US2881104A - Methods of producing refractory metal filaments of flattened zig-zag form - Google Patents

Methods of producing refractory metal filaments of flattened zig-zag form Download PDF

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Publication number
US2881104A
US2881104A US576510A US57651055A US2881104A US 2881104 A US2881104 A US 2881104A US 576510 A US576510 A US 576510A US 57651055 A US57651055 A US 57651055A US 2881104 A US2881104 A US 2881104A
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United States
Prior art keywords
spiral
zig
flattened
refractory metal
ductile
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Expired - Lifetime
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US576510A
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English (en)
Inventor
Jones David John
Gossling Brian Stephen
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General Electric Co PLC
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General Electric Co PLC
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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
    • 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
    • H01J9/08—Manufacture of heaters for indirectly-heated cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K3/00—Apparatus or processes adapted to the manufacture, installing, removal, or maintenance of incandescent lamps or parts thereof
    • H01K3/02—Manufacture of incandescent bodies

Definitions

  • This invention relates to a method of producing filaments of refractory metal in the form of a flattened zig-zag.
  • the invention relates to the preparation of such filaments of relatively small dimensions that is to say dimensions such that if a zig-zag were made in known manner on a jig, the jig would be inconveniently small.
  • a method of making a filament of refractory metal in the form of a substantially flattened zig-zag comprises the steps of associating a filamentary spiral of said refractory metal with at least one ductile metal in a relatively compact structure pressing said structure into a substantially flattened shape, thus causing said ductile metal or metals to flow in contact with said spiral and thereafter chemically removing the ductile metallic material.
  • a method of making a filament of refractory material in the form of a substantially flattened zig-zag comprises the steps of placing a filamentary spiral of refractory metal upon a relatively ductile metallic mandrel so as to form a relatively compact structure pressing said structure so as to flatten it to a desired extent, chemically removing the ductile metal and thereafter heat treating the flattened filament so as to set it.
  • said pressing may take place at a temperature between 200 C. and 400 C. so that said refractory metal becomes relatively ductile.
  • Either or both the spiral or ductile metal or metals may be heated before or during the pressing process so as to remove residual stresses.
  • silica tungsten wire of diameter 0.125 mm. is wound on a tungsten wire mandrel of diameter 0.63 mm. to form a spiral having a pitch of 0.605 mm., the overall length of the spiral thus formed being 8 mm.
  • the spiral is then removed from the tungsten mandrel and placed on an annealed cooper wire mandrel of diameter 0.604 mm.
  • the spiral and the copper mandrel are then pressed between two plain hardened steel plates at a pressure of the order of five tons per sq. inch so as to cause the copper to flow in contact with the spiral which is thus flattened to the required extent.
  • the flattened spiral and mandrel compact is then dipped in nitric acid so as to remove the copper and leave a flattened zig-zag filament of silica tungsten having an overall length of 9.5 mm. and a width of 1.4 mm.
  • the flattened filament is then furnaced in a hydrogen atmosphere at a temperature of about 1400 C. for ten minutes. This serves to set the filament in its flattened zig-zag shape.
  • the spiral having been placed on the mandrel is plated with copper to a depth of 0.5 mm. This is to ensure the rigid disposition of the spiral on the mandrel.
  • the spiral itself may be plated with copper to a suitable depth and then flattened without the necessity of placing the spiral on a mandrel.
  • the filament is plated with copper to a suitable depth before being wound into a spiral.
  • the spiral and the mandrel are annealed either separately or together either before or during the pressing, thus all residual stresses are removed from the materials.
  • the pressing takes place at a temperature such that the silica tungsten filament becomes relatively ductile, a suitable temperature being one of the order of 300 C.
  • a zig-zag silica tungsten filament prepared in accordance with the invention is particularly useful as an elec tron source in an electric discharge device such as for example, an X-ray tube or cathode ray tube.
  • Such an electron source is capable of providing a very uniform electron distribution which is hence relatively simple to control.
  • Figure l is a view of the filament
  • Figure 2 is a view, partly cut away to show internal details, of the X-ray tube.
  • the X-ray tube comprises a sealed evacuated glass envelope 1 in which is mounted an electrode structure.
  • the electrode structure includes a cathode constituted by a silica tungsten filament 2 of flattened zig-zag form produced in accordance with the invention; the filament 2 (which is shown in detail in Figure 1) is disposed within a groove formed in a machined nickel cathode head 3, the filament 2 being disposed parallel to and slightly recessed from the face of the head 3 opposite a copper anode 4.
  • a tungsten face 5 is formed upon the operating surface of the anode 4 and serves as a target.
  • a window 6 is formed in the envelope 1 between the cathode and the target, the window 6 being constituted by a reduced thickness of the glass envelope.
  • a method of making a filament of refractory metal in the form of a substantially flattened zig-zag comprising the steps of placing a filamentary spiral of said refractory metal in intimate contact with at least one ductile metal so as to form a relatively compact structure in which said spiral is supported by said ductile metal, pressing said structure into a substantially flattened shape in which the spiral of refractory metal is flattened into zig-zag shape, thus causing said ductile metal or metals to flow in contact with said spiral and thereafter chemically removing the ductile metallic material.
  • a method of making a filament of refractory metal in the form of a substantially flattened zig-zag comprising the steps. of disposing a filamentary spiral of refractory metal around andin intimate contact with a relatively ductile metallic mandrel so as to form a relatively compact structure in which said spiral is supported by said ductile metal, pressing said structure so as to flatten it to an IBXtCl'lll such that the spiral of refractory metal is flattened into zig-zag shape, chemically removing the ductile metal and thereafter heat treating the flattened filament so as to set it.
  • a method of making a filament of refractory metal in the form of substantially flattened zig-zag comprising the steps of placing an open-wound filamentary spiral of said refractory metal in intimate contact with at least one ductile metal so as to form a relatively compact structure, in which said spiral is supported by said ductile metal, pressing said structure into a substantiallyfiattened shape in which the spiral of refractory metal is flattened into zig-zag shape, thus causing said ductile metal or metals to flow in contact with said spiral, and thereafter chemically removing the ductile metallic material.
  • a method of making .a filament of refractory metal in the form of a substantially flattened zig-zag comprising the steps or placing a filamentary spiral of said refractory metal ,in intimate contact withat least one ductile metal so as to form a relatively compact structure, in which said spiral is supported by said ductile metal, pressing said structure into a substantially flattened shape without restraining transverse flow thereof under pressure so that the ductile metal and spiral will spread in a direction transverse to the length of the spiral, thereby flattening the spiral into a zig-zag shape, thus causing said ductile metal or metals to fiow in con tact with said spiral, and'thereafter chemically removing the ductile metallic material.
  • a method of making a filament of refractory metal in'the form of a substantially flattened zig-zag comprising the steps of placing a filamentary spiral of said refractory metal in intimate contact with at least one ductile metal so as to form a relatively compact structure, in which said spiral is supported by said ductile metal, pressing said structure into a substantially flattened shape without restraining longitudinal or transverse .flow thereof under pressure so that the ductile metal and spiral will spread parallel and transverse to the length of the spiral, thus causing said ductile metal or metas to flow in contact with said spiral, and thereafter chemically removing the ductile metallic material.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Lasers (AREA)
  • Powder Metallurgy (AREA)
US576510A 1954-12-03 1955-12-05 Methods of producing refractory metal filaments of flattened zig-zag form Expired - Lifetime US2881104A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB35096/54A GB798945A (en) 1954-12-03 1954-12-03 Improvements in or relating to electric discharge devices

Publications (1)

Publication Number Publication Date
US2881104A true US2881104A (en) 1959-04-07

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US (1) US2881104A (et)
DE (1) DE1070740B (et)
GB (1) GB798945A (et)
NL (2) NL202520A (et)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3530010A (en) * 1968-07-22 1970-09-22 Research Corp Method of making blazed optical diffraction gratings
US4923529A (en) * 1987-10-22 1990-05-08 Tungsram Reszvenytarsasag Equipment for continuous heat treatment of tungsten filaments wound on molybdenum cores

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT222751B (de) * 1960-06-17 1962-08-10 Egyesuelt Izzolampa Verfahren zur Herstellung von Glühlampenwendeln

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1738960A (en) * 1926-03-30 1929-12-10 Mutscheller Arthur Vacuum discharge device and method of using the same
US2047555A (en) * 1933-05-31 1936-07-14 Parsons & Co Ltd C A Manufacture of hollow turbine blades
US2069081A (en) * 1932-05-31 1937-01-26 Gen Electric Electric incandescent lamp
US2165310A (en) * 1939-07-11 Filament
US2482826A (en) * 1945-08-04 1949-09-27 Tung Sol Lamp Works Inc Filament structure for thermionic tubes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2165310A (en) * 1939-07-11 Filament
US1738960A (en) * 1926-03-30 1929-12-10 Mutscheller Arthur Vacuum discharge device and method of using the same
US2069081A (en) * 1932-05-31 1937-01-26 Gen Electric Electric incandescent lamp
US2047555A (en) * 1933-05-31 1936-07-14 Parsons & Co Ltd C A Manufacture of hollow turbine blades
US2482826A (en) * 1945-08-04 1949-09-27 Tung Sol Lamp Works Inc Filament structure for thermionic tubes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3530010A (en) * 1968-07-22 1970-09-22 Research Corp Method of making blazed optical diffraction gratings
US4923529A (en) * 1987-10-22 1990-05-08 Tungsram Reszvenytarsasag Equipment for continuous heat treatment of tungsten filaments wound on molybdenum cores

Also Published As

Publication number Publication date
NL202520A (et)
GB798945A (en) 1958-07-30
DE1070740B (et)
NL96915C (et)

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