Apparatus for depositing electrically insulating coatings by means of a beam of electrons from a charge-neutralized plasma cathode

Abstract

The utility model relates to an electrically neutralized plasma cathode electron beam evaporation electrically insulating coating device, and aims at the problem of low beam plasma density and insufficient neutralization of negative charge in plasma ions during the existing electron beam evaporation electrically insulating coating. The utility model includes hollow cathode, anode, accelerating electrode, grid, plating material, crucible, grid power supply and the like, the crucible is placed in the grid, the plating material is located in the interior of the crucible, and the upper part of the grid is provided with an aperture. The hollow cathode effect of the hollow cathode grid is utilized to enhance the beam plasma density, neutralize the negative charge on the surface of the electrically insulating ceramic, and realize the electrically insulating electron beam evaporation process.

Description

Technical Field

[0001] This utility model relates to a charge-neutralizing plasma cathode electron beam evaporation device for depositing an electrically insulating coating, belonging to the field of coating evaporation. Background Technology

[0002] Electrically insulating coatings play an important role in both functional and protective coatings. These coatings include oxides, nitrides, borides, carbides, and other compounds. They typically possess excellent properties such as high hardness, high temperature resistance, and corrosion resistance, and are widely used in high-tech fields such as aerospace, defense, advanced equipment manufacturing, and nuclear industry.

[0003] In the field of optical thin films, coatings such as SiO2 and HfO2 are used as low-refractive-index materials in optical thin films for lasers and precision instruments. The surface roughness and uniformity of the coating affect the imaging accuracy of coherent optical systems. In large-scale integrated circuits, coatings such as SiO2 and HfO2 can improve the optoelectronic properties of gate insulating layers, such as breakdown voltage, leakage current, and dielectric constant. Ceramic coatings such as Al2O3 and SiC are good tritium permeation barrier coatings in nuclear fusion reactors to reduce tritium permeability. With the increase of Mach number in hypersonic vehicles, the surface temperature of the vehicle may reach 2000℃. Preparing high thermal emissivity coatings (SiO2, Al2O3, HfO2, etc.) can improve the high-temperature resistance of the vehicle.

[0004] Currently, there are many methods for preparing electrically insulating coatings. Physical vapor deposition (PVD) based on evaporation and sputtering principles has a series of excellent properties such as high adhesion and dense structure. Improving the process avoids target poisoning due to non-conductivity. Magnetron sputtering technologies such as radio frequency (RF), HiPIMS, and twin targets are used to deposit coatings such as Si3N4, SiO2, and Al2O3 [Wei Boyang, Liu Dongmei, Fu Xiuhua, et al. Study on film thickness uniformity of magnetron sputtering system based on twin targets [J]. Acta Optica Sinica, 2021, 41(7): 1-6. Jianliang Lin. High rate reactive sputtering of Al2O3 coatings by HiPIMS [J]. Surface & Coatings Technology, 2019, 357: 402-411]. This method suffers from problems such as low deposition rate (0.8 nm / min when using RF magnetron deposition of Al2O3 coating) and poor plasma stability [Ke Shi, Long Wang, Wei Zhang, et al. Different Fe(Al) transitioncoatings on the performance of Al2O3 coating[J]. Fusion Engineering and Design, 2020, 160, 111835-111844.]. Laser evaporation technology can utilize high energy density to achieve evaporation coatings on various target materials (including electrically insulating materials), but when the power density input to the target exceeds a threshold, the target material undergoes explosive boiling, causing contamination of the light radiation input window glass and the shielding target surface [Mahmood MA, Bănică A, Ristoscu C, et al. Laser Coatings via State-of-the-Art AdditiveManufacturing: A Review[J]. Coatings, 2021, 11, 296-298.].

[0005] Therefore, although there are many methods and techniques for depositing electrically insulating coatings, none of them fully meet the requirements for efficient and high-quality deposition.

[0006] Compared to other methods, electron beam evaporation technology utilizes a high-energy electron beam to rapidly heat electrically insulating materials, enabling the deposition of electrically insulating coatings. It offers advantages such as high coating quality and high deposition rate. However, the non-conductivity of electrically insulating materials causes surface charge accumulation, affecting the efficiency and process stability of electron beam evaporation coatings [Yushkov Y, Oks EM, Tyunkov A, et al. Alumina coating deposition by electron-beam evaporation of ceramic using a forevacuum plasma-cathode electron source[J]. Ceram. Int.2019, 45: 9782–9787.].

[0007] Currently, based on the principle of plasma cathode electron emission, plasma cathode electron sources are obtained in the high-pressure range (pre-stage pressure), generating electron beams within a high-pressure range of 5 Pa to 100 Pa. This addresses the problem of charge accumulation during electron beam evaporation of electrically insulating materials to some extent [Yushkov YG, Oks EM, Oskomov K, et al. On the effect of ceramic target composition on coatings deposited by electron-beam evaporation at forevacuum pressure[J]. Ceram. Int., 2020, 46: 27641-27646.]. The reason is that under high pressure (pre-stage pressure), the electron beam collides with gas molecules during its high-speed movement to form beam plasma. The negative charges carried by the electron beam to the surface of the electrically insulating material are neutralized by the positive ions in the beam plasma, reducing the levitation potential of the electrically insulating material surface.

[0008] The Siberian Branch of the Russian Academy of Sciences [Zolotukhina DB, Oksa EM, Tyunkova AV, et al. Effect of a dielectric cavity on the ion etching of dielectrics by electron beam-produced plasma generated by a forevacuum plasma electronsource[J]. 2021, 192: 110483-110488.] utilized a plasma cathode electron beam (voltage 18-22 kV, beam current 20-30 mA, power density 500 W / mm²) 2 The generated plasma neutralizes the surface charge of electrically insulating materials, enabling direct electron beam treatment of non-conductive materials under pre-stage pressure.

[0009] Although the accumulation of charge can be reduced by forming a plasma beam, problems such as the accumulation of charge and the complexity of microstructure control still exist, limiting industrial applications [Yushkov Y, Oks EM, Tyunkov A, et al. Deposition of boron-containing coatings by electron-beam evaporation of boron-containing targets[J]. Ceram. Int., 2020, 46: 4519-4525.]. Therefore, solving the problem of charge accumulation and improving process stability during electron beam evaporation of electrically insulating coatings is of great significance. Summary of the Invention

[0010] To address the problem of insufficient plasma ion neutralization of negative charges during electron beam deposition of electrically insulating coatings due to low beam plasma density, this invention provides a charge-neutralizing plasma cathode electron beam deposition device for electrically insulating coatings. This invention incorporates a hollow cathode grid in the beam plasma transport region, utilizing the hollow cathode effect to enhance beam plasma density. This effectively neutralizes accumulated negative charges on the surface of the electrically insulating ceramic, preventing a reduction in electron beam energy reaching the ceramic surface and thus achieving a successful electrically insulating electron beam deposition process.

[0011] The technical solution adopted by this utility model to solve the above problems is as follows:

[0012] This utility model discloses a charge-neutralized plasma cathode electron beam evaporation device for electro-insulating coating. The utility model includes a hollow cathode 1, an anode 2, an accelerating electrode 3, a cathode water-cooled flange 4, an anode barrel 5, an arc discharge power supply 6, an electron accelerating power supply 7, an anode and cathode insulating flange 8, an accelerating electrode insulating flange 9, an electron beam 10, a grid 11, a plating material 12, a crucible 13, a grid power supply 14, a workpiece 15, a vacuum chamber 16, and a workpiece holder 17.

[0013] The plasma cathode electron source includes a hollow cathode 1, an anode 2, an accelerating electrode 3, a cathode water-cooled flange 4, an anode barrel 5, an arc discharge power supply 6, an electron accelerating power supply 7, an anode-cathode insulating flange 8, and an accelerating electrode insulating flange 9. The cathode water-cooled flange 4 cools the hollow cathode 1. The anode 2 is located inside the anode barrel 5 and is electrically connected. The hollow cathode 1 is detachably mounted on the cathode water-cooled flange 4. The cathode water-cooled flange 4 and the anode barrel 5 are vacuum-sealed together using the anode-cathode insulating flange 8. The anode barrel 5 and the accelerating electrode 3 are vacuum-sealed together using the accelerating electrode insulating flange 9. The accelerating electrode 3 is detachably vacuum-sealed and electrically connected to the vacuum chamber 16. The plasma cathode electron source is located on the upper part of the vacuum chamber 16, and a crucible is placed inside the grid 11. 13. The plating material 12 is located inside the crucible 13. The grid 11 and the crucible 13 are located at the bottom of the vacuum chamber 16. The grid 11 has an opening at the top. The workpiece holder 17 is located at the upper right of the vacuum chamber 16. The workpiece holder 17 is insulated from the vacuum chamber 16. The workpiece 15 is detachably mounted on the workpiece holder 17. The electron accelerating power supply 7 obtains an electron beam 10 with a certain energy to heat, melt, evaporate and deposit the plating material 12 onto the workpiece 15. The cathode and anode of the arc discharge power supply 6 are respectively connected to the hollow cathode 1 and the anode barrel 5. The cathode and anode of the electron accelerating power supply 7 are respectively connected to the anode barrel 5 and the accelerating electrode 3. The cathode and anode of the grid power supply 14 are respectively connected to the grid 11 and the vacuum chamber 16. The grid power supply 14 enhances the plasma density in the grid 11. The vacuum chamber 16 is grounded.

[0014] Furthermore, the aperture range of the upper part of the grid 11 is from 20 mm to the diameter of the grid 11, and the plating material 12 is SiO2, Al2O3, SiC, or HfO2.

[0015] The beneficial effects of this utility model are as follows: This utility model proposes a charge-neutralizing plasma electron beam welding device for insulating ceramics. It utilizes the hollow cathode effect to enhance the density of the beam plasma and sets a hollow cathode grid discharge in the transport region of the beam plasma to effectively neutralize the accumulated negative charge on the surface of the electrically insulating ceramic, avoid reducing the energy of the ceramic electron beam, and achieve the electrically insulating electron beam evaporation process well. It has a broader application prospect and meets the scientific research and industrial needs of electrically insulating ceramic coatings. Attached Figure Description

[0016] Figure 1This is a schematic diagram of the structure of this utility model.

[0017] The component names and labels involved in the diagram are as follows:

[0018] 1. Hollow cathode; 2. Anode; 3. Accelerating electrode; 4. Anode barrel; 5. Arc discharge power supply; 6. Electron accelerating power supply; 7. Anode and cathode insulating flange; 8. Accelerating electrode insulating flange; 9. Electron beam; 10. Grid; 11. Plating material; 12. Crucible; 13. Grid power supply; 14. Workpiece; 15. Vacuum chamber; 16. Workpiece holder; 17. Detailed Implementation

[0019] Specific implementation method one: Combining Figure 1 This embodiment describes a charge-neutralized plasma cathode electron beam evaporation electro-insulating coating device, comprising a hollow cathode 1, an anode 2, an accelerating electrode 3, a cathode water-cooled flange 4, an anode barrel 5, an arc discharge power supply 6, an electron accelerating power supply 7, an anode and cathode insulating flange 8, an accelerating electrode insulating flange 9, an electron beam 10, a grid 11, a coating material 12, a crucible 13, a grid power supply 14, a workpiece 15, a vacuum chamber 16, and a workpiece holder 17.

[0020] The plasma cathode electron source includes a hollow cathode 1, an anode 2, an accelerating electrode 3, a cathode water-cooled flange 4, an anode barrel 5, an arc discharge power supply 6, an electron accelerating power supply 7, an anode-cathode insulating flange 8, and an accelerating electrode insulating flange 9. The cathode water-cooled flange 4 cools the hollow cathode 1. The anode 2 is located inside the anode barrel 5 and is electrically connected. The hollow cathode 1 is detachably mounted on the cathode water-cooled flange 4. The cathode water-cooled flange 4 and the anode barrel 5 are vacuum-sealed together using the anode-cathode insulating flange 8. The anode barrel 5 and the accelerating electrode 3 are vacuum-sealed together using the accelerating electrode insulating flange 9. The accelerating electrode 3 is detachably vacuum-sealed and electrically connected to the vacuum chamber 16. The plasma cathode electron source is located on the upper part of the vacuum chamber 16, and a crucible is placed inside the grid 11. 13. The plating material 12 is located inside the crucible 13. The grid 11 and the crucible 13 are located at the bottom of the vacuum chamber 16. The grid 11 has an opening at the top. The workpiece holder 17 is located at the upper right of the vacuum chamber 16. The workpiece holder 17 is insulated from the vacuum chamber 16. The workpiece 15 is detachably mounted on the workpiece holder 17. The electron accelerating power supply 7 obtains an electron beam 10 with a certain energy to heat, melt, evaporate and deposit the plating material 12 onto the workpiece 15. The cathode and anode of the arc discharge power supply 6 are respectively connected to the hollow cathode 1 and the anode barrel 5. The cathode and anode of the electron accelerating power supply 7 are respectively connected to the anode barrel 5 and the accelerating electrode 3. The cathode and anode of the grid power supply 14 are respectively connected to the grid 11 and the vacuum chamber 16. The grid power supply 14 enhances the plasma density in the grid 11. The vacuum chamber 16 is grounded.

[0021] Specific Implementation Method Two: Combining Figure 1In this embodiment, the aperture range of the upper part of the grid 11 of the charge-neutralizing plasma cathode electron beam evaporation electro-insulating coating device is from 20 mm to the diameter of the grid 11, and the coating material 12 is SiO2, Al2O3, SiC, or HfO2. Other components and connections are the same as in specific embodiment one.

[0022] The working process of this utility model is as follows:

[0023] Step 1: Install and fix the plasma cathode electron source into the vacuum chamber 16, install and fix the workpiece 15, and install and fix the grid 11.

[0024] Step 2: Connect the arc discharge power supply 6, the electron acceleration power supply 7, and the grid power supply 14, and evacuate the vacuum.

[0025] Step 3: Start the arc discharge power supply 6, electron acceleration power supply 7, and grid power supply 14 to obtain the electron beam 10, adjust the process parameters, and realize thin film deposition.

[0026] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model's technical solution. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present utility model's technical solution, based on the technical essence of the present utility model and within the spirit and principles of the present utility model, shall still fall within the protection scope of the present utility model's technical solution.

Claims

1. A device for charge-neutralizing plasma cathode electron beam evaporation of an electrically insulating coating, characterized in that: The charge-neutralized plasma cathode electron beam evaporation electro-insulating coating device includes a hollow cathode (1), an anode (2), an accelerating electrode (3), a cathode water-cooled flange (4), an anode barrel (5), an arc discharge power supply (6), an electron accelerating power supply (7), an anode and cathode insulating flange (8), an accelerating electrode insulating flange (9), an electron beam (10), a grid (11), a coating material (12), a crucible (13), a grid power supply (14), a workpiece (15), a vacuum chamber (16), and a workpiece holder (17). The plasma cathode electron source includes a hollow cathode (1), an anode (2), an accelerating electrode (3), a cathode water-cooled flange (4), an anode barrel (5), an arc discharge power supply (6), an electron accelerating power supply (7), an anode and cathode insulating flange (8), and an accelerating electrode insulating flange (9). The cathode water-cooled flange (4) cools the hollow cathode (1). The anode (2) is located inside the anode barrel (5) and is electrically connected. The hollow cathode (1) is detachably mounted on the cathode water-cooled flange (4). The cathode water-cooled flange (4) and the anode barrel (5) are vacuum-sealed together using the anode and cathode insulating flange (8). The anode barrel (5) and the accelerating electrode (3) are vacuum-sealed together using the accelerating electrode insulating flange (9). The accelerating electrode (3) and the vacuum chamber (16) are detachably vacuum-sealed and electrically connected. The plasma cathode electron source is located on the upper part of the vacuum chamber (16). A crucible (13) is placed inside the grid (11). The plating material (12) is located inside the crucible (13). The grid (11) and the crucible (13) are located at the bottom of the vacuum chamber (16). The grid (11) has an opening at the top. The workpiece holder (17) is located at the upper right of the vacuum chamber (16). The workpiece holder (17) is insulated from the vacuum chamber (16). The workpiece (15) is detachably mounted on the workpiece holder (17). The electron accelerating power supply (7) obtains an electron beam (10) of a certain energy to heat, melt, evaporate and deposit the plating material (12) onto the workpiece (15). The cathode and anode of the arc discharge power supply (6) are connected to the hollow cathode (1) and the anode barrel (5) respectively. The cathode and anode of the electron accelerating power supply (7) are connected to the anode barrel (5) and the accelerating electrode (3) respectively. The cathode and anode of the grid power supply (14) are connected to the grid (11) and the vacuum chamber (16) respectively. The grid power supply (14) enhances the plasma density in the grid (11). The vacuum chamber (16) is grounded.

2. The plasma cathode electron beam evaporation device for charge neutralization of an electrically insulating coating according to claim 1, characterized in that... The aperture range of the upper part of the grid (11) is from 20 mm to the diameter of the grid (11), and the plating material (12) is SiO2, Al2O3, SiC, HfO2.

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