US1883840A - Manufacturing oxide cathodes - Google Patents

Manufacturing oxide cathodes Download PDF

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Publication number
US1883840A
US1883840A US548036A US54803631A US1883840A US 1883840 A US1883840 A US 1883840A US 548036 A US548036 A US 548036A US 54803631 A US54803631 A US 54803631A US 1883840 A US1883840 A US 1883840A
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United States
Prior art keywords
cathodes
metal
vapor
oxide cathodes
manufacturing oxide
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Expired - Lifetime
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US548036A
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English (en)
Inventor
Wiegand Erich
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General Electric Co
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General Electric Co
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
    • H01J9/042—Manufacture, activation of the emissive part

Definitions

  • Patented Oct. 18, 1932 meant V ERICH WIEGAND, F BERLIN-WAIDMANNSLUST, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF YORK MANUFACTURING OXIDE CATHODES No Drawing. Application filed June 30, 1931, Serial No. 548,036, and in Germany July '16, 1930.
  • One known method of manufacturing oxide cathodes consists inprecipitating alkaline earth metal from the vapor phase onto an unheated carrier filament and oxidizing the said metal by subsequently heating the carrier filament in oxygen, for the purpose of obtaining alkaline earth oxide. While this process may produce cathodes of relatively long life and high electron emissivity, it has been found that notwithstanding the extreme care exercised in their manufacture, such cathodes are not accurately reproducible on a quantity production basis, in so far as their electron emission is concerned. All attempts made to the present day to obviate this disadvantage have not been entirely successful and no satisfactory explanation has been offered for this failure. However, in accordance with my invention, cathodes of considerably greater uniformity are obtained when the filament is activated by following another procedure.
  • the new process consists in coating the oathode carrier with an oxygen compound and heating the carrier to such a temperature when the alkaline-earth metal is in the form of vapor that no appreciable quantity of alkaline-earth metal (in solid or liquid form) V is de osited on the said carrier but the concathode must be heated when the metal is in the vapor state depends upon the nature of the alkaline-earth metal used.
  • a temperature of the order of 900 C. is generally 'sufilcient when using barium metal, but must be somewhat higher in the case of calcium and strontium owing to their relatively low vapor pressures.
  • a process of manufacturing cathodes for electric discharge devices including the steps of coating a foundation metal of the cathode with an-oxygen compound and heating the coated metal in the vapor of an alkaline earth metal to a temperature exceeding 900 C. whereby the said metal is precluded from forming on the foundation member in solid or liquid state.
  • A' process of manufacturing cathodes for electric discharge devices including the steps of applying a dissociable oxygenous compound to the surface of a cathode foundation member and heating said member in the vapor of an alkaline earth metal to a temperature so high that the said compound becomes partially decomposed and the alkaline earth material combines with the oxygen on the oxidized surface.
  • a process of manufacturing cathodes for electric discharge devices including the steps of coating a foundation metal With tantalum oxide and heating the coated member in the presence of an alkaline earth vapor to a temperature of the order of 900 C.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Solid Thermionic Cathode (AREA)
US548036A 1930-07-16 1931-06-30 Manufacturing oxide cathodes Expired - Lifetime US1883840A (en)

Applications Claiming Priority (1)

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DE1883840X 1930-07-16

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US1883840A true US1883840A (en) 1932-10-18

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US548036A Expired - Lifetime US1883840A (en) 1930-07-16 1931-06-30 Manufacturing oxide cathodes

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US (1) US1883840A (en(2012))
NL (1) NL34423C (en(2012))

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2917415A (en) * 1956-07-24 1959-12-15 Philips Corp Method of making thermionic dispenser cathode and cathode made by said method
US3150342A (en) * 1960-02-10 1964-09-22 Morganite Resistors Ltd Non-linear resistors
US3273005A (en) * 1963-04-01 1966-09-13 Gen Electric Electron emitter utilizing nitride emissive material

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2917415A (en) * 1956-07-24 1959-12-15 Philips Corp Method of making thermionic dispenser cathode and cathode made by said method
US3150342A (en) * 1960-02-10 1964-09-22 Morganite Resistors Ltd Non-linear resistors
US3273005A (en) * 1963-04-01 1966-09-13 Gen Electric Electron emitter utilizing nitride emissive material

Also Published As

Publication number Publication date
NL34423C (en(2012))

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