A kind of preparation method of porous cathode substrate

Abstract

The invention provides a method for preparing a porous cathode substrate, which belongs to the field of powder metallurgy. The raw material powders used include various powders such as tungsten, iridium, rhenium, and scandium oxide. The various powders are mixed evenly according to a certain weight percentage, and the tungsten content is 40~100%. Mix and disperse the raw material powder particles and the binder evenly to make a granular feed, and the volume fraction of the powder in the feed is 40-75%. The feed material is formed into a green body of a certain shape on an injection molding machine, and the binder in the shaped green body is removed to obtain a porous cathode substrate. The invention has the advantages that the porous cathode substrate with special shape and size requirements can be directly prepared without mechanical processing, the material utilization rate is high, and the cost is low. It can effectively overcome the influence of harmful impurities brought by the traditional process, and improve the electron emission performance, service life and working reliability of the cathode. It can effectively control the pore size, pore distribution, porosity and pore connectivity of the material.

Description

technical field

[0001] The invention belongs to the field of powder metallurgy and provides a method for preparing a porous cathode substrate. Background technique

[0002] As the electron emission source of vacuum electronic devices, the cathode plays a vital role in the power output, lifetime, and working stability of high-power microwave devices. Due to the characteristics of high emission current density, low operating temperature and long service life, diffused cathodes are more and more widely used. Diffusion cathodes usually consist of a porous substrate (or sponge) mainly composed of tungsten and an electron-emitting active material impregnated in the porous substrate. The porous cathode substrate is an essential part of the diffused cathode. The electron emission active material impregnated in its porous framework will be lost after the surface emits electrons, and new substances should immediately diffuse to the surface of the cathode through the open pores in th...