US2786259A - Method of making supply cathodes and supply cathodes manufactured by means of these methods - Google Patents

Method of making supply cathodes and supply cathodes manufactured by means of these methods Download PDF

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Publication number
US2786259A
US2786259A US255243A US25524351A US2786259A US 2786259 A US2786259 A US 2786259A US 255243 A US255243 A US 255243A US 25524351 A US25524351 A US 25524351A US 2786259 A US2786259 A US 2786259A
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United States
Prior art keywords
cathodes
supply
methods
supply cathodes
making
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Expired - Lifetime
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US255243A
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English (en)
Inventor
Lemmens Hendrikus Johannes
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.)
US Philips Corp
North American Philips Co Inc
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US Philips Corp
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    • 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
    • H01J9/047—Cathodes having impregnated bodies

Definitions

  • This invention relates to methods of making supply cathodes, in which a part of the wall of the cathode body is constituted by a member of tungsten, molybdenum, tantalum, hafnium or niobium sintered to porosity at a high temperature, the joint between this porous member and the remaining metal part of the cathode being such as to form a supply chamber which contains alkaline earth metal compounds and in which the pores of the porous member constitute the largest openings. Furthermore the invention relates to cathodes manufactured by means of this method.
  • the aforesaid cathodes have long and high emission.
  • the part of the cathode wall not constituted by the porous member preferably consists of molybdenum.
  • this cathode part is easily contaminated, so that the emission of the cathode is adversely affected and more particularly the cathode-formation takes an extremely long time.
  • the non-porous wall part of the supply chamber is, according to the invention, pickled prior to joining it to the porous part so that the impurities are removed.
  • the pickling operation may be carried out chemically and after that it is advisable to anneal the part in question in hydrogen.
  • recourse is bad to electrolytic pickling which has the advantage that after rinsing and drying no further after-treatment is required.
  • the sole figure shows a supply cathode, the reference numeral 1 denoting a tungsten plate sintered to porosity, 2 denoting a cylindrical molybdenum case whose bottom 3 is indented so that this bottom together with the tungsten plate welded to the edge of the molybdenum case forms a chamber containing a barium-strontium carbonate pastille 4, a heater helix 5 completing the cathode.
  • a chemical pickling bath may, for example, be composed of three parts sulphuric acid of one part concentrated nitric acid and one part water. The pickling operation is followed by rinsing, drying and annealing in hydrogen at 1100 C.
  • the bottom 3 may be pickled electrolytically in a bath containing 4 parts sulphuric acid of 70% and one part concentrated phosphoric acid, the current strength being 0.25 to l a./mm.
  • cathodes made by means of the aforesaid methods have practically no deposit at the inner side of the porous member, the barium-strontium oxide being a light grey. In the presence of impurities there is a dark deposit and the barium-strontium oxide is also dark coloured.
  • a cathode constituted by a non-porous body of refractory metal forming an internal cavity in which a supply of heat-decomposable alkaline earth compounds is disposed, said cavity being closed by a porous wall member of refractory metal, the pores of which constitute the largest apertures connecting the cavity to an electron-emissive surface of the cathode, the steps immersing the non-porous body in an electrolytic bath consisting of four parts sulphuric acid of 70% concentration and one part concentrated phosphoric acid while passing a current of about 0.25 to l amp/cm. through said bath to remove impurities from said body, and welding said non-porous body to said porous member.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Solid Thermionic Cathode (AREA)
US255243A 1950-11-18 1951-11-07 Method of making supply cathodes and supply cathodes manufactured by means of these methods Expired - Lifetime US2786259A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL691583X 1950-11-18

Publications (1)

Publication Number Publication Date
US2786259A true US2786259A (en) 1957-03-26

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ID=19808176

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US255243A Expired - Lifetime US2786259A (en) 1950-11-18 1951-11-07 Method of making supply cathodes and supply cathodes manufactured by means of these methods

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US (1) US2786259A (enrdf_load_stackoverflow)
BE (1) BE507171A (enrdf_load_stackoverflow)
FR (1) FR1045204A (enrdf_load_stackoverflow)
GB (1) GB691583A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3708687A1 (de) * 1986-04-01 1987-10-08 Ceradyne Inc Vorratskathode und verfahren zu deren herstellung
US20110222959A1 (en) * 2007-08-14 2011-09-15 Zf Friedrichshafen Ag Joint and/or mount arrangement

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1253906A (en) * 1916-10-28 1918-01-15 Jacob Sutter Soldering apparatus.
US2447038A (en) * 1945-10-31 1948-08-17 Raytheon Mfg Co Cathode structure
US2460739A (en) * 1946-04-17 1949-02-01 Gen Electric Electrode construction
US2542779A (en) * 1948-01-07 1951-02-20 Columbus Metal Products Inc Electropolishing composition and process
US2624024A (en) * 1949-10-26 1952-12-30 Hartford Nat Bank & Trust Co Cathode for use in electron discharge tubes
US2688709A (en) * 1949-11-12 1954-09-07 Westinghouse Electric Corp X-ray anode and method of making same by electric welding

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1253906A (en) * 1916-10-28 1918-01-15 Jacob Sutter Soldering apparatus.
US2447038A (en) * 1945-10-31 1948-08-17 Raytheon Mfg Co Cathode structure
US2460739A (en) * 1946-04-17 1949-02-01 Gen Electric Electrode construction
US2542779A (en) * 1948-01-07 1951-02-20 Columbus Metal Products Inc Electropolishing composition and process
US2624024A (en) * 1949-10-26 1952-12-30 Hartford Nat Bank & Trust Co Cathode for use in electron discharge tubes
US2688709A (en) * 1949-11-12 1954-09-07 Westinghouse Electric Corp X-ray anode and method of making same by electric welding

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3708687A1 (de) * 1986-04-01 1987-10-08 Ceradyne Inc Vorratskathode und verfahren zu deren herstellung
US20110222959A1 (en) * 2007-08-14 2011-09-15 Zf Friedrichshafen Ag Joint and/or mount arrangement

Also Published As

Publication number Publication date
GB691583A (en) 1953-05-13
BE507171A (enrdf_load_stackoverflow)
FR1045204A (fr) 1953-11-24

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