Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
  • H01J19/28—Non-electron-emitting electrodes; Screens
  • H01J19/30—Non-electron-emitting electrodes; Screens characterised by the material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2893/00—Discharge tubes and lamps
  • H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps
  • H01J2893/0012—Constructional arrangements
  • H01J2893/0019—Chemical composition and manufacture
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/922—Static electricity metal bleed-off metallic stock
  • Y10S428/923—Physical dimension
  • Y10S428/924—Composite
  • Y10S428/926—Thickness of individual layer specified
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/922—Static electricity metal bleed-off metallic stock
  • Y10S428/9335—Product by special process
  • Y10S428/934—Electrical process
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
  • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
  • Y10T428/12063—Nonparticulate metal component
  • Y10T428/12069—Plural nonparticulate metal components
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component
  • Y10T428/12875—Platinum group metal-base component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12986—Adjacent functionally defined components

Definitions

• ABSTRACT A grid electrode for an electronic discharge vessel wherein the wire which forms the grid is first covered with a layer of an intermetallic compound comprising a high-melting metal such as zirconium or titanium and a metal of Group VIII of the Periodic System, for example platinum.
• the intermetallic compound is applied to the grid wire in powdered form and then sintered after which an outer layer of a noble metal, for example platinum is then applied electrolytically.
• the present invention relates to a method of producing grid electrodes for electronic discharge vessels whereby an intermediate coating consisting of a highmelting intermetallic compound is applied to the wires forming the grid and the intermediate coating is then covered with a layer of a noble metal, and further to a grid electrode produced by the method.
• the method is known whereby grid electrodes are coated with a noble metal of the Vlll group of the periodic system, preferably platinum, in order to reduce thermal emission.
• a noble metal of the Vlll group of the periodic system preferably platinum
• an intermediate coating should be provided between the basic metal and the outer coating.
• Carbides, borides or silicides of high-melting metals have been proposed as suitable materials for the intermediate coating.
• the principal object of the present invention is to create a grid electrode such that the thermal emission does not increase even at greatly increased loading, and which at the same time possesses a slight and reproducible secondary emission together with increased highvoltage strength.
• the intermetallic compound for the intermediate coating comprises a highmelting metal, such as zirconium or titanium, and a metal of group Vlll of the periodic system.
• the electrode produced by the method is characterized by the fact that the intermetallic compound comprises a high-melting metal and a noble metal of group Vlll of the periodic system.
• the intermetallic compound is preferably applied to the electrode core as a powder and then sintered. By suitably choosing the grain size of the powder it is possible to determine exactly the surface roughness and hence to influence the secondary emission of the electrode as required.
• the shaped grid of a conventional transmitting tube consisting of wires of molybdenum or tungsten, is annealed in hydrogen at l,000 to l,lO C to remove the oxides, etc.
• the grid is then covered by cataphoresis with ZrPt the production of which in powder form has already been described, preferably to a coating thickness of 5 a.
• the grid, together with the applied intermediate coating is then annealed in vacuo or a protective gas for minutes at l,500 l,600 C, whereupon the intermediate coating sinters, retaining 2 its roughness.
• the grid with its sintered intermediate coating, is covered electrolytically with a layer of platinum 3 ,u thick and then degassed by annealing once more in vacuo at a temperature of l,500 1,600 C. Having been degassed, the grid is ready to be fitted.
• Grids produced in this way exhibit great adhesion between the intermediate coating and the basic metal on the one hand, and the platinum coat on the other, resulting in increased high-voltage strength. This high adhesion also improves the mechanical properties of the grid, so that very fine grids, meshed grids, for example, can be produced.
• the grain size of the ZrPt powder applied to the grid it is possible to vary the roughness of the grid surface, and consequently the secondary emission, in a reproducible manner.
• Specific radiation values from 20 W/cm to 29 W/cm can be achieved at 1,525K, depending on the chosen roughness of the grid surface. This corresponds to between 65 and percent of the radiation of a black body.
• a method of producing grid electrodes for electronic discharge vessels which comprises the steps of applying to the wires forming the grid an intermediate coating consisting of a high-melting intermetallic compound constituted by a high-melting metal and platinum, and then covering said intermediate coating with an 'outer layer of platinum.
• a method as defined in claim 1 for producing grid electrodes for electronic discharge vessels wherein said intermetallic compound in powder form is applied to the wires forming said grid by electrophoresis until the thickness thereof is at least 5 t, preferably 5 to 10 ,u, and is then heated in an inert atmosphere or in vacuo to at least 1,500C, preferably l,500 to l,600C, to thereby sinter the same.
• a method as defined in claim 1 for producing grid electrodes for electronic discharge vessels wherein said outer platinum layer is applied electrolytically to the intermediate coating and said grid is then annealed in vacuo at a temperature of at least l,00OC, preferably from l,500 to 1,600C.

Landscapes

• Powder Metallurgy (AREA)
• Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
• Solid Thermionic Cathode (AREA)
• Physical Vapour Deposition (AREA)
• Electrodes For Compound Or Non-Metal Manufacture (AREA)
• Electrolytic Production Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=4436922

Family Applications (1)

Country Status (8)

Cited By (2)

Families Citing this family (3)

Citations (4)

Family Cites Families (5)

• 1971
  • 1971-12-29 CH CH1903771A patent/CH539945A/de not_active IP Right Cessation
• 1972
  • 1972-01-21 DE DE2202827A patent/DE2202827C3/de not_active Expired
  • 1972-12-13 US US00314575A patent/US3816079A/en not_active Expired - Lifetime
  • 1972-12-22 NL NLAANVRAGE7217592,A patent/NL176320C/xx not_active IP Right Cessation
  • 1972-12-27 GB GB5967072A patent/GB1362351A/en not_active Expired
  • 1972-12-27 IT IT33569/72A patent/IT972899B/it active
  • 1972-12-27 JP JP47130110A patent/JPS5812694B2/ja not_active Expired
  • 1972-12-27 FR FR7246321A patent/FR2166052B1/fr not_active Expired

Patent Citations (4)

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