the test time was extended to 240 hours. The test was stopped when there was a significant difference in corrosion resistance between the samples. Generally, it is required that no visible defects such as bubbles (bulges), peeling, rust, or chalking should appear on the coating surface within the specified time. Slight discoloration, yellowing, or darkening of the coating is acceptable.

[0100] Referring to GB / T10125-2012 "Artificial Atmosphere Corrosion Test - Salt Spray Test", CASS tests were conducted in a TMHW-90 programmable salt spray tester. The requirement was that no visible defects such as bubbles, peeling, rust, or chalking should appear on the coating surface within 96 hours. Since all samples passed after 96 hours, with no discriminatory differences, the test time was extended to 300 hours. The test was stopped when significant differences in corrosion resistance were observed between the samples. Generally, it is required that no visible defects such as bubbles (bulges), peeling, rust, or chalking should appear on the coating surface within the specified time. Slight discoloration, yellowing, or darkening of the coating is permissible. The corrosion morphology of different samples was observed using a CDM-202C metallographic microscope at 100x magnification.

[0101] Figure 1 a represents the appearance of the coating surface after 4 plasma treatments under typical conditions, using a surface tension test ink of 60mN / m to wet the coating surface and maintain it for 2 seconds without shrinkage; Figure 1b is a graph showing the relationship between the number of plasma treatments and the surface tension of the coating. The surface tension of the coating before treatment was 28 mN / m. The surface tensions after treatments 1-5 were 32, 36, 50, 60, and 72 mN / m, respectively. Since the maximum surface tension of this brand of ink is 72 mN / m, the test was only conducted up to 72 mN / m. Figure 1 As shown by curve b, the surface tension gradually increases with the number of treatments. After two treatments, the surface tension reaches an inflection point. After three treatments, the surface tension increases rapidly, and after four treatments, the target value of 60 mN / m can be achieved.

[0102] Figure 2 The graph shows the surface tension durability test curves of the plasma-treated nano-coating under nitrogen or air as the gas source conditions, with a test period of 12 months. The test method is as follows: placed at room temperature, naturally aged, and the surface tension was tested once a month. As shown in the graph, the surface tension of the coating before aging is 60 mN / m. For the plasma-treated coating under air conditions, the surface tension remains basically unchanged for the first 3 months, decreases to 56 mN / m after 4 months and remains basically unchanged for 1 month, decreases to 50 mN / m after 6 months, decreases to 45 mN / m after 7 months, and the largest decrease occurs after 8 months, dropping to 32 mN / m, and then remains basically unchanged at 32 mN / m for the next 4 months. For the plasma-treated coating under nitrogen as the gas source conditions, the surface tension decreases to 56 mN / m after 1 month, decreases to 50 mN / m after 2 months and remains basically unchanged for 1 month, the largest decrease occurs after 4 months, dropping to 38 mN / m, decreases to 32 mN / m after 5 months, and then remains basically unchanged at 32 mN / m for the next 7 months. The data above shows that, after plasma treatment of the nano-coating, the surface tension durability of the coating treated with air as the gas source is significantly better than that of the coating treated with nitrogen in the first 8 months.

[0103] The copper-accelerated acid salt spray (CASS) test was used to examine the CASS resistance of coatings with different numbers of plasma treatment cycles and untreated coatings. Samples numbered 0, 2, 3, and 4 represent no plasma treatment, 2 plasma treatments, 3 plasma treatments, and 4 plasma treatments, respectively. Samples will be similarly numbered below, and the treatment method is the same as above. Figure 3 As can be seen from this, after 96 hours of CASS testing, no visually visible abnormalities such as bubbles (bulges), peeling, rust, or powdering were observed in any of the samples. Figure 3 b shows that after 216 hours of CASS testing, the number of samples that underwent corrosion after 0, 2, 3, and 4 ion treatments were 1, 1, 0, and 1, respectively, indicating that the salt spray resistance of the samples is not related to whether the samples were ion treated or the number of treatments.

[0104] Depend on Figure 4As can be seen from this, after 96 hours of high-pressure accelerated aging test (PCT), no visually visible defects such as bubbles (bulging), peeling, rust, or powdering were observed in any of the samples. Figure 4 As shown in b, after 240 hours of PCT testing, the number of samples corroded after 0, 2, 3, and 4 plasma treatments were 1, 1, 0, and 1, respectively. This indicates that the PCT resistance of the nano-coating varies depending on whether it has undergone plasma treatment or not, with no obvious pattern, and is not significantly related to plasma treatment. Furthermore, the corrosion of the samples all occurred at the edges. According to previous research by this research group, this corrosion phenomenon is mainly caused by the thinner coating thickness at the edges.

[0105] To examine the adhesion between the coating and the adhesive before and after plasma treatment, a universal testing machine was used to perform a pull-out test on the coating. Figure 5 a and 5b show the sample appearance before and after drawing, respectively. The dashed box indicates no plasma treatment, and the solid box indicates plasma treatment. Figure 5 As shown in b, for samples 1 and 2 that were not plasma treated, after the pull rod was pulled away from the substrate, the adhesive and the pull rod remained bonded together, and the adhesive layer was pulled away from the surface of the nano-ash coating without damage to the coating. The pull strengths were 20.16 MPa and 21.26 MPa, respectively. For samples 3 and 4 that were plasma treated, after the pull rod was pulled away from the substrate, the pull rod, adhesive layer, and nano-ash coating were not separated. Instead, the NdFeB substrate was broken, causing the pull rod to separate from the substrate. The pull strengths were 32.22 MPa and 30.23 MPa, respectively. This indicates that after plasma treatment, the adhesion between the adhesive and the nano-ash coating was significantly better than that of the plasma-treated coating, and the average pull strength increased by 45.94%.

[0106] 2.6 Analysis of Plasma Treatment Mechanism

[0107] To investigate the main reasons for the increase in surface tension after plasma treatment of the coating, air, which has a better effect, was selected as the gas source, and XPS and FTIR tests were performed. Figure 6 It can be seen that before plasma treatment, O1 S C1 S The binding energies of the characteristic peaks are 530.40 eV and 284.31 eV, respectively. At these values, N1 was not observed. S The binding energy, and C1 S The peak intensity is significantly higher than that of O1S; and the plasma-treated coating shows the addition of a weak N1. S Characteristic peak, with a binding energy of 398.4 eV. [6] This indicates that under air source conditions (oxygen approximately 21%, nitrogen approximately 78%), although the O2 content is relatively high, after plasma treatment, the coating's bonding ability with O is far greater than that with N, while the C1 content at this time...S The peak intensity was significantly lower than that of O1. S This indicates that the coating introduced a large amount of oxygen, or that after plasma treatment, some C-containing functional groups or molecular chain segments were ablated by the plasma flame, resulting in a low content.

[0108] Depend on Figure 7 The infrared curve shows that, before plasma treatment, the peak is at 3339.5 cm⁻¹. -1 A gentle, dome-shaped peak exists nearby. After plasma treatment, this peak becomes significantly more prominent, primarily due to the addition of a large number of associated -OH groups on the coating surface after treatment. The infrared curve after plasma treatment is at a wavenumber of 2049.9 cm⁻¹. -1 A new absorption peak appeared, mainly due to the α-amino acid structure formed after the coating was plasma treated.

[0109] 3. Conclusion

[0110] (1) Under the condition of air as the gas source, the surface tension of the nano-coating after two plasma treatments showed an inflection point. After three treatments, the surface tension increased rapidly. After four treatments, the target value of 60mN / m could be reached. The surface tension of the nano-ash coating can be significantly improved after plasma treatment. The durability of the surface tension of the coating treated under the condition of air as the gas source is significantly better than that of nitrogen. After 6 months of natural aging at room temperature, the surface tension is still 50mN / m.

[0111] (2) Plasma treatment of the coating surface does not affect the salt spray resistance and PCT performance.

[0112] (3) After plasma treatment, the tensile strength of the coating surface increased from 20.16 MPa and 21.26 MPa before treatment to 32.22 MPa and 30.23 MPa, with an average increase of 45.94%.

[0113] (4) FTIR and XPS analysis showed that the surface tension of the coating increased mainly because the coating introduced a large amount of O elements and a small amount of N elements, resulting in a large amount of -OH and a small amount of α-amino acid structures.

[0114] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for preparing a neodymium iron boron nanocoating material, characterized in that... Includes the following steps: (1) Substrate pretreatment: degreasing, first ultrasonic water washing, acid washing, second ultrasonic water washing, water washing, deionized water washing, anhydrous ethanol washing, drying; the degreasing includes using a degreasing agent with a mass concentration of 4-6%; the acid washing includes using nitric acid with a mass concentration of 4-6%; (2) Coating preparation: The nano coating is prepared by spraying. The binder of the nano coating is a silicon-titanium modified polymer system. The nano coating is sprayed by a reciprocating sprayer. The coating thickness is controlled at 20-25μm. Curing process: surface drying at 60℃ for 10min, baking curing at 180℃ for 50min. (3) Plasma treatment of coating: Under the condition of air as the gas source, a plasma device for coating treatment is used to perform plasma treatment 2-4 times to make the surface tension of the coating reach more than 60mN / m, and after natural aging at room temperature for 6 months, the surface tension is maintained above 50mN / m. The plasma device used for coating treatment includes a housing (21), in which a plasma generator (22) and a vacuum chamber water cooling mechanism (23) are provided. A vacuum system (24) is connected to one side of the housing (21). The plasma generator (22) includes a cathode (25). A water jacket (26) is fitted around the outside of the cathode (25). An air pipe (27) is fitted around the outside of the water jacket (26). A coil (28) is wound around one end of the air pipe (27). A power source is connected to the coil (28). A replaceable cathode head (29) is provided at one end of the cathode (25). The cathode head (29) is located inside the coil (28). An anode (30) is connected to the outer end of the cathode head (29). A discharge chamber (31) is provided inside the anode (30). An electric arc (32) is provided on the surface of the discharge chamber (31). A plasma nozzle (33) is provided at one end of the anode (30). A vacuum chamber water cooling mechanism (23) is located on the side of the anode (30). An adjustment device (34) for adjusting the angle of the plasma generator (22) is provided inside the housing (21). The vacuum chamber water cooling mechanism (23) includes a shell (1), a water pipe (2), a rotating rod (3), and a first nozzle (4). The shell (1) has a sliding groove (5) and a groove (6) inside. The sliding groove (5) and the groove (6) are connected. A sealing block (7) is slidably connected inside the sliding groove (5). A flow groove (8) is opened on the sealing block (7). A connecting rod (9) is fixedly connected to the rotating rod (3). A flow limiting component is fixedly connected to the connecting rod (9). The rotating rod (3) is used to adjust the position of the sealing block (7) so that the flow groove (8) is connected to the water pipe (2). The current limiting component is a rotating plate (10), and the rotating plate (10) has a first through hole (11). The connecting rod (9) is used to cause the rotating plate (10) to rotate. A second nozzle (15) is slidably connected inside the first nozzle (4). The second nozzle (15) is in the shape of an inverted frustum. The first nozzle (4) is in the shape of an inverted frustum. The radius of the first nozzle (4) is larger than the radius of the second nozzle (15). A moving block (16) is fixedly connected to the second nozzle (15). The moving block (16) is used to cause the second nozzle (15) to slide inside the first nozzle (4). A moving groove (17) is opened inside the first nozzle (4). One end of the moving block (16) is slidably connected to the moving groove (17). The other end of the moving block (16) is connected to the second nozzle (15). A push rod (18) is installed on the moving block (16), and a limit rod (19) is detachably installed on the push rod (18). A limit groove (20) is opened on the first nozzle (4). The limit groove (20) is connected to the moving groove (17), and the limit groove (20) is engaged with the limit rod (19).

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