Lanthanum hexaboride hollow cathode heater heating wire cold end leading-out method

Abstract

The invention provides a lanthanum hexaboride hollow cathode heater heating wire cold end leading-out method, which comprises the following steps: 1) at the heater heating wire cold end leading-out section, a plurality of metal wires and a heater heating wire are closely arranged side by side; 2) the metal wires arranged in parallel serve as a whole, and the outer surface of the metal wires is closely wrapped with multiple layers of tantalum foil, wherein the diameter obtained after wrapping of the tantalum foil is uniform, and the multiple layers of tantalum foil are fixed through spot welding; 3) the tantalum foil is coated with a single single-hole ceramic tube, wherein the ceramic tube cannot slide out freely; 4) the ceramic tube is externally sleeved by multiple layers of tantalum foil, wherein one part at each of the two ends of the ceramic tube is not wrapped with the tantalum foil, and the two layers of tantalum foil are fixed through spot welding; and 5) the cold end leading-out section is tightened and fixed to a cathode tube by utilizing a long-strip tantalum foil. The method can effectively reduce the power of the cold end leading-out section and reduce the temperatureof the cold end leading-out section, thereby preventing the heat from returning to the cold end, ensuring anti-mechanical properties of the cold end and preventing cold end leading-out wires from being broken in the satellite emission process.

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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