Nickel Alloys for Oxide-Coated Cathodes

A survey is presented covering the metallurgical problems and manufacturing methods used in the refining and melting of nickel, and its fabrication into indirectly heated cathode sleeves for electron tubes. The important role of minor constituent alloys is discussed from both the metallurgical and electronic points of view. Four of the most important cathode performance characteristics are defined and the effect of base-metal composition on each one is discussed. The influences of each important element present in cathode nickel alloys are enumerated. Suggestions are made concerning present and future developmental cathode materials to meet new and more severe demands being placed upon electron tubes.