US2700000A - Thermionic cathode and method of manufacturing same - Google Patents

Thermionic cathode and method of manufacturing same Download PDF

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Publication number
US2700000A
US2700000A US273607A US27360752A US2700000A US 2700000 A US2700000 A US 2700000A US 273607 A US273607 A US 273607A US 27360752 A US27360752 A US 27360752A US 2700000 A US2700000 A US 2700000A
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United States
Prior art keywords
oxide
cathode
alkaline earth
tungsten
pores
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Expired - Lifetime
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US273607A
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English (en)
Inventor
Levi Roberto
Ray C Hughes
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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Publication date
Priority to NL96177D priority Critical patent/NL96177C/xx
Priority to IT500079D priority patent/IT500079A/it
Priority to BE517981D priority patent/BE517981A/xx
Priority to US273607A priority patent/US2700000A/en
Application filed by US Philips Corp filed Critical US Philips Corp
Priority to ES0207960A priority patent/ES207960A1/es
Priority to GB5269/53A priority patent/GB734311A/en
Priority to FR1077589D priority patent/FR1077589A/fr
Priority to CH318053D priority patent/CH318053A/de
Priority to DEN6805A priority patent/DE1089483B/de
Priority to ES0209589A priority patent/ES209589A1/es
Application granted granted Critical
Publication of US2700000A publication Critical patent/US2700000A/en
Anticipated expiration legal-status Critical
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    • 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
    • H01J9/047—Cathodes having impregnated bodies
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/14—Solid thermionic cathodes characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
    • H01J1/28—Dispenser-type cathodes, e.g. L-cathode

Definitions

  • Our invention relates to a thermionic cathode and to a method of making the same.
  • our invention relates to cathode containing a supply of an alkaline earth composition capable of furnishing free alkaline earth metal to the cathode surface.
  • Cathodes of the type containing a supply of alkaline earth compounds have been described in U. S. Patent No. 2,543,728 to H. J. Lemmens et al.
  • the supply of alkaline earth compounds are contained in a tightly closed cavity of a body;' one Wall portion of which consists of porous refractory metal, the pores of the wall forming the largest passage ways connecting the cavity tothe exterior of the cathode.
  • the body may be formed by pressing a finely-divided powdered refractory metal and heating to an elevated temperature at which .the particles sinter together and form a cohesive mass which is dense yet porous, i. e., the particles are not melted in this process, but a process of grain-growth appears to take place and the body approaches but never reaches 100%, of theoretical density.
  • sintering is effected at a temperature which will exceed the cathode operating temperature and the temperature at Y which the impregnant material melts and diffuses into the body.
  • Shaping of the body may be effected during the pressing operation but during subsequent heating the body tends to shrink and Warp and close dimensional tolerances cannot be maintained.
  • the'body is irfnpreg mated with a filler metal, i. e., ametal-which does not alloy with the metal of the body, machined, and the filler subsequently removed by volatilization at a temperature below the sintering temperature used in forming the body.
  • the pores in the body thus obtained may now be filled with an alkaline earth composition which does not react with the refractory metal in a manner unproductive of free alkaline earth metal.
  • the alkaline earth metal composition is first heated to a temperature at which the composition melts in a neutral atmosphere.
  • a neutral atmosphere we mean an atmosphere whose constituents do not react with either the refractory metal or the alkaline earth composition in a manner harmful to the operation of the cathode.
  • the atmosphere should contain insignificant amounts of watervapor, carbon dioxide and oxygen. Strongly reducing gases such as hydrogen should alsov be excluded from the atmosphere. Dry noble gases, i. e., helium, argon, neon, xenon, krypton, are examples of desirable neutral atmospheres.
  • the body After cooling, the body is mounted in an evacuated envelope and activated by heating to a temperature at which the alkaline earth composition reacts with the refractory metal to supply a layer of alkaline earth metal substantially one molecule thick on the surface of the body.
  • the cathode is now ready for operation.
  • the body may be impregnated with a filler metal, swaged, or rolled and drawn to a reduced diameter in order to produce filaments which may be processed into cathodes.
  • the body of refractory metal may be formed by extrusion and impregnated with filler metal or powdered refractory metal may be mixed with powdered filler metal and the body pressed and sintered.
  • impregnant materials only those which are capable of reacting with the refractory metal principally in a manner productive of free alkaline earth metal are envisaged by this invention.
  • refractory metals tungsten is preferred but molybdenum, hafnium, 'tantalum, niobium and rhenium among others, may be used.
  • certain alkaline earth compounds notably the nitrates react therewith to form tungstates with a consequent diminution of the amount of free alkaline earth metal being made available in the free state. It is probable that similar reactions occur with the other refractory metals and for that reason we prefer to use no nitrates of the alkaline earth metals.
  • Such preferred impregnants include fused mixtures of an alkaline earth oxide and one or more metal oxides, for instance, oxides of aluminum, beryllium, silicon, boron and thorium, which form materials having at least one phase different than an alkaline earth phase.
  • compositions of barium oxide, aluminum oxide and boric oxide are also very well suited to the invention.
  • Fig. 1 is a sectional view of one cathode according to our invention.
  • Fig. 2 is a sectional view of another embodiment of a cathode according to our invention. and in connection with the following illustrative examples.
  • Fig. 1 shows in section one form of a cathode according to our invention comprising a tube 1 of molybdenum closed at one end by a sintered tungsten disc 2 impregnated with a fused mixture of barium oxide and aluminum oxide in a :2 mol. ratio.
  • the fused mixture completely or partly fills all voids and interstices between the tungsten accessible from the exterior surface of the cathode.
  • a heater 3 is mounted within the tube for heating the cathode.
  • the underside 4 of the disc was lapped to close the pores on that side prior to impregnation of the disc with the alkaline-earth metal composition.
  • Fig. 2 shows a typical cylindrical cathode suitable for use in tubes of the magnetron type wherein large emission currents and long life are desired.
  • the cathode comprises a sintered tungsten tube 5 impregnated with a fused mixture of barium oxide, aluminum oxide and boric oxide containing in excess of 60% by weight of barium oxide with the proportions of the aluminum oxide and boric oxide varying as desired.
  • the tungsten tube is closed at both ends by molybdenum caps 6 which are secured to the tungsten tube by Welding.
  • a heater 7 is enclosed by the tube, the lead-in wires extending through the molybdenum caps.
  • the internal surface of the tungsten tube had been lapped or burnished prior to impregnation to close the pores of its internal wall.
  • the first step in the manufacture of the cathode is that of forming a dense, but porous, body of tungsten having the desired shape and dimensions. While various techniques can be used for this purpose as have been enumerated hereinabove, we prefer to form a tungsten body in accordance with the procedure specifically disclosed in U. S. application Serial No. 234,513 filed June 30, 1951 by Roberto Levi. We prefer to use the same particle size and distribution of tungsten powder disclosed therein and to press the powder and sinter at the stated pressure and temperature. This body can be machined after impregnation with copper and upon removal of the copper by subsequent volatilization at a temperature below that at which the body was sintered results in body which has dimensional stability up to high temperatures, e. g., 2000 C., required porosity, and required density.
  • the tungsten body thus obtained is impregnated With an alkaline earth composition which has a melting point between 25 C. and a temperature below that at which the tungsten was sintered and which is capable of reacting with the tungsten principally in a manner productive of free alkaline earth metal such as compositions containing alkaline earth oxides or carbonates and aluminum oxide, boric oxide, thorium oxide, beryllium oxide and silicon dioxide.
  • free alkaline earth metal such as compositions containing alkaline earth oxides or carbonates and aluminum oxide, boric oxide, thorium oxide, beryllium oxide and silicon dioxide.
  • Compositions containing barium as the alkaline earth metal are preferred but strontium and/ or calcium may be substituted for the barium in Whole or in art.
  • a quantity of barium carbonate and aluminum oxide in the mol is preferred but strontium and/ or calcium may be substituted for the barium in Whole or in art.
  • the barium carbonate is thermally dissociated into barium oxide and carbon dioxide, the latter being pumped out the furnace.
  • the barium oxide and the aluminum oxide fuse into composite mass which can be loosely called barium aluminate.
  • the mass liquifies and diffuses into the pores of the tungsten body filling all voids and interstices in whole or in part.
  • the porous tungsten body is preferably kept in contact with the molten material for the shortest possible period of time consistent with impregnation of the body.
  • the body is removed and its outer surface lightly lapped or brushed to remove any excess barium aluminate on the surface.
  • a molybdenum supporting structure can be welded to the tungsten and the body mounted in an evacuated envelope.
  • the cathode is activated by operating the cathode at a temperature somewhat higher than normal operating temperature, e. g., 1000 C. to 1200 C. until the cathode emits satisfactorily.
  • cathodes which comprise a dense tungsten body having pores therein impregnated with a mixture barium oxide and boric oxide containing over 70% by weight of barium oxide and with mixtures of barium oxide, aluminum oxide and boric oxide with over 60% by weight of barium oxide with the proportions of the latter constituents varying over wide ranges.
  • the cathodes which we have made by our process have been tested for emission and life.
  • Emission data indicates the cathode is capable of supplying about 1 amp/cm. continuously (D.-C. emission) at 1000 C. with pulsed emissions of the order of 1 amp./cm.
  • the indicated life of such cathodes is greater than 1000 hours.
  • the cathodes made by our process may be made to have exceptional dimensional stability because the tungsten body is not subject to shrinkage or warpage due to the high sintering temperatures employed.
  • filamentary type cathodes i. e. wire cathodes
  • shaping operation for example, by swaging the sintered and copper impregnated tungsten body and drawing the body to required diameter.
  • our cathode has one distinct advantage over the internal cavity type of dispenser cathode in which the alkaline earth compounds are contained within a tightly sealed cavity closed by a porous wall portion.
  • the alkaline earth compounds are contained within a tightly sealed cavity closed by a porous wall portion.
  • a cup of refractory metal such as molybdenum and weld the porous tungsten member to the cup.
  • our source of alkaline earth metal is contained wholly within pores of the tungsten body itself, it is no longer necessary to weld a closure member to the tungsten body or to use any other expedient to obtain a tight fit.
  • the cost of manufacture of our cathodes is much less than other known types of dispenser cathodes.
  • a thermionic cathode adapted to operate at an ele vated temperature comprising a sintered body of refractory metal having at least one surface portion adapted to act as an electron-emissive surfave and provided with a large number of interconnected pores forming passageways between said surface portion and at least a portion of the interior of said body, said latter portion being impregnated with a fused mixture of barium oxide and aluminum oxide containing about 60 to by weight of barium oxide.
  • a thermionic cathode adapted to operate at an elevated temperature comprising a sintered body of refractory metal having at least one surface portion adapted to act as an electron-emissive surface and provided with a large number of interconnected pores forming passageways between said surface portion and at least a portion of the interior of said body, said latter portion being impregnated with a fused mixture of barium oxide and aluminum oxide in a molecular ratio of about 5:2.
  • a method of manufacturing a thermionic cathode adapted to operate at elevated temperatures which comprises forming a porous sintered body of refractory metal, and impregnating the pores of said body with a molten mixture of barium oxide and aluminum oxide containing about 60 to 90% by weight of barium oxide.
  • a method of manufacturing a thermionic cathode adapted to operate at elevated temperatures which comprises forming a porous body of densely-sintered refractory metal, and impregnating the pores of said body with a fused mixture of barium oxide and aluminum oxide in a molecular ratio of about 5 :2.
  • a thermionic cathode adapted to operate at an elevated temperature comprising a sintered body of refractory metal having at least one surface portion adapted to act as an electron-emissive surface and provided with a large number of interconnected pores forming passage- Ways between said surface portion and at least a portion of the interior of said body, said latter portion being impregnated with a fused mixture of an alkaline earth metal oxide and an oxide selected from the group consisting of aluminum oxide, silicon dioxide, boric oxide and beryllium oxide, the alkaline earth metal oxide forming a substantial amount of the mixture.
  • a thermionic cathode adapted to operate at an elevated temperature comprising a sintered body of refractory metal having at least one surface portion adapted to act as an electron-emissive surface and provided with a large number of interconnected pores forming passageways between said surface portion and at least a portim of the interior of said body, said latter portion being impregnated with a fused mixture of barium oxide and an oxide selected from the group consisting of aluminum oxide, silicon dioxide, boric oxide, and beryllium oxide, the barium oxide forming at least about 60% by weight of the mixture.
  • a thermionic cathode adapted to operate at an elevated temperature comprising a sintered body of tungsten having at least one surface portion adapted to act as an electron-emissive surface and provided with a large nun;- ber of interconnected pores forming passageways between said surface portion and at least a portion of the interior of said body, said latter portion being impregnated with a fused mixture of barium oxide and an oxide selected from the group consisting of aluminum oxide, silicon iiioxide, boric oxide, and beryllium oxide, the barium oxide forming at least about 60% by weight of the mixture.
  • a thermionic cathode adapted to operate at an elevated temperature comprising a sintered body of refractory metal having at least one surface portion adapted to act as an electron-emissive surface and provided with a large surface portion and at least a portion of the interior of said body, said latter portion being impregnated with a fused mixture of barium oxide, boric oxide, berylliuui oxide and aluminum oxide, the barium oxide forming least about 60% by weight of the mixture.
  • a thermionic cathode adapted to operate at an elevated temperature comprising a sintered body of tungsten having at least one surface portion adapted to act as an electron-emissive surface and provided with a large number of interconnected pores forming passageways between said surface portion and at least a portion of the interior of said body, said latter portion being impregnated with a fused mixture of barium oxide and aluminum oxide in a molecular ratio of about 5 :2.
  • a method of manufacturing a thermionic cathode adapted to operate at elevated temperatures which comprises forming a porous sintered body of refractory metal, and impregnating the pores of said body with a molten mixture of an oxide selected from the group consisting of aluminum oxide, silicon dioxide, boric oxide, beryllium oxige and a substantial amount of an alkaline earth metal 0x1 e.
  • a method of manufacturing a thermionic cathode adapted to operate at elevated temperatures which comprises forming a porous sintered body of refractory metal, and impregnating the pores of said body with a molten mixture of an oxide selected from the group consisting of aluminum oxide, silicon dioxide, boric oxide, beryllium oxide and at least about by weight of barium oxide.
  • a method of manufacturing a thermionic dispenser cathode adapted to operate at elevated temperatures which comprises forming a porous sintered body of tungsten, and impregnating the pores of said body with a molten mixture of an oxide selected from the group consisting of aluminum oxide, boric oxide, silicon dioxide, and beryllium oxide and at least about 60% by weight of barium oxide.
  • a method of manufacturing a thermionic cathode adapted to operate at elevated temperatures which comprises forming a porous sintered body of refractory metal, and impregnating the pores of said body with a molten mixture of aluminum oxide and at least about 60% by weight of barium oxide.
  • a method of manufacturing a thermionic cathode adapted to operate at elevated temperatures which comprises forming a porous sintered body of tungsten, and impregnating the pores of said body with a molten mixture of barium oxide and aluminum oxide in a molecular ratio of about 5:2.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Powder Metallurgy (AREA)
  • Solid Thermionic Cathode (AREA)
  • Discharge Lamp (AREA)
US273607A 1952-02-27 1952-02-27 Thermionic cathode and method of manufacturing same Expired - Lifetime US2700000A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
NL96177D NL96177C (de) 1952-02-27
IT500079D IT500079A (de) 1952-02-27
BE517981D BE517981A (de) 1952-02-27
US273607A US2700000A (en) 1952-02-27 1952-02-27 Thermionic cathode and method of manufacturing same
ES0207960A ES207960A1 (es) 1952-02-27 1953-02-24 MEJORAS INTRODUCIDAS EN LOS CáTODOS PARA TUBOS DE DESCARGA ELÉCTRICA
GB5269/53A GB734311A (en) 1952-02-27 1953-02-25 Improvements in or relating to cathodes for use in electric discharge tubes, tubes comprising such cathodes and methods of manufacturing such cathodes
FR1077589D FR1077589A (fr) 1952-02-27 1953-02-25 Cathode pour tube à décharge
CH318053D CH318053A (de) 1952-02-27 1953-02-25 Verfahren zur Herstellung einer Kathode für elektrische Entladungsröhren
DEN6805A DE1089483B (de) 1952-02-27 1953-02-25 Verfahren zur Herstellung einer Kathode fuer eine elektrische Entladungsroehre
ES0209589A ES209589A1 (es) 1952-02-27 1953-06-01 UN MÉTODO DE FABRICACIoN DE CáTODOS PARA TUBOS DE DESCARGA ELÉCTRICA

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US273607A US2700000A (en) 1952-02-27 1952-02-27 Thermionic cathode and method of manufacturing same

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US (1) US2700000A (de)
BE (1) BE517981A (de)
CH (1) CH318053A (de)
DE (1) DE1089483B (de)
ES (2) ES207960A1 (de)
FR (1) FR1077589A (de)
GB (1) GB734311A (de)
IT (1) IT500079A (de)
NL (1) NL96177C (de)

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2813807A (en) * 1954-07-19 1957-11-19 Philips Corp Method of making a dispenser cathode
US2869017A (en) * 1956-10-24 1959-01-13 Philips Corp Thermionic dispenser cathode
US2899592A (en) * 1953-11-18 1959-08-11 coppola
US2912611A (en) * 1953-08-14 1959-11-10 Int Standard Electric Corp Thermionic cathodes
US2917415A (en) * 1956-07-24 1959-12-15 Philips Corp Method of making thermionic dispenser cathode and cathode made by said method
US2975320A (en) * 1958-12-03 1961-03-14 Rca Corp Low-temperature plasma source
US2986799A (en) * 1957-01-03 1961-06-06 Philips Corp Method of making cathodes
US2995674A (en) * 1959-02-27 1961-08-08 Raytheon Co Impregnated cathodes
US3041209A (en) * 1955-06-28 1962-06-26 Gen Electric Method of making a thermionic cathode
US3075066A (en) * 1957-12-03 1963-01-22 Union Carbide Corp Article of manufacture and method of making same
US3076916A (en) * 1959-01-21 1963-02-05 Semicon Associates Inc Impregnated tungsten cathode structures and methods for fabricating same
US3139541A (en) * 1960-07-05 1964-06-30 Monsanto Co Generation of power using emissive materials
US3155864A (en) * 1960-03-21 1964-11-03 Gen Electric Dispenser cathode
US3160780A (en) * 1961-01-17 1964-12-08 Philips Corp Indirectly heated cathode
US3258636A (en) * 1961-09-01 1966-06-28 Electron emitter with activator of sill cide, boride or carbide of solid solu- tion of barium and at least one other alkaline earth metal
US3456311A (en) * 1965-12-07 1969-07-22 Philips Corp Method and apparatus for adjusting interelectrode spacing in a cathode-ray tube
US3467879A (en) * 1966-03-08 1969-09-16 Philips Corp Planar dispenser cathode assembly with a cap member to which an electronemissive,tubular heater,and rodshaped support members are clamped
US3514324A (en) * 1967-05-01 1970-05-26 Kopco Ind Tungsten coating of dispenser cathode
US3538570A (en) * 1968-02-28 1970-11-10 Otto G Koppius Thermionic dispenser cathode
US4097762A (en) * 1975-08-14 1978-06-27 International Telephone & Telegraph Corporation Xenon arc discharge lamp having a particular electrode composition and wherein the arc discharge is obtained without heating the electrode
US4377505A (en) * 1980-12-29 1983-03-22 General Electric Company Electrical resistor and fabrication thereof
WO1985002071A1 (en) * 1983-11-02 1985-05-09 Brunswick Corporation Tuning apparatus for a radio frequency power device
US4636749A (en) * 1979-08-13 1987-01-13 Brunswick Corporation Pulsed magnetron tube having improved electron emitter assembly
US4675570A (en) * 1984-04-02 1987-06-23 Varian Associates, Inc. Tungsten-iridium impregnated cathode
US5173633A (en) * 1990-01-31 1992-12-22 Samsung Electron Devices Co., Ltd. Dispenser cathode
US5417600A (en) * 1992-01-22 1995-05-23 Mitsubishi Denki Kabushiki Kaisha Method of manufacturing an impregnation type cathode
US5418070A (en) * 1988-04-28 1995-05-23 Varian Associates, Inc. Tri-layer impregnated cathode
EP0882307B1 (de) * 1996-12-18 2004-01-28 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Sinterelektrode
US20090284124A1 (en) * 2008-04-22 2009-11-19 Wolfgang Kutschera Cathode composed of materials with different electron works functions

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2514945A1 (fr) * 1981-10-20 1983-04-22 Thomson Csf Cathode a chauffage indirect et tube electronique, a rayons cathodiques notamment, muni d'une telle cathode

Citations (3)

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Publication number Priority date Publication date Assignee Title
US1735080A (en) * 1923-01-12 1929-11-12 Philips Nv Electron-emitting cathode
US2389060A (en) * 1943-08-13 1945-11-13 Callite Tungsten Corp Refractory body of high electronic emission
US2547869A (en) * 1947-10-31 1951-04-03 Sylvania Electric Prod Fluorescent lamp electrode

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH159791A (de) * 1931-02-14 1933-01-31 Aeg Glühkathode für elektrische Entladungsgefässe.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1735080A (en) * 1923-01-12 1929-11-12 Philips Nv Electron-emitting cathode
US2389060A (en) * 1943-08-13 1945-11-13 Callite Tungsten Corp Refractory body of high electronic emission
US2547869A (en) * 1947-10-31 1951-04-03 Sylvania Electric Prod Fluorescent lamp electrode

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2912611A (en) * 1953-08-14 1959-11-10 Int Standard Electric Corp Thermionic cathodes
US2899592A (en) * 1953-11-18 1959-08-11 coppola
US2813807A (en) * 1954-07-19 1957-11-19 Philips Corp Method of making a dispenser cathode
US3041209A (en) * 1955-06-28 1962-06-26 Gen Electric Method of making a thermionic cathode
US2917415A (en) * 1956-07-24 1959-12-15 Philips Corp Method of making thermionic dispenser cathode and cathode made by said method
US2869017A (en) * 1956-10-24 1959-01-13 Philips Corp Thermionic dispenser cathode
US2986799A (en) * 1957-01-03 1961-06-06 Philips Corp Method of making cathodes
US3075066A (en) * 1957-12-03 1963-01-22 Union Carbide Corp Article of manufacture and method of making same
US2975320A (en) * 1958-12-03 1961-03-14 Rca Corp Low-temperature plasma source
US3076916A (en) * 1959-01-21 1963-02-05 Semicon Associates Inc Impregnated tungsten cathode structures and methods for fabricating same
US2995674A (en) * 1959-02-27 1961-08-08 Raytheon Co Impregnated cathodes
US3155864A (en) * 1960-03-21 1964-11-03 Gen Electric Dispenser cathode
US3139541A (en) * 1960-07-05 1964-06-30 Monsanto Co Generation of power using emissive materials
US3160780A (en) * 1961-01-17 1964-12-08 Philips Corp Indirectly heated cathode
US3258636A (en) * 1961-09-01 1966-06-28 Electron emitter with activator of sill cide, boride or carbide of solid solu- tion of barium and at least one other alkaline earth metal
US3456311A (en) * 1965-12-07 1969-07-22 Philips Corp Method and apparatus for adjusting interelectrode spacing in a cathode-ray tube
US3467879A (en) * 1966-03-08 1969-09-16 Philips Corp Planar dispenser cathode assembly with a cap member to which an electronemissive,tubular heater,and rodshaped support members are clamped
US3514324A (en) * 1967-05-01 1970-05-26 Kopco Ind Tungsten coating of dispenser cathode
US3538570A (en) * 1968-02-28 1970-11-10 Otto G Koppius Thermionic dispenser cathode
US4097762A (en) * 1975-08-14 1978-06-27 International Telephone & Telegraph Corporation Xenon arc discharge lamp having a particular electrode composition and wherein the arc discharge is obtained without heating the electrode
US4636749A (en) * 1979-08-13 1987-01-13 Brunswick Corporation Pulsed magnetron tube having improved electron emitter assembly
US4377505A (en) * 1980-12-29 1983-03-22 General Electric Company Electrical resistor and fabrication thereof
WO1985002071A1 (en) * 1983-11-02 1985-05-09 Brunswick Corporation Tuning apparatus for a radio frequency power device
US4675570A (en) * 1984-04-02 1987-06-23 Varian Associates, Inc. Tungsten-iridium impregnated cathode
US5418070A (en) * 1988-04-28 1995-05-23 Varian Associates, Inc. Tri-layer impregnated cathode
US5173633A (en) * 1990-01-31 1992-12-22 Samsung Electron Devices Co., Ltd. Dispenser cathode
US5417600A (en) * 1992-01-22 1995-05-23 Mitsubishi Denki Kabushiki Kaisha Method of manufacturing an impregnation type cathode
EP0882307B1 (de) * 1996-12-18 2004-01-28 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Sinterelektrode
US20090284124A1 (en) * 2008-04-22 2009-11-19 Wolfgang Kutschera Cathode composed of materials with different electron works functions

Also Published As

Publication number Publication date
ES207960A1 (es) 1953-07-16
DE1089483B (de) 1960-09-22
IT500079A (de)
CH318053A (de) 1956-12-15
NL96177C (de)
GB734311A (en) 1955-07-27
ES209589A1 (es) 1953-07-16
FR1077589A (fr) 1954-11-09
BE517981A (de)

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