Accession Number : ADD011877

Title :   Atomically Mixed Alloy Coated Cathodes Specification.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Haas,G A ; Shih,A ; Marrian,C R K

Report Date : 04 Apr 1985

Pagination or Media Count : 20

Abstract : The present invention pertains generally to cathodes used in thermionic electron tubes, often used in ultra high frequency and microwave radio transmitters. It is an object of this invention to produce thermionic tube cathodes which consistntly exhibit current densities higher than heretofore achieved. Another object of the present invention is to manufacture cathodes using a method that consistently results in cathodes with a large, defined, level of current density. Another object of the present invention is to produce cathodes with reduced surface work functions by means of atomic scale mixing of two selected metals in a cathode surface coating. A tungsten or tungsten-based matrix cathode impregnated with BaO is simultaneously coated with vapors of two metallic elements, in particular, tungsten and iridium, such that a binary alloy forms on the surface. A layer of BaO then spontaneously dispenses onto the surface of the binary alloy. One of the metallic elements associates with the oxygen of BaO and other with the barium. The molecular dipole of BaO thus becomes more pronounced, and the surface work function results in a greater rate of electron emission from the cathode.

Descriptors :   *PATENT APPLICATIONS, *CATHODES(ELECTRON TUBES), *ELECTRON TUBES, CATHODES, INVENTIONS, CURRENT DENSITY, OXYGEN, REDUCTION, BINARY ALLOYS, IRIDIUM, METALS, MICROWAVE EQUIPMENT, ELECTRON EMISSION, SURFACES, TRANSMITTERS, RADIO TRANSMITTERS, BARIUM OXIDES, METAL COATINGS, ULTRAHIGH FREQUENCY, VAPORS

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE