EP0441698B1 - Herstellungsverfahren einer Impregnierungskathode und mittels eines solchen Verfahrens gewonnene Kathode - Google Patents

Herstellungsverfahren einer Impregnierungskathode und mittels eines solchen Verfahrens gewonnene Kathode Download PDF

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Publication number
EP0441698B1
EP0441698B1 EP91400272A EP91400272A EP0441698B1 EP 0441698 B1 EP0441698 B1 EP 0441698B1 EP 91400272 A EP91400272 A EP 91400272A EP 91400272 A EP91400272 A EP 91400272A EP 0441698 B1 EP0441698 B1 EP 0441698B1
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EP
European Patent Office
Prior art keywords
cathode
impregnated
powder
barium
mixture
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
EP91400272A
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English (en)
French (fr)
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EP0441698A1 (de
Inventor
Arvind Shroff
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 Electron Devices SA
Original Assignee
Thomson Tubes Electroniques
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Filing date
Publication date
Application filed by Thomson Tubes Electroniques filed Critical Thomson Tubes Electroniques
Publication of EP0441698A1 publication Critical patent/EP0441698A1/de
Application granted granted Critical
Publication of EP0441698B1 publication Critical patent/EP0441698B1/de
Anticipated expiration legal-status Critical
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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
    • H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
    • H01J1/28—Dispenser-type cathodes, e.g. L-cathode
    • 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

Definitions

  • the present invention relates to a method of manufacturing an impregnated cathode and a cathode obtained by this method. It finds an application in the production of cathodes for electronic tubes and more particularly but not exclusively for cathode ray display tubes.
  • Impregnated cathodes are commonly used to provide electronic current densities of up to 1 to 2 A / cm2 continuously and more in pulses.
  • the impregnated cathodes known from the prior art consist of a porous body of refractory metal, such as pure tungsten, or else of a mixture of tungsten, either with a metal originating from the platinum mine (mixed matrix), such as known from document FR A 2 356 263, either with scandium oxide or other rare earths in low concentration (3 to 5% by weight).
  • This porous body is generally obtained by compressing a finely divided powder of the metal (or mixture of metals) using an isostatic press or a uniaxial press.
  • the compacts thus obtained are then heated under hydrogen at high temperature, in order to sinter the particles together and to increase the density of the porous body.
  • the porous body To facilitate the machining of the porous body, it is infiltrated with copper or plastic, then machined to the desired shape. Subsequently, the copper or plastic is removed by dissolving in an acid or by heating.
  • the porous body of the desired shape is then brazed on a molybdenum skirt which serves to hold, on one side, the emissive patch and, on the other, a filament potted in alumina which allows the heating of the cathode .
  • a molybdenum skirt which serves to hold, on one side, the emissive patch and, on the other, a filament potted in alumina which allows the heating of the cathode .
  • the pores of the porous body can be filled with barium and calcium aluminates.
  • the body is impregnated with these aluminates, which constitute the emissive material of the finished cathode.
  • the porous body is kept in close contact with an aluminate composition brought, under a reducing atmosphere, to a temperature above its melting point. Contact is ensured, either by immersing the porous body in the aluminate, or by placing the aluminate on the porous body. At the time of fusion, the aluminate diffuses by capillarity or by flow inside the open pores and fills them. The cathode is then cleaned mechanically and chemically, in order to remove the aluminate residues which have remained stuck on the surfaces.
  • the cathode is activated, under vacuum, at a temperature at which tungsten reduces barium and calcium aluminate to release barium oxide.
  • Metallic barium is produced in areas where the aluminate is in contact with the refractory metal (pores). The metallic barium reaches the end of the pores and diffuses over the entire emissive surface where it forms with oxygen a surface monolayer which promotes electronic emissivity by lowering the work of electron output.
  • the deposition, on the emissive surface of these impregnated cathodes, of a film of osmium, iridium, ruthenium, or an alloy of these bodies, this film having a thickness of a few thousand Angstroms can improve emissivity by a factor of around 3.
  • the mixed matrix cathode, covered with a refractory metal film, is known from document FR 4 2 469 792 in the name of the applicant.
  • the method according to the present invention aims precisely to remedy these drawbacks.
  • the invention recommends an original method which provides the advantages of impregnated cathodes, which makes it possible to obtain cathodes of equal quality but with a procedure which is substantially simplified compared to those known from the prior art.
  • the process according to the invention has for characteristic those of claim 1.
  • the powder of tungsten or of a mixture of tungsten and of a metal of the platinum mine or of a scandium oxide or of the three materials is mixed with a powder of aluminate, barium and calcium in the desired stoichiometric proportions, then this mixture is pressed in the form of pellets and sintered, under a hydrogen atmosphere, at a temperature higher than the melting temperature of aluminates.
  • the mixture comprises tungsten or tungsten powder and other materials as above, with barium and calcium and alumina carbonates in the desired stoichiometric proportions.
  • This mixture is then compressed and sintered at the same temperature than before. In this way, the aluminate is formed during "in situ" sintering.
  • the emissive surface of the pellet obtained according to the method of the invention is covered with a film of osmium, iridium or rhenium to increase its emissive properties.
  • the filament is brought and potted in a conventional manner, and the cathode is activated in the same manner as above.
  • the method according to the invention makes it possible to obtain all the advantages known from the prior art of impregnated cathodes, whether they are of simple matrix (pure tungsten) or mixed, covered or not, but with simplified procedures, shorter and less expensive, with a significantly reduced number of steps compared to the prior art, which makes it possible to obtain an equal quality of finished product with less critical handling and therefore with fewer controls.
  • the method according to the invention is therefore particularly suitable for industrial production at high speed and at low cost of cathodes with high current density and with a relatively long service life, which makes it possible to envisage their use in equipment intended for wide distribution.
  • the invention therefore relates to a method of manufacturing an impregnated cathode, characterized in that an emissive pellet is produced by co-pressing and sintering a mixture of at least one powder of refractory metal with a powder of barium and calcium aluminates, or with barium and calcium carbonates added with alumina.
  • the subject of the invention is also an impregnated cathode as obtained by implementing the method which has just been defined.
  • the invention also relates to variants of impregnated cathodes which can be produced using the process which has just been defined; for example cathodes produced according to the method of the invention and then covered with a metal film of platinum mine or the like in order to increase its electronic emissivity or to lower the operating temperature while keeping the emissivity constant.
  • the subject of the invention is also variants of impregnated cathodes which can be produced starting from the very principle of the process of the invention, for example of cathodes produced according to the process of the invention, but with, in addition to the mixture of the powder of a refractory metal and the aluminates or carbonates of barium and calcium, addition of the oxide of scandium or rare earths,
  • Other variants of the process according to the invention could easily be imagined and implemented by a person skilled in the art, in order to reap the advantages obtained by the invention with particular advantages known by elsewhere, for specific applications.
  • FIG. 1 we see an example of an impregnated cathode manufactured according to the method of the invention, illustrated in these main steps in this FIG. 1.
  • the emitting tablet (1) is formed by pressing (c) and sintering (d), in a conventional manner, of a mixture (b), of a powder (w) of at least one refractory metal with a powder (y) barium and calcium aluminate or barium and calcium carbonates with alumina.
  • At least one of the starting powders (w) is a powder of known elements such as tungsten, molybdenum, tantalum, rhenium or the alloys containing them, or a powder of an element capable of improving the electronic emission, such as osmium, ruthenium, iridium or alloys containing at least one of these elements or, finally, a powder of scandium oxide or particles of oxides containing scandium.
  • the skirt (4) can be made integral with the assembly by crimping (f) on the cup (3).
  • the heating filament (5) previously covered with an alumina film (not shown), can be mounted in the skirt and held in place by an alumina body (6) commonly known by the English word “potting ".
  • This "potting" operation can be done, for example, by sintering at 1800 ° C. under hydrogen from an alumina powder deposited using a suspension around the filament inside the skirt.
  • the emissive patch could be covered with a thin metallic film with a thickness of between 10 and 30,000 Angstroms, for example, the metallic material being able to be selected from the group comprising osmium, ruthenium, iridium, and the alloys containing any of these.
  • This film can be deposited by conventional means of sputtering, vacuum deposition, or any other suitable means.
  • the method according to the invention has the advantage, compared to the prior art, of being feasible with a significantly reduced number of steps, and with less critical handling for the quality of the product. This results in the possibility of a better production yield, simultaneously with an accelerated rate and at lower cost per part.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Solid Thermionic Cathode (AREA)
  • Powder Metallurgy (AREA)

Claims (5)

  1. Verfahren zum Herstellen einer imprägnierten Katode, dadurch gekennzeichnet, daß durch Pressen und Sintern einer Mischung aus wenigstens einem Pulver (w) aus hitzebeständigem Metall und einem Pulver (y) aus Aluminaten von Barium und Calcium oder Carbonaten von Barium und Calcium mit hinzugefügtem Aluminiumoxid unter Wasserstoffatmosphäre bei einer zum Erreichen der Schmelztemperatur der Aluminate ausreichenden Temperatur eine emittierende Pille (1) hergestellt wird.
  2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Mischung von wenigstens einem Pulver aus hitzebeständigem Metall Wolframpulver gemischt mit dem Pulver aus einer natürlichen Metallegierung der Platingruppe enthält.
  3. Verfahren nach einem der Ansprüche 1 bis 2 mit Hinzufügung des Pulvers aus Scandiumoxid oder von seltenen Erden mit schwacher Konzentration in der Größenordnung von 5 %.
  4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die emittierende Pille (1) nach dem Pressen und Sintern mit einer dünnen Schicht der natürlichen Metallegierung der Platingruppe überzogen wird.
  5. Imprägnierte Katode, hergestellt nach einem der Ansprüche 1 bis 4.
EP91400272A 1990-02-09 1991-02-05 Herstellungsverfahren einer Impregnierungskathode und mittels eines solchen Verfahrens gewonnene Kathode Expired - Lifetime EP0441698B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9001518A FR2658360B1 (fr) 1990-02-09 1990-02-09 Procede de fabrication d'une cathode impregnee et cathode obtenue par ce procede.
FR9001518 1990-02-09

Publications (2)

Publication Number Publication Date
EP0441698A1 EP0441698A1 (de) 1991-08-14
EP0441698B1 true EP0441698B1 (de) 1995-09-27

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EP91400272A Expired - Lifetime EP0441698B1 (de) 1990-02-09 1991-02-05 Herstellungsverfahren einer Impregnierungskathode und mittels eines solchen Verfahrens gewonnene Kathode

Country Status (7)

Country Link
US (1) US5334085A (de)
EP (1) EP0441698B1 (de)
JP (1) JP2710700B2 (de)
CA (1) CA2035170C (de)
DE (1) DE69113290T2 (de)
FR (1) FR2658360B1 (de)
HK (1) HK34097A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101992374A (zh) * 2010-10-08 2011-03-30 杭州兴达机械有限公司 减速箱体微孔修补装置及方法

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4234843A1 (de) * 1992-10-15 1994-04-21 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Niederdruckentladungslampe und Herstellungsverfahren für eine Niederdruckentladungslampe
JPH0850849A (ja) * 1994-05-31 1996-02-20 Nec Kansai Ltd 陰極部材およびそれを用いた電子管
KR20020068644A (ko) * 2001-02-21 2002-08-28 삼성에스디아이 주식회사 금속 음극 및 이를 구비한 방열형 음극구조체
US6771014B2 (en) * 2001-09-07 2004-08-03 The Boeing Company Cathode design
RU2297068C2 (ru) * 2005-05-16 2007-04-10 Саратовский государственный университет им. Н.Г. Чернышевского Способ изготовления металлопористых катодов из вольфрамового порошка
RU2293394C1 (ru) * 2005-05-16 2007-02-10 Саратовский государственный университет им. Н.Г. Чернышевского Способ изготовления металлопористых катодов из вольфрамового порошка
RU2293395C1 (ru) * 2005-05-16 2007-02-10 Саратовский государственный университет им. Н.Г. Чернышевского Способ изготовления металлопористых катодов из вольфрамового порошка
US12507741B2 (en) * 2024-06-24 2025-12-30 Abby Howenstein Shower brassiere

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL89470C (de) * 1953-03-04
NL108501C (de) * 1957-01-26
SU528632A1 (ru) * 1975-03-24 1976-09-15 Предприятие П/Я А-1067 Способ изготовлени металлопористого прессованного катода
FR2469792A1 (fr) * 1979-11-09 1981-05-22 Thomson Csf Cathode thermo-ionique, son procede de fabrication et tube electronique incorporant une telle cathode
JPS58154131A (ja) * 1982-03-10 1983-09-13 Hitachi Ltd 含浸形陰極
NL8201371A (nl) * 1982-04-01 1983-11-01 Philips Nv Werkwijzen voor het vervaardigen van een naleveringskathode en naleveringskathode vervaardigd volgens deze werkwijzen.
JPS61128441A (ja) * 1984-11-28 1986-06-16 Toshiba Corp 含浸形陰極の製造方法
FR2596198A1 (fr) * 1986-03-19 1987-09-25 Thomson Csf Cathodes pour klystron a faisceaux multiples, klystron comportant de telles cathodes et procede de fabrication de telles cathodes
JPS63175313A (ja) * 1987-01-14 1988-07-19 Nec Corp 含浸型陰極およびその製造方法
JPS63254636A (ja) * 1987-04-10 1988-10-21 Hitachi Ltd 含浸形陰極
JPS63311082A (ja) * 1987-06-12 1988-12-19 日本鋼管株式会社 高密度焼結体の製造装置
NL8701584A (nl) * 1987-07-06 1989-02-01 Philips Nv Werkwijze voor de vervaardiging van een naleveringskathode; naleveringskathode vervaardigd volgens de werkwijze; lopende golfbuis, klystron en zendbuis bevattende een kathode vervaardigd volgens de werkwijze.
US4837480A (en) * 1988-03-28 1989-06-06 Hughes Aircraft Company Simplified process for fabricating dispenser cathodes
JP2635415B2 (ja) * 1989-07-21 1997-07-30 関西日本電気株式会社 含浸型陰極の製造方法
NL8902793A (nl) * 1989-11-13 1991-06-03 Philips Nv Scandaatkathode.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101992374A (zh) * 2010-10-08 2011-03-30 杭州兴达机械有限公司 减速箱体微孔修补装置及方法

Also Published As

Publication number Publication date
JPH0785782A (ja) 1995-03-31
US5334085A (en) 1994-08-02
HK34097A (en) 1997-03-27
DE69113290D1 (de) 1995-11-02
CA2035170A1 (fr) 1991-08-10
EP0441698A1 (de) 1991-08-14
FR2658360A1 (fr) 1991-08-16
JP2710700B2 (ja) 1998-02-10
DE69113290T2 (de) 1996-03-07
FR2658360B1 (fr) 1996-08-14
CA2035170C (fr) 2001-05-29

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