EP0549034B1 - Kathode und Verfahren zu ihrer Herstellung - Google Patents

Kathode und Verfahren zu ihrer Herstellung Download PDF

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Publication number
EP0549034B1
EP0549034B1 EP92203887A EP92203887A EP0549034B1 EP 0549034 B1 EP0549034 B1 EP 0549034B1 EP 92203887 A EP92203887 A EP 92203887A EP 92203887 A EP92203887 A EP 92203887A EP 0549034 B1 EP0549034 B1 EP 0549034B1
Authority
EP
European Patent Office
Prior art keywords
scandium
layer
tungsten
cathode
metallic
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 - Lifetime
Application number
EP92203887A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0549034A1 (de
Inventor
Georg Dr. Gärtner
Jan Dr. Hasker
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.)
Philips Intellectual Property and Standards GmbH
Koninklijke Philips NV
Original Assignee
Philips Patentverwaltung GmbH
Koninklijke Philips Electronics NV
Philips Electronics NV
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
Application filed by Philips Patentverwaltung GmbH, Koninklijke Philips Electronics NV, Philips Electronics NV filed Critical Philips Patentverwaltung GmbH
Publication of EP0549034A1 publication Critical patent/EP0549034A1/de
Application granted granted Critical
Publication of EP0549034B1 publication Critical patent/EP0549034B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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

  • the invention relates to a cathode with a matrix body impregnated with an alkaline earth compound, on the surface of which a cover layer is applied, which contains high-melting metal such as, in particular, tungsten and scandium.
  • a cathode of this type is known from US-PS 48 55 637.
  • a cover layer applied by sputtering is proposed, which consists of individual layers of different densities each containing tungsten and scandium.
  • Hot cathodes with cover layers containing scandium have a high emission at relatively low temperatures, for example 100 A / cm2 at 950 ° C.
  • these cathodes are well suited because of their high emission. It is important that the cathodes show good resistance or regenerability after an ion bombardment that occurs when the tube is formed or in poor vacuum conditions. Ion bombardment causes the barium-oxygen surface complex to evaporate on tungsten, which is responsible for the high emission of such an alkaline earth replenishment cathode. A good recovery after ion bombardment requires a quick delivery of the components involved, especially from Scandium.
  • the invention has for its object to design a cathode of the type mentioned in such a way that a high emission at low operating temperature and at the same time a rapid recovery after ion bombardment and a long service life are achieved.
  • the cover layer contains at least two layers of different composition, a metallic layer having scandium and a high-melting metal such as in particular tungsten and / or rhenium being applied to the impregnated matrix body, and a metallic layer as the final layer a high-melting metal such as tungsten is applied.
  • the first metallic layer consists of tungsten and scandium.
  • the metallic scandium segregates particularly quickly to the tungsten surface. A possible excessive evaporation of scandium can be prevented by applying at least one layer containing scandium oxide between the first metallic layer containing scandium and tungsten and the final tungsten layer.
  • the subsequent delivery of alkaline earth oxide through the cover layer to the tungsten surface can be improved in that the cover layer is provided with openings extending up to the matrix body.
  • cathodes according to the invention can be produced particularly advantageously by first producing metallic layers of scandium and / or rhenium by means of a plasma-activated CVD process in particular, preferably by means of a plasma produced by direct current glow discharge, and that subsequently a last layer Metallic tungsten layer is applied by means of a CVD process.
  • intermetallic scandium compounds directly in the cover layer by simultaneously supplying such suitable gases which contain scandium in the form of, in particular, organic compounds and, on the other hand, another metal such as, in particular, rhenium.
  • a suitable process variant consists in that the constituents of the cover layer are each applied in the form of separate and optionally alternating layers.
  • a desired structure can then be implemented particularly easily in terms of process technology.
  • the desired intermetallic connection form can then be formed by suitable thermal aftertreatment.
  • scandium oxide layers in the cover layer, these can be formed in a simple manner by at least one of the scandate layers being reoxidized by means of an oxygen-containing plasma before the subsequent layer is applied.
  • I-cathode pills which consist of a tungsten matrix impregnated with 4BaO.CaO.Al2O3 or with 5BaO.3CaO.2Al2O3.
  • the I-cathode pills 1 were each provided by means of a plasma-activated CVD process (PCVD) with scandium-containing and approximately 20 ⁇ m thick cover layers 2, 3 and 4.
  • the cover layers contain a first metallic layer 5 or 6 or 7 and a final tungsten layer.
  • the layer of the intermetallic compound Re24Sc5 according to FIG. 2 can also be achieved from the outset by simultaneous deposition from the gas phase.
  • the cover layer 4 consists of Sc and W layers which are initially applied in an alternating sequence.
  • a Sc2O3 layer is provided below the final W layer. All individual layers of the top layer 4 are applied by PCVD.
  • the cover layers 3 and 4 are provided with openings 8 and 9, which are approximately 1 to 2 ⁇ m wide, which follow one another at intervals of approximately 20 ⁇ m and were punched through previously polished cover layers by means of an NdYAG or excimer laser .
  • PCVD deposition can be carried out using suitable known devices.
  • a plurality of cathode pills 1 can be arranged on the inner wall of a support cylinder and then coated in a device according to EP-B-0204 356.
  • Metallic Sc layers can be deposited from an Ar carrier gas loaded with Sc (C5H7O2) 3 or with Sc (C5H4F3O2) 3 or with Sc (C5HF6O2) 3, the PCVD reactor H2 with about 10 to 20 times the flux in Comparison to the SC connection is added. After the deposition of a respective Sc layer, an Ar / H2 plasma aftertreatment is advantageously carried out.
  • a simultaneous deposition for the immediate formation of an intermetallic Sc / Re layer can advantageously be carried out from a Sc (C5H7O2) 3 / ReF6 / H2 gas mixture with Ar / H2 intermediate treatments.
  • Another Sc- ⁇ -diketonate or an Sc-halide can also be used as the starting compound containing scandium.
  • 3 can be formed from a metallic Sc layer in that it is subsequently treated by means of a plasma-activated oxygen-rich gas mixture, in particular Ar / O2.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Vapour Deposition (AREA)
  • Solid Thermionic Cathode (AREA)
EP92203887A 1991-12-21 1992-12-14 Kathode und Verfahren zu ihrer Herstellung Expired - Lifetime EP0549034B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4142535A DE4142535A1 (de) 1991-12-21 1991-12-21 Scandat-kathode und verfahren zur ihrer herstellung
DE4142535 1991-12-21

Publications (2)

Publication Number Publication Date
EP0549034A1 EP0549034A1 (de) 1993-06-30
EP0549034B1 true EP0549034B1 (de) 1995-09-27

Family

ID=6447855

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92203887A Expired - Lifetime EP0549034B1 (de) 1991-12-21 1992-12-14 Kathode und Verfahren zu ihrer Herstellung

Country Status (4)

Country Link
US (1) US5936334A (ja)
EP (1) EP0549034B1 (ja)
JP (1) JPH05266786A (ja)
DE (2) DE4142535A1 (ja)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6034469A (en) 1995-06-09 2000-03-07 Kabushiki Kaisha Toshiba Impregnated type cathode assembly, cathode substrate for use in the assembly, electron gun using the assembly, and electron tube using the cathode assembly
DE19527723A1 (de) * 1995-07-31 1997-02-06 Philips Patentverwaltung Elektrische Entladungsröhre oder Entladungslampe und Scandat-Vorratskathode
DE19828729B4 (de) * 1998-06-29 2010-07-15 Philips Intellectual Property & Standards Gmbh Scandat-Vorratskathode mit Barium-Calcium-Aluminat-Schichtabfolge und korrespondierende elektrische Entladungsröhre
US6420822B1 (en) * 1999-07-15 2002-07-16 Northrop Grumman Corporation Thermionic electron emitter based upon the triple-junction effect
US20030025435A1 (en) * 1999-11-24 2003-02-06 Vancil Bernard K. Reservoir dispenser cathode and method of manufacture
DE19961672B4 (de) * 1999-12-21 2009-04-09 Philips Intellectual Property & Standards Gmbh Scandat-Vorratskathode
EP2178997A2 (en) * 2007-07-23 2010-04-28 Hyperbranch Medical Technology, Inc. Polymeric masking materials for spanning wound sites, and methods of use thereof
CN104299869B (zh) * 2014-09-26 2017-01-11 北京工业大学 一种浸渍型Re3W-Sc2O3混合基阴极材料及其制备方法

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4101800A (en) * 1977-07-06 1978-07-18 The United States Of America As Represented By The Secretary Of The Navy Controlled-porosity dispenser cathode
NL8403032A (nl) * 1984-10-05 1986-05-01 Philips Nv Werkwijze voor het vervaardigen van een scandaatnaleveringskathode, naleveringskathode vervaardigd met deze werkwijze.
JPS61183838A (ja) * 1985-02-08 1986-08-16 Hitachi Ltd 含浸形カソ−ド
KR900009071B1 (ko) * 1986-05-28 1990-12-20 가부시기가이샤 히다찌세이사구쇼 함침형 음극
JPS63224127A (ja) * 1987-03-11 1988-09-19 Hitachi Ltd 含浸形陰極
KR910002969B1 (ko) * 1987-06-12 1991-05-11 미쓰비시전기주식회사 전자관음극(cathode for an electron tube)
NL8702727A (nl) * 1987-11-16 1989-06-16 Philips Nv Scandaatkathode.
FR2647952A1 (fr) * 1989-05-30 1990-12-07 Thomson Tubes Electroniques Cathode thermoelectronique impregnee pour tube electronique
DE4114856A1 (de) * 1991-05-07 1992-11-12 Licentia Gmbh Vorratskathode und verfahren zu deren herstellung

Also Published As

Publication number Publication date
US5936334A (en) 1999-08-10
DE4142535A1 (de) 1993-06-24
JPH05266786A (ja) 1993-10-15
DE59203841D1 (de) 1995-11-02
EP0549034A1 (de) 1993-06-30

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