US2683671A - Low primary and secondary electron emission surface - Google Patents

Low primary and secondary electron emission surface Download PDF

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US2683671A
US2683671A US299374A US29937452A US2683671A US 2683671 A US2683671 A US 2683671A US 299374 A US299374 A US 299374A US 29937452 A US29937452 A US 29937452A US 2683671 A US2683671 A US 2683671A
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tantalum
secondary electron
electrode
electron emission
emission surface
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US299374A
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John H Findlay
Dewey D Knowles
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CBS Corp
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Westinghouse Electric Corp
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    • 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
    • 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
    • Y10S428/9265—Special properties
    • Y10S428/929—Electrical contact feature
    • 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
    • Y10S428/937—Sprayed metal
    • 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.]
    • Y10T428/12049—Nonmetal component
    • Y10T428/12056—Entirely inorganic
    • 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
    • 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
    • Y10T428/12104—Particles discontinuous
    • Y10T428/12111—Separated by nonmetal matrix or binder [e.g., welding electrode, etc.]
    • 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
    • Y10T428/12139—Nonmetal particles in particulate 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
    • Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
    • Y10T428/12819—Group VB 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
    • Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
    • Y10T428/12826—Group VIB metal-base component

Definitions

  • Our invention relates to an electronic electrode and more particularly to an electrode having a low primary and secondary emission surface for use in a vacuum tube.
  • an ordinary carbon or graphite surface has a low secondary emission ratio which is about unity. Such a surface being bla i; will substantially cooler than would other surfaces of a lighter color and hence have a low primary emission. It is also known that a surface comprising finely powdered carbon on a piece of base metal has a much lower secondary emission ratio, e. g. about .5. However, these carbon powders cannot be made to stick to the base metal tightly enough for many applications.
  • an object of our invention to provide an electrode having a surface with a very low secondary emission coeificient, the surface of which adheres tightly to a base metal.
  • Another object of our invention is to provide an electrode which operates effectively as if it had powdered carbon adhering thereon tightly.
  • the single figure is an enlarged showing in cross-section of apparatus built in accordance with one embodiment of our invention.
  • an electrode for a vacuum tube comprising a supporting base metal 2 preferably of molybdenum or tantalum.
  • this base metal is prepared with a smooth surface.
  • a layer 4 of fine particles of tantalum powder is then painted or sprayed on the base metal and fired or sintered so as to cause the tantalum powder s to adhere to the base metal 2.
  • the firing or sintering is performed so that a strong adhesion is obtained between the powder l and the base metal 2 while retaining substantially the granular structure of the tantalum powder.
  • the powdered tantalum surface 4 which has been caused to adhere to the molybdenum base 2 is then graphitized by heating it in a hydrogen atmosphere containing benzene vapor, in accordance with principles well known in the art so as to form a very thin adherent layer of graphite 6 around the exposed portions of the particles of tantalum powder 5.
  • the layer of graphite 5 is preferably much thinner than the diameter of the particles of tantalum powder 5.
  • a structure built in accordance with this embodiment of my invention has the advantage that electrons which are emitted from the region between the particles of graphite coated tantalum powder 4, t are likely to strike another particle of graphite coated tantalum powder 6., 8 rather than move out into the open space beyond.
  • Our electrode therefore, has the advantage of granulated carbon in that it produces a very low secondary emission ratio.
  • our electrode has the advantage that the surface which provides the low secondary emission is tightly connected to the supporting metal base.
  • the body of the electrode may be of a material other than molybdenum or tantalum. If such is the case, it is understood that the molybdenum or tantalum which are referred to as the base metal might be a coat ing on the outside of an electrode, the main structural body of which could be made of another material such as, for example, copper.
  • An electronic electrode comprising: a metallic supporting element, a plurality of small particles of tantalum powder fastened to said element, and a coating of graphite on the ex posed surfaces of said particles.
  • An electronic electrode comprising: a supporting element having a surface of a material of the group comprising molybdenum and tantalum, and a plurality of small graphitized particles of tantalum powder sintered onto said element.

Description

y 1954 J. H. FINDLAY ET AL 2,683,67
LOW PRIMARY AND SECONDARY ELECTRON EMISSION SURFACE Filed July 17, 1952 GRAPHITE TANTALUM BASE METAL (MOLYBDENUM 0R TANTALUM) WITNESSES: INVENTORS Dewey D. Knowles and 9" it John H. Findlay.
Patented July 13, 1954 m, A E.
UNTED LOW PRIMARY AND SECONDARY ELECTRON EMISSEGN SURFACE Application July 1'7, 1952, Serial No. 299,374
2 Claims.
Our invention relates to an electronic electrode and more particularly to an electrode having a low primary and secondary emission surface for use in a vacuum tube.
In accordance with the prior art of which we are aware, it is known that an ordinary carbon or graphite surface has a low secondary emission ratio which is about unity. Such a surface being bla i; will substantially cooler than would other surfaces of a lighter color and hence have a low primary emission. It is also known that a surface comprising finely powdered carbon on a piece of base metal has a much lower secondary emission ratio, e. g. about .5. However, these carbon powders cannot be made to stick to the base metal tightly enough for many applications.
It is accordingly, an object of our invention to provide an electrode having a surface with a very low secondary emission coeificient, the surface of which adheres tightly to a base metal.
Another object of our invention is to provide an electrode which operates effectively as if it had powdered carbon adhering thereon tightly.
The invention with respect to both the organization and the operation thereof, together with other objects and advantages may be best understood from the following description of specific embodiments when read in connection with the accompanying drawing, in which:
The single figure is an enlarged showing in cross-section of apparatus built in accordance with one embodiment of our invention.
In accordance with one embodiment of our invention, we provide an electrode for a vacuum tube comprising a supporting base metal 2 preferably of molybdenum or tantalum. In accordance with the preferred embodiment of our invention, this base metal is prepared with a smooth surface. A layer 4 of fine particles of tantalum powder is then painted or sprayed on the base metal and fired or sintered so as to cause the tantalum powder s to adhere to the base metal 2. The firing or sintering is performed so that a strong adhesion is obtained between the powder l and the base metal 2 while retaining substantially the granular structure of the tantalum powder. There is, thus, provided a coating on the surface of the base metal 2 which is substantially a layer of small particles of tantalum. The powdered tantalum surface 4 which has been caused to adhere to the molybdenum base 2 is then graphitized by heating it in a hydrogen atmosphere containing benzene vapor, in accordance with principles well known in the art so as to form a very thin adherent layer of graphite 6 around the exposed portions of the particles of tantalum powder 5. The layer of graphite 5 is preferably much thinner than the diameter of the particles of tantalum powder 5.
A structure built in accordance with this embodiment of my invention has the advantage that electrons which are emitted from the region between the particles of graphite coated tantalum powder 4, t are likely to strike another particle of graphite coated tantalum powder 6., 8 rather than move out into the open space beyond.
Our electrode, therefore, has the advantage of granulated carbon in that it produces a very low secondary emission ratio. However, in addition, our electrode has the advantage that the surface which provides the low secondary emission is tightly connected to the supporting metal base.
It is understood that in some applications it may be desirable to build the body of the electrode of a material other than molybdenum or tantalum. If such is the case, it is understood that the molybdenum or tantalum which are referred to as the base metal might be a coat ing on the outside of an electrode, the main structural body of which could be made of another material such as, for example, copper.
Although we have shown and described specific embodiments of our invention, we are aware that other modifications thereof are possible. Our invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and the spirit of the invention.
We claim as our invention:
1. An electronic electrode comprising: a metallic supporting element, a plurality of small particles of tantalum powder fastened to said element, and a coating of graphite on the ex posed surfaces of said particles.
2. An electronic electrode comprising: a supporting element having a surface of a material of the group comprising molybdenum and tantalum, and a plurality of small graphitized particles of tantalum powder sintered onto said element.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,854,926 DeBroske Apr. 19, 1932 1,981,652 Long Nov. 20, 1934 2,107,520 Schade Feb. 8, 1938 2,128,631 Eaton Aug. 30, 1938 2,417,460 Eitel Mar. 113, 1.94:7

Claims (1)

1. AN ELECTRONIC ELECTRODE COMPRISING: A METALLIC SUPPORTING ELEMENT, A PLURALITY OF SMALL PARTICLES OF TANTALUM POWDER FASTENED TO SAID ELEMENT, AND A COATING OF GRAPHITE ON THE EXPOSED SURFACES OF SAID PARTICLES.
US299374A 1952-07-17 1952-07-17 Low primary and secondary electron emission surface Expired - Lifetime US2683671A (en)

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2840493A (en) * 1952-11-22 1958-06-24 Westinghouse Electric Corp Method of emission suppression in vacuum tubes, especially magnetron hats
US2933439A (en) * 1957-02-25 1960-04-19 Chicago Dev Corp Electrolytic production of laminated metal articles
US2987815A (en) * 1953-05-25 1961-06-13 Mack Trucks Method of attaching cemented carbide facings to valve lifters and the like
US3088195A (en) * 1958-06-16 1963-05-07 Copperweld Steel Co Cladding with powdered metal to form bimetallic products
US3109716A (en) * 1957-07-22 1963-11-05 Owens Corning Fiberglass Corp Lamellar metal structure
US3139671A (en) * 1962-04-16 1964-07-07 Bendix Corp Method for attaching a composition metal-ceramic material to a backing member
US3174219A (en) * 1958-12-12 1965-03-23 Varta Ag Method of making a sintered electrode
US3473900A (en) * 1967-02-21 1969-10-21 Union Carbide Corp Aluminum-carbon fiber composites
US3555334A (en) * 1967-11-03 1971-01-12 Philips Corp Cathode with graphite end shields
US3639797A (en) * 1967-10-23 1972-02-01 Hitachi Ltd Cathode-ray tube having a plated inner metal layer of high-tensile strength

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1854926A (en) * 1930-06-06 1932-04-19 Broske Ernest D De Process for carbon-coating electrodes
US1981652A (en) * 1931-04-28 1934-11-20 Bell Telephone Labor Inc Method of coating electrodes
US2107520A (en) * 1936-02-26 1938-02-08 Rca Corp Electron discharge device
US2128631A (en) * 1934-10-20 1938-08-30 Jules A Perrault System of optically reproducing electric impulses
US2417460A (en) * 1945-07-25 1947-03-18 Eitel Mccullough Inc Nonemissive electrode for electron tube and method of making the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1854926A (en) * 1930-06-06 1932-04-19 Broske Ernest D De Process for carbon-coating electrodes
US1981652A (en) * 1931-04-28 1934-11-20 Bell Telephone Labor Inc Method of coating electrodes
US2128631A (en) * 1934-10-20 1938-08-30 Jules A Perrault System of optically reproducing electric impulses
US2107520A (en) * 1936-02-26 1938-02-08 Rca Corp Electron discharge device
US2417460A (en) * 1945-07-25 1947-03-18 Eitel Mccullough Inc Nonemissive electrode for electron tube and method of making the same

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2840493A (en) * 1952-11-22 1958-06-24 Westinghouse Electric Corp Method of emission suppression in vacuum tubes, especially magnetron hats
US2987815A (en) * 1953-05-25 1961-06-13 Mack Trucks Method of attaching cemented carbide facings to valve lifters and the like
US2933439A (en) * 1957-02-25 1960-04-19 Chicago Dev Corp Electrolytic production of laminated metal articles
US3109716A (en) * 1957-07-22 1963-11-05 Owens Corning Fiberglass Corp Lamellar metal structure
US3088195A (en) * 1958-06-16 1963-05-07 Copperweld Steel Co Cladding with powdered metal to form bimetallic products
US3174219A (en) * 1958-12-12 1965-03-23 Varta Ag Method of making a sintered electrode
US3139671A (en) * 1962-04-16 1964-07-07 Bendix Corp Method for attaching a composition metal-ceramic material to a backing member
US3473900A (en) * 1967-02-21 1969-10-21 Union Carbide Corp Aluminum-carbon fiber composites
US3639797A (en) * 1967-10-23 1972-02-01 Hitachi Ltd Cathode-ray tube having a plated inner metal layer of high-tensile strength
US3555334A (en) * 1967-11-03 1971-01-12 Philips Corp Cathode with graphite end shields

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