EP0524887A1 - Process and apparatus for the production of powders, in particular metal powders by atomisation - Google Patents

Process and apparatus for the production of powders, in particular metal powders by atomisation Download PDF

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Publication number
EP0524887A1
EP0524887A1 EP92402141A EP92402141A EP0524887A1 EP 0524887 A1 EP0524887 A1 EP 0524887A1 EP 92402141 A EP92402141 A EP 92402141A EP 92402141 A EP92402141 A EP 92402141A EP 0524887 A1 EP0524887 A1 EP 0524887A1
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EP
European Patent Office
Prior art keywords
head
atomized
powders
atomization
plasma
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Granted
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EP92402141A
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German (de)
French (fr)
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EP0524887B1 (en
Inventor
André Accary
Jean L. Coutiere
André Lacour
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Aubert and Duval SA
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Aubert and Duval SA
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00Making metallic powder or suspensions thereof
    • B22F9/02Making metallic powder or suspensions thereof using physical processes
    • B22F9/06Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/10Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying using centrifugal force
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00Making metallic powder or suspensions thereof
    • B22F9/02Making metallic powder or suspensions thereof using physical processes
    • B22F9/06Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00Making metallic powder or suspensions thereof
    • B22F9/02Making metallic powder or suspensions thereof using physical processes
    • B22F9/06Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/082Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
    • B22F2009/0848Melting process before atomisation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00Making metallic powder or suspensions thereof
    • B22F9/02Making metallic powder or suspensions thereof using physical processes
    • B22F9/06Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/082Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
    • B22F2009/086Cooling after atomisation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00Making metallic powder or suspensions thereof
    • B22F9/02Making metallic powder or suspensions thereof using physical processes
    • B22F9/06Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/082Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
    • B22F2009/0896Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid particle transport, separation: process and apparatus
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00Supplementary information concerning processes or compositions relating to powder metallurgy
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00Aspects linked to processes or compositions used in powder metallurgy

Definitions

  • the present invention relates to a method and a device for producing powders and in particular metal powders by atomization.
  • the present invention aims to overcome these technical problems and in particular to be able to disperse a sufficiently hot metallic liquid, without there being any chemical interaction between the dispersing means and the liquid, to create a quenching zone eliminating any possibility of pollution of the atomized metal, and to provide a "cold chain” allowing the powders obtained to be used without polluting them before manufacturing the final solid product, after compaction and sintering.
  • a device for the production of powders and in particular of metallic powders by atomization comprising means for melting the material to be atomized, an atomization enclosure in which is arranged a dispersion head rotating at high speed for diffusing the molten material in atomized form, means for cooling the atomized material and the head and means for collecting the cooled powder material thus obtained, characterized in that said melting means comprise at least one vertical oven inductive plasma producing a gas envelope plasmagens containing the upper face of the dispersion head and said cooling means comprise a first series of members for distributing a cooling fluid disposed in the upper part of the atomization enclosure to create a cold zone at the periphery of the envelope and a second series of bodies for circulating a cooling fluid disposed in the lower part of the enclosure to create a cold zone on the underside of the head.
  • said first series of members for distributing a cooling fluid consists of a ramp of nozzles producing jets of tangential fluid at the surface of said envelope and of nozzles producing a tangential washing at the compound.
  • said envelope of plasma gases consists of a cylindrical tube whose vertical axis is parallel to the vertical axis of the rotary head, and preferably the axis of the cylindrical tube is coincident with the 'axis of the head.
  • said vertical inductive plasma furnace is arranged above the upper face of the rotary head.
  • Another object of the invention is a method for manufacturing powders and in particular metallic powders by atomization, comprising the continuous melting of the material to be atomized flowing vertically and coaxially above a dispersing head rotating at great speed. speed intended to diffuse the molten material in atomized form, in an envelope of plasma-producing gases, then quenching of the atomized material and collection of the cooled powder material thus obtained, characterized in that the material is atomized by fusion by dispersing it by friction on the upper face of the rotary head and quenching by passing said atomized material through a cooling vortex situated at the periphery of the envelope of plasma gas.
  • Yet another object of the invention lies in the ultra pure metallic powders obtained by the above process.
  • the device of the invention can absorb a large heat flow produced by a plasma torch and onto which the liquid material falls.
  • the atomized material then enters a quenching zone at the periphery of the head formed by a cylindrical tube of plasma gas moving parallel to the vertical axis of the head and enveloped in cold fluid.
  • the powders obtained are recovered in a collection zone comprising at least one chamber containing a neutral gas in the gaseous, liquid or solid state, before their use in formed or shaped products.
  • the powders obtained by the process of the invention with very rapid cooling are ultra pure and have a very fine particle size.
  • Figure 1 is a schematic representation of the atomizing device of the present invention.
  • FIG. 2 is an enlarged view of the central part of the device in FIG. 1.
  • FIG. 3 represents the quenching zone with the members for distributing the cooling fluid.
  • FIGS. 4a and 4b schematically represent embodiments of the means for melting and supplying molten metal to the atomization enclosure.
  • the material to be melted and to be atomized is introduced by supply means A into the apparatus, for example in the initial form of a cylindrical bar 1 whose diameter is related to the power of the melting means, notably consisting of a plasma oven B.
  • the material to be atomized is initially in the form of pieces of various sizes, powders, shots or else may be directly brought to the molten state in the device.
  • the bar 1 is placed vertically in the axis of the oven B, the valve V1 then being closed, maintaining the oven B and the enclosure C under a neutral atmosphere. After vacuuming and purging the bar supply chamber several times, valve V1 is open. The bar 1 is then lowered with a hydropneumatic or electromechanical cylinder regulated at the speed which corresponds to the desired flow rate. It is preheated in the preheating furnace 3 by the induced currents with one or more inducing turns 5 at a frequency between 10 and 30 kHz, depending on its diameter.
  • the bar then enters the inductive plasma oven 4.
  • the plasma is ignited by creating an electric arc between the bar brought to high voltage and a retractable mobile electrode 8 located at ground.
  • a retractable mobile electrode 8 located at ground.
  • the vein or the liquid drops of molten materials pass more or less long over the hottest part of the plasma to, on the one hand, reach overheating and , on the other hand, pass through the most reactive area of the oven.
  • a cold cage 7 is used to protect the oven enclosure, and polished to increase the thermal efficiency of the plasma.
  • the bar 1 is thus heated at its periphery by direct induction of the HF fields - skin effect -, and by thermal conduction and convection of the plasma gases. It melts in a cone, point directed downwards, with an angle whose opening depends on the nature of the plasma gases. There is thus a casting which is, depending on the power of the furnace and the penetration of the bar into the plasma, continuous or not and perfectly axial. As for the diameter of the liquid stream or of the drops, it depends on the flow of liquid and the opening of the cone.
  • the material to be atomized is first received in fusion in a cold crucible (as in French patent 2 697 050) from which it flows by gravity passing through an electromagnetic and / or composite nozzle before enter the atomization enclosure as shown in Figures 4a and 4b.
  • the electromagnetic and / or composite nozzle constitutes a means of feeding and regulating the flow of molten metal and optionally makes it possible to maintain the metal in the desired thermal state.
  • the device shown in FIGS. 4a and 4b comprises means B for melting the solid material (metal) M consisting for example of a plasma torch.
  • the molten material then flows into a cold crucible 100 to form a bath of molten metal.
  • the heat losses on the surface of the bath are possibly compensated by additional heating means B ′.
  • the material in the molten state then flows vertically through the bottom of the crucible through an electromagnetic nozzle 101 (FIG. 4a) or composite 102 (FIG. 4b).
  • French Patent No. 87 00 866 already describes a composite nozzle 102 used for controlling a flow of liquid metal operating for example with a coil 102b at 450 kHz.
  • the electromagnetic nozzle 101 comprises a peripheral coil 101b inducing a high frequency field so as to create a constriction of the liquid stream thus causing a variation in the flow of molten material.
  • the molten material then enters the atomization enclosure to come into contact with the dispersion head 9.
  • the molten material flows into the atomization enclosure C at the center of the upper face of a dispersion or atomization head driven in rotation by the spindle 10 at a speed of up to '' at 125,000 rpm.
  • the shape of the dispersion head 9 is determined according to the optimal thermal mapping and advantageously, it is produced in the form of a cylinder whose dimensions are determined by the nature of the constituent material and the temperature sought on the upper side coming into contact with the molten material according to the particle size sought for the powders.
  • the upper face of the head is preferably located in a substantially horizontal plane and is crossed vertically by a heat flow generated by the plasma gases heated by induction by the inductor 6.
  • the plasma zone consists of an envelope of plasma gas in cylindrical tube shape whose vertical axis is parallel, being close to or coincident with the vertical axis of said head 9.
  • the underside of the cylindrical head 9 and the spindle 10 are cooled by axial circulation 11 of a fluid cooling which can be either water for the most important thermal fluxes, or a gas or a liquid gas such as argon or helium for example, in the case where a surface temperature of the head is desired more high.
  • the atomizing cylindrical head 9 is either made of copper, or of tungsten, or of a refractory alloy or not depending on the surface temperature which must be reached.
  • the underside of the cylinder constituting said head 9 is advantageously provided with a hemispherical cavity licked by the cooling fluid 11 circulating axially.
  • the cooling of the underside of the head 9 creates a temperature gradient in the mass thereof which is included for copper between 60 and 180 ° C / cm and between 200 and 500 ° C / cm for tungsten.
  • the supply of heat by the plasma to the liquid metal up to the very surface of the head and the thermal resistance between the liquid material and the said head mean that the dispersed material remains liquid (despite the heat extracted through the head)
  • atomization means "erosion” consisting in diffusing and dispersing the liquid by friction and thus avoiding its "wetting" with the upper side of the head.
  • the liquid particles pass directly from the plasma zone 12 which envelops the head, to a quench zone 13 consisting of a cooling medium, two-phase or not, forming a vortex around the plasma.
  • FIG. 3 there is a ramp of eighteen nozzles 15 distributing a total flow of liquid argon sufficient to obtain complete cooling of the powders.
  • the nozzle ejection axis X 15 is inclined relative to the plane of the upper face of the head 9 with a jet width determined so as to obtain rapid cooling and a rotation effect of opposite direction (counter-rotating) to that of the head 9 in order to brake the movement of powders.
  • the nozzle ejection orifice 15 is located above the powder ejection triangle.
  • the refrigerant vortex 13 thus formed entrains the liquid and then solid particles in spiral trajectories, thus avoiding, on the one hand, direct impacts with the walls of the enclosure C, on the other hand, gas turbulence towards the top of the device, turbulence which may disturb the plasma and atomization.
  • the nozzles 16 oriented towards the walls of the enclosure project onto them a mist of argon which flows along the walls, thus driving the powders down and thus ensuring a tangential washing to the enclosure.
  • the mixture of liquid and powder is deposited at the bottom of enclosure C.
  • the powder obtained is therefore deposited at the bottom of the enclosure C and is recovered in the container 17.
  • the cooling and the collection of the powder are thus carried out using a neutral gas in the gaseous, liquid or solidified state after immersion of the collected powder in the liquid phase.
  • the invention also provides the possibility of combining in the same unit several atomization devices arranged around the energy sources: medium frequency preheating generator (MF) and plasma torch generator (HF).
  • MF medium frequency preheating generator
  • HF plasma torch generator
  • the operation is semi-continuous, in sequence of 2 bars.
  • D denotes a flow, P a pressure, T a temperature, V a valve, B a flange.
  • the method and the device of the invention make it possible to manufacture powders from various families of materials and in particular superalloys based on nickel, titanium and titanium alloys, aluminum, Niobium alloys, etc.

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  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)

Abstract

Device for the production of metal powders by atomisation, comprising means (B) for melting the material to be atomised, an atomisation chamber (C) in which is disposed a dispersion head (9) rotating at high speed in order to diffuse the molten material in atomised form, means (9) for cooling the atomised material and the head (9) and means (17) for collecting the cooled powdered material thus obtained, the said melting means (B) comprising at least one inductive plasma tower furnace (4) producing an envelope of plasma-producing gases (12) containing the upper face of the dispersion head and the said cooling means comprising a first series of members (15, 16) for dispensing a coolant fluid arranged in the upper part of the atomisation chamber in order to create a cold zone (13) at the periphery of the envelope (12) and a second series of members (11) for circulating a coolant fluid arranged in the lower part of the chamber (C) in order to create a cold zone at the lower face of the head (9). <IMAGE>

Description

La présente invention concerne un procédé et un dispositif de production de poudres et notamment de poudres métalliques par atomisation.The present invention relates to a method and a device for producing powders and in particular metal powders by atomization.

Il existe déjà des installations de production de poudres métalliques, dans lesquelles on utilise des techniques d'atomisation. Selon ces techniques connues, on verse du métal en fusion sur un disque horizontal entraîné en rotation par une broche tournant autour d'un axe vertical. Le métal est alors projeté vers l'extérieur du disque sous l'effet de la force centrifuge et se divise en fines gouttelettes de métal qui se solidifient au contact d'un fluide ou d'une paroi froide.Metallic powder production facilities already exist, in which atomization techniques are used. According to these known techniques, molten metal is poured onto a horizontal disc driven in rotation by a spindle rotating around a vertical axis. The metal is then projected towards the outside of the disc under the effect of centrifugal force and is divided into fine metal droplets which solidify on contact with a fluid or a cold wall.

Cependant, quelles que soient les techniques actuelles, les principaux inconvénients sont, d'une part, le problème de la pollution des poudres lors des opérations de fusion, d'atomisation, de trempe et de collecte, d'autre part, les difficultés rencontrées pour atomiser un liquide de matériau parfaitement homogène.However, whatever the current techniques, the main disadvantages are, on the one hand, the problem of powder pollution during melting, atomization, quenching and collection operations, on the other hand, the difficulties encountered to atomize a liquid of perfectly homogeneous material.

La présente invention a pour but de surmonter ces problèmes techniques et notamment de pouvoir disperser un liquide métallique suffisamment chaud, sans qu'il y ait une quelconque interaction chimique entre les moyens de dispersion et le liquide, de créer une zone de trempe éliminant toute possibilité de pollution du métal atomisé, et de prévoir une "chaîne du froid" permettant d'utiliser les poudres obtenues sans les polluer avant de fabriquer le produit massif final, après compaction et frittage.The present invention aims to overcome these technical problems and in particular to be able to disperse a sufficiently hot metallic liquid, without there being any chemical interaction between the dispersing means and the liquid, to create a quenching zone eliminating any possibility of pollution of the atomized metal, and to provide a "cold chain" allowing the powders obtained to be used without polluting them before manufacturing the final solid product, after compaction and sintering.

Ce but est atteint selon l'invention au moyen d'un dispositif de production de poudres et notamment de poudres métalliques par atomisation comprenant des moyens de fusion du matériau à atomiser, une enceinte d'atomisation dans laquelle est disposée une tête de dispersion tournant à grande vitesse pour diffuser le matériau en fusion sous forme atomisée, des moyens de refroidissement du matériau atomisé et de la tête et des moyens de collecte du matériau en poudre refroidie ainsi obtenu caractérisé en ce que lesdits moyens de fusion comprennent au moins un four vertical à plasma inductif produisant une enveloppe de gaz plasmagènes contenant la face supérieure de la tête de dispersion et lesdits moyens de refroidissement comprennent une première série d'organes de distribution d'un fluide de refroidissement disposée dans la partie supérieure de l'enceinte d'atomisation pour créer une zone froide à la périphérie de l'enveloppe et une seconde série d'organes de circulation d'un fluide de refroidissement disposée dans la partie inférieure de l'enceinte pour créer une zone froide à la face inférieure de la tête.This object is achieved according to the invention by means of a device for the production of powders and in particular of metallic powders by atomization comprising means for melting the material to be atomized, an atomization enclosure in which is arranged a dispersion head rotating at high speed for diffusing the molten material in atomized form, means for cooling the atomized material and the head and means for collecting the cooled powder material thus obtained, characterized in that said melting means comprise at least one vertical oven inductive plasma producing a gas envelope plasmagens containing the upper face of the dispersion head and said cooling means comprise a first series of members for distributing a cooling fluid disposed in the upper part of the atomization enclosure to create a cold zone at the periphery of the envelope and a second series of bodies for circulating a cooling fluid disposed in the lower part of the enclosure to create a cold zone on the underside of the head.

Selon une caractéristique avantageuse de l'invention, ladite première série d'organes de distribution d'un fluide de refroidissement est constituée d'une rampe de buses produisant des jets de fluide tangentiels à la surface de ladite enveloppe et de buses produisant un lavage tangentiel à l'enceinte.According to an advantageous characteristic of the invention, said first series of members for distributing a cooling fluid consists of a ramp of nozzles producing jets of tangential fluid at the surface of said envelope and of nozzles producing a tangential washing at the compound.

Selon une autre caractéristique de l'invention ladite enveloppe de gaz plasmagènes est constituée d'un tube cylindrique dont l'axe vertical est parallèle à l'axe vertical de la tête rotative, et de préférence l'axe du tube cylindrique est confondu avec l'axe de la tête.According to another characteristic of the invention, said envelope of plasma gases consists of a cylindrical tube whose vertical axis is parallel to the vertical axis of the rotary head, and preferably the axis of the cylindrical tube is coincident with the 'axis of the head.

Selon encore une autre caractéristique, ledit four vertical à plasma inductif est disposé au-dessus de la face supérieure de la tête rotative.According to yet another characteristic, said vertical inductive plasma furnace is arranged above the upper face of the rotary head.

Un autre objet de l'invention est un procédé de fabrication de poudres et notamment de poudres métalliques par atomisation, comprenant la fusion continue du matériau à atomiser s'écoulant verticalement et de façon coaxiale au-dessus d'une tête de dispersion tournant à grande vitesse destinée à diffuser le matériau en fusion sous forme atomisée, dans une enveloppe de gaz plasmagènes, puis la trempe du matériau atomisé et la collecte du matériau en poudre refroidie ainsi obtenu, caractérisé en ce que l'on réalise l'atomisation du matériau en fusion en le dispersant par frottement sur la face supérieure de la tête rotative et la trempe par passage dudit matériau atomisé dans un vortex réfrigérant situé à la périphérie de l'enveloppe de gaz plasmagènes.Another object of the invention is a method for manufacturing powders and in particular metallic powders by atomization, comprising the continuous melting of the material to be atomized flowing vertically and coaxially above a dispersing head rotating at great speed. speed intended to diffuse the molten material in atomized form, in an envelope of plasma-producing gases, then quenching of the atomized material and collection of the cooled powder material thus obtained, characterized in that the material is atomized by fusion by dispersing it by friction on the upper face of the rotary head and quenching by passing said atomized material through a cooling vortex situated at the periphery of the envelope of plasma gas.

Encore un autre objet de l'invention réside dans les poudres métalliques ultra pures obtenues par le procédé précédent.Yet another object of the invention lies in the ultra pure metallic powders obtained by the above process.

Grâce à la tête de dispersion refroidie tournant avec une vitesse pouvant aller jusqu'à 125 000 tr/min, le dispositif de l'invention peut absorber un flux de chaleur important produit par un chalumeau plasma et sur lequel vient tomber le matériau liquide. Le matériau atomisé pénètre ensuite dans une zone de trempe à la périphérie de la tête formée par un tube cylindrique de gaz plasmagènes se déplaçant parallèlement à l'axe vertical de la tête et enveloppé de fluide froid. Enfin, les poudres obtenues sont récupérées dans une zone de collecte comprenant au moins une chambre renfermant un gaz neutre à l'état gazeux, liquide ou solide, avant leur utilisation dans des produits formés ou façonnés.Thanks to the cooled dispersion head rotating with a speed of up to 125,000 rpm, the device of the invention can absorb a large heat flow produced by a plasma torch and onto which the liquid material falls. The atomized material then enters a quenching zone at the periphery of the head formed by a cylindrical tube of plasma gas moving parallel to the vertical axis of the head and enveloped in cold fluid. Finally, the powders obtained are recovered in a collection zone comprising at least one chamber containing a neutral gas in the gaseous, liquid or solid state, before their use in formed or shaped products.

Les poudres obtenues par le procédé de l'invention avec un refroidissement très rapide sont ultra pures et possède une granulométrie très fine.The powders obtained by the process of the invention with very rapid cooling are ultra pure and have a very fine particle size.

L'invention sera mieux comprise à la lecture de la description qui va suivre et se rapportant aux dessins annexés.The invention will be better understood on reading the description which follows and relating to the accompanying drawings.

La figure 1 est une représentation schématique du dispositif d'atomisation de la présente invention.Figure 1 is a schematic representation of the atomizing device of the present invention.

La figure 2 est une vue agrandie de la partie centrale du dispositif de la figure 1.FIG. 2 is an enlarged view of the central part of the device in FIG. 1.

La figure 3 représente la zone de trempe avec les organes de distribution du fluide de refroidissement.FIG. 3 represents the quenching zone with the members for distributing the cooling fluid.

Les figures 4a et 4b représentent de façon schématique des modes de réalisation des moyens de fusion et d'alimentation en métal fondu de l'enceinte d'atomisation.FIGS. 4a and 4b schematically represent embodiments of the means for melting and supplying molten metal to the atomization enclosure.

Comme représenté sur les figures 1 et 2, le matériau à fondre et à atomiser est introduit par des moyens d'alimentation A dans l'appareil par exemple sous forme initiale d'un barreau cylindrique 1 dont le diamètre est en rapport avec la puissance des moyens de fusion, constitués notamment d'un four plasma B.As shown in FIGS. 1 and 2, the material to be melted and to be atomized is introduced by supply means A into the apparatus, for example in the initial form of a cylindrical bar 1 whose diameter is related to the power of the melting means, notably consisting of a plasma oven B.

Selon des variantes de mise en oeuvre du procédé le matériau à atomiser est initialement sous forme de morceaux de tailles variées, de poudres, de grenailles ou bien encore peut être directement amené à l'état fondu dans le dispositif.According to variants of the implementation of the process, the material to be atomized is initially in the form of pieces of various sizes, powders, shots or else may be directly brought to the molten state in the device.

Le barreau 1 est placé verticalement dans l'axe du four B, la vanne V1 étant alors fermée, maintenant le four B et l'enceinte C sous atmosphère neutre. Après avoir fait le vide et purgé plusieurs fois la chambre d'alimentation du barreau A la vanne V1 est ouverte. Le barreau 1 est alors descendu avec un vérin hydropneumatique ou électromécanique régulé à la vitesse qui correspond au débit de coulée désiré. Il est préchauffé dans le four de préchauffage 3 par les courants induits avec une ou plusieurs spires inductrices 5 à une fréquence comprise entre 10 et 30 kHz, selon son diamètre.The bar 1 is placed vertically in the axis of the oven B, the valve V1 then being closed, maintaining the oven B and the enclosure C under a neutral atmosphere. After vacuuming and purging the bar supply chamber several times, valve V1 is open. The bar 1 is then lowered with a hydropneumatic or electromechanical cylinder regulated at the speed which corresponds to the desired flow rate. It is preheated in the preheating furnace 3 by the induced currents with one or more inducing turns 5 at a frequency between 10 and 30 kHz, depending on its diameter.

On peut aussi réaliser la fusion du matériau à atomiser au moyen d'un dispositif de fusion par induction directe en cage froide avec confinement électromagnétique de la charge fondue comme décrit dans le brevet français 88 04 460.It is also possible to carry out the melting of the material to be atomized by means of a melting device by direct induction in a cold cage with electromagnetic confinement of the molten charge as described in French patent 88 04 460.

Le barreau pénètre ensuite dans le four à plasma inductif 4. Le plasma est allumé en créant un arc électrique entre le barreau porté à haute tension et une électrode mobile escamotable 8 se trouvant à la masse. Selon la position plus ou moins avancée du barreau dans la flamme, lors de la coulée, la veine ou les gouttes liquides de matériaux fondus traversent plus ou moins longtemps la partie la plus chaude du plasma pour, d'une part, atteindre une surchauffe et,d'autre part, traverser la zone la plus réactive du four.The bar then enters the inductive plasma oven 4. The plasma is ignited by creating an electric arc between the bar brought to high voltage and a retractable mobile electrode 8 located at ground. Depending on the more or less advanced position of the bar in the flame, during the casting, the vein or the liquid drops of molten materials pass more or less long over the hottest part of the plasma to, on the one hand, reach overheating and , on the other hand, pass through the most reactive area of the oven.

On utilise de préférence une cage froide 7 pour protéger l'enceinte du four, et polie pour accroître le rendement thermique du plasma. Le barreau 1 est ainsi chauffé à sa périphérie par induction directe des champs HF -effet de peau-, et par conduction et convection thermiques des gaz plasmagènes. Il fond en cône, pointe dirigée vers le bas, avec un angle dont l'ouverture est fonction de la nature des gaz plasmagènes. On a ainsi une coulée qui est, selon la puissance du four et la pénétration du barreau dans le plasma, continue ou non et parfaitement axiale. Quant au diamètre de la veine liquide ou des gouttes, il est fonction du débit de liquide et de l'ouverture du cône.Preferably, a cold cage 7 is used to protect the oven enclosure, and polished to increase the thermal efficiency of the plasma. The bar 1 is thus heated at its periphery by direct induction of the HF fields - skin effect -, and by thermal conduction and convection of the plasma gases. It melts in a cone, point directed downwards, with an angle whose opening depends on the nature of the plasma gases. There is thus a casting which is, depending on the power of the furnace and the penetration of the bar into the plasma, continuous or not and perfectly axial. As for the diameter of the liquid stream or of the drops, it depends on the flow of liquid and the opening of the cone.

Dans ces conditions, le matériau à atomiser est d'abord reçu en fusion dans un creuset froid (comme dans le brevet français 2 697 050) d'où il s'écoule par gravité en passant par une busette électromagnétique et/ou composite avant de pénétrer dans l'enceinte d'atomisation comme représenté sur les figures 4a et 4b. La busette électromagnétique et/ou composite constitue un moyen d'alimentation et de régulation du débit de métal fondu et permet éventuellement de maintenir le métal à l'état thermique désiré.Under these conditions, the material to be atomized is first received in fusion in a cold crucible (as in French patent 2 697 050) from which it flows by gravity passing through an electromagnetic and / or composite nozzle before enter the atomization enclosure as shown in Figures 4a and 4b. The electromagnetic and / or composite nozzle constitutes a means of feeding and regulating the flow of molten metal and optionally makes it possible to maintain the metal in the desired thermal state.

Le dispositif représenté sur les figures 4a et 4b comprend des moyens de fusion B du matériau (métal) solide M constitués par exemple d'une torche plasma. Le matériau fondu s'écoule ensuite dans un creuset froid 100 pour former un bain de métal fondu. Les pertes thermiques à la surface du bain sont éventuellement compensées par des moyens de chauffe complémentaires B′. Le matériau à l'état fondu s'écoule ensuite verticalement par le fond du creuset au travers d'une busette électromagnétique 101 (figure 4a) ou composite 102 (figure 4b).The device shown in FIGS. 4a and 4b comprises means B for melting the solid material (metal) M consisting for example of a plasma torch. The molten material then flows into a cold crucible 100 to form a bath of molten metal. The heat losses on the surface of the bath are possibly compensated by additional heating means B ′. The material in the molten state then flows vertically through the bottom of the crucible through an electromagnetic nozzle 101 (FIG. 4a) or composite 102 (FIG. 4b).

Le brevet français n° 87 00 866 décrit déjà une busette composite 102 utilisé pour le contrôle d'un débit de métal liquide fonctionnant par exemple avec une bobine 102b sous 450 kHz.French Patent No. 87 00 866 already describes a composite nozzle 102 used for controlling a flow of liquid metal operating for example with a coil 102b at 450 kHz.

La busette électromagnétique 101 comprend une bobine périphérique 101b induisant un champ à haute fréquence de façon à créer une striction de la veine liquide entraînant ainsi une variation du débit de matériau fondu. Le matériau fondu pénètre ensuite dans l'enceinte d'atomisation pour venir au contact de la tête de dispersion 9.The electromagnetic nozzle 101 comprises a peripheral coil 101b inducing a high frequency field so as to create a constriction of the liquid stream thus causing a variation in the flow of molten material. The molten material then enters the atomization enclosure to come into contact with the dispersion head 9.

Sur les figures 1 et 2, le matériau fondu s'écoule dans l'enceinte d'atomisation C au centre de la face supérieure d'une tête de dispersion ou d'atomisation entraînée en rotation par la broche 10 à une vitesse pouvant aller jusqu'à 125 000 tr/min. La forme de la tête de dispersion 9 est déterminée en fonction de la cartographie thermique optimale et de manière avantageuse, elle est réalisée sous la forme d'un cylindre dont les dimensions sont déterminées par la nature de la matière constitutive et la température recherchée sur la face supérieure entrant en contact avec le matériau en fusion en fonction de la granulométrie recherchée pour les poudres. La face supérieure de la tête est située de préférence dans un plan sensiblement horizontal et est traversée verticalement par un flux thermique généré par les gaz plasmagènes chauffés par induction par l'inducteur 6. La zone plasma est constituée d'une enveloppe de gaz plasmagène en forme de tube cylindrique dont l'axe vertical est parallèle, en étant voisin ou confondu avec l'axe vertical de ladite tête 9. La face inférieure de la tête cylindrique 9 et la broche 10 sont refroidies par circulation axiale 11 d'un fluide de refroidissement qui peut être soit de l'eau pour les flux thermiques les plus importants, soit un gaz ou un gaz liquifié comme l'argon ou l'hélium par exemple, dans le cas où l'on désire une température superficielle de la tête plus élevée.In FIGS. 1 and 2, the molten material flows into the atomization enclosure C at the center of the upper face of a dispersion or atomization head driven in rotation by the spindle 10 at a speed of up to '' at 125,000 rpm. The shape of the dispersion head 9 is determined according to the optimal thermal mapping and advantageously, it is produced in the form of a cylinder whose dimensions are determined by the nature of the constituent material and the temperature sought on the upper side coming into contact with the molten material according to the particle size sought for the powders. The upper face of the head is preferably located in a substantially horizontal plane and is crossed vertically by a heat flow generated by the plasma gases heated by induction by the inductor 6. The plasma zone consists of an envelope of plasma gas in cylindrical tube shape whose vertical axis is parallel, being close to or coincident with the vertical axis of said head 9. The underside of the cylindrical head 9 and the spindle 10 are cooled by axial circulation 11 of a fluid cooling which can be either water for the most important thermal fluxes, or a gas or a liquid gas such as argon or helium for example, in the case where a surface temperature of the head is desired more high.

La tête cylindrique d'atomisation 9 est soit en cuivre, soit en tungstène, soit en alliage réfractaire ou non selon la température superficielle que l'on doit atteindre.The atomizing cylindrical head 9 is either made of copper, or of tungsten, or of a refractory alloy or not depending on the surface temperature which must be reached.

La face inférieure du cylindre constituant ladite tête 9 est avantageusement pourvue d'une cavité hémisphérique léchée par le fluide de refroidissement 11 circulant de façon axiale. Le refroidissement de la face inférieure de la tête 9 crée un gradient de température dans la masse de celle-ci qui est compris pour du cuivre entre 60 et 180°C/cm et entre 200 et 500°C/cm pour du tungstène.The underside of the cylinder constituting said head 9 is advantageously provided with a hemispherical cavity licked by the cooling fluid 11 circulating axially. The cooling of the underside of the head 9 creates a temperature gradient in the mass thereof which is included for copper between 60 and 180 ° C / cm and between 200 and 500 ° C / cm for tungsten.

L'apport de chaleur par le plasma au métal liquide jusqu'à la surface même de la tête et la résistance thermique entre le matériau liquide et ladite tête font que le matériau dispersé reste liquide (malgré la chaleur extraite à travers la tête)The supply of heat by the plasma to the liquid metal up to the very surface of the head and the thermal resistance between the liquid material and the said head mean that the dispersed material remains liquid (despite the heat extracted through the head)

Pour accroître la résistance thermique et, d'une part avoir une tête de dispersion la plus froide possible eu égard à ses propriétés mécaniques, d'autre part, avoir un liquide à disperser suffisamment chaud pour rester homogène, l'atomisation s'effectue par "érosion", l'"érosion" consistant à diffuser et disperser le liquide par frottement et éviter ainsi son "mouillage" avec la face supérieure de la tête.To increase the thermal resistance and, on the one hand to have the coolest possible dispersion head having regard to its mechanical properties, on the other hand, to have a liquid to be dispersed hot enough to remain homogeneous, atomization is carried out by "erosion" means "erosion" consisting in diffusing and dispersing the liquid by friction and thus avoiding its "wetting" with the upper side of the head.

L'utilisation de la "torche" plasma permet de :

  • a. fondre le matériau dans des conditions géométriques et thermocinétiques optimales, pour obtenir une coulée parfaitement axiale et stable ;
  • b. surchauffer la veine liquide pour obtenir un liquide homogène ;
  • c. créer un flux thermique à travers la face supérieure de la tête d'atomisation 9 et assurer une cartographie thermique compatible avec la tenue mécanique de ladite tête ;
  • d. maintenir la pureté des produits lors de l'atomisation jusqu'à la trempe.
The use of the plasma "torch" allows to:
  • at. melt the material under optimal geometrical and thermokinetic conditions, to obtain a perfectly axial and stable casting;
  • b. overheating the liquid vein to obtain a homogeneous liquid;
  • vs. create a thermal flow through the upper face of the atomization head 9 and ensure thermal mapping compatible with the mechanical strength of said head;
  • d. maintain the purity of the products during atomization until quenching.

Après atomisation, les particules liquides passent directement de la zone plasma 12 qui enveloppe la tête, à une zone de trempe 13 constituée d'un milieu réfrigérant, diphasique ou non, formant un vortex autour du plasma. A cet effet une série de buses 15 placées sur une rampe circulaire 14 dans le haut de l'enceinte d'atomisation C, envoie le fluide de refroidissement tangentiellement au tube de gaz plasmagènes 12.After atomization, the liquid particles pass directly from the plasma zone 12 which envelops the head, to a quench zone 13 consisting of a cooling medium, two-phase or not, forming a vortex around the plasma. To this end, a series of nozzles 15 placed on a circular ramp 14 at the top of the atomization enclosure C, sends the cooling fluid tangentially to the plasma gas tube 12.

Selon un mode de réalisation avantageux tel que représenté sur la figure 3 on dispose d'une rampe de dix huit buses 15 distribuant un débit total d'argon liquide suffisant pour obtenir un refroidissement complet des poudres.L'axe d'éjection X des buses 15 est incliné par rapport au plan de la face supérieure de la tête 9 avec une largeur de jet déterminée de façon à obtenir un refroidissement rapide et un effet de rotation de sens contraire (contra-rotatif) à celui de la tête 9 afin de freiner le mouvement des poudres.According to an advantageous embodiment as shown in FIG. 3, there is a ramp of eighteen nozzles 15 distributing a total flow of liquid argon sufficient to obtain complete cooling of the powders. The nozzle ejection axis X 15 is inclined relative to the plane of the upper face of the head 9 with a jet width determined so as to obtain rapid cooling and a rotation effect of opposite direction (counter-rotating) to that of the head 9 in order to brake the movement of powders.

L'orifice d'éjection des buses 15 est situé au-dessus du triangle d'éjection des poudres.The nozzle ejection orifice 15 is located above the powder ejection triangle.

Le passage de la zone plasma constituée de l'enveloppe de gaz plasmagènes 12 à haute température, à la zone de trempe 13 à basse température, d'une part, élimine les réactions chimiques qui se produisent entre 1 500°C et 200°C et tout particulièrement celles d'oxydation dans le cas de métaux et alliages et, d'autre part, évite la formation de phases intermédiaires ne permettant pas d'obtenir des structures microcristallines et même amorphes.The passage from the plasma zone consisting of the envelope of plasma gases 12 at high temperature, to the quenching zone 13 at low temperature, on the one hand, eliminates the chemical reactions which occur between 1500 ° C and 200 ° C and very particularly those of oxidation in the case of metals and alloys and, on the other hand, avoids the formation of phases intermediates not allowing microcrystalline and even amorphous structures to be obtained.

Le vortex réfrigérant 13 ainsi constitué entraîne les particules liquides, puis solides, dans des trajectoires en spirales, évitant ainsi, d'une part, les chocs directs avec les parois de l'enceinte C, d'autre part, les turbulences des gaz vers le haut de l'appareil, turbulences qui risquent de perturber le plasma et l'atomisation.The refrigerant vortex 13 thus formed entrains the liquid and then solid particles in spiral trajectories, thus avoiding, on the one hand, direct impacts with the walls of the enclosure C, on the other hand, gas turbulence towards the top of the device, turbulence which may disturb the plasma and atomization.

Les buses 16 orientées vers les parois de l'enceinte, projettent sur celles-ci un brouillard d'argon qui ruisselle le long des parois, entraînant ainsi les poudres vers le bas et assurant ainsi un lavage tangentiel à l'enceinte.The nozzles 16 oriented towards the walls of the enclosure, project onto them a mist of argon which flows along the walls, thus driving the powders down and thus ensuring a tangential washing to the enclosure.

Le mélange de liquide et de poudre se dépose dans le bas de l'enceinte C.The mixture of liquid and powder is deposited at the bottom of enclosure C.

La poudre obtenue se dépose donc au fond de l'enceinte C et est récupérée dans le conteneur 17.The powder obtained is therefore deposited at the bottom of the enclosure C and is recovered in the container 17.

Le refroidissement et la collecte de la poudre sont ainsi réalisés en utilisant un gaz neutre à l'état gazeux, liquide ou solidifié après immersion de la poudre collectée en phase liquide.The cooling and the collection of the powder are thus carried out using a neutral gas in the gaseous, liquid or solidified state after immersion of the collected powder in the liquid phase.

L'invention prévoit également la possibilité de combiner dans une même unité plusieurs dispositifs d'atomisation disposés autour des sources énergétiques : générateur de préchauffage moyenne fréquence (MF) et générateur de la torche plasma (HF).The invention also provides the possibility of combining in the same unit several atomization devices arranged around the energy sources: medium frequency preheating generator (MF) and plasma torch generator (HF).

La description qui va suivre illustre un exemple de mode opératoire du procédé de l'invention en référence au dispositif illustré sur la figure 1.The description which follows illustrates an example of the operating mode of the method of the invention with reference to the device illustrated in FIG. 1.

ExempleExample

Elaboration dans le dispositif de l'invention, de 10 kg de poudre d'alliage avec deux barreaux de 24 mm de diamètre.Elaboration in the device of the invention, of 10 kg of alloy powder with two bars of 24 mm in diameter.

L'opération est semi-continue, par séquence de 2 barreaux.The operation is semi-continuous, in sequence of 2 bars.

On commencera par l'opération de chargement du barreau n° 1 puis par celle de préchauffage par le four Moyenne Fréquence de 10 kHz de 30 kW, suivie de celles de fusion par la torche plasma de 100 kW, de dispersion centrifuge et de refroidissement par de l'argon liquide dans l'hélium gazeux, enfin par celle de récupération de la poudre dans un collecteur refroidi par azote liquide.We will start with the loading operation of the bar n ° 1 then by that of preheating by the Medium Frequency oven of 10 kHz of 30 kW, followed by those of fusion by the plasma torch of 100 kW, of centrifugal dispersion and of cooling by liquid argon in gaseous helium, finally by that of recovery of the powder in a collector cooled by liquid nitrogen.

Dans toute la suite, D désigne un débit, P une pression, T une température, V une vanne, B une bride.In the following, D denotes a flow, P a pressure, T a temperature, V a valve, B a flange.

Opérations PRELIMINAIRES : PRELIMINARY Operations:

  • Dégazage à la température ambiante avec la pompe PV1, puis à la pompe moléculaire PV2 pour obtenir dans l'enceinte le collecteur, le disperseur ou tête rotative, les conduites d'argon et l'accumulateur d'argon liquide, un vide statique de 10-5 torr ;Degassing at room temperature with the PV1 pump, then with the PV2 molecular pump to obtain in the enclosure the collector, the disperser or rotary head, the argon pipes and the liquid argon accumulator, a static vacuum of 10 -5 torr;
  • Balayage par l'argon U à 1 bar ;Argon U sweep at 1 bar;
  • Fermeture de la vanne V1Closing of valve V1
  • Vide à 10-3 torr ;Vacuum at 10-3 torr;
  • Remplissage avec l'hélium par la vanne V4 via un dispositif de régulation de pression (MKS) pour maintien à 2 bars ;Filling with helium by the V4 valve via a pressure regulation device (MKS) to maintain at 2 bars;
  • Ouverture de la vanne VA9 du palier à gaz du disperseur, avec PA9 = 2 bars ;Opening of valve VA9 of the disperser gas bearing, with PA9 = 2 bars;
  • Mise en rotation du disperseur à basse vitesse, à 5 000 tr/min environ ;Rotation of the disperser at low speed, at around 5,000 rpm;
  • Introduction de l'eau de refroidissement de la tête, à un débit DE1 = 10 g/s ;Introduction of cooling water from the head, at a flow rate DE1 = 10 g / s;
  • Mise en froid de l'enceinte et du collecteur à l'azote liquide à 3 bars ;Cooling of the enclosure and the collector with liquid nitrogen at 3 bars;
  • Mise en froid de l'accumulateur à 2 bars ;Cooling of the accumulator to 2 bars;
  • Remplissage de l'accumulateur par condensation de l'argon UFilling the accumulator by condensing argon U
  • Introduction d'argon gazeux dans la cage froide de la torche plasma par la vanne VA2 à un débit DA2 = 0,3 l/s ;Introduction of gaseous argon into the cold cage of the plasma torch by the valve VA2 at a flow DA2 = 0.3 l / s;
  • Mise en pression, PA6 = 3 bars, de l'accumulateur d'argon (non représenté) et ouverture des vannes VA3, VA4 et VA5 pour dégazage des canalisations d'argon liquide et amorçage des pompes cryogéniques ;Pressurization, PA6 = 3 bars, of the argon accumulator (not shown) and opening of the valves VA3, VA4 and VA5 for degassing of the liquid argon pipes and priming of the pumps cryogenic;
  • Remplissage des réservoirs d'expansion d'azote liquide (non représenté) jusqu'aux niveaux "ni" respectivement aux pressions PNi = 2 bars, pour i = 1 à 6.Filling the liquid nitrogen expansion tanks (not shown) up to the "ni" levels respectively at pressures PNi = 2 bars, for i = 1 to 6.
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Pour obtenir 10 kg de poudre d'alliage dans un collecteur, il faut

  • 1 h 8 min en décantant entre 2 barreaux ou
  • 48 min en remplissant l'accumulateur d'argon liquide avec de l'argon liquide en réserve.
To obtain 10 kg of alloy powder in a collector,
  • 1 h 8 min by decanting between 2 bars or
  • 48 min by filling the accumulator with liquid argon with liquid argon in reserve.

Le procédé et le dispositif de l'invention permettent de fabriquer des poudres de diverses familles de matériaux et notamment de superalliages à base de nickel, de titane et d'alliages de titane, d'aluminium, d'alliages de Niobium....The method and the device of the invention make it possible to manufacture powders from various families of materials and in particular superalloys based on nickel, titanium and titanium alloys, aluminum, Niobium alloys, etc.

Claims (21)

Dispositif de production de poudres et notamment de poudres métalliques par atomisation comprenant des moyens de fusion (B) du matériau à atomiser (1), une enceinte d'atomisation (C) dans laquelle est disposée une tête de dispersion (9) tournant à grande vitesse pour diffuser le matériau en fusion sous forme atomisée, des moyens de refroidissement du matériau atomisé et de la tête (9) et des moyens de collecte (17) du matériau en poudre refroidie ainsi obtenu, caractérisé en ce que lesdits moyens de fusion (B) comprennent au moins un four vertical à plasma inductif (4) produisant une enveloppe de gaz plasmagènes (12) contenant la face supérieure de la tête de dispersion et lesdits moyens de refroidissement comprennent une première série d'organes de distribution (15,16) d'un fluide de refroidissement disposée dans la partie supérieure de l'enceinte d'atomisation pour créer une zone froide (13) à la périphérie de l'enveloppe (12) et une seconde série d'organes de circulation (11) d'un fluide de refroidissement disposée dans la partie inférieure de l'enceinte (C) pour créer une zone froide à la face inférieure de la tête (9).Device for producing powders and in particular metal powders by atomization comprising means for melting (B) of the material to be atomized (1), an atomization enclosure (C) in which is disposed a dispersion head (9) rotating at great speed speed for diffusing the molten material in atomized form, means for cooling the atomized material and the head (9) and means for collecting (17) the cooled powder material thus obtained, characterized in that said melting means ( B) comprise at least one vertical inductive plasma oven (4) producing an envelope of plasma gas (12) containing the upper face of the dispersion head and said cooling means comprise a first series of distribution members (15,16 ) a coolant disposed in the upper part of the atomization enclosure to create a cold zone (13) at the periphery of the envelope (12) and a second series of members circulation (11) of a cooling fluid disposed in the lower part of the enclosure (C) to create a cold zone on the underside of the head (9). Dispositif selon la revendication 1, caractérisé en ce que ladite première série d'organes de distribution d'un fluide de refroidissement est constituée d'une rampe de buses (15) produisant des jets de fluide tangentiels à la surface de ladite enveloppe et de buses (16) produisant un lavage tangentiel à l'enceinte.Device according to claim 1, characterized in that said first series of members for distributing a cooling fluid consists of a nozzle ramp (15) producing jets of fluid tangential to the surface of said envelope and of nozzles (16) producing a tangential washing to the enclosure. Dispositif selon la revendication 2, caractérisé en ce que lesdites buses de la première série sont placées au-dessus du triangle d'éjection des poudres et possèdent un axe d'éjection X incliné par rapport au plan de la face supérieure de la tête de dispersion (9).Device according to claim 2, characterized in that said nozzles of the first series are placed above the powder ejection triangle and have an ejection axis X inclined relative to the plane of the upper face of the dispersion head (9). Dispositif selon l'une des revendications précédentes, caractérisé en ce que ladite enveloppe de gaz plasmagènes est constituée d'un tube cylindrique dont l'axe vertical est parallèle à l'axe vertical de la tête rotative (9).Device according to one of the preceding claims, characterized in that the said envelope of plasma-producing gases consists of a cylindrical tube whose vertical axis is parallel to the vertical axis of the rotary head (9). Dispositif selon la revendication 3, caractérisé en ce que l'axe vertical du tube cylindrique est voisin ou confondu avec l'axe vertical de la tête.Device according to claim 3, characterized in that the vertical axis of the cylindrical tube is close to or coincident with the vertical axis of the head. Dispositif selon l'une des revendications précédentes, caractérisé en ce que ledit four vertical à plasma inductif (4) est disposé au-dessus de la face supérieure de la tête rotative (9).Device according to one of the preceding claims, characterized in that the said vertical inductive plasma oven (4) is arranged above the upper face of the rotary head (9). Dispositif selon l'une des revendications précédentes, caractérisé en ce que ladite tête de dispersion est cylindrique et sa face supérieure est disposée dans un plan sensiblement horizontal.Device according to one of the preceding claims, characterized in that said dispersion head is cylindrical and its upper face is arranged in a substantially horizontal plane. Dispositif selon l'une des revendications précédentes, caractérisé en ce que ledit four à plasma inductif (4) est associé à un four de préchauffage (3) à courants induits.Device according to one of the preceding claims, characterized in that said inductive plasma oven (4) is associated with a preheating oven (3) with induced currents. Dispositif selon l'une des revendications précédentes, caractérisé en ce qu'il comporte en outre un creuset froid (100) disposé sous les moyens de fusion (A) pour recevoir le matériau à atomiser à l'état fondu et une busette (101,102) de réglage du débit dudit matériau fondu pour alimenter l'enceinte d'atomisation (C).Device according to one of the preceding claims, characterized in that it further comprises a cold crucible (100) disposed under the melting means (A) for receiving the material to be atomized in the molten state and a nozzle (101,102) adjusting the flow rate of said molten material to feed the atomization enclosure (C). Procédé de fabrication de poudres et notamment de poudres métalliques par atomisation, comprenant la fusion continue du matériau à atomiser s'écoulant verticalement et de façon coaxiale au-dessus d'une tête de dispersion tournant (9) à grande vitesse destinée à diffuser le matériau en fusion sous forme atomisée, dans une enveloppe de gaz plasmagènes, puis la trempe du matériau atomisé et la collecte du matériau en poudre refroidie ainsi obtenu, caractérisé en ce que l'on réalise l'atomisation du matériau en fusion en le dispersant par frottement sur la face supérieure de la tête rotative (9) et la trempe par passage dudit matériau atomisé dans un vortex réfrigérant situé à la périphérie de l'enveloppe de gaz plasmagènes.Process for the manufacture of powders and in particular of metallic powders by atomization, comprising the continuous melting of the material to be atomized flowing vertically and coaxially over a rotating dispersing head (9) at high speed intended for diffusing the material molten in atomized form, in a casing of plasma gas, then quenching the atomized material and collecting the cooled powder material thus obtained, characterized in that the atomization of the molten material is carried out by dispersing it by friction on the upper face of the rotary head (9) and quenching by passing said atomized material through a cooling vortex situated at the periphery of the envelope of plasma gases. Procédé selon la revendication 10, caractérisé en ce qu'on effectue la collecte des poudres dans un gaz neutre à l'état gazeux, liquide ou solide.Process according to claim 10, characterized in that the powder is collected in a neutral gas in the gaseous, liquid or solid state. Procédé selon l'une des revendications 10 ou 11, caractérisé en ce qu'on réalise l'atomisation à des pressions supérieures à la pression atmosphérique.Method according to one of claims 10 or 11, characterized in that atomization is carried out at pressures greater than atmospheric pressure. Procédé selon l'une des revendications 10 à 12, caractérisé en ce qu'on allume le plasma par création d'un arc électrique haute tension entre le matériau à atomiser (1) et une électrode placée dans l'axe du four (4).Method according to one of claims 10 to 12, characterized in that the plasma is ignited by creation of a high voltage electric arc between the material to be atomized (1) and an electrode placed in the axis of the furnace (4) . Procédé selon l'une des revendications 10 à 13, caractérisé en ce qu'on effectue la trempe du matériau atomisé par contact avec un fluide froid, gazeux, liquide ou diphasique permettant d'obtenir des structures microcristallines ou amorphes.Method according to one of claims 10 to 13, characterized in that the atomized material is quenched by contact with a cold, gaseous, liquid or two-phase fluid making it possible to obtain microcrystalline or amorphous structures. Procédé selon l'une des revendications 10 à 14, caractérisé en ce qu'on liquéfie les gaz produits lors de la trempe dans un condenseur et on récupère les poudres avec une partie des gaz liquéfiés dans au moins un conteneur permettant de maintenir le mélange à l'état liquide ou solide.Method according to one of claims 10 to 14, characterized in that the gases produced during the quenching are liquefied in a condenser and the powders are recovered with part of the liquefied gases in at least one container making it possible to maintain the mixture at liquid or solid state. Procédé selon l'une des revendications 10 à 15, caractérisé en ce qu'on effectue la rotation de la tête de dispersion (9) à une vitesse comprise entre 30 000 et 125 000 t/mn.Method according to one of claims 10 to 15, characterized in that the dispersion head (9) is rotated at a speed of between 30,000 and 125,000 rpm. Procédé selon l'une des revendications 10 à 16, caractérisé en ce qu'on réalise, dans la tête de dispersion (9), un gradient de température de 60 à 180°C/cm pour une tête en cuivre et de 200 à 500°C/cm pour une tête en tungstène.Method according to one of claims 10 to 16, characterized in that a temperature gradient of 60 to 180 ° C / cm is obtained for the copper head and from 200 to 500 in the dispersion head (9) ° C / cm for a tungsten head. Procédé selon l'une des revendications 10 à 17, caractérisé en ce qu'on effectue la trempe du matériau atomisé au moyen de buses (15) distribuant un débit total d'argon liquide suffisant pour obtenir un refroidissement complet des poudres ; l'axe d'éjection desdites buses étant incliné par rapport au plan de la face supérieure de ladite tête de dispersion (9) et la largeur du jet étant déterminé de façon à produire un effet contra-rotatif à celui de ladite tête (9) pour freiner le mouvement des poudres.Method according to one of claims 10 to 17, characterized in that the atomized material is quenched by means of nozzles (15) distributing a total flow of liquid argon sufficient to obtain complete cooling of the powders; the axis of ejection of said nozzles being inclined relative to the plane of the upper face of said dispersion head (9) and the width of the jet being determined so as to produce a counter-rotating effect to that of said head (9) to slow down the movement of powders. Procédé selon l'une des revendications 10 à 18, caractérisé en ce que le matériau à atomiser est initialement sous forme d'un barreau cylindrique (1).Method according to one of claims 10 to 18, characterized in that the material to be atomized is initially in the form of a cylindrical bar (1). Procédé selon l'une des revendications 10 à 19, caractérisé en ce que le matériau à atomiser est d'abord reçu à l'état fondu dans un creuset froid (100) d'où il s'écoule au travers d'une busette (101,102) de réglage du débit vers l'enceinte d'atomisation (C).Method according to one of claims 10 to 19, characterized in that the material to be atomized is first received in the molten state in a cold crucible (100) from which it flows through a nozzle ( 101.102) for adjusting the flow rate to the atomization enclosure (C). Poudres métalliques ultra pures obtenues par le procédé selon l'une des revendications 10 à 20.Ultra pure metallic powders obtained by the process according to one of claims 10 to 20.
EP92402141A 1991-07-25 1992-07-24 Process and apparatus for the production of powders, in particular metal powders by atomisation Expired - Lifetime EP0524887B1 (en)

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FR9109462 1991-07-25
FR9109462A FR2679473B1 (en) 1991-07-25 1991-07-25 METHOD AND DEVICE FOR PRODUCING POWDERS AND ESPECIALLY METAL POWDERS BY ATOMIZATION.

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106216704A (en) * 2016-10-10 2016-12-14 江西悦安超细金属有限公司 A kind of feed arrangement and plasma combination centrifugal atomizing fuel pulverizing plant

Families Citing this family (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5855642A (en) * 1996-06-17 1999-01-05 Starmet Corporation System and method for producing fine metallic and ceramic powders
US6972115B1 (en) 1999-09-03 2005-12-06 American Inter-Metallics, Inc. Apparatus and methods for the production of powders
GB2354256B (en) * 1999-09-15 2001-11-07 Korea Atomic Energy Res Uranium high-density dispersion fuel
JP2001254103A (en) * 2000-03-13 2001-09-18 Sanei Kasei Kk Metallic grain having nanocomposite structure and its producing method by self-organizing
US20030156964A1 (en) * 2000-06-26 2003-08-21 Masami Kikuchi Method and apparatus for producing magnetic rare earth alloy powder, method for producing bonded magnet, method for producing rare earth sintering magnet, and method and apparatus for improving purity of inert gas
US7913884B2 (en) * 2005-09-01 2011-03-29 Ati Properties, Inc. Methods and apparatus for processing molten materials
CN100413617C (en) * 2006-08-18 2008-08-27 陕西科技大学 Device for preparing metal ultrafine powder and its method
US8268035B2 (en) * 2008-12-23 2012-09-18 United Technologies Corporation Process for producing refractory metal alloy powders
WO2011054113A1 (en) * 2009-11-05 2011-05-12 Ap&C Advanced Powders & Coatings Inc. Methods and apparatuses for preparing spheroidal powders
CN101906516B (en) * 2010-09-02 2012-01-11 唐山市长智农工具设计制造有限公司 Metal product quenching medium cyclic utilization device
DK3116636T3 (en) 2014-03-11 2020-10-12 Tekna Plasma Systems Inc METHOD AND DEVICE FOR THE PREPARATION OF POWDER PARTICULARS BY SPRAYING A FEEDING MATERIAL IN THE FORM OF AN Oblong ELEMENT
US20180169763A1 (en) * 2015-06-05 2018-06-21 Pyrogenesis Canada Inc. Plasma apparatus for the production of high quality spherical powders at high capacity
CA3013154C (en) * 2015-07-17 2019-10-15 Ap&C Advanced Powders And Coatings Inc. Plasma atomization metal powder manufacturing processes and systems therefor
EP4159345A1 (en) 2016-04-11 2023-04-05 AP&C Advanced Powders And Coatings Inc. Reactive metal powders in-flight heat treatment processes
US11110540B2 (en) * 2016-05-02 2021-09-07 Electronics And Telecommunications Research Institute Extruder for metal material and 3D printer using the same
WO2018035599A1 (en) 2016-08-24 2018-03-01 5N Plus Inc. Low melting point metal or alloy powders atomization manufacturing processes
TWI618589B (en) * 2016-12-23 2018-03-21 悅城科技股份有限公司 Device and method for manufacturing material particles
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JP7012350B2 (en) * 2017-12-18 2022-01-28 株式会社大阪真空機器製作所 Rotating disk device for centrifugal atomizer, centrifugal atomizer, and method for manufacturing metal powder
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CA3090714C (en) 2018-02-15 2021-07-20 5N Plus Inc. High melting point metal or alloy powders atomization manufacturing processes
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CN110883338A (en) * 2019-12-11 2020-03-17 湖南天际智慧材料科技有限公司 Device for preparing micro-nano powder material by radio frequency plasma
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2276121A1 (en) * 1974-06-28 1976-01-23 United Kingdom Government APPARATUS AND METHOD FOR THE PRODUCTION OF A METAL OBJECT BY CENTRIFUGAL ATOMIZATION OF MELTED METAL
FR2595595A1 (en) * 1986-03-17 1987-09-18 Aubert & Duval Acieries Method for cooling and collecting metallic powders produced by atomisation of liquid metal
WO1987005548A1 (en) * 1986-03-13 1987-09-24 Cheney Richard F Powder atomizing methods and apparatus
FR2629573A1 (en) * 1988-04-05 1989-10-06 Aubert & Duval Acieries Continuous melting head for metals or alloys

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58197206A (en) * 1982-04-30 1983-11-16 Hitachi Metals Ltd Production of powder of high grade metal or its alloy
US5120352A (en) * 1983-06-23 1992-06-09 General Electric Company Method and apparatus for making alloy powder
US5263689A (en) * 1983-06-23 1993-11-23 General Electric Company Apparatus for making alloy power
FR2588781B1 (en) * 1985-10-17 1988-04-08 Aubert & Duval Acieries DEVICE FOR ATOMIZING METALS OR ALLOYS
US4731517A (en) * 1986-03-13 1988-03-15 Cheney Richard F Powder atomizing methods and apparatus
US4762553A (en) * 1987-04-24 1988-08-09 The United States Of America As Represented By The Secretary Of The Air Force Method for making rapidly solidified powder
WO1989000470A1 (en) * 1987-07-20 1989-01-26 Battelle Development Corporation Double disintegration powder method
US4781754A (en) * 1987-09-24 1988-11-01 General Motors Corporation Rapid solidification of plasma sprayed magnetic alloys
US5084091A (en) * 1989-11-09 1992-01-28 Crucible Materials Corporation Method for producing titanium particles
US5272718A (en) * 1990-04-09 1993-12-21 Leybold Aktiengesellschaft Method and apparatus for forming a stream of molten material

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2276121A1 (en) * 1974-06-28 1976-01-23 United Kingdom Government APPARATUS AND METHOD FOR THE PRODUCTION OF A METAL OBJECT BY CENTRIFUGAL ATOMIZATION OF MELTED METAL
WO1987005548A1 (en) * 1986-03-13 1987-09-24 Cheney Richard F Powder atomizing methods and apparatus
FR2595595A1 (en) * 1986-03-17 1987-09-18 Aubert & Duval Acieries Method for cooling and collecting metallic powders produced by atomisation of liquid metal
FR2629573A1 (en) * 1988-04-05 1989-10-06 Aubert & Duval Acieries Continuous melting head for metals or alloys

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106216704A (en) * 2016-10-10 2016-12-14 江西悦安超细金属有限公司 A kind of feed arrangement and plasma combination centrifugal atomizing fuel pulverizing plant
CN106216704B (en) * 2016-10-10 2018-05-04 江西悦安超细金属有限公司 A kind of feed arrangement and plasma combine centrifugal atomizing fuel pulverizing plant

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FR2679473A1 (en) 1993-01-29
DE69218846T2 (en) 1997-10-23
EP0524887B1 (en) 1997-04-09
CA2074684A1 (en) 1993-01-26
FR2679473B1 (en) 1994-01-21
US5340377A (en) 1994-08-23
DE69218846D1 (en) 1997-05-15
US5529292A (en) 1996-06-25

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