US3630770A - Method for fabricating lanthanum boride cathodes - Google Patents

Method for fabricating lanthanum boride cathodes Download PDF

Info

Publication number
US3630770A
US3630770A US3630770DA US3630770A US 3630770 A US3630770 A US 3630770A US 3630770D A US3630770D A US 3630770DA US 3630770 A US3630770 A US 3630770A
Authority
US
United States
Prior art keywords
lanthanum
plasma
boride
gas
lanthanum boride
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.)
Expired - Lifetime
Application number
Other languages
English (en)
Inventor
Louis J Favreau
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.)
General Electric Co
Original Assignee
General Electric Co
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 General Electric Co filed Critical General Electric Co
Application granted granted Critical
Publication of US3630770A publication Critical patent/US3630770A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/42—Plasma torches using an arc with provisions for introducing materials into the plasma, e.g. powder or liquid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/16—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed
    • B05B7/22—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc
    • B05B7/222—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc using an arc
    • B05B7/226—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc using an arc the material being originally a particulate material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
    • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
    • 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
    • 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
    • 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
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31678—Of metal

Definitions

  • ABSTRACT A method for fabricating cathodes with a lanthanum boride coating is disclosed in which the coating is applied to any base metal by spraying with a plasma flame spray.
  • One plasma source is a spray gun utilizing an electric arc discharge through which a plasma gas is passed so that a plasma of ionized gas issues from the spray gun into which is injected a carrier gas having lanthanum boride powder suspended therein.
  • the high-temperature plasma flame appearing at the nozzle of the spray gun melts the lanthanum boride (LaB almost instantly and the droplets formed thereby are carried to the surface of a prepared base material.
  • This invention relates generally to improved cathodes for electron discharge devices and more particularly pertains to a method for making an improved cathode by the application of lanthanum boride.
  • the borides of the alkaline earth and rare earth metals and thorium have been found to improve the thermionic emission characteristics of cathode materials such as nickel, tungsten, tantalum, molybdenum, and rhenium when such metals are coated with the aforementioned borides.
  • the desirable properties of the rare earth metals are well known in the art and are fully discussed, for example, in US. Pat. No. 2,639,399 to J. M. Lafferty.
  • lanthanum boride, LaB is particularly desirable for electron emitters.
  • One of the difiiculties previously encountered in utilizing lanthanum boride however is that it did not adhere readily to cathode base metals. Accordingly, there was a serious need for the development of a process for applying lanthanum boride (LaB to cathode base metals in such a manner that the LaB would adhere to the base metal.
  • the present invention describes such a process.
  • the present invention pertains to a method for fabricating lanthanum boride cathodes including the steps of cleaning the base cathode metal by sandblasting techniques and spraying the base metal with molten lanthanum boride which may conveniently be obtained from a plasma flame spray gun operating with a SOO-ampere-arc current and with plasma gas passed through the arc to create a plasma flame into which is injected lanthanum boride powder suspended in a gaseous carrier.
  • the resulting spray issuing from the nozzle of the spray gun is pennitted to strike the base metal to form a coating thereon.
  • This coating is not only harder and more tenacious than any prior art coatings, but also produces a cathode with unusually higher electron emission characteristics than lanthanum boride cathodes made by conventional methods such as painting, vacuum sintering and cataphoretic deposition.
  • FIG. l of the drawing there is illustrated a plasma flame spray gun 1] for producing lanthanum boride coatings in accordance with the invention.
  • Spray guns found suitable for this purpose are marketed by Metco of Westbury, Long Island, NY. and are designated by type Nos. 2M and 3MB.
  • the plasma flame spray gun It provides a plasma flame 12 which can be controlled over a wide temperature range so as to ensure the proper melt temperature for the lanthanum boride.
  • the heat for spraying is generated by an electric arc of extremely high intensity and is transferred to the material to be sprayed by a plasma gas which is brought to the spray gun 11 through a gas line 13 which terminates at a point behind the electric arc.
  • the plasma gas being applied under pressure, drives the electric are through the nozzle of the spray gun Ill and directs the flame 12 toward the material to be sprayed.
  • the plasma gas consists essentially of a primary gas selected from the group consisting of nitrogen, argon, and helium and a secondary gas of hydrogen.
  • the primary gas is mixed with from S to 15 percent by volume of the secondary gas to form the desired plasma gas.
  • the electric are utilized in the spray gun I 1 is provided by a direct current which is supplied from a rectifier type power supply unit through electrical conductors l4 and 15.
  • a direct current which is supplied from a rectifier type power supply unit through electrical conductors l4 and 15.
  • This coolant which may be water, for example, is conducted to and away from the nozzle by a coolant line to appropriately connected to a heat exchanger.
  • the lanthanum boride is brought to the spray gun 11 in the form of a powder suspended in a carrier gas stream which is taken from the primary gas nitrogen, argon, or helium.
  • the lanthanum boride suspended in the carrier gas stream is brought to the nozzle of the spray gun I] by a line 17.
  • the lanthanum boride thus introduced into the nozzle of the spray gun 11 is melted by the flame 12 and the droplets formed thereby are propelled to the surface being coated by the blast of plasma gas as it rushes through the nozzle orifice.
  • the plasma flame 12 is directed toward strips of cathode base material such as, for example, tantalum, tungsten, nickel, rhenium, or molybdenum.
  • the strips 18 are supported by a support member 19 which is held in a fixed position by a vise 20.
  • the strips 18, the support member 19, and vise are all enclosed in a hood 21 which collects the hot gases and rents them to the outside air.
  • a piece of rhenium metal is selected so that cathode base strips can be subsequently cut therefrom.
  • the surface of the rhenium must be prepared properly. This is accomplished by washing the metal thoroughly in a solvent and then blasting the metal with an abrasive such as alumina with a particle size of 325-mesh at an air pressure of 7080 psi.
  • the degree of roughening produced by the abrasive blasting naturally depends upon the type and mesh size of the abrasive, the air pressure, and the hardness of the surface.
  • the foregoing air pressure and the particle size were found acceptable for the making of lanthanum boride coated cathodes, but are indicated solely for the purpose of illustration and are not meant by way of limitation.
  • the rhenium metal is then cut into strips of the size desired for the finished cathode. Considerable care must be exercised so as not to contaminate the surface of the rhenium after it is cleaned.
  • the strips 18 thus out are placed or formed on the support member R9 in preparation for the plasma spraying.
  • the best lanthanum boride coatings have been achieved when the plasma gas has been formulated in approximate proportions of percent to 15 percent by volume of argon gas to hydrogen gas, respectively.
  • Argon has been found to be preferable to nitrogen since nitrogen reacts with the lanthanum to cause nitriding which adversely affects the emission characteristics of the resultant cathode if exposed to moisture in the air.
  • Helium produces no such affects and could be used interchangeably with argon.
  • the means for achieving this proportion or ratio of gases can readily be achieved by measuring the individual flow rates of the two gases into a unitary gas line. Such apparatus is a part of the prior art since it is found in the Metco type 2M and 3Mb plasma spray guns with which the present invention may be practiced, and accordingly need not be discussed further.
  • the purpose of the hydrogen in the plasma gas is to cause burning with the atmospheric oxygen in the area surrounding the plasma spray so as to provide more protection for the lanthanum boride droplets from undesirable chemical action than that afforded by the presence of the inert gas alone.
  • the primary gas is also utilized as a carrier gas for the lanthanum boride powder. This is accomplished by introducing a portion of the primary gas into a powder feed unit (not shown) in which lanthanum boride powder is contained.
  • the size of the lanthanum boride powder may range between 5 to 150 microns with very good results in the final coating; however, it is preferable to use lanthanum boride powder in the 5- to lO-micron size for the coatings described herein.
  • the powder contained in the powder feed unit is agitated so that as the primary gas passes therethrough, the lanthanum boride powder is picked up and conveyed to the spray gun 11 through the gas line 17.
  • the most desirable results have been achieved when the are current for the spray gun is approximately 500 amperes. With this are current and the plasma gas supplied to the spray gun in the aforementioned proportions, the lanthanum boride powder introduced into the gas stream is melted by the plasma flame 12 and the droplets formed thereby are propelled to the surface of the rhenium strips. As illustrated in FlG. l, the plasma flame spray gun 22 is positioned or spaced from the rhenium strips by a distance such that the tip or point of the plasma flame 12 just strikes the surface of the rhenium strips. in this way, minimum heating of the base metal occurs and the best coating results are obtained.
  • FIG. 3 illustrates a cross-sectional view of a cathode strip 18 with a coating 22 of lanthanum boride applied in accordance with the instant invention.
  • the lanthanum boride coating applied by the foregoing process is much harder and forms a more tenacious bond with the base material than by any of the prior art processes.
  • An additional advantage of the lanthanum boride coating applied in accordance with the instant invention resides in the higher thermionic emission characteristics of the resultant cathode which exceed those of lanthanum boride cathodes produced by conventional techniques. The exact reason for this improvement is not clearly understood; however, it may be a result of the existence of free lanthanum or possibly a result of an increase in surface area of emission.
  • cathodes made in accordance with the present invention are almost completely activated, i.e., capable of emission, apparently because some slight decomposition of the lanthanum boride takes place which releases free lanthanum metal.
  • This has the additional advantage of eliminating the requirement of high-temperature activation and therefore may permit the use of tantalum and other metals as base metals for cathodes where lower emission characteristics can be tolerated.
  • a method for making a lanthanum-bonde-coated cathode having improved thermionic emission characteristics and a tenacious bond between the lanthanum boride and a cathode base metal comprising spraying molten lanthanum boride on the surface of said cathode base metal.
  • a plasma gas with hydrogen and a gas selected from the group consisting of argon, nitrogen, and helium,
  • step of injecting lanthanum boride powder into the plasma of ionized gas further comprises suspending the lanthanum boride powder in a carrier gas selected from the group consisting of argon, nitrogen, and helium.
  • cathode base metal is selected from the group consisting of tungsten, rhenium, tantalum, nickel, and molybdenum.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Plasma & Fusion (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electromagnetism (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Coating By Spraying Or Casting (AREA)
US3630770D 1969-04-30 1969-04-30 Method for fabricating lanthanum boride cathodes Expired - Lifetime US3630770A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US82056569A 1969-04-30 1969-04-30

Publications (1)

Publication Number Publication Date
US3630770A true US3630770A (en) 1971-12-28

Family

ID=25231157

Family Applications (1)

Application Number Title Priority Date Filing Date
US3630770D Expired - Lifetime US3630770A (en) 1969-04-30 1969-04-30 Method for fabricating lanthanum boride cathodes

Country Status (5)

Country Link
US (1) US3630770A (enrdf_load_html_response)
DE (1) DE2020709A1 (enrdf_load_html_response)
FR (1) FR2040505A1 (enrdf_load_html_response)
GB (1) GB1304216A (enrdf_load_html_response)
NL (1) NL7006281A (enrdf_load_html_response)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833494A (en) * 1972-05-30 1974-09-03 Philips Corp Method of manufacturing a lanthanum hexaboride-activated cathode for an electric discharge tube
JPS5093077A (enrdf_load_html_response) * 1973-12-15 1975-07-24
US3944866A (en) * 1974-04-08 1976-03-16 Canadian Patents & Development Ltd. Thermionic emitter of lanthanum strontium vanadates
US4249105A (en) * 1977-10-03 1981-02-03 Nippon Hoso Kyokai Gas-discharge display panel
US4279709A (en) * 1979-05-08 1981-07-21 The Dow Chemical Company Preparation of porous electrodes
EP0068536A1 (en) * 1981-06-12 1983-01-05 Koninklijke Philips Electronics N.V. Method of manufacturing a luminescent screen
US4377773A (en) * 1980-12-12 1983-03-22 The United States Of America As Represented By The Department Of Energy Negative ion source with hollow cathode discharge plasma
US4871703A (en) * 1983-05-31 1989-10-03 The Dow Chemical Company Process for preparation of an electrocatalyst
EP0451051A1 (fr) * 1990-04-04 1991-10-09 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Gaz plasmagène et application de ce gaz à la projection plasma d'oxyde métallique
US5294462A (en) * 1990-11-08 1994-03-15 Air Products And Chemicals, Inc. Electric arc spray coating with cored wire
US20030181065A1 (en) * 2002-03-21 2003-09-25 O'donnell Robert J. Low contamination components for semiconductor processing apparatus and methods for making components
EP1770837A1 (fr) * 2005-10-03 2007-04-04 ECET - Européenne de Conception et d'Etudes Technologiques Procédé de préparation d'une bougie d'allumage, et bougie d'allumage ainsi obtenue
US11186917B2 (en) 2018-01-30 2021-11-30 The Board Of Trustees Of The University Of Alabama Composite electrodes and methods for the fabrication and use thereof

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3148441A1 (de) * 1981-12-08 1983-07-21 Philips Patentverwaltung Gmbh, 2000 Hamburg Verfahren zur herstellung einer thermionischen kathode
DE19609813C1 (de) * 1996-03-13 1997-07-10 Forschungszentrum Juelich Gmbh Aus einem metallischen Hochtemperaturwerkstoff bestehendes Verbindungselement mit lanthanhaltiger Oberfläche
DE102004061569A1 (de) 2004-12-21 2006-07-06 Linde Ag Verwendung einer Gasmischung und Verfahren zum Lichtbogenspritzen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2659685A (en) * 1950-03-31 1953-11-17 Gen Electric Boride cathodes

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2659685A (en) * 1950-03-31 1953-11-17 Gen Electric Boride cathodes

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Encyclopedia of Science & Technology Vol. 8, 1960 McGraw-Hill *

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833494A (en) * 1972-05-30 1974-09-03 Philips Corp Method of manufacturing a lanthanum hexaboride-activated cathode for an electric discharge tube
JPS5093077A (enrdf_load_html_response) * 1973-12-15 1975-07-24
US3944866A (en) * 1974-04-08 1976-03-16 Canadian Patents & Development Ltd. Thermionic emitter of lanthanum strontium vanadates
US4249105A (en) * 1977-10-03 1981-02-03 Nippon Hoso Kyokai Gas-discharge display panel
US4279709A (en) * 1979-05-08 1981-07-21 The Dow Chemical Company Preparation of porous electrodes
US4377773A (en) * 1980-12-12 1983-03-22 The United States Of America As Represented By The Department Of Energy Negative ion source with hollow cathode discharge plasma
EP0068536A1 (en) * 1981-06-12 1983-01-05 Koninklijke Philips Electronics N.V. Method of manufacturing a luminescent screen
US4871703A (en) * 1983-05-31 1989-10-03 The Dow Chemical Company Process for preparation of an electrocatalyst
EP0451051A1 (fr) * 1990-04-04 1991-10-09 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Gaz plasmagène et application de ce gaz à la projection plasma d'oxyde métallique
FR2660825A1 (fr) * 1990-04-04 1991-10-11 Air Liquide Gaz plasmagene et application de ce gaz a la projection plasma d'oxyde metallique.
AU627114B2 (en) * 1990-04-04 1992-08-13 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Plasma producing gas and use thereof for plasma projection of metallic oxide
US5271869A (en) * 1990-04-04 1993-12-21 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Plasma producing gas for plasma projection of metallic oxide
US5294462A (en) * 1990-11-08 1994-03-15 Air Products And Chemicals, Inc. Electric arc spray coating with cored wire
WO2003080892A1 (en) * 2002-03-21 2003-10-02 Lam Research Corporation Low contamination components for semiconductor processing apparatus and methods for making components
US20090123735A1 (en) * 2002-03-21 2009-05-14 Lam Research Corporation Low contamination components for semiconductor processing apparatus and methods for making components
US6780787B2 (en) 2002-03-21 2004-08-24 Lam Research Corporation Low contamination components for semiconductor processing apparatus and methods for making components
US20050003240A1 (en) * 2002-03-21 2005-01-06 Lam Research Corporation Low contamination components for semiconductor processing apparatus and methods for making components
US20030181065A1 (en) * 2002-03-21 2003-09-25 O'donnell Robert J. Low contamination components for semiconductor processing apparatus and methods for making components
US8935990B2 (en) 2002-03-21 2015-01-20 Lam Research Corporation Low contamination components for semiconductor processing apparatus and methods for making components
US8318327B2 (en) 2002-03-21 2012-11-27 Lam Research Corporation Low contamination components for semiconductor processing apparatus and methods for making components
US20090068845A1 (en) * 2002-03-21 2009-03-12 Lam Research Corporation Low contamination components for semiconductor processing apparatus and methods for making components
US20090120790A1 (en) * 2002-03-21 2009-05-14 Lam Research Corporation Low contamination components for semiconductor processing apparatus and methods for making components
EP1770837A1 (fr) * 2005-10-03 2007-04-04 ECET - Européenne de Conception et d'Etudes Technologiques Procédé de préparation d'une bougie d'allumage, et bougie d'allumage ainsi obtenue
US7727425B2 (en) 2005-10-03 2010-06-01 Vibro Meter France Method for manufacturing an ignition plug and ignition plug produced in that manner
RU2406196C2 (ru) * 2005-10-03 2010-12-10 Вибро Метер Франс Способ изготовления запальной свечи и запальная свеча
FR2891542A1 (fr) * 2005-10-03 2007-04-06 Ecet Europ De Conception Et D Procede de preparation d'une ceramique semi-conductrice, ceramique ainsi obtenue et bougie d'allumage l'utilisant.
US20070077846A1 (en) * 2005-10-03 2007-04-05 Aurelien Jankowiak Method for manufacturing an ignition plug and ignition plug produced in that manner
US11186917B2 (en) 2018-01-30 2021-11-30 The Board Of Trustees Of The University Of Alabama Composite electrodes and methods for the fabrication and use thereof
US11959182B2 (en) 2018-01-30 2024-04-16 The Board Of Trustees Of The University Of Alabama Composite electrodes and methods for the fabrication and use thereof

Also Published As

Publication number Publication date
DE2020709A1 (de) 1970-11-12
FR2040505A1 (enrdf_load_html_response) 1971-01-22
GB1304216A (enrdf_load_html_response) 1973-01-24
NL7006281A (enrdf_load_html_response) 1970-11-03

Similar Documents

Publication Publication Date Title
US3630770A (en) Method for fabricating lanthanum boride cathodes
US3064114A (en) Apparatus and process for spraying molten metal
US2697130A (en) Protection of metal against oxidation
US2694764A (en) Electric arc welding
JP2007184269A5 (enrdf_load_html_response)
CA2040184C (en) Plasma spray device with external powder feed
US2982845A (en) Electric arc spraying
US5744777A (en) Small particle plasma spray apparatus, method and coated article
US3360682A (en) Apparatus and method for generating high-enthalpy plasma under high-pressure conditions
JP2006130503A (ja) プラズマ溶射装置
US3075065A (en) Hyperthermal tunnel apparatus and electrical plasma-jet torch incorporated therein
US3114826A (en) High-temperature spray apparatus
CN112899607A (zh) 一种在氧化铝陶瓷表面敷镍或敷镍合金的方法
CN112830814A (zh) 一种在氮化铝陶瓷表面敷铜或敷铜合金的方法
US3515839A (en) Plasma torch
US4048348A (en) Method of applying a fused silica coating to a substrate
JP3206925B2 (ja) プラズマを発生させるためのガス
US3404034A (en) Preparation of metal-coated powders and cathode structures
US3304460A (en) Means for producing radiant energy
GB1350168A (en) Plasma spray gun
CN105722295B (zh) 一种三阴极等离子喷枪
Zhang et al. Influence of plasma spraying on the performance of oxide cathodes
GB863190A (en) Heat-fusible material spray gun and method for coating a surface with a heat-fusiblematerial
CN211184390U (zh) 一种小规格大功率非转移等离子炬
US6680085B2 (en) Method and device for thermal spraying for the coating of surfaces