EP0056749B1 - Cathode à chauffage direct, et son procédé de fabrication - Google Patents

Cathode à chauffage direct, et son procédé de fabrication Download PDF

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Publication number
EP0056749B1
EP0056749B1 EP82400030A EP82400030A EP0056749B1 EP 0056749 B1 EP0056749 B1 EP 0056749B1 EP 82400030 A EP82400030 A EP 82400030A EP 82400030 A EP82400030 A EP 82400030A EP 0056749 B1 EP0056749 B1 EP 0056749B1
Authority
EP
European Patent Office
Prior art keywords
tungsten
oxide
cathode
mixture
rare earths
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP82400030A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0056749A3 (en
EP0056749A2 (fr
Inventor
Guy Clerc
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=9254238&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0056749(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0056749A2 publication Critical patent/EP0056749A2/fr
Publication of EP0056749A3 publication Critical patent/EP0056749A3/fr
Application granted granted Critical
Publication of EP0056749B1 publication Critical patent/EP0056749B1/fr
Expired legal-status Critical Current

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Classifications

    • 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

Definitions

  • the subject of the present invention is a cathode for a high frequency electronic tube, and more particularly a thermoelectronic emission cathode with direct heating.
  • the cathodes are generally produced from tungsten or thoriated tungsten wires for reasons of thermoelectronic emissivity, the operating temperature is then between 1,900 and 2,000 ° K.
  • Mechanical problems then arise due to the difference in thermal behavior of the materials, problems imperfectly resolved by expensive mechanical assemblies. It has been proposed to avoid thermo-mechanical problems inside the tube while ensuring good thermo-electronic emissivity by introducing direct heating from a pyrolytic graphite support and by depositing a material on the graphite surface. emitting at a lower temperature than tungsten or thoriated tungsten such as lanthanum hexaboride La B 6 for example.
  • Such a structure makes it possible to obtain electronic emission at a temperature between 1,400 and 1,500 ° C.
  • emissive materials such as lanthanum hexaboride is their high chemical activity vis-à-vis hot graphite, which can lead to the destruction of the cathode.
  • Application FR-A-2,445,605 discloses a direct heating cathode comprising a pyrolytic graphite support heated by the Joule effect and an emissive layer based on lanthanum hexaboride which is separated from the support by an intermediate layer.
  • the present invention relates to a direct heating cathode working at the same temperature as the lanthanum hexaboride cathode, but not requiring an intermediate layer between the graphite and the emissive layer.
  • the advantage lies in the elimination of the intermediate layer.
  • the present invention relates to a direct heating cathode comprising a support cut out of pyrolytic graphite heated by the Joule effect and an emissive coating, characterized in that this coating consists of an emissive layer composed of a mixture of tungsten and rare earth oxide.
  • the present invention relates to a direct heating cathode comprising a support cut out of pyrolytic graphite heated by the Joule effect and an emissive coating, characterized in that this coating consists of an emissive layer and a surface layer, the emissive layer being composed of a mixture of tungsten and rare earth oxide and the surface layer consisting of tungsten hemicarbide.
  • the present invention relates to a direct heating cathode comprising a support cut out of pyrolytic graphite heated by the Joule effect and an emissive coating, characterized in that this coating consists of an emissive layer composed of a mixture of tungsten , rare earth oxide and tungsten carbide.
  • This comprises a support 1 of pyrolytic graphite with a thickness of approximately 200 ⁇ m, on which is deposited, by plasma or by cathode sputtering, or by any other means known to those skilled in the art, a homogeneous layer 2 of a mixture of tungsten and lanthanum oxide, the latter being in proportions of between 0.5% and 10%, the thickness of layer 2 can be between 50 and 100 ⁇ m.
  • the tungsten of the emissive layer can be transformed in its surface part 3, over a thickness of 10 to 20 k tm, into tungsten hemicarb W 2 C. This transformation is carried out in the usual way by heating the cathode in vapors of hydrocarbon at a temperature of about 1,800 ° C.
  • tungsten carbide can be codeposited with tungsten and lanthanum oxide, in a proportion ranging from 10% to 50% carbide, 0.5 to 10% lanthanum oxide, the balance being made by tungsten. This variant eliminates the carburetion process of tungsten.
EP82400030A 1981-01-16 1982-01-08 Cathode à chauffage direct, et son procédé de fabrication Expired EP0056749B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8100782 1981-01-16
FR8100782A FR2498372A1 (fr) 1981-01-16 1981-01-16 Cathode a chauffage direct, son procede de fabrication, et tube electronique incorporant une telle cathode

Publications (3)

Publication Number Publication Date
EP0056749A2 EP0056749A2 (fr) 1982-07-28
EP0056749A3 EP0056749A3 (en) 1982-08-25
EP0056749B1 true EP0056749B1 (fr) 1984-10-17

Family

ID=9254238

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82400030A Expired EP0056749B1 (fr) 1981-01-16 1982-01-08 Cathode à chauffage direct, et son procédé de fabrication

Country Status (5)

Country Link
US (1) US4577134A (ja)
EP (1) EP0056749B1 (ja)
JP (1) JPS57138744A (ja)
DE (1) DE3260969D1 (ja)
FR (1) FR2498372A1 (ja)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3148441A1 (de) * 1981-12-08 1983-07-21 Philips Patentverwaltung Gmbh, 2000 Hamburg Verfahren zur herstellung einer thermionischen kathode
US4810926A (en) * 1987-07-13 1989-03-07 Syracuse University Impregnated thermionic cathode
DE4026300A1 (de) * 1990-08-20 1992-02-27 Siemens Ag Elektronenemitter einer roentgenroehre
DE69409306T2 (de) * 1993-07-29 1998-07-30 Nec Corp Thermisch emittierende Kathode, Herstellungsverfahren einer solchen thermisch emittierende Kathode und Elektronenstrahl-Gerät
FR2733856B1 (fr) * 1995-05-05 1997-08-29 Thomson Tubes Electroniques Cathode pour canon a electrons a grille, grille destinee a etre associee avec une telle cathode et canon a electrons comportant une telle cathode
FR2775118B1 (fr) 1998-02-13 2000-05-05 Thomson Tubes Electroniques Grille pour tube electronique a faisceau axial a performances ameliorees
FR2789800B1 (fr) 1999-02-16 2001-05-11 Thomson Tubes Electroniques Generateur radiofrequence de tres grande puissance
DE102008020187A1 (de) * 2008-04-22 2009-10-29 Siemens Aktiengesellschaft Kathode mit einem Flachemitter
CN106756169B (zh) * 2011-12-20 2018-07-17 株式会社东芝 钨合金、以及使用该钨合金的钨合金部件、放电灯、发射管和磁控管
US20170330725A1 (en) * 2016-05-13 2017-11-16 Axcelis Technologies, Inc. Lanthanated tungsten ion source and beamline components

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3389977A (en) * 1964-08-05 1968-06-25 Texas Instruments Inc Tungsten carbide coated article of manufacture
US3719856A (en) * 1971-05-19 1973-03-06 O Koppius Impregnants for dispenser cathodes
CH582951A5 (ja) * 1973-07-09 1976-12-15 Bbc Brown Boveri & Cie
NL175480C (nl) * 1974-06-12 1984-11-01 Philips Nv Elektrode voor een ontladingslamp, werkwijze voor de vervaardiging van een dergelijke elektrode en ontladingslamp voorzien van een dergelijke elektrode.
CH579824A5 (ja) * 1974-10-25 1976-09-15 Bbc Brown Boveri & Cie
US4019081A (en) * 1974-10-25 1977-04-19 Bbc Brown Boveri & Company Limited Reaction cathode
JPS6053418B2 (ja) * 1976-08-09 1985-11-26 株式会社日立製作所 電子管陰極構体
DE2732960C2 (de) * 1977-07-21 1982-04-01 Philips Patentverwaltung Gmbh, 2000 Hamburg Glühkathode und Verfahren zu ihrer Herstellung
DE2838020B2 (de) * 1978-08-31 1981-04-02 Siemens AG, 1000 Berlin und 8000 München Direkt geheizte Kathode für eine Elektronenröhre mit koaxialem Elektrodenaufbau und Verfahren zu ihrer Herstellung
FR2445605A1 (fr) * 1978-12-27 1980-07-25 Thomson Csf Cathode a chauffage direct et tube electronique haute frequence comportant une telle cathode

Also Published As

Publication number Publication date
JPS57138744A (en) 1982-08-27
EP0056749A3 (en) 1982-08-25
EP0056749A2 (fr) 1982-07-28
DE3260969D1 (en) 1984-11-22
FR2498372A1 (fr) 1982-07-23
US4577134A (en) 1986-03-18
FR2498372B1 (ja) 1983-07-22

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