US1562164A - Process of coating electrodes - Google Patents

Process of coating electrodes Download PDF

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Publication number
US1562164A
US1562164A US363301A US36330120A US1562164A US 1562164 A US1562164 A US 1562164A US 363301 A US363301 A US 363301A US 36330120 A US36330120 A US 36330120A US 1562164 A US1562164 A US 1562164A
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US
United States
Prior art keywords
coating
alkaline earth
oxide
metal
coated
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
US363301A
Inventor
James E Harris
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.)
AT&T Corp
Original Assignee
Western Electric Co Inc
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 Western Electric Co Inc filed Critical Western Electric Co Inc
Priority to US363301A priority Critical patent/US1562164A/en
Application granted granted Critical
Publication of US1562164A publication Critical patent/US1562164A/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
    • 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
    • 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
    • Y10S428/934—Electrical process

Definitions

  • This invention relates to a process I of coating and has particular reference to the coating of filamentary material with a substance capable of thermionic activity for use in vacuum tubes.
  • An object of the invention is to provlde a process whereby base metal cores may be coated with thermionic material '.-without oxidation.
  • Another object is to provide a, process whereby substantially all metals may be coated with thermionic material by means.
  • cores metals such as platinum and other of the noble metals which did not oxidize in air. If certain metal cores such as tungsten, iron,- molybdenum, chromium or alloys thereof are used and the coating is baked in air, it is found that the core metal oxidizes and the oxide forms with the alkaline earth metal compound a stable compound which does not break down into the oxide of the alkaline earth metal when heated in the vacuum bulb. Consequently] no thermionic action ensues.
  • My present process involves introducing the material to be coated as an electrode in a heated bath of a molten compound or mixture of compounds of the alkaline earth metals, the anode consisting of some material such as carbon which is not readily at: tacked b the electrolyte.
  • the coating is thus app 'ed in the absence of air giving the Application med March 4, m. Serial Io. 868,801.
  • the material is then me ted and heated to about 600 degrees C. and a current is passed through the ath using the filamentary material to' be coated as the cathode, with an anode of a bath-resisting material such as carbon.
  • a current is passed through the ath using the filamentary material to' be coated as the cathode, with an anode of a bath-resisting material such as carbon.
  • t has been found that a cur rent density of about 3.6 amperes per sq. cm. gives very good results especially when platinum is coated in a bath consisting of anhydrous barium chloride.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Electrolytic Production Of Metals (AREA)

Description

Patented Nov. 17, 1925 UNITED STATES- JAMES E. HARRIS, 0] EAST ORANGE. NEW JERSEY, ASQIGNOB TO,
PATENT OFFICE.
' ELECTRIC comm, INCORPORATED, 0! NEW YORK, I. Y., A CORPORATION OF nnw YORK.
PROCESS OI COATING- ELECTRODES.
Io Drawing.
To all whom it may concern:
Be it known that I James E. Harms, a citizen of the United States residm at East Orange, in the county of Essex, tate of New Jersey, have invented certaln new and useful Improvements in Processescf Coatin Electrodes, of which the follow ng is a full, clear, concise, and exact description.
This invention relates to a process I of coating and has particular reference to the coating of filamentary material with a substance capable of thermionic activity for use in vacuum tubes.
An object of the invention is to provlde a process whereby base metal cores may be coated with thermionic material '.-without oxidation.
Another object is to provide a, process whereby substantially all metals may be coated with thermionic material by means.
of a sim 1e and. economical process involvin a bat and electrolytic action.
the older processes which involved baking on the coating in air, it was necessar to use as cores metals such as platinum and other of the noble metals which did not oxidize in air. If certain metal cores such as tungsten, iron,- molybdenum, chromium or alloys thereof are used and the coating is baked in air, it is found that the core metal oxidizes and the oxide forms with the alkaline earth metal compound a stable compound which does not break down into the oxide of the alkaline earth metal when heated in the vacuum bulb. Consequently] no thermionic action ensues.
My present process involves introducing the material to be coated as an electrode in a heated bath of a molten compound or mixture of compounds of the alkaline earth metals, the anode consisting of some material such as carbon which is not readily at: tacked b the electrolyte. The coating is thus app 'ed in the absence of air giving the Application med March 4, m. Serial Io. 868,801.
used at the same time, ual parts are used. The material is then me ted and heated to about 600 degrees C. and a current is passed through the ath using the filamentary material to' be coated as the cathode, with an anode of a bath-resisting material such as carbon. There is deposited on the filament an alkaline earth metal coating of a composltion such that upon exposure to air, it is convertible, in art at least, to alkaline earth metal oxide. t has been found that a cur rent density of about 3.6 amperes per sq. cm. gives very good results especially when platinum is coated in a bath consisting of anhydrous barium chloride.
It has been found that. such metals as iron, nickel, tungsten, molybdenum, and alloys of the same can by this process be coated without the formation of oxides of the metal of the core and the formation of stable com ounds thereof with the alkaline earth meta s. This arises from thefact that the coating takes place in the absence of air. Any compound 0 the alkaline earth metals may be used as a bath, providing it has a melting point sufliciently low for convenience.
What is claimed is:
1. The method of applying an alkalineearth metal oxide coating to a metal, the oxide of which is combinable with alkaline earth metal compounds to form compounds not reducible to alkaline earth metal oxide upon heating in vacuum, said method comprising reparing an electrolyte com osed of an a kahne earth metalcompoun arranging in said electrol a filament of the metal to be coated an electrolytically depositing on said filament an alkaline earth metal coatin which is convertible, in part barium oxide and strontium oxide to a. convertible, in part at least, to barium oxide tungsten filament, said method comprising and strontium oxide upon exposure to air.
preparing an electrolyte composed 0 a ba- In witness whereof, I hereunto subscribe rium compound and a strontium compound, my name this 27th day of February A. D., 5 arranging said tungsten filament in said 1920.
electrolyte and electrolytically depositing on said tungsten filament a coating which is JAMES E. HARRIS.
US363301A 1920-03-04 1920-03-04 Process of coating electrodes Expired - Lifetime US1562164A (en)

Priority Applications (1)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431986A (en) * 1942-07-22 1947-12-02 American Rolling Mill Co Coloring stainless steel
US2709154A (en) * 1948-04-05 1955-05-24 Josephine Maria Hansgirg Corrosion resisting coatings

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431986A (en) * 1942-07-22 1947-12-02 American Rolling Mill Co Coloring stainless steel
US2709154A (en) * 1948-04-05 1955-05-24 Josephine Maria Hansgirg Corrosion resisting coatings

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