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EP0204909A1 - Matériau d'électrode pour une espace de décharges électriques - Google Patents

Matériau d'électrode pour une espace de décharges électriques Download PDF

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Publication number
EP0204909A1
EP0204909A1 EP86104346A EP86104346A EP0204909A1 EP 0204909 A1 EP0204909 A1 EP 0204909A1 EP 86104346 A EP86104346 A EP 86104346A EP 86104346 A EP86104346 A EP 86104346A EP 0204909 A1 EP0204909 A1 EP 0204909A1
Authority
EP
European Patent Office
Prior art keywords
tungsten
phase
electrode material
sintered
electrodes
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.)
Granted
Application number
EP86104346A
Other languages
German (de)
English (en)
Other versions
EP0204909B1 (fr
Inventor
Sylvia Härdtle
Rainer Dr. Schmidberger
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.)
Dornier GmbH
Original Assignee
Dornier GmbH
Dornier System GmbH
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 Dornier GmbH, Dornier System GmbH filed Critical Dornier GmbH
Publication of EP0204909A1 publication Critical patent/EP0204909A1/fr
Application granted granted Critical
Publication of EP0204909B1 publication Critical patent/EP0204909B1/fr
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T1/00—Details of spark gaps
    • H01T1/02—Means for extinguishing arc
    • H01T1/04—Means for extinguishing arc using magnetic blow-out
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K15/00—Acoustics not otherwise provided for
    • G10K15/04—Sound-producing devices
    • G10K15/06—Sound-producing devices using electric discharge
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T1/00—Details of spark gaps
    • H01T1/24—Selection of materials for electrodes

Definitions

  • the invention relates to an electrode material for a spark gap for generating shock waves for the contact-free comminution of concrements in bodies of living beings.
  • a device for crushing concrements located in the body of a living being with a focusing chamber is known, the focusing chamber being part of an ellipsoid of revolution and in one focus of which shock waves can be generated by spark discharge.
  • the concretion is in the second focus.
  • the focusing chamber is filled with a liquid.
  • the electrical energy stored in a capacitor is converted into mechanical shock wave energy by electrical underwater spark discharge. If the electrical underwater spark discharge is ignited in the focal point of the elliptical rotation focusing chamber, then Generate shock waves of high amplitude (1 Kbar with short pulse lengths (1 ⁇ sec) almost point-like in the second focal point.
  • the concretions in the body of living beings can be broken up into fragments that can be removed with these shock waves.
  • the materials for the electrode tips include Tantalum and tungsten suggested.
  • the electrodes are subject to high thermal and mechanical loads.
  • tantalum has a high thermal erosion resistance, its mechanical strength is not sufficient for a long service life, i. H. for the generation of a large number of underwater spark discharges.
  • tungsten also does not have a long service life due to its high brittleness. It is destroyed very quickly by the mechanical load.
  • Electrode materials commonly used in technology are composite materials, for example tungsten copper Alloys that combine the refractory properties of tungsten with the good electrical conductivity of copper. These materials, too, are too brittle for the applications mentioned and suffer severe mechanical abrasion. These materials have a copper content of ⁇ 20%. Since the electrodes are subjected to high thermal loads, a molten phase of Cu (melting point 1083 ° C) is formed, which extends from the surface over a depth of approx. 100 ⁇ m or more into the interior of the electrode tip. The higher the proportion of binder phase and the higher the melting temperature of the binder phase, the greater the erosion of such melting areas,
  • DE-OS 32 26 648 balancing bullets made of a pre-alloyed tungsten powder which contain very small polygonal tungsten grains (less than 5 pm) in the sintered state, between which a matrix metal is distributed in a thin layer.
  • the literature does not mention any electrical or thermal properties such as electrical or thermal conductivity, resistance to erosion, ignition behavior, scaling behavior, resistance to corrosion or oxidation, which would suggest transfer of the material from the defense technology to electrodes or spark gaps.
  • the invention has for its object to provide an electrode material, the erosion resistance compared to the previously used steel electrodes is significantly increased due to high thermal and mechanical stability, the erosion is evenly distributed over the surface (which has no material breakouts) and the electrical conductivity is sufficiently high ( ⁇ 10 4 ⁇ -1 cm -1 at room temperature).
  • Embodiments of the inventions are the subject of subclaims.
  • the use of already alloyed tungsten heavy metal powder according to the invention allows the production of very fine-grained sintered tungsten heavy metal electrodes, since the sintering process can take place without a liquid phase. These electrodes therefore have an extremely high yield strength and tensile strength.
  • the material mentioned offers the advantage of a combination of the high thermal load capacity of the tungsten with the high mechanical strength, which is given by the fine-grained composite material with a tough nickel-based alloy.
  • the fine-grained nature of the material is important in two ways. On the one hand, the fine-grained nature of the sintered material leads to an increase in the yield strength compared to conventionally liquid-phase sintered material (Hall-Petch relationship).
  • the fine granularity of the material ensures that the thermal and mechanical stress caused by the spark is always distributed over a large number of structural components (grains) at the point of the spark strike.
  • fine-grained material also acts against the very microscopic stress a spark as a composite material with the combined properties of high thermal load capacity of the tungsten and high strength and ductility of the binder alloy. Due to the fine grain of the material, the electrodes burn off very evenly. This causes a small migration of the spark base on the electrodes, so that, with focusing shock wave application, small pressure fluctuations occur in the second focus with successive spark discharges.
  • Coarse-grained tungsten heavy metal electrodes such as those obtained by liquid phase sintering, show coarse-eruption-like erosion, which results in very strong pressure fluctuations when the shock wave is focused.
  • the erosion of such electrodes is significantly greater than that of electrodes with a fine-grained structure.
  • cracks and spalling can be seen, which both lead to increased erosion and to the above lead to irregular sparks that do not originate from the geometric electrode tip and therefore lead to pressure fluctuations.
  • High strength even in the thermally stressed area of the electrode tips can therefore only be obtained using very fine-grained material.
  • Physical properties such as thermal conductivity and electrical conductivity of the material according to the invention do not differ from coarse-grained material of the same alloy composition. With a tungsten content of 90 percent by weight of the alloy, these physical properties are approximately the same as with pure tungsten.
  • the corrosion resistance of the electrodes according to the invention in aqueous media and moist air is significantly better than that of the steel electrodes.
  • Alloyed tungsten heavy metal powder with the composition 90% by weight of tungsten, 6% by weight of nickel, 2% by weight of cobalt, 2% by weight of iron is pressed under all-round pressure into cylinders 8 mm in length and 60 mm in length.
  • the pressure is 300 Nmm 2 .
  • the compacts are first presintered in a hydrogen atmosphere at 900 ° C. for 10 hours and then sintered in vacuo at a pressure of 1o -5 mbar for 5 h at 1 360 o .
  • the blanks then present have a diameter of approx. 5 mm and a length of 45 mm.
  • the blanks are machined into the desired electrode shape.
  • the erosion of such electrodes during underwater spark discharge is 2.5 times less than that of conventional steel electrodes.
  • FIG. 1 shows the metallographic cut of an electrode according to the invention after use in the region of the electrode tip.
  • the magnification scale is 50: 1.
  • the burnup is evenly distributed over the surface in the area of the tip.
  • FIG. 2 shows the structure in the tip area in a magnification of 1000 times. Over a depth of approx. 25 pm, the outer layer shows a structure with rounded tungsten grains. The rounding was carried out by melting the binder alloy under the influence of the spark discharge. A flattening of the tungsten grains on the outer edge under the influence of the pressure surges can also be clearly seen.
  • At the core of the electrode is the typical solid-phase sintered structure with polygonal tungsten grains.
  • FIG. 3 shows the structure in the transition area between the spark impact area and the less loaded area of the electrode, in which the binder alloy did not melt,

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Powder Metallurgy (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Surgical Instruments (AREA)
EP86104346A 1985-05-29 1986-05-09 Matériau d'électrode pour une espace de décharges électriques Expired EP0204909B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19853519163 DE3519163A1 (de) 1985-05-29 1985-05-29 Elektrodenmaterial fuer eine funkenstrecke
DE3519163 1985-05-29

Publications (2)

Publication Number Publication Date
EP0204909A1 true EP0204909A1 (fr) 1986-12-17
EP0204909B1 EP0204909B1 (fr) 1989-11-08

Family

ID=6271862

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86104346A Expired EP0204909B1 (fr) 1985-05-29 1986-05-09 Matériau d'électrode pour une espace de décharges électriques

Country Status (3)

Country Link
EP (1) EP0204909B1 (fr)
JP (1) JPS61276549A (fr)
DE (1) DE3519163A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0326713A1 (fr) * 1988-01-04 1989-08-09 GTE Products Corporation Alliages tungstène-nickel-fer
US5008071A (en) * 1988-01-04 1991-04-16 Gte Products Corporation Method for producing improved tungsten nickel iron alloys
FR2673492A1 (fr) * 1991-03-01 1992-09-04 Technomed Int Sa Electrode en alliage refractaire hautement allie et appareil de generation d'onde de pression en comportant application.
GB2278851A (en) * 1993-06-07 1994-12-14 Nwm De Kruithoorn Bv Heavy metal alloys
EP1083239A1 (fr) * 1999-09-09 2001-03-14 Advanced Materials Technologies, Pte Ltd. Alliage d'tungstène amagnétiques à haute densité
CN104889384A (zh) * 2015-06-10 2015-09-09 深圳市威勒达科技开发有限公司 一种W-Re复合粉末材料及其制备方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2649252B1 (fr) * 1989-06-30 1993-01-15 Technomed Int Sa Procede et dispositif de decharge d'un arc electrique dans un liquide electriquement conducteur et application au lithotrypteur
DE10112461C2 (de) * 2001-03-15 2003-12-24 Hmt Ag Vorrichtung zur Erzeugung elektrischer Entladungen in einem wässrigen Medium

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1297870B (de) * 1966-03-31 1969-06-19 Hermsdorf Keramik Veb Verfahren zur pulvermetallurgischen Herstellung einer quaternaeren Wolframlegierung mit verbesserter Bruchdehnung
US3557793A (en) * 1965-04-06 1971-01-26 Jury Grigorievich Ediny Method for crushing stones in urinary bladder and instrument for same
US3745000A (en) * 1970-10-22 1973-07-10 Gte Sylvania Inc Process for producing tungsten-alloy emitter type electrode
US4012230A (en) * 1975-07-07 1977-03-15 The United States Of America As Represented By The United States Energy Research And Development Administration Tungsten-nickel-cobalt alloy and method of producing same
DE2635635A1 (de) * 1976-08-07 1978-02-09 Dornier System Gmbh Funkenstrecke zur zerstoerung von konkrementen in koerpern von lebewesen
EP0098944A2 (fr) * 1982-07-16 1984-01-25 DORNIER SYSTEM GmbH Poudre en alliage de tungstène

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3557793A (en) * 1965-04-06 1971-01-26 Jury Grigorievich Ediny Method for crushing stones in urinary bladder and instrument for same
DE1297870B (de) * 1966-03-31 1969-06-19 Hermsdorf Keramik Veb Verfahren zur pulvermetallurgischen Herstellung einer quaternaeren Wolframlegierung mit verbesserter Bruchdehnung
US3745000A (en) * 1970-10-22 1973-07-10 Gte Sylvania Inc Process for producing tungsten-alloy emitter type electrode
US4012230A (en) * 1975-07-07 1977-03-15 The United States Of America As Represented By The United States Energy Research And Development Administration Tungsten-nickel-cobalt alloy and method of producing same
DE2635635A1 (de) * 1976-08-07 1978-02-09 Dornier System Gmbh Funkenstrecke zur zerstoerung von konkrementen in koerpern von lebewesen
EP0098944A2 (fr) * 1982-07-16 1984-01-25 DORNIER SYSTEM GmbH Poudre en alliage de tungstène

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0326713A1 (fr) * 1988-01-04 1989-08-09 GTE Products Corporation Alliages tungstène-nickel-fer
US5008071A (en) * 1988-01-04 1991-04-16 Gte Products Corporation Method for producing improved tungsten nickel iron alloys
FR2673492A1 (fr) * 1991-03-01 1992-09-04 Technomed Int Sa Electrode en alliage refractaire hautement allie et appareil de generation d'onde de pression en comportant application.
WO1992016039A1 (fr) * 1991-03-01 1992-09-17 Technomed International Electrode en alliage refractaire hautement allie et appareil de generation d'onde de pression en comportant application
GB2278851A (en) * 1993-06-07 1994-12-14 Nwm De Kruithoorn Bv Heavy metal alloys
US5462576A (en) * 1993-06-07 1995-10-31 Nwm De Kruithoorn B.V. Heavy metal alloy and method for its production
GB2278851B (en) * 1993-06-07 1997-04-09 Nwm De Kruithoorn Bv Heavy metal alloys
EP1083239A1 (fr) * 1999-09-09 2001-03-14 Advanced Materials Technologies, Pte Ltd. Alliage d'tungstène amagnétiques à haute densité
CN104889384A (zh) * 2015-06-10 2015-09-09 深圳市威勒达科技开发有限公司 一种W-Re复合粉末材料及其制备方法

Also Published As

Publication number Publication date
DE3519163C2 (fr) 1987-03-26
JPS61276549A (ja) 1986-12-06
DE3519163A1 (de) 1986-12-04
EP0204909B1 (fr) 1989-11-08

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