US2536673A - Zirconium coating for electron discharge devices - Google Patents

Zirconium coating for electron discharge devices Download PDF

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Publication number
US2536673A
US2536673A US10735A US1073548A US2536673A US 2536673 A US2536673 A US 2536673A US 10735 A US10735 A US 10735A US 1073548 A US1073548 A US 1073548A US 2536673 A US2536673 A US 2536673A
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US
United States
Prior art keywords
zirconium
coating
particles
zirconium oxide
electron discharge
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
US10735A
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English (en)
Inventor
Emil G Widell
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RCA Corp
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RCA Corp
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Filing date
Publication date
Priority to NL70766D priority Critical patent/NL70766C/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US10735A priority patent/US2536673A/en
Application granted granted Critical
Publication of US2536673A publication Critical patent/US2536673A/en
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
    • H01J7/00—Details not provided for in the preceding groups and common to two or more basic types of discharge tubes or lamps
    • H01J7/14—Means for obtaining or maintaining the desired pressure within the vessel
    • H01J7/18—Means for absorbing or adsorbing gas, e.g. by gettering
    • H01J7/183—Composition or manufacture of getters
    • 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
    • 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
    • H01J2893/0022—Manufacture
    • 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
    • H01J2893/0022—Manufacture
    • H01J2893/0023—Manufacture carbonising and other surface treatments
    • 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

Definitions

  • Elements comprising a base metal coated with zirconium have heretofore been employed in electron discharge devices for securing a desired heat dissipation and gettering action.
  • An additional object is to provide a coating of zirconium on an electrode of an electron discharge device that will not appreciably alloy with the basemetal of the electrode at the elevated temperatures to which it is necessary to subject the device.
  • a further object is to provide a zirconium coating on an element of an electron discharge device for conferring good heat dissipation and gettering action thereto, wherein the coating includes an agent which serves to prevent undesired alloying between the zirconium and the metal of said element.
  • Another object is to include in the zirconium coating an agent that is effective for preventing alloying of the base metal and the coating, and limiting the quantity of said agent in relation to the zirconium in such a manner that the amount of said agent in the coating is large enough to prevent substantial alloying with the base metal but insufficient to harm the heat disslpation and gettering action of the coating.
  • a still further object is to provide a coating including zirconium and zirconium oxide in predetermined quantity relations whereby the zirconium oxide effectively prevents substantial alloying between the zirconium and the base on which it is coated, and at the same time only very negligibly interferes with the heat radiating and gettering properties of the zirconium.
  • Zirconium metal in powdered form suitably carried by a binder and applied as a coatin to an electrode, such as the anode, of an electron discharge device and subsequently baked to remove the binder and partially sinter the particles of zirconium, exhibits desirable heat radiation properties because it presents a dark surface approaching the charatceristics of a black body, and good gettering action resulting from the porous mass which is capable of absorbing relatively large quantities of deleterious gases.
  • zirconium metal alloys with the base metal of the electrode at the elevated temperatures required for fabrication and subsequent use of the device.
  • the resultant alloy is unsuitable either for good heat dissipation or gettering. Some means is therefore required to prevent such alloyin while preserving the heat radiating and gettering properties of the coating.
  • this means comprises zirconium oxide added to the powdered coating mixture in a quantity having a critical relationship to the quantity of the zirconium metal. It has been determined that an addition of zirconium oxide within a critical range of quantity values with respect to the zirconium metal not only effectively prevents substantial alloying between the zirconium and the base as will impair the desirable properties of the zirconium previously referred to. but permits a de sirable and limited alloying action between the coating and the base which is required for good adherence of the coating on the base.
  • the mixture to be sprayed on a metal base to provide a coating of zirconium thereon is prepared by adding to from one to nineteen parts of powdered zirconium hydride, or powdered zirconium metal, by weight, one part of powdered zirconium oxide.
  • This mixture is suitably held by a binder and sprayed on the base metal to be coated in a conventional manner.
  • the sprayed element is then heated to liberate the hydrogen and in the event the element constitutes a part of an electron discharge device, the heat applied is high enough to thoroughly outgas the part.
  • a molybdenum anode for a high power el tron discharge device having a coating thereon comprising one part zirconium oxide, and three parts zirconium hydride by weight, has successfully withstood temperatures as high as 1740 C. without significant alloying between the molybdenum and the zirconium coating. In addition, the coating was firmly adherent and showed no tendency toward peeling and cracking.
  • the maximum permissible amount of zirconium oxide in the mixture without appreciably harming the desirable characteristics of the coating referred to is one part of zirconium oxide to one part of zirconium hydride by weight.
  • This lower limit is one part of zirconium oxide to nineteen parts zirconium hydride or powdered zirconium metal, by weight.
  • a lesser amount of zirconium oxide than this should not be used if an appreciable and undesired amount of alloying of the zirconium and the metal base is to be prevented.
  • anode base metal may be supplied with a coating either of powdered zirconium metal or powdered zirconium hydride. If the hydride is used the anode may be either pro-baked in a vacuum to decompose the hydride before assembly in an electron discharge device, or the sprayed anode may be mounted in such device and the hydride may be decomposed during exhaust. Iron anodes are usually mounted in the device prior to decomposition of the hydride, while molybdenum anodes are usually pre-baked. With zirconium Oxide present in the coating material in the amounts indicated, the elevated temperatures required for the baking and exhaust have no harmful effects on the zirconium coating.
  • the spray mixture is prepared, for example, by first milling zirconium hydride powder received from commercial sources for a period of about 24 hours. The resultant pulverized material is then mixed with a critical amount of finely powdered electrical fused zirconium oxide, the amount of the latter bein determined by the standards described herein. The zirconium oxide and the zirconium hydride are then milled for an additional four hours to insure a thorough mixing together thereof. A plastic vehicle for the mixture may then be added. A variety of suchvehicles are known and are available inv the art. As a result of this mixing, the zirconium hydride particles are partially separated from each other and when sprayed on to the base metal, they are also partially separated from the base metal.
  • This partial separation of the zirconium hydride particles from the base metal continues after baking and pernits only a limited sintering or alloying effect to occur between the resulting zirconium and base metal. which, when the portions of zirconium oxide specified herein are used, is just sufficient to cause the coating to adhere firmly to the metal base.
  • zirconium oxide may be, I know that its presence in the coating mixture in the proportions indicated herein, has the very useful effect of preventing more alloying between the zirconium and the metal base than is required for securing a firm bond therebetween, while preserving the desirable characteristics of the coating with respect to good heat radiation and gettering.
  • FIG. 1 there is shown in the single figure thereof a fragmentary crosssectional view of an anode of an electron discharge device with a portion thereof greatly enlarged t illustrate the nature of the coating applied to the base metal.
  • the base metal ll! of the anode is shown, provided with a coating II for increasing heat radiation therefrom and for absorbing deleterious gases within an envelope within which the anode may be used.
  • the coating includes a plurality of discreet particles [2, shown in solid black, of zirconium metal, and a plurality of particles l3 of zirconium oxide, shown in white and disposed between the z'rconium particles.
  • the relative amounts of zirconium and zirconium oxide particles observe the ratio range previously referred to herein.
  • the particles I3 surround one or a group of particles I2, and that a limited number of particles l2 of zirconium engage the surface of the base metal ll! of the anode. This limited number of zirconium particles is sufficient to form an adherent bond between the anode base II and the coating II when sintered or alloyed with the base l at the baking or exhaust temperatures required for the completion of the device.
  • the presence of the particles l3 effectively prevents alloying of a larger number of particles It with the base l0 than are in actual contact therebetween due to the shielding action of the particles l3.
  • the surface ll of the coating will retain its good heat radiating properties and will have unimpaired gettering action and good adherence to the base l0.
  • An article comprising a structure having thereon a coating comprising a mixture of three parts by weight of zirconium and one part of zirconium oxide.
  • An article comprising a structure having thereon a coating comprising a mixture of from 1 to 19 parts by weight of zirconium metal and one part of zirconium oxide.
  • An electrode for an electron discharge device comprising a structure having thereon a coating of good heat dissipating. adhering and gettering characteristics, said coating comprising a mixture of from 1 to 19 parts of zirconium particles and one' part of zirconium oxide particles. said coating having a surface adjacent said structure consisting of a plurality of said zirconium particles separated by said zirconium oxide articles, some of said zirconium particles in said surface being sintered to said structure, whereby said coating is firmly adherent to said structure and is free from excessive alloying therewith.
  • An electrode for an electron discharge device comprising a structure having thereon a coating of a homogeneous body formed by a mixture of zirconium particles and a predetermined relative amount of zirconium oxide particles. groups of zirconium particles being surrounded by a plurality of said zirconium oxide particles. 9. surface of said body engaging said structure, said surface being fused to said structure at a plurality of locations displaced from said zirconium oxide particles. said body having another and free surface, said free surface including a plurality of zirconium metal particles for good heat dissipation and gettering action. 7 '5.
  • An article comprising a" structure having thereon a coating comprising a mixture of zirconium and zirconium oxide particles, the amount of said zirconium particles being from to 94% by weight and the amount of said zirconium oxide particles being from 50% to 6% of said mixture.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Gas-Filled Discharge Tubes (AREA)
  • Discharge Lamp (AREA)
US10735A 1948-02-25 1948-02-25 Zirconium coating for electron discharge devices Expired - Lifetime US2536673A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NL70766D NL70766C (en(2012)) 1948-02-25
US10735A US2536673A (en) 1948-02-25 1948-02-25 Zirconium coating for electron discharge devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US10735A US2536673A (en) 1948-02-25 1948-02-25 Zirconium coating for electron discharge devices

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US2536673A true US2536673A (en) 1951-01-02

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NL (1) NL70766C (en(2012))

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2690982A (en) * 1952-02-05 1954-10-05 Lewis And Kaufman Inc Coated electrode
US2756166A (en) * 1951-01-27 1956-07-24 Continental Can Co Vacuum metallizing and apparatus therefor
US2763919A (en) * 1950-07-28 1956-09-25 Thompson Prod Inc Coated refractory body
US2772985A (en) * 1951-08-08 1956-12-04 Thompson Prod Inc Coating of molybdenum with binary coatings containing aluminum
US2822301A (en) * 1952-06-03 1958-02-04 Continental Can Co Vacuum metallizing and apparatus therefor
US2822302A (en) * 1956-01-16 1958-02-04 Radio Mfg Company Inc Non-emissive electrode
US2843541A (en) * 1956-05-17 1958-07-15 Senderoff Seymour Electrophoretic deposition of barium titanate
US2887413A (en) * 1954-12-17 1959-05-19 Patelhold Patentverwertung Thermionic cathode for electron tubes and method for producing same
US2982019A (en) * 1953-05-22 1961-05-02 Union Carbide Corp Method of protecting magnesium with a coating of titanium or zirconium
US2982017A (en) * 1953-05-22 1961-05-02 Union Carbide Corp Method of protecting magnesium with a coating of titanium
US3089949A (en) * 1958-11-28 1963-05-14 Westinghouse Electric Corp Arc welding method and article
US3657784A (en) * 1970-03-05 1972-04-25 Johnson Matthey Co Ltd Cladding of metals
US3988636A (en) * 1974-04-02 1976-10-26 Hitachi, Ltd. Magnetron with cathode end shields coated with secondary electron emission inhibiting material
US4118542A (en) * 1977-01-17 1978-10-03 Wall Colmonoy Corporation Controlled atmosphere and vacuum processes
US4925741A (en) * 1989-06-08 1990-05-15 Composite Materials Technology, Inc. Getter wire

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1958967A (en) * 1931-10-22 1934-05-15 Allg Elek Tatz Ges Electron discharge tube and method of making same
US2029144A (en) * 1933-05-04 1936-01-28 Gen Electric Electric discharge device or vacuum tube
GB482022A (en) * 1936-04-09 1938-03-22 Philips Nv Improved method of introducing an alkali or alkaline earth metal into an exhausted receptacle
US2368060A (en) * 1942-01-01 1945-01-23 Bell Telephone Labor Inc Coating of electron discharge device parts
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
US1958967A (en) * 1931-10-22 1934-05-15 Allg Elek Tatz Ges Electron discharge tube and method of making same
US2029144A (en) * 1933-05-04 1936-01-28 Gen Electric Electric discharge device or vacuum tube
GB482022A (en) * 1936-04-09 1938-03-22 Philips Nv Improved method of introducing an alkali or alkaline earth metal into an exhausted receptacle
US2368060A (en) * 1942-01-01 1945-01-23 Bell Telephone Labor Inc Coating of electron discharge device parts
US2417460A (en) * 1945-07-25 1947-03-18 Eitel Mccullough Inc Nonemissive electrode for electron tube and method of making the same

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2763919A (en) * 1950-07-28 1956-09-25 Thompson Prod Inc Coated refractory body
US2756166A (en) * 1951-01-27 1956-07-24 Continental Can Co Vacuum metallizing and apparatus therefor
US2772985A (en) * 1951-08-08 1956-12-04 Thompson Prod Inc Coating of molybdenum with binary coatings containing aluminum
US2690982A (en) * 1952-02-05 1954-10-05 Lewis And Kaufman Inc Coated electrode
US2822301A (en) * 1952-06-03 1958-02-04 Continental Can Co Vacuum metallizing and apparatus therefor
US2982017A (en) * 1953-05-22 1961-05-02 Union Carbide Corp Method of protecting magnesium with a coating of titanium
US2982019A (en) * 1953-05-22 1961-05-02 Union Carbide Corp Method of protecting magnesium with a coating of titanium or zirconium
US2887413A (en) * 1954-12-17 1959-05-19 Patelhold Patentverwertung Thermionic cathode for electron tubes and method for producing same
US2822302A (en) * 1956-01-16 1958-02-04 Radio Mfg Company Inc Non-emissive electrode
US2843541A (en) * 1956-05-17 1958-07-15 Senderoff Seymour Electrophoretic deposition of barium titanate
US3089949A (en) * 1958-11-28 1963-05-14 Westinghouse Electric Corp Arc welding method and article
US3657784A (en) * 1970-03-05 1972-04-25 Johnson Matthey Co Ltd Cladding of metals
US3988636A (en) * 1974-04-02 1976-10-26 Hitachi, Ltd. Magnetron with cathode end shields coated with secondary electron emission inhibiting material
US4118542A (en) * 1977-01-17 1978-10-03 Wall Colmonoy Corporation Controlled atmosphere and vacuum processes
US4925741A (en) * 1989-06-08 1990-05-15 Composite Materials Technology, Inc. Getter wire

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Publication number Publication date
NL70766C (en(2012))

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