EP0024764A1 - Procédé de fabrication d'une anode tournante pour tubes à rayons X et anode obtenue selon ce procédé - Google Patents

Procédé de fabrication d'une anode tournante pour tubes à rayons X et anode obtenue selon ce procédé Download PDF

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Publication number
EP0024764A1
EP0024764A1 EP80200778A EP80200778A EP0024764A1 EP 0024764 A1 EP0024764 A1 EP 0024764A1 EP 80200778 A EP80200778 A EP 80200778A EP 80200778 A EP80200778 A EP 80200778A EP 0024764 A1 EP0024764 A1 EP 0024764A1
Authority
EP
European Patent Office
Prior art keywords
target layer
support
tungsten
anode
weight
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.)
Ceased
Application number
EP80200778A
Other languages
German (de)
English (en)
Inventor
Frederik Magendans
Gerhardus Albertus Te Raa
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.)
Koninklijke Philips NV
Original Assignee
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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 Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical Philips Gloeilampenfabrieken NV
Publication of EP0024764A1 publication Critical patent/EP0024764A1/fr
Ceased legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00X-ray tubes
    • H01J35/02Details
    • H01J35/04Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/08Anodes; Anti cathodes
    • H01J35/10Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes
    • H01J35/108Substrates for and bonding of emissive target, e.g. composite structures

Definitions

  • the invention relates to a method of producing a rotary anode for an X-ray tube, wherein a tungsten or a tungsten alloy target layer is provided on a support by plasma spraying.
  • the invention also relates to an anode thus produced.
  • Rotary anodes produced by a method embodying the invention are particularly suitable for X-ray tubes to which a high load is applied during use, such as X-ray tubes for medical purposes.
  • German Patent Application 2346925 discloses a method of producing a rotary anode for an X-ray tube wherein a tungsten or a tungsten-rhenium alloy target layer, that is to say the layer which is bombarded by the electrons when the rotary anode is used in an X-ray tube, is provided on a molybdenum or a molybdenum alloy support by plasma spraying.
  • a graphite support is used is described in German Auslegeschrift 2251656.
  • a method of producing a rotary anode for an X-ray tube wherein a target layer consisting of tungsten or a tungsten alloy is provided on a support by plasma spraying is characterized in that the target layer is provided by plasma spraying in an oxygen-free medium at a pressure of 2 - 55 kPa.
  • a target layer having a density of over 97 % can be obtained.
  • Plasma spraying W at a reduced pressure is known per se from Moses A. Levinstein, Cienca Y technica de la Soldadura (Madrid) 12, No. 66, pages 1-9 (1962) (see also Chemical Abstracts, 58, 4243f 1963), but in contrast with the results obtained by the Applicants, a density of not more than 92.7 % was then obtained. It was also reported that a reduction in pressure resulted in lower densities.
  • the support is preferably preheated to a temperature above 1000°C prior to the provision of the target layer. This results in an improved adhesion and density of the target layer on the support.
  • Plasma spraying with a power of more than 30 kW generally results in a higher density of the target layer.
  • the tungsten or tungsten alloy to be sprayed is preferably used in the form of a powder having a particle size of not more than 45 / um.
  • a spraying distance (i.e. the distance between the spray gun nozzle and the support) of not less than 150 mm is preferred.
  • the drawing shows a rotary anode comprising a support 1 and a target layer 2.
  • the portion of the target layer denoted by 3 is the place onto which the electron beam in the X-ray tube is focused (i.e. the focal path).
  • the support 1 may consist of molybdenum or of a molybdenum alloy known to be suitable for X-ray rotary anodes. Particularly suitable is a molybdenum alloy having 0.40-0.55 % by weight of Ti, 0.06 - 0.12 % by weight of Zr and 0.01 - 0.03 % by weight of C.
  • the support may alternatively consist of graphite. In that case a carbon transfer inhibiting layer, for example a rhenium layer, should be provided between the support and the target layer.
  • One or more further layers may be present between the target layer and the support, for example a layer of pure tungsten.
  • the target layer 2 consists of tungsten or a tungsten alloy. All alloys known to be suitable for this purpose are very satisfactory. Particularly good results (high density) have been obtained with tungsten-rhenium alloys (0.7 % by weight or rhenium) and with tungsten-rhenium-tantalum alloys (0-7 % by weight of rhenium, 0-4 % by weight of tantalum).
  • the surface of the target layer (except the focal path 3) and/or the surface of the support may be roughened, or these surfaces may be coated with heat-radiation improving material (for example rough tungsten).
  • the target layer prefferably has a composition which varies from the inside to the outside (for example in respect of the rhenium content).
  • the rotary anode is produced in the following manner.
  • a support 1 is produced in a manner which is known per se, for example by casting, forging and pressing. The surface of the support is properly cleaned.
  • the support is then placed in a special, hermetically sealable chamber of the type described in the-above- mentioned article by E. Muehlberger.
  • the chamber is evacuated and filled with Ar. He or N 2 may alternatively be used. These gases may be mixed together and/or be mixed with H 2 (0 - 10 % by volume). This cycle is preferably repeated a few times to remove any residual oxygen.
  • the chamber is filled with one of the above- mentioned gases or gas mixtures to the desired pressure (2 - 50 kPa). A pressure of 2 - 25 kPa is preferably used.
  • the material for the target layer is sprayed onto the support with a plasma gun. (Approximately 35 kW of power is supplied to the plasma gun).
  • the support is preheated with the plasma gun to a temperature above 1000 0 C before the material of the target layer is sprayed. It is possible to vary the composition of the sprayed material continuously during spraying in order to obtain a gradient in the composition of the target layer.
  • a target layer of a thickness of 1.5 - 2.0 mm is preferably applied. It is possible to provide the target layer only in the region of the focal path 3 by using a mask.
  • the support together with the target layer is allowed to cool in the chamber. Finally, the product obtained is removed from the chamber and worked further, the focal path 3 then being ground.

Landscapes

  • Coating By Spraying Or Casting (AREA)
EP80200778A 1979-08-27 1980-08-19 Procédé de fabrication d'une anode tournante pour tubes à rayons X et anode obtenue selon ce procédé Ceased EP0024764A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL7906417 1979-08-27
NL7906417A NL7906417A (nl) 1979-08-27 1979-08-27 Werkwijze voor het vervaardigen van een draaianode voor roentgenbuizen en zo verkregen anode.

Publications (1)

Publication Number Publication Date
EP0024764A1 true EP0024764A1 (fr) 1981-03-11

Family

ID=19833732

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80200778A Ceased EP0024764A1 (fr) 1979-08-27 1980-08-19 Procédé de fabrication d'une anode tournante pour tubes à rayons X et anode obtenue selon ce procédé

Country Status (2)

Country Link
EP (1) EP0024764A1 (fr)
NL (1) NL7906417A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2521776A1 (fr) * 1982-02-18 1983-08-19 Plansee Metallwerk Anode tournante pour tube a rayon x
EP0116385A1 (fr) * 1983-01-25 1984-08-22 Koninklijke Philips Electronics N.V. Procédé de fabrication d'une anode tournante pour tubes à rayons X et anode ainsi obtenue
EP0177079A1 (fr) * 1984-09-14 1986-04-09 Koninklijke Philips Electronics N.V. Procédé de fabrication d'une anode rotative pour tubes à rayons X et anode rotative fabriquée selon ce procédé
EP0850899A1 (fr) * 1996-12-24 1998-07-01 Sulzer Metco AG Procédé de revêtement d'un substrat en carbone ou d'un substrat nonmétallique comprenant du carbone et substrat revêtu selon ce procédé

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010009A (en) * 1958-09-29 1961-11-21 Plasmadyne Corp Method and apparatus for uniting materials in a controlled medium
US3243636A (en) * 1963-01-30 1966-03-29 Tubix Soc Rotary anode for X-ray tubes
FR2204041A1 (fr) * 1972-10-20 1974-05-17 Siemens Ag
FR2210009A1 (fr) * 1972-12-06 1974-07-05 Philips Nv
US3839618A (en) * 1972-01-03 1974-10-01 Geotel Inc Method and apparatus for effecting high-energy dynamic coating of substrates

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010009A (en) * 1958-09-29 1961-11-21 Plasmadyne Corp Method and apparatus for uniting materials in a controlled medium
US3243636A (en) * 1963-01-30 1966-03-29 Tubix Soc Rotary anode for X-ray tubes
US3839618A (en) * 1972-01-03 1974-10-01 Geotel Inc Method and apparatus for effecting high-energy dynamic coating of substrates
FR2204041A1 (fr) * 1972-10-20 1974-05-17 Siemens Ag
FR2210009A1 (fr) * 1972-12-06 1974-07-05 Philips Nv

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2521776A1 (fr) * 1982-02-18 1983-08-19 Plansee Metallwerk Anode tournante pour tube a rayon x
EP0116385A1 (fr) * 1983-01-25 1984-08-22 Koninklijke Philips Electronics N.V. Procédé de fabrication d'une anode tournante pour tubes à rayons X et anode ainsi obtenue
EP0177079A1 (fr) * 1984-09-14 1986-04-09 Koninklijke Philips Electronics N.V. Procédé de fabrication d'une anode rotative pour tubes à rayons X et anode rotative fabriquée selon ce procédé
EP0850899A1 (fr) * 1996-12-24 1998-07-01 Sulzer Metco AG Procédé de revêtement d'un substrat en carbone ou d'un substrat nonmétallique comprenant du carbone et substrat revêtu selon ce procédé

Also Published As

Publication number Publication date
NL7906417A (nl) 1981-03-03

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Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

Designated state(s): AT DE FR NL

17P Request for examination filed

Effective date: 19810325

STAA Information on the status of an ep patent application or granted ep patent

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18R Application refused

Effective date: 19820712

RIN1 Information on inventor provided before grant (corrected)

Inventor name: TE RAA, GERHARDUS ALBERTUS

Inventor name: MAGENDANS, FREDERIK