Dynamic progressive micro-discharge polishing method for ion thruster grid electrode assembly
By dynamically controlling the inter-gate voltage and beam current during the operation of the ion thruster, and using micro-discharge plasma etching to remove gate burrs, the damage and contamination problems of gate component surface treatment are solved, achieving a highly efficient and contamination-free gate surface polishing effect.
Patent Information
- Application Number
- CN202511470233.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-15
- Publication Date
- 2026-01-09
AI Technical Summary
Existing technologies struggle to efficiently remove hole edges and surface burrs from ion thruster gate assemblies without damaging the gate, especially for carbon/carbon composite gates, and traditional electrochemical etching methods pose environmental pollution risks.
In the actual operation of the ion thruster, controllable micro-discharge is induced by dynamically adjusting the inter-gate voltage and the extracted beam current. The local high-temperature plasma generated by the micro-discharge is used to remove burrs on the gate surface in situ, and a gradient loading strategy and thermodynamic equilibrium plasma etching are adopted.
It achieves efficient removal of gate burrs without disassembly or chemical treatment, significantly improving gate surface quality. It features high efficiency, no pollution, and strong process compatibility, and is suitable for gate components made of various materials.
Smart Images
Figure CN121306873A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of spacecraft space electric propulsion technology, belongs to the field of vacuum electronics, and particularly relates to a dynamic gradual micro-discharge polishing method for a grid assembly of an ion thruster. BACKGROUND
[0002] The grid assembly of the ion thruster is composed of two to three grid electrodes with thousands of small holes, the voltage between the grids can be as high as thousands of volts, and the distance between the grids is usually less than 1 mm, so the grid assembly has the characteristics of high voltage and small distance. In order to avoid unnecessary breakdown discharge between the grids, the surface finish of the grid is required to be high.
[0003] At present, after the metal molybdenum grid is formed with holes, the small hole edges or surfaces are polished by using an electrochemical corrosion method. During the precise hole forming process of the carbon / carbon composite grid, carbon fibers and other sharp ends are inevitably left. The traditional electrochemical corrosion method is not suitable for the carbon / carbon composite grid which has a particularly stable chemical property, and the chemical corrosion method also has the disadvantages of over-corrosion caused by improper control, environmental pollution risk, etc.
[0004] Therefore, it is a technical problem to be solved by those skilled in the art to develop a simple and easy-to-use grid surface polishing method which is not easy to cause over-polishing and damage to the grid. SUMMARY
[0005] To achieve the above-mentioned purpose, the present application provides a dynamic gradual micro-discharge polishing method for a grid assembly of an ion thruster. In the actual running state of the ion thruster, under the environment of the extracted beam between the grids, the voltage between the grids and the extracted beam are dynamically controlled to induce controllable micro-discharge, so as to realize in-situ removal of the burrs on the surface of the grid.
[0006] Therefore, the present application provides the following technical scheme: A dynamic gradual micro-discharge polishing method for a grid assembly of an ion thruster, comprising the following steps: Designing a working condition coupling polishing mechanism according to the actual working condition of the ion thruster; Using a gradient loading strategy to perform plasma etching through the micro-discharge effect for thermodynamic equilibrium; Dynamically adjusting the loading rate to ensure the uniformity of surface treatment.
[0007] Further, the gradient loading strategy is used to perform plasma etching through the micro-discharge effect for thermodynamic equilibrium, which comprises: After the ion thruster is started, the initial voltage between the screen grid and the acceleration grid is set to 20%-30% of the rated working voltage, the extracted beam density is set to 10%-15% of the rated extracted beam density, and stable discharge is maintained for 20-30 minutes. The system is configured with N loading stages, and the inter-gate voltage and beam current density are alternately increased in a stepwise manner to generate local high-temperature plasma at the edge of the gate hole until the inter-gate voltage and beam current density both reach their rated values, causing the burrs at the edge of the gate hole to melt or evaporate, thereby achieving the effect of polishing the gate surface.
[0008] Furthermore, the N loading stages are 6 to 18 loading stages.
[0009] Furthermore, the voltage increase in each loading stage is 10%-20% of the rated value, and the beam current density increase is 5%-10% of the rated value.
[0010] Furthermore, the interval between two adjacent loading stages is 20-30 minutes.
[0011] Furthermore, the gate-to-gate voltage increase is 100~200 V and the beam current density increase is 0.2~0.5 mA / cm² during each loading stage. 2 .
[0012] Furthermore, the plasma etching that employs a gradient loading strategy and achieves thermodynamic equilibrium through micro-discharge effect also includes: when either the gate voltage or the beam current density has reached its rated value, in the remaining loading stage, only the other parameter that has not reached its rated value is adjusted until both parameters reach their rated values.
[0013] Furthermore, the plasma etching that employs a gradient loading strategy and achieves thermodynamic equilibrium through micro-discharge effect also includes: evacuating the polishing system and using an inert gas as the working gas.
[0014] Furthermore, the inert gas is xenon, argon, or krypton.
[0015] Furthermore, the vacuum is evacuated to 1×10 -4 ~1.5×10 -3 Pa.
[0016] Furthermore, the dynamic adjustment of the loading rate includes: feeding back the micro-discharge frequency and intensity through beam fluctuation monitoring, and dynamically adjusting the loading rate based on the feedback.
[0017] The technical solution of this invention has the following advantages: 1. Under normal beam extraction conditions of an ion thruster, this invention induces a controllable micro-discharge phenomenon on the gate surface by gradually increasing the inter-gate voltage and the extracted beam current density in stages. The localized high-temperature plasma generated by the micro-discharge is used to remove burrs on the gate hole edges and surface in situ. Simultaneously, by optimizing the voltage-beam current co-loading path, uniform etching and ablation of burrs are achieved, significantly improving the gate surface quality.
[0018] 2. This invention can be implemented directly after the ion thruster is assembled, without disassembly or chemical treatment, and is not likely to damage the grid. It has the characteristics of strong process compatibility, high efficiency and no pollution.
[0019] 3. This invention is not only applicable to carbon / carbon gate components, but also to gate components made of other materials such as molybdenum and titanium for polishing.
[0020] 4. This invention is applicable to newly assembled gate assemblies during the production process. It can also be used during the use (service) of gate assemblies, especially in the middle and later stages of their lifespan, to remove excess material between the gates caused by wear, deposits, and detachment. Attached Figure Description
[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0022] Figure 1 This is a gradient parameter loading diagram of the method provided in this embodiment of the invention for dynamic progressive plasma polishing of a carbon / carbon gate assembly with a diameter of 30 cm. Figure 2 These are comparison images of the gate aperture microstructure before and after dynamic progressive plasma polishing of a 30 cm diameter carbon / carbon gate assembly, provided by the method of this invention. Detailed Implementation
[0023] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.
[0024] Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. All raw materials or instruments used are commercially available conventional products, including but not limited to those used in the embodiments of this application.
[0025] Please see Figure 1 and 2 This application provides a process parameter loading diagram and effect diagram for a dynamic progressive micro-discharge polishing method for an ion thruster gate assembly, as shown in the embodiments of this application. Figure 1 and 2 As shown, in order to remove burrs from the edges and surfaces of newly assembled gate components during production, or to remove excess material between the gates due to wear, deposition, and detachment during the use (service) of the gate components, especially in the later stages of their lifespan, without disassembly or chemical treatment and without over-polishing to avoid damage to the gate, this application provides a dynamic progressive micro-discharge polishing method for ion thruster gate components. Under normal beam extraction conditions of the ion thruster, the inter-gate voltage and extraction beam current density are gradually increased in stages to induce a controllable micro-discharge phenomenon on the gate surface. The local high-temperature plasma generated by the micro-discharge is used to remove burrs from the edges and surfaces of the gate holes in situ. On the one hand, a specific working condition coupling polishing mechanism is designed according to the actual working conditions of the ion thruster. Under the actual beam extraction state, the spatiotemporal distribution characteristics of the micro-discharge are precisely controlled by utilizing the synergistic change of the inter-gate electric field strength and beam current density. On the other hand, a gradient loading strategy is adopted, with gradually increasing loading parameters in stages, so that the burr tips preferentially undergo field-induced electron emission, gradually forming a thermodynamically balanced plasma etching environment.
[0026] The specific steps include: The working condition coupling polishing mechanism is designed based on the actual working conditions of the ion thruster. A gradient loading strategy is adopted to perform thermodynamically balanced plasma etching through the micro-discharge effect; The loading rate is dynamically adjusted to ensure uniformity of the gate surface treatment.
[0027] In this embodiment, after the ion thruster is started, the initial voltage between the screen gate and the accelerating gate is set to 20%-30% of the rated operating voltage, and the extracted beam current density is set to 10%-15% of the rated extracted beam current density, and a stable discharge is maintained for 20-30 minutes. N loading stages are set, with the inter-gate voltage and beam current density alternately increased in a step-by-step manner. This generates localized high-temperature plasma at the edge of the gate aperture until both the inter-gate voltage and beam current density reach their rated values, causing the burrs at the edge of the gate aperture to melt or evaporate, achieving the effect of polishing the gate surface. The inter-gate voltage increase in each loading stage is 10%-20% (100~200 V) of the rated value, and the beam current density increase is 5%-10% (0.2~0.5 mA / cm²) of the rated value. 2 The interval between two adjacent loading stages is 20-30 minutes. When either the inter-gate voltage or the beam current density has reached its rated value, in the remaining loading stages, only the other parameter that has not reached its rated value is adjusted until both parameters reach their rated values. The micro-discharge frequency and intensity are fed back through beam current fluctuation monitoring, and the loading rate is dynamically adjusted based on this feedback.
[0028] In this embodiment, the entire polishing system is evacuated to a vacuum level of 1×10⁻⁶. -4 ~1.5×10 -3 Pa, and uses inert gases such as xenon, argon or krypton as working gas.
[0029] Please see Figure 1 In a preferred embodiment of this application, a dynamic progressive micro-discharge polishing method for an ion thruster gate assembly is provided. This method involves performing dynamic progressive plasma polishing on a carbon / carbon gate assembly with a 30 cm aperture, using a step-by-step process parameter incrementing load, such as... Figure 1 As shown.
[0030] After the ion thruster is started, the initial voltage between the screen grid and the accelerating grid is set to 400 V, the rated inter-grid voltage is set to 2000 V, and the extracted beam current density is set to 0.80 mA / cm². 2 The rated extracted beam current density is 4.00 mA / cm². 2 The stable discharge time is set to 30 minutes.
[0031] The system employs 17 loading stages, progressively increasing the inter-gate voltage and beam current density in a stepped manner. This generates localized high-temperature plasma at the gate aperture edge until both the inter-gate voltage and beam current density reach their rated values. This melts or evaporates the burrs at the gate aperture edge, achieving a polishing effect on the gate surface. The inter-gate voltage increase is 200 V / cycle, and the extracted beam current density increase is 0.40 mA / cm² in each loading stage. 2 / Second-rate.
[0032] In the first loading stage, the inter-gate voltage was increased from the initial voltage of 400 V to 600 V, and the extracted beam current density was maintained at 0.80 mA / cm². 2 In the second loading stage, the inter-gate voltage remains unchanged at 600 V, while the extracted beam current density is increased to 1.20 mA / cm². 2 In the third loading stage, the inter-gate voltage was increased to 800 V while the extracted beam current density remained unchanged. In the fourth loading stage, the inter-gate voltage remained unchanged at 800 V while the extracted beam current density was increased to 1.60 mA / cm². 2 During each loading stage, the inter-gate voltage and extracted beam current alternately increase, with increases of 200 V / cycle and 0.40 mA / cm, respectively. 2 This process is repeated until the inter-gate voltage and the lead-out beam current reach their rated values of 2000 V and 4.00 mA / cm², respectively. 2 .
[0033] In this preferred embodiment, the entire polishing system is evacuated to a vacuum level of 1×10⁻⁶. -4 Pa, and argon is used as the working gas.
[0034] Please see Figure 2 Using the method described in this application, the microstructure of the gate aperture of a 30 cm diameter carbon / carbon gate assembly before and after dynamic progressive plasma polishing is compared as follows: Figure 2 As shown, before polishing, the gate hole edges and surfaces had burrs; after polishing, the gate hole edges and surfaces were smooth and burr-free. Therefore, the method of this embodiment can eliminate gate hole burrs without disassembly or chemical treatment, is less likely to damage the gate, and significantly improves the gate surface quality.
[0035] In summary, this invention, under normal beam extraction conditions of an ion thruster, induces controllable micro-discharge on the gate surface by gradually increasing the inter-gate voltage and extracted beam current density in stages. The localized high-temperature plasma generated by this micro-discharge then removes burrs from the gate hole edges and surface in situ. On one hand, a specific operating condition coupling polishing mechanism is designed based on the actual operating conditions of the ion thruster. Under real beam extraction conditions, the spatiotemporal distribution characteristics of the micro-discharge are precisely controlled by utilizing the synergistic changes in the inter-gate electric field strength and beam current density. On the other hand, a gradient loading strategy is adopted, with gradually increasing loading parameters in stages, to preferentially induce field-induced electron emission at the burr tips, gradually forming a thermodynamically balanced plasma etching environment. This method requires no disassembly or chemical treatment, is less likely to damage the gate, and features strong process compatibility, high efficiency, and no pollution.
[0036] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A dynamic progressive micro-discharge polishing method for an ion thruster gate assembly, characterized in that, Includes the following steps: The working condition coupling polishing mechanism is designed based on the actual working conditions of the ion thruster. A gradient loading strategy is adopted to perform thermodynamically balanced plasma etching through the micro-discharge effect; The loading rate is dynamically adjusted to ensure uniformity of the gate surface treatment.
2. The dynamic progressive micro-discharge polishing method according to claim 1, characterized in that, The plasma etching employing a gradient loading strategy and utilizing the micro-discharge effect to achieve thermodynamic equilibrium includes: After the ion thruster is started, the initial voltage between the screen grid and the acceleration grid is set to 20%-30% of the rated operating voltage, the extracted beam current density is set to 10%-15% of the rated extracted beam current density, and stable discharge is maintained for 20-30 minutes. The system is configured with N loading stages, and the inter-gate voltage and beam current density of each loading stage are alternately increased in a stepwise manner to generate local high-temperature plasma at the edge of the gate hole until the inter-gate voltage and beam current density both reach their rated values, causing the burrs at the edge of the gate hole to melt or evaporate, thereby achieving the effect of polishing the gate surface.
3. The dynamic progressive micro-discharge polishing method according to claim 2, characterized in that, The N loading stages consist of 6 to 18 loading stages. The inter-gate voltage increase in each loading stage is 10%-20% of the rated value, and the beam current density increase is 5%-10% of the rated value. The interval between two adjacent loading stages is 20-30 minutes.
4. The dynamic progressive micro-discharge polishing method according to claim 2, characterized in that, The gate-to-gate voltage increase during each loading stage is 100~200 V, and the beam current density increase is 0.2~0.5 mA / cm². 2 .
5. The dynamic progressive micro-discharge polishing method according to claim 2, characterized in that, The plasma etching method employing a gradient loading strategy and achieving thermodynamic equilibrium through micro-discharge effect further includes: when either the gate voltage or the beam current density has reached its rated value, in the remaining loading stage, only the other parameter that has not reached its rated value is adjusted until both parameters reach their rated values.
6. The dynamic progressive micro-discharge polishing method according to claim 1 or 2, characterized in that, The plasma etching method employing a gradient loading strategy and achieving thermodynamic equilibrium through micro-discharge effect further includes: evacuating the polishing system and using an inert gas as the working gas.
7. The dynamic progressive micro-discharge polishing method according to claim 6, characterized in that, The inert gas is xenon, argon, or krypton; the vacuum is evacuated to 1×10⁻⁶. -4 ~1.5×10 -3 Pa.
8. The dynamic progressive micro-discharge polishing method according to claim 1, characterized in that, The dynamic adjustment of the loading rate includes: monitoring the micro-discharge frequency and intensity through beam fluctuation monitoring, and dynamically adjusting the loading rate based on the feedback.