A method for leading out the cold end of the lanthanum hexaboride hollow cathode heating wire heating wire

Abstract

A method for leading out the cold end of the lanthanum hexaboride hollow cathode heater heating wire of the present invention: 1) multiple metal wires are arranged closely side by side with the heater heating wire at the lead-out section of the cold end of the heater heating wire; 2) the wires arranged in parallel As a whole, all metal wires are tightly wrapped with multi-layer tantalum foils on their outer surfaces, and the outer diameter of the wrapped tantalum foils is guaranteed to be uniform, and the multi-layer tantalum foils are spot-welded and fixed to each other. 3) Put a single single-hole ceramic tube on the outside of the tantalum foil to ensure that the ceramic tube cannot slide out freely; 4) Wrap the multi-layer tantalum foil outside the ceramic tube, leaving a part at both ends of the ceramic tube without wrapping the tantalum foil, and put the two The layers of tantalum foil are spot welded and fixed to each other. 5) Utilize the strip-shaped tantalum foil to tighten and fix the lead-out section of the cold end to the cathode tube. The invention can effectively reduce the power of the lead-out section of the cold end, reduce the temperature of the lead-out section of the cold end, prevent the heat from back-immersing to the cold end, ensure the mechanical resistance of the cold end, and prevent the lead-out line of the cold end from breaking during satellite launch.

Description

technical field [0001] The invention relates to a method for leading out the cold end of a lanthanum hexaboride hollow cathode heating wire heating wire. Background technique [0002] Lanthanum hexaboride hollow cathodes for aerospace electric thrusters have the advantages of high electron emission current density and low requirements on the purity of working gases. The structure of the common lanthanum hexaboride hollow cathode is shown in figure 1 As shown, it is mainly composed of cathode tube 5, lanthanum hexaboride emitter 4, cathode top 6, heater 3, ignition electrode 1, heat insulation layer 2 and other parts. The heater packs a heating wire into a hollow cylinder through ceramics (see figure 2 ), throw out two leads. The heater is set on the cathode tube through a hollow cylinder, and the lead wire of the heater generates Joule heating effect through the current, which preheats the lanthanum hexaboride emitter in the cathode tube. After the lanthanum hexaboride r...

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Problems solved by technology

[0004] At present, in order to improve the reliability of the heater, a complete tungsten-rhenium heating wire with equal diameter is used. The heater is small in size, and the length of the heating wire packaged inside the heater is limited. The lead-out line to the cathode base plate is relatively long, which leads to a large proportion of lead resistance, and a large part of the power is dissipated in the lead-out line, which cannot heat the emitter, resulting in waste of power and excessive temperature of the cathode base plate

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