US1817636A - Electron emissive materials - Google Patents

Electron emissive materials Download PDF

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Publication number
US1817636A
US1817636A US196996A US19699627A US1817636A US 1817636 A US1817636 A US 1817636A US 196996 A US196996 A US 196996A US 19699627 A US19699627 A US 19699627A US 1817636 A US1817636 A US 1817636A
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United States
Prior art keywords
cathode
acid
compound
oxide
core
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US196996A
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English (en)
Inventor
Meyer Friedrich
Spanner Hans-Joachim
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Electrons Inc
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Electrons Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields
    • H01J61/06—Main electrodes
    • H01J61/067—Main electrodes for low-pressure discharge lamps
    • H01J61/0675—Main electrodes for low-pressure discharge lamps characterised by the material of the electrode
    • H01J61/0677—Main electrodes for low-pressure discharge lamps characterised by the material of the electrode characterised by the electron emissive material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/14—Solid thermionic cathodes characterised by the material

Definitions

  • salts of the oxyacids and even salts of non-volatile oxyacids are possessed to a very marked extent of the characteristie of emitting electrons even at a very low temperature.
  • the salts under consideration are the compounds of the oxides of the highly electropositive metals, with those oxygen compounds of the elements which are referred to as anhydrides of amphoteric.
  • the compounds less Vacid than titanic acid consequently said compounds are, for example, the aluminates, zincates, chromites, zirconiates,l etc. of the highly electropositive metals.
  • highly electropositive metals it is meant alkaline and alkaline earth metals. At'increasing acidity of the acid residue the capability of the substance to emit electronsu decreases.
  • the alkaline earth metal salt of Zirconic acid can still be referred to as an excellent emitting substance whereas the titanate has no useful electronic emission.
  • Oxides whicharev more acid than titanic acid anhydride are ⁇ therefore not suitable for the corresponding acid residues, the electron aliinity of the acid residue being in that case already so high that the emission electrons (valence electrons) are too strongly bound.
  • the emission temperature of these compounds is but inimaterially higher than of the alkaline earth metal oxide emitters heretofore know-n.
  • These new compounds have however a stability with respect to volatilization with temperature increase above the normal temperature of effective electron emission that is not possessed by the simple compounds, for example, the oxides. 'In contradistinction to barium which if applied as an oxide to a platinum substratum soon volatilizes under the influence of the glow discharge current, the above compounds are capable,
  • a thermionic tube is shown containing an anode Vand a cathode having a core 1 and a 'coating 2 of a salt as described in the above.
  • the compounds herein disclosed may be prepared beforehand (see manual off Gmelin entitled Gmelin-Krauts Handbook for Anorganic Chemistry, published at Heidelberg, Germany, Carl Winter, editor) and applied to the substratum or c'ore. It is however, desirable that the compounds should be prepared by chemical combination taking place on the cathode core. Thus, the advantage is ⁇ obtained that substances can be started with which are absolutely resistant to air.
  • the course may be adopted to apply to the substratum thc alkaline earth metal carbonates with hydrated or anhydrous aluminium or ⁇ .zirconium oxide respectively and a small quantity of an agglutinant and to heat subsequently, since the carbonio acid is easily driven out in a vacuum, the corresponding salt being formed at the same time.
  • a further possibility of preparing the compounds consists in making an alloy or a powder mixture of the, two metals, e. g. barium and zirconium and oxidizing this composition. y f,
  • the slats just described also may be used in conjunction with other electron emitting substances, and it is even possible in order to increase their mechanic strength or their stability in respect to temperature variations, to add supporting substances, for example, alkaline earth metal fluorides or an excess of aluminium oxides.
  • Examples of the resultant salts herein disclosed may be referred to briefly as leach being a salt of an amphoteric acid less acid than titanic acid, and in which salt the metal element outside the acid Wegical is highly 'eletropositive, or is one ofthe alkali and alkali earth metals, or is a metal at least as electropositive as calcium, or is a metal of the category which consists of potassium, rubidium, caesium, calcium, strontium and barium referred to generally in the art as the alkaline metals.
  • the electron emitter of the present invention may consist of one such salt or a plurality thereof intimately associated. With such salt or salts there may also be intimately associated one or more of the heretofore well known simple binary compound emitters, such as oxides, carbides, or sulphides, for example, barium oxide.
  • amphoteric has its usual meaning, referring to those compounds which may act either as acids or bases, and their anhydrides.
  • barium aluminate is the barium salt of an amphoteric substance in kits acid aspect, whose anhydride is an amphoteric oxide (A1203).
  • an incandescent cathode for discharge devices comprising a core and an emitting substance thereon at least the surface of which is exposed to ionic bombardment, said substance comprising a salt of an alkaline earth metal, said salt having as a component a compound capable of forming by chemical conversion an amphoteric compound whichI is less acid than titanic acid.
  • an incandescent cathode for discharge devices comprising a core and an emitting substance exposed to bombardment thereon having distributed throughout its mass a salt of a highly electro-positive metal, said .salt havingas a component a compound capable of forming by chemical conversion an amphoteric conpound which is less acid than titanic acl 3.
  • An incandescent ⁇ cathode according to claim 2 in which a plurality of diderent ones of said salts are mixed to form an emitting substance.
  • a cathode comprising a core and an incandescent electron emissive substance thereon exposed to ionic bombardment and comprising, at least at the surface of said substance the compound of a highly electro-positive metal oxide and a metal oxide which is capable of forming by chemical conversion an amphoteric compound less acid than titanic acid.
  • An electric discharge tube containing a gaseous medium having an incandescent electron emissive cathode, said cathode consisting of a core and a compound exposed to ionic bombardment, the element of which compound is a highly electro-positive metal tron emissive cathode, said cathode consisting of a core and a compound exposed to ionic bombardment, the element of which compound is a highly electro-positive metal and the radical of which consists of a mixture of oxide of aluminum and oxide of zirconium.
  • an anode and a cathode in combination, an anode and a cathode, said cathode being subjected to destructive forces and consisting of a core and an electron emissive and toughened material thereon exposed to ionic bombardment and including an emissively effective salt of a compound from which an amphoteric compound less acid than titanic acid may be chemically produced in association with aluminum oxide, said aluminum' oxide being present in excess of the amount entering into chemical combination with the other ingredients of the said material.
  • an electron emitting tube in combination, an anode and a cathode, said cathode ⁇ consisting of a core and an electron emissive material thereon exposed to ionic bombardment including an emissively effective salt of a compound capable of forming by chemical conversion an edective electron emissive salt of an amphoteric compound less acid than titanic acid in association with an alkaline earth metal fluoride and aluminum oxide, said aluminum oxide being present in excess of the amount entering into chemical combination in the material.
  • an anode and a cathode consisting of an electron emissive cathode, operable at moderate'temperature and rugged to endure positive of a core and a coating of barium aluminate.
  • An incandescent cathode according to claim 2 containing a supporting substance such as an alkaline earth metal iiuoride.
  • an incandescent cathode for discharge devices comprising a core and an emitting substance exposed to lbombardment thereon having at least on its surface a salt of a highly electropositive metal, said salt having as a component a compound capable of forming by chemical conversion an amphoteric compound which is less acid than titanic acid, said coating also comprising an ingredient to give mechanical strength and resistance to temperature variations.
  • van anode and a cathode said cathode consisting of an electron emissive substance operable at moderate temperatures and rugged to endure positive ion bombardment to which it is subjected consisting of a core and a coating comprising strontium aluminate.
  • An electricvdischarge tube containing a gaseous medium having an incandescent cathode consisting of a core and coating exposed to ionic bombardment, said coating comprising a compound of barium oxide, said compound having as a component a compound capable of forming by chemical conversion an amphoteric compound less acid than titanic acid and a compound of strontium oxide, said compound having a a compound component a compound capable of forming by chemical conversion an amphrteric compound less acid than titanic aci

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  • Discharge Lamp (AREA)
  • Solid Thermionic Cathode (AREA)
US196996A 1926-06-09 1927-06-06 Electron emissive materials Expired - Lifetime US1817636A (en)

Applications Claiming Priority (1)

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DE272440X 1926-06-09

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US1817636A true US1817636A (en) 1931-08-04

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US196996A Expired - Lifetime US1817636A (en) 1926-06-09 1927-06-06 Electron emissive materials
US350771A Expired - Lifetime US1925701A (en) 1926-06-09 1929-03-28 Electron emissive device

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US350771A Expired - Lifetime US1925701A (en) 1926-06-09 1929-03-28 Electron emissive device

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US (2) US1817636A (enrdf_load_stackoverflow)
FR (1) FR657054A (enrdf_load_stackoverflow)
GB (1) GB272440A (enrdf_load_stackoverflow)
NL (1) NL24414C (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2499192A (en) * 1948-01-15 1950-02-28 Gen Electric Dispenser type cathode
US2552654A (en) * 1948-08-30 1951-05-15 Rca Corp Heat-resistant cathode coatings
US2831137A (en) * 1955-02-23 1958-04-15 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Cathode coating

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2662196A (en) * 1948-11-04 1953-12-08 Western Union Telegraph Co Concentrated arc lamp
US2663816A (en) * 1949-09-28 1953-12-22 Sylvania Electric Prod Electric discharge lamp
US2605432A (en) * 1949-10-19 1952-07-29 Electrons Inc Indirectly heated cathode structure
BE518639A (enrdf_load_stackoverflow) * 1952-03-24
US2845567A (en) * 1954-02-04 1958-07-29 Itt Indirectly heated thermionic cathode
DE1035791B (de) * 1956-05-29 1958-08-07 Philips Nv Glimmentladungsroehre mit aktivierter kalter Kathode und Verfahren zum Herstellen einer mit einer solchen Kathode versehenen Roehre

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2499192A (en) * 1948-01-15 1950-02-28 Gen Electric Dispenser type cathode
US2552654A (en) * 1948-08-30 1951-05-15 Rca Corp Heat-resistant cathode coatings
US2831137A (en) * 1955-02-23 1958-04-15 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Cathode coating

Also Published As

Publication number Publication date
US1925701A (en) 1933-09-05
GB272440A (en) 1928-04-26
NL24414C (enrdf_load_stackoverflow)
FR657054A (fr) 1929-05-16

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