Sintered cathode materials for electric vacuum devices

1. A number of Pt, Pd, Ru, Rh, Os, Ir, Ag, W, Mo, Ni, Ni+30% Re, Re, and Re+30% Ni base powder metallurgy alloys containing a beryllate active phase have been developed. Such alloys exhibit, under intense electron bombardment conditions, high and stable coefficients of secondary electron emission and low, controllable levels of thermionic emission. 2. Effective high-temperature thermionic emitters based on tungsten and rhenium with additions of yttrium and gadolinium tetraborides have been formulated. These are distinguished from W+Y2O3 type emitters by simplicity of aging, absence of sparking and breakdowns, and stability of operation. 3. Using the powder metallurgy technique, thin-walled cylindrical tungsten-tantalum alloy cathodes were produced characterized by satisfactory shape stability and long useful life at high temperatures (1700–1900°C) 4. The use of powder metallurgy billets produced from powders containing intermetallic compounds of platinum and palladium with barium reduces by two-thirds labor in the manufacture of platinum-barium and palladium-barium alloy strip. The method lends itself to the manufacture of strip in nickel alloys of increased alkaline-earth metal content.