A cascade sheet interlayer structure and a preparation method thereof

Abstract

The application relates to the technical field of plasma, and discloses a cascade sheet interlayer structure and a preparation method thereof. The cascade sheet interlayer structure comprises a cascade assembly and a sealing ring. A transition layer is coated on the upper surface of a first cascade sheet, and an insulating layer is further coated on the transition layer, so that a coating layer covering the first cascade sheet is formed, and the insulation between the first cascade sheet and a second cascade sheet is realized by the insulating layer. Compared with a hard insulating sheet, the surfaces of the first cascade sheet, the transition layer and the insulating layer connected in sequence form a closely-adhered microstructure, so that the thermal resistance between the insulating layer and the first cascade sheet is small, and the heat transfer effect between the cascade sheets is improved. When the second cascade sheet is pressed to adhere to the insulating layer and cooperate with the first cascade sheet, the compression force borne by the insulating layer can be dispersed into the first cascade sheet, and the insulating layer is not easy to be crushed. The upper and lower end surfaces of the sealing ring are respectively adhered to the second cascade sheet and the first cascade sheet and tightly abut against each other, so as to realize the interlayer sealing of the cascade sheets.

Description

Technical Field

[0001] This invention relates to the field of plasma technology, and in particular to a cascaded interlayer structure and its preparation method. Background Technology

[0002] Cascaded arc plasma sources are the core components of linear plasma devices for generating high-density plasma beams. In a cascaded arc plasma generator, multiple cascaded plates are stacked sequentially to form a cascaded structure, positioned between the cathode holder and the anode body; a discharge channel is opened in the middle of the cascaded plates to allow plasma to pass through. As a key core component of the cascaded arc plasma source, the cascaded plates primarily perform the important functions of confining the plasma beam, stabilizing the arc discharge, and promptly removing the heat load deposited within the plasma discharge channel. Insulation is required between the cascaded plate layers to maintain a large potential difference; furthermore, a sealed design is necessary between the cascaded plate layers to maintain a low-pressure environment within the discharge channel.

[0003] Chinese patent application CN104772305A discloses a device for cleaning the first mirror of a tokamak using a DC cascaded arc plasma torch. The cascaded arc plasma torch generation system includes a cascaded source. The cascaded source comprises a cylindrical cathode, a cathode holder, an annular anode, and cascaded plate units, with the cascaded plate units positioned between the cylindrical cathode and the annular anode. Each cascaded plate unit includes multiple parallel cascaded plates, each with a small hole at its center forming a discharge channel. A polytetrafluoroethylene (PTFE) sheet, an O-ring, and a boron nitride (PTFE) sheet are positioned between adjacent cascaded plates. Along the radial direction of the cascaded plates, from the inside out, are the PTFE sheet, the O-ring, and the PTFE sheet. The boron nitride sheet directly faces the discharge channel, providing insulation, high-temperature resistance, and resistance to plasma ablation. The O-ring is embedded between the boron nitride sheet and the PTFE sheet for sealing. The PTFE sheet is located on the outermost side and provides a large area of ​​insulation.

[0004] Because the temperature in the discharge channel is high, and the O-ring is located between the boron nitride sheet and the PTFE sheet, its proximity to the discharge channel makes it susceptible to heat transfer to the O-ring, causing it to deform due to the high temperature and ultimately leading to seal failure. If the O-ring is placed on the outermost side to keep it away from the discharge channel, the boron nitride and PTFE sheets are directly compressed by the two cascaded sheets when they are pressed together, lacking the buffer of the intermediate O-ring. The hard boron nitride sheet is easily crushed. Furthermore, the boron nitride and PTFE sheets are difficult to fill the surface gaps when bonded to the cascaded sheets, resulting in a small actual contact area and high interlayer thermal resistance, which reduces the overall heat transfer performance of the cascaded arc plasma source. Summary of the Invention

[0005] The purpose of this invention is to provide a cascaded interlayer structure and its preparation method to solve the problems of easy sealing failure and high interlayer contact thermal resistance in existing cascaded layers.

[0006] To achieve the above objectives, the present invention provides a cascaded interlayer structure, which includes cascaded components and sealing rings; The cascaded assembly includes at least two cascaded plates, with the lower cascaded plate defined as the first cascaded plate and the upper cascaded plate as the second cascaded plate. The first cascaded plate has a first discharge channel penetrating its upper and lower surfaces. The outer peripheral surface of the first cascaded plate has a first sealing groove, which surrounds the first discharge channel and penetrates the upper surface of the first cascaded plate. The second cascaded plate has a second discharge channel penetrating its upper and lower surfaces. The outer peripheral surface of the second cascaded plate has a second sealing groove, which surrounds the second discharge channel and penetrates the lower surface of the second cascaded plate. The upper surface of the first cascade is coated with a transition layer, and the upper surface of the transition layer is coated with an insulating layer; both the transition layer and the insulating layer are arranged around the first discharge channel, and the distance between the inner edge of the insulating layer and the outer edge of the first discharge channel is L1, where L1 > 10 mm; the insulating layer is used to achieve insulation between the first cascade and the second cascade; the lower surface of the second cascade is attached to the insulating layer; The first sealing groove and the second sealing groove together form an installation groove; the sealing ring is disposed in the installation groove, and its upper and lower sides respectively abut against the second cascade piece and the first cascade piece.

[0007] Furthermore, the first cascaded chip has a first cooling cavity for the flow of cooling medium, and the first cooling cavity is arranged around the first discharge channel; The second cascaded chip has a second cooling cavity for the flow of cooling medium, and the second cooling cavity is arranged around the second discharge channel; The outer edges of the first cooling cavity, the second cooling cavity, and the insulating layer are all flush with each other.

[0008] Furthermore, a spraying groove is formed on the upper surface of the first cascaded sheet; The spraying tank is arranged around the first discharge channel and is isolated from the first discharge channel and the first sealing tank, respectively. The transition layer is applied in the spray tank; the upper surface of the transition layer is flush with the upper surface of the first cascaded sheet.

[0009] Furthermore, in the radial direction of the first cascade, the inner and outer surfaces of the insulating layer are flush with the inner and outer surfaces of the transition layer.

[0010] Furthermore, the thickness of the insulating layer is greater than the thickness of the transition layer.

[0011] The present invention also provides a method for preparing a cascaded interlayer structure, which includes the following steps: S1. Prepare two cascade substrates. In one cascade substrate, process a first discharge channel that penetrates its upper and lower surfaces and process a first sealing groove on its outer peripheral surface. In the other cascade substrate, process a second discharge channel that penetrates its upper and lower surfaces and process a second sealing groove on its outer peripheral surface to form the second cascade. S2. Spray a transition material onto the upper surface of the cascade substrate with the first sealing groove to form a transition layer on the cascade substrate; S3. Spray insulating material onto the upper surface of the transition layer to form an insulating layer on the upper surface of the transition layer, thus forming the first cascaded sheet; S4. Detect the porosity and surface roughness of the insulating layer and determine whether they meet the standards; S5. Align and press the second cascade plate and the first cascade plate together; embed the sealing ring into the mounting groove; thus obtaining the cascade plate interlayer structure. S6. Perform vacuum negative pressure leak detection test and electrical breakdown insulation performance test on the cascaded interlayer structure in sequence; S7. Perform high-temperature fatigue testing on the first cascaded wafer.

[0012] Further, step S2 involves spraying a transition material onto the upper surface of the cascade substrate with the first sealing groove to form a transition layer on the cascade substrate, specifically including: S21. A spraying groove is machined on the upper surface of the cascaded substrate with the first sealing groove, wherein the spraying groove is not connected to the first sealing groove or the discharge channel of the cascaded substrate. S22. The inner wall of the spraying tank is sandblasted. S23. Spray transition material into the spray tank until the spray tank is filled to form the transition layer; The transition material is a nickel-chromium alloy.

[0013] Further, step S3 involves spraying an insulating material onto the upper surface of the transition layer to form an insulating layer on the upper surface of the transition layer; the fabrication of the first cascaded sheet specifically includes: S31. Spray insulating material onto the upper surface of the transition layer to form an insulating layer; and the thickness of the insulating layer is greater than the thickness of the transition layer. The insulating material is either aluminum oxide or boron nitride. S32. Perform metallographic polishing on the insulating layer to form the first cascade.

[0014] Further, step S4 involves detecting the porosity and surface roughness of the insulating layer and determining whether they meet the standards, specifically including: S41. The cross-sectional morphology of the insulating layer is observed using a metallographic microscope, and the porosity of the insulating layer is tested to see if it is ≤3%. If the porosity is ≤3%, the porosity is qualified; if the porosity is >3%, the porosity is unqualified. S42. Use a roughness measuring instrument to detect the surface roughness of the insulating layer and determine whether the surface roughness is ≤0.01; if the surface roughness is ≤0.01, the surface roughness is qualified; if the surface roughness is >0.01, the surface roughness is unqualified.

[0015] Furthermore, it also includes the following steps: S8. Repeat steps S4-S6 above, and compare the results of porosity, surface roughness, vacuum negative pressure leak detection test and electrical breakdown insulation performance test with the results of each item before step S7.

[0016] The cascaded interlayer structure and its preparation method provided by this invention have the following advantages compared with the prior art: This invention provides a cascaded interlayer structure, comprising a cascaded assembly and a sealing ring. A transition layer is coated on the upper surface of the first cascaded piece, and an insulating layer is then coated on the upper surface of the transition layer. The insulating layer surrounding the first discharge channel provides insulation between the first and second cascaded pieces. The transition layer is coated on the upper surface of the first cascaded piece, and the insulating layer is then coated on the transition layer, thereby forming a coating covering the first cascaded piece. Compared to a rigid insulating sheet, the surfaces of the first cascaded piece, the transition layer, and the insulating layer are sequentially connected, forming a tightly fitted microstructure. This results in lower thermal resistance between the insulating layer and the first cascaded piece, improving heat transfer between the first and second cascaded pieces. Furthermore, when the second cascaded piece is pressed down to adhere to the insulating layer and engage with the first cascaded piece, the compressive force on the insulating layer is dispersed into the first cascaded piece, reducing the risk of crushing. The sealing ring can then be placed in an mounting groove formed by the first and second sealing grooves, achieving interlayer sealing through contact with the second and first cascaded pieces on its upper and lower sides. In addition, there is a distance L1 between the inner edge of the insulating layer and the outer edge of the first discharge channel, where L1 > 10 mm, which can prevent the insulating layer from facing the plasma directly and reduce the possibility of it being ablated.

[0017] This invention provides a method for preparing a cascaded interlayer structure. The method involves sequentially machining a first discharge channel and a first sealing groove on a cascaded substrate, spraying a transition material onto the substrate to form a transition layer, and spraying an insulating material on top of the transition layer to form an insulating layer, thereby producing a first cascaded sheet. A second cascaded sheet is then prepared by machining a second discharge channel and a second sealing groove on another cascaded substrate. The second and first cascaded sheets are then aligned and pressed together. A sealing ring is embedded in an mounting groove to obtain the cascaded interlayer structure. The cascaded interlayer structure is subjected to vacuum negative pressure leak detection and electrical breakdown insulation performance tests, and the first cascaded sheet with the transition and insulating layers is subjected to high-temperature fatigue testing to assess the adhesion stability of the transition and insulating layers. This allows for the external testing of the sealing and insulation properties of the cascaded interlayer structure using a linear plasma device. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of the cascaded interlayer structure according to an embodiment of the present invention; Figure 2 yes Figure 1 Enlarged view of region A in the middle; Figure 3 This is a three-dimensional structural diagram of the cascaded interlayer structure according to an embodiment of the present invention; Figure 4 This is a top view schematic diagram of the first cascaded sheet according to an embodiment of the present invention.

[0019] In the diagram, 100 is the interlayer structure of the cascaded plates; 1 is the cascaded assembly; 10 is the mounting groove; 11 is the first cascaded plate; 110 is the first discharge channel; 1101 is the first sealing groove; 1102 is the spraying groove; 1103 is the first cooling chamber; 1104 is the first water inlet; 1105 is the first water outlet; 111 is the transition layer; 112 is the insulating layer; 113 is the first fixing ear; 12 is the second cascaded plate; 120 is the second discharge channel; 1201 is the second sealing groove; 121 is the second fixing ear; 1202 is the second cooling chamber; 1203 is the second water inlet; 1204 is the second water outlet; and 2 is the sealing ring. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] It should be noted that existing technologies use boron nitride sheets, O-rings, and PTFE sheets arranged sequentially from the inside to the outside along the radial direction of the cascaded sheets to achieve insulation and sealing between adjacent cascaded sheets. Microscopic gaps exist between the surfaces of the cascaded sheets, boron nitride sheets, O-rings, and PTFE sheets, determined by their respective surface roughness, and no object surface can be perfectly flat. While O-rings have deformation capabilities, they can undergo plastic deformation when pressed between adjacent cascaded sheets, filling the microscopic gaps and increasing the actual contact area to improve heat transfer; however, boron nitride sheets are hard materials and are easily crushed. When boron nitride sheets and PTFE sheets are bonded to the cascaded sheets, it is difficult to fill the surface gaps, resulting in a small actual contact area, high interlayer contact thermal resistance, and reduced overall heat transfer performance of the cascaded arc plasma source.

[0022] However, the O-ring is positioned between the boron nitride and PTFE sheets, relatively close to the discharge channel. The cascaded sheets on both sides of the O-ring experience high temperatures, making them prone to deformation due to high temperatures, leading to interlayer seal failure. Conversely, placing the O-ring directly on the outside of the PTFE sheet, while reducing high-temperature deformation by being further away from the discharge channel, still results in the boron nitride and PTFE sheets being directly compressed by the two cascaded sheets during compression. Without the buffer of the intermediate O-ring, the rigid boron nitride and PTFE sheets are easily crushed.

[0023] like Figure 1 , Figure 2 and Figure 4 As shown, a cascaded interlayer structure 100 according to an embodiment of the present invention includes a cascaded assembly 1 and a sealing ring 2; The cascaded assembly 1 includes at least two cascaded plates, with the lower cascaded plate defined as the first cascaded plate 11 and the upper cascaded plate as the second cascaded plate 12. The first cascaded plate 11 has a first discharge channel 110 penetrating its upper and lower surfaces. The outer peripheral surface of the first cascaded plate 11 has a first sealing groove 1101, which surrounds the first discharge channel 110 and penetrates the upper surface of the first cascaded plate 11. The second cascaded plate 12 has a second discharge channel 120 penetrating its upper and lower surfaces. The outer peripheral surface of the second cascaded plate 12 has a second sealing groove 1201, which surrounds the second discharge channel 120 and penetrates the lower surface of the second cascaded plate 12. The upper surface of the first cascade 11 is coated with a transition layer 111, and the upper surface of the transition layer 111 is coated with an insulating layer 112; both the transition layer 111 and the insulating layer 112 are arranged around the first discharge channel 110; and the distance between the inner edge of the insulating layer 112 and the outer edge of the first discharge channel 110 is L1, where L1 > 10 mm; the insulating layer is used to achieve insulation between the first cascade 11 and the second cascade 12; the lower surface of the second cascade 12 is attached to the insulating layer 112; The first sealing groove 1101 and the second sealing groove 1201 enclose each other to form an installation groove 10; the sealing ring 2 is disposed in the installation groove 10, and its upper and lower sides respectively abut against the second cascade piece 12 and the first cascade piece 11.

[0024] Based on the above technical solution, by coating a transition layer 111 on the upper surface of the first cascade 11, and then coating an insulating layer 112 on the upper surface of the transition layer 111, the insulating layer 112 surrounding the first discharge channel 110 achieves insulation between the first cascade 11 and the second cascade 12. The transition layer 111 is coated on the upper surface of the first cascade 11, and the insulating layer 112 is then coated on the transition layer 111, thereby forming a coating covering the first cascade 11. Compared to a rigid insulating sheet, the surfaces of the first cascade 11, the transition layer 111, and the insulating layer 112, which are sequentially connected, form a tight seal. The close-fitting microstructure results in a low thermal resistance between the insulating layer 112 and the first-stage plate 11, which improves the heat transfer effect between the first-stage plate 11 and the second-stage plate 12. When the second-stage plate 12 is pressed down to fit the insulating layer 112 and cooperates with the first-stage plate 11, the compressive force on the insulating layer 112 can be dispersed into the first-stage plate 11, making it less likely to be crushed. Thus, the sealing ring 2 can be placed in the mounting groove 10 formed by the first sealing groove 1101 and the second sealing groove 1201, and the interlayer seal is achieved by the contact between the upper and lower sides of the sealing ring 2 and the second-stage plate 12 and the first-stage plate 11.

[0025] In addition, there is a distance L1 between the inner edge of the insulating layer 112 and the outer edge of the first discharge channel 110, where L1 > 10 mm, which can prevent the insulating layer 112 from facing the plasma directly and reduce the possibility of it being ablated.

[0026] Specifically, 10mm < L1 < 20mm, so that the insulating layer 112 can avoid direct contact with the plasma while having sufficient radial dimensions to ensure that the insulating layer 112 can achieve interlayer insulation and heat transfer between the first cascade 11 and the second cascade 12.

[0027] Preferably, such as Figure 3 and Figure 4As shown, the outer peripheral surface of the first cascade plate 11 is fixed with a first fixing lug 113, and a plurality of first fixing lugs 113 are spaced apart circumferentially thereon; the outer peripheral surface of the second cascade plate 12 is fixed with a number of second fixing lugs 121 equal to the number of first fixing lugs 113, and a plurality of second fixing lugs 121 are spaced apart circumferentially thereon. Bolts are passed sequentially through the first fixing lugs 113 and the second fixing lugs 121 and then tightened with nuts to achieve a compression fit between the cascade plates. Specifically, for ease of machining and positioning, the plurality of first fixing lugs 113 are distributed at 90° intervals.

[0028] Preferably, such as Figure 1 and Figure 2 As shown, the first cascade plate 11 has a first cooling chamber 1103 for the flow of cooling medium, and the first cooling chamber 1103 is arranged around the first discharge channel 110. The first cooling chamber 1103 penetrates the outer peripheral surfaces of the two opposite sides of the first cascade plate 11 and forms a first inlet 1104 and a first outlet 1105 respectively. Thus, the cooling medium can enter the first cooling chamber 1103 through the first inlet 1104, cool and exchange heat with the peripheral wall of the first discharge channel 110 and the first cascade plate 11, and then flow out from the first outlet 1105.

[0029] The second cascade plate 12 has a second cooling chamber 1202 for the flow of cooling medium. The second cooling chamber 1202 is arranged around the second discharge channel 120. The second cooling chamber 1202 penetrates the outer peripheral surfaces of the two opposite sides of the second cascade plate 12 and forms a second water inlet 1203 and a second water outlet 1204, respectively, so that the peripheral wall of the second discharge channel 120 and the second cascade plate 12 can be cooled by the cooling medium.

[0030] The outer edges of the first cooling cavity 1103, the outer edges of the second cooling cavity 1202, and the insulating layer 112 are flush with each other.

[0031] It is understandable that the temperature gradually decreases from the inside to the outside along the radial direction of the first cascade 11. Therefore, the heat transfer path is from the inside to the outside. Since the insulating layer 112 not only provides insulation but also undertakes interlayer heat transfer, the heat in the area corresponding to the first cascade 11 directly below it and the heat in the area corresponding to the second cascade 12 directly above it will be transferred to the insulating layer 112. The heat of the insulating layer 112 will also be transferred from its outer edge to its outer periphery. In order to reduce the temperature in the area near the outer edge of the insulating layer 112, the outer edges of the first cooling cavity 1103, the second cooling cavity 1202, and the insulating layer 112 are made to be flush with each other. This ensures that the temperature of the first cascade 11 and the second cascade 12 corresponding to the outer edge of the insulating layer 112 is low, and avoids the insulating layer 112 transferring a large amount of heat to its outer periphery, which would cause the sealing ring 2 to be affected by high temperature.

[0032] Furthermore, such as Figure 1 and Figure 2 As shown, a spraying groove 1102 is formed on the upper surface of the first cascade plate 11; The spraying groove 1102 is arranged around the first discharge channel 110 and is isolated from the first discharge channel 110 and the first sealing groove 1101 respectively. The transition layer 111 is coated in the spray tank 1102; the upper surface of the transition layer 111 is flush with the upper surface of the first cascade sheet 11.

[0033] It is understood that by opening the spraying groove 1102 on the upper surface of the first cascade 11 to define the coating area of ​​the transition layer 111, it is convenient to coat the transition layer 111; and the spraying groove 1102 is arranged around the first discharge channel 110 and is isolated from the first discharge channel 110 and the first sealing groove 1101 respectively, so that the transition layer 111 coated in the spraying groove 1102 and the insulating layer 112 that needs to be connected to the first cascade 111 are both at a certain distance from the first discharge channel 110, thereby reducing the ablation effect of plasma in the first discharge channel 110 on the transition layer 111.

[0034] By making the upper surface of the transition layer 111 flush with the upper surface of the first cascade 11, it is easy to determine whether the transition layer 111 has been sprayed to a sufficient thickness by checking whether the spraying groove 1102 is filled when applying the transition layer 111.

[0035] Specifically, the spraying groove 1102 is annular and coaxially arranged with the first discharge channel 110. Its inner wall diameter is greater than 40 mm and its outer wall diameter is less than 80 mm, and its depth is 0.1 mm to 0.2 mm.

[0036] Specifically, the transition layer 111 is made of nickel-chromium alloy and has a coating thickness of 100 μm.

[0037] Furthermore, such as Figure 1 and Figure 2 As shown, in the radial direction of the first cascade 11, the inner and outer surfaces of the insulating layer 112 are flush with the inner and outer surfaces of the transition layer 111.

[0038] It is understood that by making the inner and outer surfaces of the insulating layer 112 flush with the inner and outer surfaces of the transition layer 111, the effect of the insulating layer 112 adhering to the first cascade 11 can be ensured, and the possibility of contact between the second cascade 12 and the transition layer 111 due to insufficient coating of the insulating layer 112 can be avoided.

[0039] Furthermore, since the transition layer 111 is sprayed into the spraying tank 1102, and the spraying tank 1102 is isolated from the first discharge channel 110 and the first sealing tank 1101 respectively, the inner edge of the insulating layer 112 has a distance L1 between it and the outer edge of the first discharge channel 110, while... (See also...) Figure 4 The outer edge of the insulating layer 112 is spaced from the inner edge of the first sealing groove 1101, thereby preventing the insulating layer 112 from directly contacting the sealing ring 2. This prevents the heat in the insulating layer 112 from being rapidly transferred to the outer periphery of the sealing ring 2, which could lead to the sealing ring 2 deforming due to high temperature and causing sealing failure.

[0040] Furthermore, such as Figure 1 and Figure 2 As shown, the thickness of the insulating layer 112 is greater than the thickness of the transition layer 111.

[0041] It is understandable that, since the insulating layer 112 is used for insulation, it must be relatively thick to ensure that the first cascade 11 and the second cascade 12 do not come into direct contact, and the insulating layer 112 needs to have sufficient thickness to achieve an effective insulating effect.

[0042] Specifically, the coating thickness of the transition layer 111 is 100 μm; the coating thickness of the insulating layer 112 is 200 μm.

[0043] Furthermore, such as Figure 1 and Figure 2 As shown, the upper surface of the transition layer 111 is flush with the upper plane of the first cascaded sheet 11.

[0044] It is understandable that the thickness of the transition layer 111 can be determined by spraying it until the spray tank 1102 is filled.

[0045] It should be noted that if the sealing and insulation performance of the cascaded interlayer structure is insufficient, it may easily damage the linear plasma device due to problems such as vacuum leakage and discharge breakdown after being installed on it. Therefore, the cascaded interlayer structure cannot be directly installed on the linear plasma device for testing and evaluating its sealing and insulation performance.

[0046] Furthermore, since existing technologies typically place ceramic sheets and sealing rings between conventional cascaded sheets to achieve sealing and insulation, there is a lack of processes for preparing the aforementioned cascaded interlayer structure 100 and testing the sealing and insulation performance of the cascaded interlayer structure 100 outside the linear plasma device.

[0047] In view of this, embodiments of the present invention also provide a method for preparing a cascaded interlayer structure, used to prepare the above-mentioned cascaded interlayer structure 100, which includes the following steps: S1. Prepare two cascade substrates. In one cascade substrate, process a first discharge channel 110 that penetrates its upper and lower surfaces and process a first sealing groove 1101 on its outer peripheral surface. In the other cascade substrate, process a second discharge channel 120 that penetrates its upper and lower surfaces and process a second sealing groove 1201 on its outer peripheral surface to form the second cascade 12. S2. Spray a transition material onto the upper surface of the cascade substrate with the first sealing groove 1101 to form a transition layer 111 on the cascade substrate; S3. Spray insulating material onto the upper surface of transition layer 111 to form insulating layer 112 on the upper surface of transition layer; thus forming the first cascade 11. S4. Detect the porosity and surface roughness of the insulating layer 112, and determine whether they meet the standards; S5. Align and press the second cascade plate 12 and the first cascade plate 11 together; embed the sealing ring 2 into the mounting groove 10; thus obtaining the cascade plate interlayer structure 100. S6. Vacuum negative pressure leak detection test and electrical breakdown insulation performance test are performed sequentially on the cascaded interlayer structure 100. S7. Conduct high-temperature fatigue testing on the first-stage connecting piece 11.

[0048] Based on the above scheme, the first cascade 11 is obtained by sequentially processing a first discharge channel 110 and a first sealing groove 1101 on a cascade substrate, spraying a transition material on the cascade substrate to form a transition layer 111, and spraying an insulating material on the transition layer to form an insulating layer 112; the second cascade 12 is obtained by processing a second discharge channel 120 and a second sealing groove 1201 on another cascade substrate; the second cascade 12 and the first cascade 11 are then aligned and pressed together; and the sealing ring 2 is embedded in the mounting groove 10; thus, the cascade interlayer structure 100 is obtained. By sequentially performing vacuum negative pressure leak detection and electrical breakdown insulation performance tests on the cascade interlayer structure 100, and separately conducting high-temperature fatigue tests on the first cascade 11 with transition layer 111 and insulation layer 112 to test the adhesion stability of transition layer 111 and insulation layer 112, the sealing and insulation performance of the cascade interlayer structure 100 can be tested outside the linear plasma device.

[0049] Further, step S2 involves spraying a transition material onto the upper surface of the cascade substrate with the first sealing groove to form a transition layer on the cascade substrate, specifically including: S21. A spraying groove 1102 is machined on the upper surface of the cascade substrate with the first sealing groove 1101. The spraying groove 1102 is not connected to the first sealing groove 1101 or the discharge channel of the cascade substrate. S22. The inner wall of the spraying tank 1102 is sandblasted and sanded. S23. Spray transition material into the spray tank 1102 until the spray tank 1102 is filled to form the transition layer 111; The transition material is a nickel-chromium alloy.

[0050] It should be noted that since the common insulating layer 112 spraying material is aluminum oxide or boron nitride, which has a large difference in thermal expansion coefficient with the cascade substrate, direct spraying is prone to coating peeling under high temperature conditions; therefore, it is necessary to spray nickel-chromium alloy as a transition layer 111 to buffer thermal expansion stress and improve the interfacial adhesion between the substrate and the insulating layer 112.

[0051] It is understandable that the inner wall of the spray tank 1102 is sandblasted and sanded to improve the surface roughness of the substrate and ensure the adhesion between the subsequent sprayed transition material and the cascade substrate.

[0052] Specifically, the nickel-chromium alloy is sprayed using a plasma thermal spraying process, with a coating thickness of 100 μm.

[0053] Further, step S3 involves spraying an insulating material onto the upper surface of the transition layer 111 to form an insulating layer 112 on the upper surface of the transition layer; the fabrication of the first cascade 11 specifically includes: S31. Spray insulating material onto the upper surface of the transition layer 111 to form an insulating layer 112; and the thickness of the insulating layer 112 is greater than the thickness of the transition layer 111. The insulating material is either aluminum oxide or boron nitride. S32. Perform metallographic polishing on the insulating layer 112 to form the first cascade 11.

[0054] Understandably, aluminum oxide or boron nitride is sprayed onto the upper surface of the transition layer 111 to form an insulating layer 112, providing a reliable insulating barrier between the cascaded layers. Metallographic polishing ensures a smooth upper surface for the insulating layer 112, preventing damage to the cascaded layers.

[0055] Specifically, aluminum oxide or boron nitride is coated onto the transition layer 111 by a plasma thermal spraying process, with a coating thickness of 300 μm; the aluminum oxide or boron nitride layer is thinned to 200 μm by metallographic polishing, and its surface roughness is controlled to 0.01 or below.

[0056] Further, step S4 involves detecting the porosity and surface roughness of the insulating layer 112 and determining whether they meet the standards, specifically including: S41. The cross-sectional morphology of the insulating layer 112 is observed using a metallographic microscope, and the porosity of the insulating layer 112 is checked to see if it is ≤3%. If the porosity is ≤3%, the porosity is qualified; if the porosity is >3%, the porosity is unqualified. S42. Use a roughness measuring instrument to detect the surface roughness of the insulating layer 112 and determine whether the surface roughness is ≤0.01; if the surface roughness is ≤0.01, the surface roughness is qualified; if the surface roughness is >0.01, the surface roughness is unqualified.

[0057] It is understandable that by detecting porosity and surface roughness, the insulation layer 112 is ensured to be sufficiently dense, thereby ensuring the insulation effect between the first cascade 11 and the second cascade 12. Furthermore, by using a smooth plane with low surface roughness, the actual contact area between the insulation layer 112 and the second cascade 12 is increased, thereby reducing interlayer thermal resistance and improving heat transfer.

[0058] Preferably, a high-resolution scanning electron microscope (SEM) can also be used to characterize the surface microstructure of the insulating layer 112.

[0059] Furthermore, it also includes the following steps: S8. Repeat steps S4-S6 above, and compare the results of porosity, surface roughness, vacuum negative pressure leak detection test and electrical breakdown insulation performance test with the results of each item before step S7.

[0060] It is understandable that by repeating the above steps S4-S6, the results of porosity, surface roughness, vacuum negative pressure leak detection test, and electrical breakdown insulation performance test can be obtained. By comparing the results of porosity, surface roughness, vacuum negative pressure leak detection test, and electrical breakdown insulation performance test with the structure before repeating steps S4-S6, the degree of degradation of various properties after high-temperature fatigue can be evaluated, thereby assessing the long-term operational reliability of the insulation and sealing of the cascade interlayer structure.

[0061] Specifically, step S8 can be performed multiple times.

[0062] Preferably, step S6, which sequentially performs vacuum negative pressure leak detection and electrical breakdown insulation performance testing on the cascaded interlayer structure 100, specifically includes the following steps: S61. Perform a vacuum negative pressure leak test to verify whether the overall vacuum degree of the cascaded interlayer structure 100 is ≤1×10⁻⁶. -9 Pa; S62. Apply voltages of 50V, 100V, 200V, 300V, 400V, 500V, 600V, 700V, 800V, 900V, and 1000V sequentially to the cascaded interlayer structure 100 and conduct electrical breakdown insulation performance tests step by step. Preferably, step S7, which involves conducting a high-temperature fatigue test on the first cascaded wafer 11, specifically includes: The first cascade 11 was placed in a heat treatment furnace and high-temperature fatigue tests were carried out sequentially at 300℃ for 8 hours, 500℃ for 8 hours, and 700℃ for 8 hours to assess the interfacial adhesion stability of the transition layer 111, the insulating layer 112 and the first cascade 11 under high-temperature conditions.

[0063] The working process of this invention is as follows: Insulation between the first cascade 11 and the second cascade 12 is achieved through the insulating layer 112. As a coating, the insulating layer 112 has lower interlayer contact thermal resistance compared to existing insulating ceramic sheets. Furthermore, the insulating layer 112 maintains a certain distance from both the first discharge channel 110 and the second discharge channel 120, reducing the erosive effect of plasma on the insulating layer 112 and the transition layer 111. The mounting groove 10 is formed by the first sealing groove 1101 on the outer periphery of the first cascade 11 and the second sealing groove 1201 on the outer periphery of the second cascade 12. The sealing ring 2 is compressed and placed within the mounting groove 10. This achieves interlayer sealing between the first cascade 11 and the second cascade 12 while reducing the possibility of deformation and erosion due to the sealing ring 2's distance from the first discharge channel 110 and the second discharge channel 120.

[0064] In summary, the cascaded interlayer structure 100 provided by this embodiment of the invention includes a cascaded assembly 1 and a sealing ring 2. A transition layer 111 is coated on the upper surface of the first cascaded piece 11, and then an insulating layer 112 is coated on the upper surface of the transition layer 111. The insulating layer 112, which surrounds the first discharge channel 110, achieves insulation between the first cascaded piece 11 and the second cascaded piece 12. The transition layer 111 is coated on the upper surface of the first cascaded piece 11, and the insulating layer 112 is coated on the transition layer 111, thereby forming a coating covering the first cascaded piece 11. Compared to a rigid insulating sheet, the first cascaded piece 11, the transition layer 111, and the insulating layer 112 provide a more robust and efficient insulation solution. The interconnected surfaces of the 12 layers form a tightly fitted microstructure, resulting in low thermal resistance between the insulating layer 112 and the first-stage plate 11, thus improving heat transfer between the first-stage plate 11 and the second-stage plate 12. Furthermore, when the second-stage plate 12 is pressed down to adhere to the insulating layer 112 and engages with the first-stage plate 11, the compressive force on the insulating layer 112 is dispersed into the first-stage plate 11, reducing the risk of crushing. Therefore, the sealing ring 2 can be placed in the mounting groove 10 formed by the first sealing groove 1101 and the second sealing groove 1201, achieving interlayer sealing through contact between its upper and lower sides and the second-stage plate 12 and the first-stage plate 11. Additionally, the inner edge of the insulating layer 112 is spaced L1, where L1 > 10 mm, between the inner edge and the outer edge of the first discharge channel 110, preventing the insulating layer 112 from directly facing the plasma and reducing the possibility of ablation.

[0065] This invention provides a method for preparing a cascaded interlayer structure, used to prepare the aforementioned cascaded interlayer structure 100. The method involves sequentially machining a first discharge channel 110 and a first sealing groove 1101 on a cascaded substrate, spraying a transition material onto the cascaded substrate to form a transition layer 111, and spraying an insulating material over the transition layer to form an insulating layer 112, thereby obtaining a first cascaded sheet 11. A second cascaded sheet 12 is then prepared by machining a second discharge channel 120 and a second sealing groove 1201 on another cascaded substrate. The second cascaded sheet 12 and the first cascaded sheet 11 are then aligned and pressed together. A sealing ring 2 is embedded in an mounting groove 10 to obtain the cascaded interlayer structure 100. By sequentially performing vacuum negative pressure leak detection and electrical breakdown insulation performance tests on the cascade interlayer structure 100, and separately conducting high-temperature fatigue tests on the first cascade 11 with transition layer 111 and insulation layer 112 to test the adhesion stability of transition layer 111 and insulation layer 112, the sealing and insulation performance of the cascade interlayer structure 100 can be tested outside the linear plasma device.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A cascaded interlayer structure, characterized in that, Includes cascaded components and seals; The cascaded assembly includes at least two cascaded plates, with the lower cascaded plate defined as the first cascaded plate and the upper cascaded plate as the second cascaded plate. The first cascaded plate has a first discharge channel penetrating its upper and lower surfaces. The outer peripheral surface of the first cascaded plate has a first sealing groove, which surrounds the first discharge channel and penetrates the upper surface of the first cascaded plate. The second cascaded plate has a second discharge channel penetrating its upper and lower surfaces. The outer peripheral surface of the second cascaded plate has a second sealing groove, which surrounds the second discharge channel and penetrates the lower surface of the second cascaded plate. The upper surface of the first cascade is coated with a transition layer, and the upper surface of the transition layer is coated with an insulating layer; both the transition layer and the insulating layer are arranged around the first discharge channel, and the distance between the inner edge of the insulating layer and the outer edge of the first discharge channel is L1, where L1 > 10 mm; the insulating layer is used to achieve insulation between the first cascade and the second cascade; the lower surface of the second cascade is attached to the insulating layer; The first sealing groove and the second sealing groove together form an installation groove; the sealing ring is disposed in the installation groove, and its upper and lower sides respectively abut against the second cascade piece and the first cascade piece; The first cascaded chip has a first cooling cavity for the flow of cooling medium, and the first cooling cavity is arranged around the first discharge channel; The second cascaded chip has a second cooling cavity for the flow of cooling medium, and the second cooling cavity is arranged around the second discharge channel; The outer edges of the first cooling cavity, the second cooling cavity, and the insulating layer are all flush with each other.

2. The cascaded interlayer structure as described in claim 1, characterized in that, The upper surface of the first cascaded sheet is provided with a spraying groove; The spraying tank is arranged around the first discharge channel and is isolated from the first discharge channel and the first sealing tank, respectively. The transition layer is applied in the spray tank; the upper surface of the transition layer is flush with the upper surface of the first cascaded sheet.

3. The cascaded interlayer structure as described in claim 2, characterized in that, In the radial direction of the first cascade, the inner and outer surfaces of the insulating layer are flush with the inner and outer surfaces of the transition layer.

4. The cascaded interlayer structure as described in claim 1, characterized in that, The thickness of the insulating layer is greater than the thickness of the transition layer.

5. A method for preparing a cascaded interlayer structure, used to prepare the cascaded interlayer structure as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Prepare two cascade substrates. In one cascade substrate, process a first discharge channel that penetrates its upper and lower surfaces and process a first sealing groove on its outer peripheral surface. In the other cascade substrate, process a second discharge channel that penetrates its upper and lower surfaces and process a second sealing groove on its outer peripheral surface to form the second cascade. S2. Spray a transition material onto the upper surface of the cascade substrate with the first sealing groove to form a transition layer on the cascade substrate; S3. Spray insulating material onto the upper surface of the transition layer to form an insulating layer on the upper surface of the transition layer, thus forming the first cascaded sheet; S4. Detect the porosity and surface roughness of the insulating layer and determine whether they meet the standards; S5. Align and press the second cascade plate and the first cascade plate together; embed the sealing ring into the mounting groove; thus obtaining the cascade plate interlayer structure. S6. Perform vacuum negative pressure leak detection test and electrical breakdown insulation performance test on the cascaded interlayer structure in sequence; S7. Perform high-temperature fatigue testing on the first cascaded wafer.

6. The method for preparing a cascaded interlayer structure as described in claim 5, characterized in that, Step S2 involves spraying a transition material onto the upper surface of the cascade substrate with the first sealing groove to form a transition layer on the cascade substrate, specifically including: S21. A spraying groove is machined on the upper surface of the cascaded substrate with the first sealing groove, wherein the spraying groove is not connected to the first sealing groove or the discharge channel of the cascaded substrate. S22. The inner wall of the spraying tank is sandblasted and sanded. S23. Spray transition material into the spray tank until the spray tank is filled to form the transition layer; The transition material is a nickel-chromium alloy.

7. The method for preparing a cascaded interlayer structure as described in claim 5, characterized in that, Step S3 involves spraying an insulating material onto the upper surface of the transition layer to form an insulating layer, thus creating the first cascade. Specifically, this includes: S31. Spray insulating material onto the upper surface of the transition layer to form an insulating layer; and the thickness of the insulating layer is greater than the thickness of the transition layer. The insulating material is either aluminum oxide or boron nitride. S32. Perform metallographic polishing on the insulating layer to form the first cascade.

8. The method for preparing a cascaded interlayer structure as described in claim 5, characterized in that, Step S4 involves detecting the porosity and surface roughness of the insulating layer and determining whether they meet the standards. Specifically, this includes: S41. The cross-sectional morphology of the insulating layer is observed using a metallographic microscope, and the porosity of the insulating layer is tested to see if it is ≤3%. If the porosity is ≤3%, the porosity is qualified; if the porosity is >3%, the porosity is unqualified. S42. Use a roughness measuring instrument to detect the surface roughness of the insulating layer and determine whether the surface roughness is ≤0.01; if the surface roughness is ≤0.01, the surface roughness is qualified; if the surface roughness is >0.01, the surface roughness is unqualified.

9. The method for preparing a cascaded interlayer structure as described in claim 5, characterized in that, It also includes the following steps: S8. Repeat steps S4-S6 above, and compare the results of porosity, surface roughness, vacuum negative pressure leak detection test and electrical breakdown insulation performance test with the results of each item before step S7.

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