Emission needle wetting method and automatic wetting device thereof

Abstract

The invention discloses an emission needle wetting method and an automatic wetting device of the method, and relates to the technical field of electric propulsion. The device comprises a vacuum cabin, a rack, an emission needle heat shield heating unit, a propellant heat shield heating unit, a motion unit and a control unit. The emission needle heat shield heating unit is connected with the motion unit and vertically corresponds to the propellant heat shield heating unit; the propellant heat shield heating unit is fixed to the rack, the motion unit is connected with the rack and is opposite to the emission needle heat shield heating unit, and the rack is arranged in the vacuum cabin; the control unit is connected with the emission needle heat shield heating unit and the propellant heat shield heating unit and transmits emission needle heating control information and propellant heating control information; and the control unit is connected with the motion unit and transmits the motion control information. Automatic wetting of an electric thruster emission needle can be achieved, and the advantages of being efficient, simple, reliable and high in repeating rate are achieved.

Description

technical field [0001] The invention relates to a technology in the field of electric propulsion, in particular to a firing needle infiltration method and an automatic infiltration device thereof. Background technique [0002] The needle-type field emission electric thruster is an electric thruster based on liquid metal ion source technology. The liquid metal propellant is transported to the tip of the emission needle along the fine grooves on the surface of the emission needle, and is ionized and accelerated under the action of a strong electric field. The ejection produces thrust. In order to improve the fluidity of the propellant on the surface of the emitter needle, it is necessary to remove the oxide film on the surface of the emitter needle and infiltrate the emitter needle in liquid metal. However, it is difficult to realize the wetting of the emitter needle in a vacuum environment. [0003] At present, there are mainly four types of infiltration devices for launch n...

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Problems solved by technology

In order to improve the fluidity of the propellant on the surface of the emitter needle, it is necessary to remove the oxide film on the surface of the emitter needle and infiltrate the emitter needle in liquid metal, however, it is difficult to achieve the wetting of the emitter needle in a vacuum environment

[0003] At present, there are mainly four types of infiltration devices for launch needles: 1. As mentioned in Duan Junyi’s doctoral thesis "Research on the Working Performance and Launch Mechanism of Field Emission Electric Thrusters" of Shanghai Jiaotong University, the tungsten needle tip is directly placed in a molten liquid state In metal indium, they are heated together and taken out after a period of time. This kind of infiltration device is simple and direct, but the oxide film on the surface of the emission needle needs to be cleaned by chemical corrosion in advance, and the re-oxidation of the cleaned emission needle cannot be avoided during the infiltration process in the atmosphere. , leading to poor wetting effect of the emitter needle and liquid metal; 2. As mentioned in Ma Xiangguo's doctoral thesis "Development of Liquid Metal Ion Source for Nano-focused Ion Beam System" of the Institute of Electrical Engineering, Chinese Academy of Sciences, put the tungsten emitter tip into the vacuum system At the same time, the storage tank is heated to a certain temperature and the infiltration is completed after a period of time. The shortcoming of this device is that even if the heating temperature is higher than the evaporation temperature of the oxide film, the tungsten emission tip is directly in contact with the liquid gallium. , affecting the removal effect of oxide film; 3. As mentioned in Wang Dawen's "Vacuum Science and Technology", the tungsten emission tip is overlapped with another tungsten wire, and current is passed through it to make the tungsten wire heat up to high temperature. Although a device for heating and removing the oxide film on the surface of the emitting needle is simple, the overlapping of the two tungsten wires is not easy to be reliable, and it is easy to cause the heating circuit to be disconnected. In the system, a pair of spiral tungsten wires are energized and heated to emit electrons, and the tungsten emission tip is bombarded to reach a high temperature. The tungsten needle moves up and down through the transmission device, so that the tungsten tip is immersed in liquid gallium. Emit the oxide film on the surface of the needle and realize automatic infiltration, but the spiral tungsten wire needs to be heated to a very high temperature to emit electrons, the heating efficiency is low, and the structure is complex

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