US3689795A - Boron-containing rotating x-ray target - Google Patents

Boron-containing rotating x-ray target Download PDF

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Publication number
US3689795A
US3689795A US147615A US3689795DA US3689795A US 3689795 A US3689795 A US 3689795A US 147615 A US147615 A US 147615A US 3689795D A US3689795D A US 3689795DA US 3689795 A US3689795 A US 3689795A
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US
United States
Prior art keywords
boron
tungsten
improvement
molybdenum
focal track
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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
US147615A
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English (en)
Inventor
Friedrich Benesovsky
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Schwarzkopf Technologies Corp
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Schwarzkopf Technologies Corp
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Assigned to SCHWARZKOPF TECHNOLOGIES CORPORATION, A CORP. OF MD reassignment SCHWARZKOPF TECHNOLOGIES CORPORATION, A CORP. OF MD CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE ON 05/21/1991 Assignors: SCHWARZKOPF DEVELOPMENT CORPORATION, A CORP. OF MD
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/08—Anodes; Anti cathodes
    • H01J35/10—Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes
    • H01J35/108—Substrates for and bonding of emissive target, e.g. composite structures
    • 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
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12771—Transition metal-base component
    • Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
    • Y10T428/12826—Group VIB metal-base component
    • Y10T428/12833—Alternative to or next to each other

Definitions

  • the focal track is frequently made of tungsten or of a tungsten alloy with anotherjmetal such as rhenium. Because of the expense of the materials used in the focal track, in commercial X-ray targets the entire target neednot be 'made of-the same alloy but, more usually, the target is a composite of a base and an outer layer or focal track intended for the bombardment of electrons.
  • the focal track and the base are frequently made of different materials.
  • Molybdenum is a material frequently used in the base of rotating targets. Apart from cost, the use of molybdenum has the advantage that due to the lower specific gravity of molybdenum, the centrifugal forces generated during the rotation of the anode are reduced. Accordingly, higher speeds of rotation are possible. There are problems, however, with composites of molybdenum bases and tungsten alloy focal tracks. Under heavy duty operating conditions, cracks may develop in the molybdenum or at the molybdenumtungsten interface because of the difference in thermal expansion between the molybdenum and the tungsten alloy. g
  • the body or base upon which the focal track is imposed is comprised of a molybdenum alloy containing from 50 to 500 parts per million (by weight) of boron.
  • the molybdenum alloy will contain from 100 to 200 partsper million of boron.
  • the presence of boron not only serves to reduce the stresses caused by differential thermal expansion, but it also serves to increase the high temperature strength and recrystallization of the body portion and also its cold ductility.
  • the high temperature strength of the body portion of the rotating target can be further increased by the addition of hafnium to the body portion in a quantity of up to about 2 percent by weight. Where hafnium is used, at least about 0.05 percent by weight should be present.
  • the molybdenum body or base can also contain alloying additions, i.e., up to about percent by weight, of other refractory metals, for example,
  • the focal track can be made of pure tungsten, but is preferably made of tungsten alloyed with at least about 0.5 percent by weight, preferably from about 5 percent to 25 percent by weight, of rhenium. If desired, the focal track can also contain other alloying ingredients in addition to or in place of rhenium.
  • the tungsten alloy used in the focal track may contain from about 0.05 to about 5 percent by weight of platinum. Where platinum is employed, the tungsten-platinum alloy should contain from about 0.15 toabout 1.5 percent by weight of platinum. The presence of platinum serves to increase the service life of the focal track by decreasing toughening.
  • the focal track may also contain amounts of up to 5 percent osmium and up to 2 percent iridium by weight for the purpose of improving target performance.
  • osmium a minimum of about 0.1 percent by weight can be used and where iridium is employed, a minimum of about 0.05 percent by weight can be used.
  • the thickness of the tungsten or tungsten alloy layer of the focal track should be at least about 0.1 mm. Focal tracks of thicknesses in excess of about 2 mm. are generally not economically warranted.
  • the method of producing the alloy of the invention is conveniently carried out by powder metallurgical techniques.
  • powders of the various alloy components can be mixed together at an appropriate sintering temperature to cause alloy formation.
  • the sintering temperature will generally be in the range of from about 1,600 to 2,400 C.
  • the base can be formed either by powder metallurgical techniques or by any other convenient method and the base is then subjected to having the focal track sprayed on as by vapor deposition or any other convenient method.
  • the boron addition is preferably made to the molybdenum by use of molybdenum boride powder.
  • powdered boron itself or another suitable compound of boron can also be employed. If hafnium addition is used, it is conveniently added in the form of powdered hafnium boride.
  • the powders employed in carrying out the powder metallurgical techniques will have particle sizes in the range of from 1 to 50 microns.
  • a convenient target for use in an X-ray tube can be made with the use of a cylindrical die which is slightly larger than the rotating target.
  • the die is filled with molybdenum powder of a particle size range of from 2 to 10 microns and containing sufficient molybdenum boride powder of the same particle size range mixed therewith to bring the total boron content to 0.1 percent by weight based upon the combined weights of molybdenum and boron. If desired, the hafnium boride thickness of approximately mm.
  • a second layer of a powder mixture of tungsten powder mixed with 10 percent by weight of rhenium powder is added to a thickness of about 2.5 mm.
  • the powder within the cylinder is then compacted at a pressure of 4 tons per square centimeter into a circular compact.
  • the compact is then sintered for 4 hours at 2,000 C. in a hydrogen atmosphere and then allowed to cool under hydrogen.
  • sintering and cooling can be carried out in an atmosphere of an inert gas.
  • part of the boron may be oxidized by traces of oxygen contained in the powder and in the gaseous atmosphere. Such oxidized boron will be in the form of volatile boron trioxide.
  • the residual boron content of the final sintered product may therefore be slightly lower than that of the original powder, and in this instance was 0.03 percent.
  • the resultant product is then forged and ground to a product of thelprescribed' tolerance.
  • Metallographic examination shows the existence of a good bond between the molybdenum alloy body and the tungsten alloy focal track.
  • the boron contained in the molybdenum body which diffuses partly into the tungsten alloy serves to produce a fine grained transition between the two layers.
  • a rotating X-ray target comprising a molybdenum-containing body and a tungsten-containing focal track
  • the improvement which serves to reduce the tendency towards cracking. comprising the presence in the molybdenum-containing body of from 50 to 500 parts per million of boron.
  • the focal track contains an alloying addition of at least one metal of the group consisting of osmium and iridium.

Landscapes

  • Powder Metallurgy (AREA)
  • X-Ray Techniques (AREA)
US147615A 1970-06-02 1971-05-27 Boron-containing rotating x-ray target Expired - Lifetime US3689795A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT494570A AT300140B (de) 1970-06-02 1970-06-02 Drehanode für Röntgenröhren

Publications (1)

Publication Number Publication Date
US3689795A true US3689795A (en) 1972-09-05

Family

ID=3570185

Family Applications (1)

Application Number Title Priority Date Filing Date
US147615A Expired - Lifetime US3689795A (en) 1970-06-02 1971-05-27 Boron-containing rotating x-ray target

Country Status (6)

Country Link
US (1) US3689795A (enrdf_load_stackoverflow)
AT (1) AT300140B (enrdf_load_stackoverflow)
DE (1) DE2120736A1 (enrdf_load_stackoverflow)
FR (1) FR2095612A5 (enrdf_load_stackoverflow)
GB (1) GB1298293A (enrdf_load_stackoverflow)
NL (1) NL7106682A (enrdf_load_stackoverflow)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3869635A (en) * 1972-06-28 1975-03-04 Siemens Ag Rotary anode for an x-ray tube
US4004174A (en) * 1973-11-02 1977-01-18 Tokyo Shibaura Electric Co., Ltd. Rotary anode structure for an X-ray tube
US4195247A (en) * 1978-07-24 1980-03-25 General Electric Company X-ray target with substrate of molybdenum alloy
EP0218434A3 (en) * 1985-09-30 1988-06-01 Kabushiki Kaisha Toshiba X-ray tube
US4780902A (en) * 1985-07-11 1988-10-25 Schwarzkopf Development Corporation Rotary anode for X-ray tubes
EP0405897A3 (en) * 1989-06-26 1991-03-20 Union Carbide Coatings Service Technology Corp. Coated article
US5222116A (en) * 1992-07-02 1993-06-22 General Electric Company Metallic alloy for X-ray target
US6554179B2 (en) 2001-07-06 2003-04-29 General Atomics Reaction brazing of tungsten or molybdenum body to carbonaceous support
US20050226387A1 (en) * 2004-04-08 2005-10-13 General Electric Company Apparatus and method for light weight high performance target
US20060172454A1 (en) * 2005-01-21 2006-08-03 Hans-Henning Reis Molybdenum alloy
US20080118031A1 (en) * 2006-11-17 2008-05-22 H.C. Starck Inc. Metallic alloy for X-ray target
CN107074662A (zh) * 2014-11-07 2017-08-18 攀时奥地利公司 金属氧化物薄膜，沉积金属氧化物薄膜的方法及包含金属氧化物薄膜的装置
EP4531071A3 (en) * 2023-09-07 2025-07-09 GE Precision Healthcare LLC X-ray tube anode with optimized area focal spot track

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1142211A (en) * 1978-11-20 1983-03-01 Richard G. Weber Rotatable x-ray target having off-focal track coating
RU2179767C2 (ru) * 2000-04-12 2002-02-20 Государственный научно-исследовательский институт Научно-производственного объединения "Луч" Способ изготовления анода рентгеновской трубки

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1625427A (en) * 1920-12-21 1927-04-19 Westinghouse Lamp Co Target for X-ray tubes
US3414754A (en) * 1965-11-20 1968-12-03 Siemens Ag Anode plate for x-ray tubes
US3539859A (en) * 1956-03-30 1970-11-10 Radiologie Cie Gle X-ray generator tube with graphite rotating anode

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1625427A (en) * 1920-12-21 1927-04-19 Westinghouse Lamp Co Target for X-ray tubes
US3539859A (en) * 1956-03-30 1970-11-10 Radiologie Cie Gle X-ray generator tube with graphite rotating anode
US3414754A (en) * 1965-11-20 1968-12-03 Siemens Ag Anode plate for x-ray tubes

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3869635A (en) * 1972-06-28 1975-03-04 Siemens Ag Rotary anode for an x-ray tube
US4004174A (en) * 1973-11-02 1977-01-18 Tokyo Shibaura Electric Co., Ltd. Rotary anode structure for an X-ray tube
US4195247A (en) * 1978-07-24 1980-03-25 General Electric Company X-ray target with substrate of molybdenum alloy
US4780902A (en) * 1985-07-11 1988-10-25 Schwarzkopf Development Corporation Rotary anode for X-ray tubes
EP0218434A3 (en) * 1985-09-30 1988-06-01 Kabushiki Kaisha Toshiba X-ray tube
EP0405897A3 (en) * 1989-06-26 1991-03-20 Union Carbide Coatings Service Technology Corp. Coated article
US5222116A (en) * 1992-07-02 1993-06-22 General Electric Company Metallic alloy for X-ray target
US6554179B2 (en) 2001-07-06 2003-04-29 General Atomics Reaction brazing of tungsten or molybdenum body to carbonaceous support
US20050226387A1 (en) * 2004-04-08 2005-10-13 General Electric Company Apparatus and method for light weight high performance target
US20060151578A1 (en) * 2004-04-08 2006-07-13 Tiearney Thomas C Jr Method for making a light weight high performance target
US7194066B2 (en) 2004-04-08 2007-03-20 General Electric Company Apparatus and method for light weight high performance target
US7505565B2 (en) 2004-04-08 2009-03-17 General Electric Co. Method for making a light weight high performance target
US20060172454A1 (en) * 2005-01-21 2006-08-03 Hans-Henning Reis Molybdenum alloy
US20080118031A1 (en) * 2006-11-17 2008-05-22 H.C. Starck Inc. Metallic alloy for X-ray target
CN107074662A (zh) * 2014-11-07 2017-08-18 攀时奥地利公司 金属氧化物薄膜，沉积金属氧化物薄膜的方法及包含金属氧化物薄膜的装置
EP4531071A3 (en) * 2023-09-07 2025-07-09 GE Precision Healthcare LLC X-ray tube anode with optimized area focal spot track

Also Published As

Publication number Publication date
NL7106682A (enrdf_load_stackoverflow) 1971-12-06
GB1298293A (en) 1972-11-29
AT300140B (de) 1972-07-10
DE2120736A1 (de) 1971-12-09
FR2095612A5 (enrdf_load_stackoverflow) 1972-02-11

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Owner name: SCHWARZKOPF TECHNOLOGIES CORPORATION, A CORP. OF M

Free format text: CHANGE OF NAME;ASSIGNOR:SCHWARZKOPF DEVELOPMENT CORPORATION, A CORP. OF MD;REEL/FRAME:005931/0448

Effective date: 19910517