Improving the material properties of vacuum devices electrodes by technology rational improvement

Abstract

The material of the electrodes of high-current vacuum and plasma electronics is traditionally obtained by powder metallurgy methods (mixing components, pressing blanks, hydrogen sintering in a given mode). However, the material of the cathodes produced according to the adopted technology, has a number of significant limitations. They are caused by the impossibility of a uniform distribution and grinding of the initial powder components by the adopted grinding in globe mills, as well as by abundant gas emission during the sintering time. The nonuniformity of the distribution of the composition in the structure, low density, high porosity, low mechanical strength of the emitting material with a metal matrix give a decrease in the operating properties of the cathodes, which leads to a decrease in the lifetime of electronic tubes. This problem is proposed to be solved by directional changes in the physical and mechanical properties of the electrode material by selecting the gravimetric consist of the base material components and improving the existing production process. The article presents the analysis of research results, changes in the structure of the material by optical and scanning microscopy methods, and also describes a complex of acquired physical and mechanical properties of experimental samples obtained by modernized technology. Thus, the developed innovative techniques allowed to increase the hardness by 36%; density by 19%, and to reduce porosity by 25% in relation to traditional cathodes. Such changes in the physical and mechanical properties make it possible to predict an increase in the service life of produced and developed vacuum tubes operating in current flow regimes up to 100 kA and in highly stressed electromagnetic fields up to 500 kV.