Sintered cathode materials for electric vacuum devices

Conclusions

• 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.