EP3487649A1 - Process for manufacturing a shell mold - Google Patents

Process for manufacturing a shell mold

Info

Publication number
EP3487649A1
EP3487649A1 EP17754752.8A EP17754752A EP3487649A1 EP 3487649 A1 EP3487649 A1 EP 3487649A1 EP 17754752 A EP17754752 A EP 17754752A EP 3487649 A1 EP3487649 A1 EP 3487649A1
Authority
EP
European Patent Office
Prior art keywords
model
slip
powder
contact
zirconia
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP17754752.8A
Other languages
German (de)
French (fr)
Other versions
EP3487649B1 (en
Inventor
Wen Zhang
Patrice Henri Claude RAGOT
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.)
Safran Aircraft Engines SAS
Safran SA
Original Assignee
Safran Aircraft Engines SAS
Safran SA
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 Safran Aircraft Engines SAS, Safran SA filed Critical Safran Aircraft Engines SAS
Publication of EP3487649A1 publication Critical patent/EP3487649A1/en
Application granted granted Critical
Publication of EP3487649B1 publication Critical patent/EP3487649B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
    • B22C1/04—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives for protection of the casting, e.g. against decarbonisation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
    • B22C1/165—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents in the manufacture of multilayered shell moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
    • B22C1/08—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives for decreasing shrinkage of the mould, e.g. for investment casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • B22C9/04—Use of lost patterns

Definitions

  • the present invention relates to the manufacture of a foundry mold in a process called "lost wax", for the manufacture of precision metal parts.
  • This type of mold is also called shell mold.
  • a model of the piece to be made in wax or in a removable material is first made which can easily be melted or eliminated from the mold produced.
  • the model is successively tempered, sanded and / or coated with a reinforcement and dried.
  • the quenching operation is carried out in one or more slip (s).
  • the sanding operation also called stuccage, consists in reinforcing the deposit constituted by the slip layer deposited on the model during quenching.
  • the water is removed from the different layers.
  • the model is eliminated for example during a passage in an autoclave (treatment by pressure and temperature).
  • the mold undergoes heat treatment in order to give it the characteristics necessary for the casting of the metal.
  • a mold For the manufacture of precision metal parts, a mold must be stable when casting a molten metal. Stable means that the molten metal should not react the mold material so that it deforms.
  • the composition of the first layer in contact with the model commonly called the contact layer, is chemically compatible and closely matches the profile of the model. .
  • This contact layer is the result of soaking the model in a contact slip.
  • the contact layer must be homogeneous, stable, fluid, dense, non-reactive with the molten metal of the precision part to be manufactured and compatible with the following layers of the mold.
  • the expansion coefficients of the contact layer and the subsequent layers constituting the mold must be compatible so as to avoid any damage caused by a difference in thermal expansion of the layers.
  • alumina is not compatible with certain constituent alloys of the precision metal parts to be produced
  • electro-fused silica lacks refractoriness
  • zircon in addition to being radioactive, loses stability as it becomes more stable. that the temperature of the molten alloy increases.
  • the invention aims in particular to provide a simple, effective and economical solution to these problems.
  • the invention proposes a method of manufacturing a multi-layered shell mold, including at least one contact layer, from a model of a piece to be made of wax or other similar material, the method comprising a step of dipping the model in a contact slip forming the contact layer and comprising a binder and a powder, the powder comprising a mullite-zirconia composite.
  • a mullite-zirconia composite powder makes it possible to limit the chemical interactions between the carapace mold and the metal alloy introduced by casting into the shell mold.
  • the aforementioned composite is preferably substantially or almost exclusively formed of mullite and zirconia. Of course, it is understood that it may include impurities in negligible amount. These impurities can be calcium or sodium, in particular.
  • the binder can be inorganic or organic or be a mixture of organic and inorganic compounds.
  • the mullite-zirconia composite powder makes it possible, in particular, to produce a contact slip having good rheological stability, good chemical inertness with respect to the molten alloy and whose production is controlled.
  • a composite is a material composed of several elementary components, the combination of which confers on the set of properties that none of the components taken separately possesses.
  • the mullite-zirconia composite powder can be obtained by chemical synthesis using a mullite precursor such as alumina and / or silica and a precursor of zirconia such as zircon. The grains of the powder are then formed of an aggregate of mullite and zirconia.
  • the grains of the mullite-zirconia composite powder have an average size of between 5 and 20 ⁇ and a size distribution ranging between a submicron size up to a size of 100 ⁇ .
  • the contact layer may have a thickness less than or equal to 1 mm. It is desirable to limit the thickness of the contact layer to avoid mechanically weakening the shell mold due to the presence of zirconia.
  • the zirconia content in the powder is between 5% and 90% by weight and preferably between 10% and 50% by weight and even more preferably between 30% and 50%.
  • the binder is colloidal silica.
  • the contact slip also comprises at least one wetting agent and / or at least one anti-foaming agent.
  • the method comprises, following the dipping of the model in the contact slip, steps in which: - we sand the model,
  • a second slip which may preferably be devoid of zirconia so as to give it better mechanical strength
  • the model dipped in the second slip is coated with a reinforcing material
  • the steps of dipping in the second slip, coating in the reinforcing material and drying of the model coated with the reinforcing material and dried are repeated.
  • This method prior to soaking the model in the contact slip, comprises a step of producing the contact slip comprising the substeps where:
  • the binder is introduced into a container
  • the molar zirconia composite powder is added to the mixer,
  • the mixture of inorganic colloid binder and of composite powder is allowed to stabilize.
  • the phase of producing the contact slip also comprises a sub-step of adding the anti-foaming agent and / or the wetting agent.
  • the invention also relates to the use of a mold according to the method which has just been described for the manufacture of a cast and solidified turbine engine part.
  • FIG. 1 is a flowchart showing the steps for producing a lost wax foundry mold according to the invention.
  • FIG. 2 is a schematic sectional view of a foundry mold prior to a heat treatment step.
  • FIGS. 3 and 4 are images obtained by scanning electron microscopy of the grains of two different mullite-zirone composites, both of which can be used in the process according to the invention;
  • FIG. 5 is an illustration of different grains of a powder of the mullite-zirconia composite.
  • FIG. 1 a flow chart showing the steps of manufacturing a lost wax mold 1 for the manufacture of precision parts.
  • the name "shell mold” is also used to call this type of mold, however, in the rest of the description, we will use the simplified term of mold 1.
  • the mold schematically represented in section in the figure
  • the method for producing the mold 1 comprises steps 100 to
  • the model 6, in wax is made of the precision part to be manufactured.
  • the model 6 is made to the exact dimensions of the precision part and includes a high quality external surface condition. Thus, only some slight asperities may be visible or detectable on the outer surface of the model 6 so that the final precision part will need only a finishing pass (ie machining operation) to to grind the outer surface of the precision piece obtained.
  • the model 6 will have a surface condition such that a finishing pass will not be necessary and the precision piece can be used directly at the exit of the mold.
  • the precision part to be manufactured will be a turbomachine blade that must have an outer surface free of asperities so as to:
  • a contact layer 2 may have a thickness less than or equal to 1 mm.
  • the contact layer 2 has an essential role in the use of the mold 1 since it is it that will give the precision piece produced its outer surface. It is thus necessary that the contact slip is dense and resistant at the same time, and that its viscosity and its covering power are controlled.
  • the viscosity and the density are necessary so that during soaking, the contact slip conforms perfectly to the model 6 in wax, and more specifically the outer surface 7 of the model 6 in wax without creating, between the contact slip and the surface 7 6, air bubbles which would form, on an internal surface 8 of the mold 1, a cavity that is favorable for the creation of roughness on the outer surface of the precision piece.
  • the contact slip is composed of an inorganic and / or organic binder and a powder, in this case a mullite-zirconia composite.
  • the binder is a mineral colloidal binder such as colloidal silica in a mass quantity of between 10% and 40% and preferably between 20% and 30%.
  • the inorganic binder may be sodium silicate or ethyl silicate and the organic binder comprises water.
  • the powder comprises, by mass, a zirconia content between
  • the mass distribution of the elements making up the contact slip is as follows:
  • binder (colloidal silica): 29.8%;
  • composite powder (mullite-zirconia): 70.0%;
  • the mass distribution is here given by way of example, it being understood that a variation of the mass distribution of between 0.1% and 10% is possible.
  • the other additives that may be added may be a bactericidal agent to limit the bacteria and increase the stability of the slip, or other organic binders to ensure a uniform and resistant deposit of the contact layer 2 on the model 6 in wax.
  • the contact slip also comprises a wetting agent and an anti-foaming agent.
  • the preparation of the contact slip can be carried out as follows:
  • the inorganic colloidal binder and the wetting agent are introduced and mixed in a container, in this case a mixer, the mullite-zirconia composite powder is then added to the mixer,
  • the anti-foaming agent is added,
  • the mixer is kept running for a period of between 1 hour and 48 hours, and preferably for a period of 24 hours,
  • the resulting mixture is transferred into a container for soaking the model, for example a quench tank, and
  • the mixture is allowed to stabilize for a period of between 24 hours and 48 hours, and preferably for a period of 24 hours.
  • the mixture in the quench tank is then the slip contact.
  • composition of the contact slip has many advantages over the slip of the prior art, including improved service life, good chemical stability, reduced manufacturing time, non-radioactive formulation and improved quality of the sealant. mold obtained.
  • the slip of contact according to the invention offers:
  • a third step 300 the model 6 dipped in the contact slip, is sandblasted and then dried. Sandblasting is done in a way little aggressive with a powder that will not affect the contact layer 2 and in particular the state of the inner surface 8 of the mold 1.
  • the sandblasting makes it possible in particular to reinforce the layer 2 of contact and to facilitate the attachment of a second layer of the mold 1.
  • a fourth step 400 the model 6 is immersed surrounded by the sanded and dried contact layer 2, in a second slip may be of the same composition as the contact slip or different composition.
  • a fifth step 500 the model, taken out of the second slip, is sanded and then dried.
  • a model 6 is obtained on which are superimposed the contact layer 2 and a first reinforcing layer 3.
  • steps 400 and 500 can be repeated according to the thickness to be given to mold 1.
  • mold 1 is not limiting and a higher or lower number of reinforcement layers 3 could be provided.
  • a sixth step 600 the model 6 in wax is melted so that only the mold 1 remains.
  • a seventh (and last) step 700 the mold 1, comprising an adequate number of reinforcement layers (here three layers 3, 4, 5 of reinforcement) undergoes a heat treatment, in this case a baking in an oven in order to solidify the mold 1.
  • a heat treatment in this case a baking in an oven in order to solidify the mold 1.
  • the elimination of the model 6 in wax is carried out before the heat treatment of the mold 1. It is also possible that the model 6 in wax is eliminated during the heat treatment step 700, the temperature for consolidate the mold 1 being sufficient to melt the wax of the model 6, the steps 600 and 700 then being combined in a single step.
  • a material for example a metal alloy for the manufacture of the blades, can be cast in the mold 1, against the inner surface 8. After cooling, this cast material then forms the part precision to manufacture.
  • the mold 1 can be removed mechanically (breaking the mold 1), chemically (dissolution of the mold 1), or by a mechanical and chemical combination.
  • contact layer 2 has a low (or nonexistent) risk of chemical reaction with a large variety of materials that can be cast to form the precision piece.
  • the mullite-zirconia composite assures a good ease of implementation of the slip and makes it possible to cover the wax models 6 with complex geometries and in particular to lodge in the grooves and other inaccessible cavities so that all the details wax models 6 are reproduced on the contact layer 2.
  • mullite-zirconia composite offers the advantage of not being radioactive, and therefore manipulable without specific equipment.
  • FIGs 3 and 4 show two images obtained by scanning electron microscopy grains of two different mullite-zirone composites can both be used in the method according to the invention.
  • the mullite-zirconia composite can be obtained by melt synthesis (FIG. 3) or by solid state reactive sintering synthesis (FIG. 4) followed in either case by cooling solidification.
  • the mullite-zirconia composite blocks obtained then undergo micronization or ultrafine grinding.
  • the mullite of zirconia can not be distinguished within a grain 9 because of a greater homogeneity of the distribution of mullite and zirconia within a grain of the mullite-zirconia composite powder.
  • Figure 5 is a schematic illustration of several grains of a mullite-zirconia composite powder showing the diversity of grain shapes.
  • the grains of the mullite-zirconia composite powder have an average size of between 5 and 20 ⁇ and a size distribution ranging between a submicron size up to a size of 100 ⁇ .

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)

Abstract

The invention relates to a process for manufacturing a shell mold (1) having several layers (2, 3, 4, 5) including at least one contact layer (2), from a model (6) of a part to be manufactured made of wax or other similar material, the process comprising a step of dipping the model (6) in a contact slip forming the contact layer (2) and comprising an inorganic or organic binder and a powder, wherein the powder is a mullite-zirconia composite.

Description

PROCEDE DE FABRICATION DE MOULE CARAPACE  PROCESS FOR PRODUCING CARAPACE MOLD
La présente invention concerne la fabrication d'un moule de fonderie dans un procédé dit « à cire perdue », pour la fabrication de pièces métalliques de précision. Ce type de moule est également appelé moule carapace. The present invention relates to the manufacture of a foundry mold in a process called "lost wax", for the manufacture of precision metal parts. This type of mold is also called shell mold.
La réalisation des moules en « cire perdue » est connue et largement utilisée notamment pour la fabrication de pièces de précision ayant des géométries complexes ou de pièces de précision en très petite séries voire uniques.  The production of molds "lost wax" is known and widely used especially for the manufacture of precision parts with complex geometries or precision parts in very small or even unique series.
Pour fabriquer un moule en cire perdue, on réalise d'abord un modèle de la pièce à fabriquer en cire ou dans un matériau éliminable qui pourra être fondu ou éliminé facilement du moule fabriqué.  In order to manufacture a lost wax mold, a model of the piece to be made in wax or in a removable material is first made which can easily be melted or eliminated from the mold produced.
Le modèle est successivement trempé, sablé et/ou enduit d'un renfort et séché. L'opération de trempe est réalisée dans une ou plusieurs barbotine(s). L'opération de sablage, également appelée stuccage, consiste à renforcer le dépôt constitué par la couche de barbotine déposée sur le modèle lors de la trempe. Après chaque opération de trempe et de sablage et/ou d'enduction, l'eau est éliminée des différentes couches. Ensuite, le modèle est éliminé par exemple lors d'un passage dans un autoclave (traitement par la pression et la température). Enfin, le moule subit un traitement thermique dans le but de lui conférer les caractéristiques nécessaires pour la coulée du métal.  The model is successively tempered, sanded and / or coated with a reinforcement and dried. The quenching operation is carried out in one or more slip (s). The sanding operation, also called stuccage, consists in reinforcing the deposit constituted by the slip layer deposited on the model during quenching. After each quenching and sanding and / or coating operation, the water is removed from the different layers. Then, the model is eliminated for example during a passage in an autoclave (treatment by pressure and temperature). Finally, the mold undergoes heat treatment in order to give it the characteristics necessary for the casting of the metal.
Pour la fabrication de pièces métalliques de précision, un moule doit être stable lors de la coulée d'un métal fondu. Par stable, on entend que le métal fondu ne doit pas faire réagir le matériau du moule de telle sorte que celui-ci se déforme.  For the manufacture of precision metal parts, a mold must be stable when casting a molten metal. Stable means that the molten metal should not react the mold material so that it deforms.
Afin que le moule présente un état de surface parfait pour la réalisation d'une pièce, il est important que la composition de la première couche en contact avec le modèle, couramment appelée couche de contact, soit compatible chimiquement et épouse fidèlement le profil du modèle. Cette couche de contact est le résultat du trempage du modèle dans une barbotine de contact. La couche de contact se doit d'être homogène, stable, fluide, dense, non réactive avec le métal fondu de la pièce de précision à fabriquer et compatible avec les couches suivantes du moule. Par ailleurs, les coefficients de dilatation de la couche de contact et des couches suivantes constituant le moule doivent être compatibles de sorte à éviter tout endommagement causé par une différence de dilatation thermique des couches. In order for the mold to have a perfect surface state for producing a part, it is important that the composition of the first layer in contact with the model, commonly called the contact layer, is chemically compatible and closely matches the profile of the model. . This contact layer is the result of soaking the model in a contact slip. The contact layer must be homogeneous, stable, fluid, dense, non-reactive with the molten metal of the precision part to be manufactured and compatible with the following layers of the mold. Furthermore, the expansion coefficients of the contact layer and the subsequent layers constituting the mold must be compatible so as to avoid any damage caused by a difference in thermal expansion of the layers.
Il est connu d'utiliser différentes barbotines qui comprennent soit de l'alumine, soit du zircon, ou soit de la silice électro fondue. Chacun de ces composés présente au moins un inconvénient particulier. A titre d'exemple, l'alumine n'est pas compatible avec certains alliages constitutifs des pièces métalliques de précision à produire, la silice électro fondue manque de réfractarité, et le zircon, en plus d'être radioactif, perd en stabilité à mesure que la température de l'alliage fondu augmente.  It is known to use different slips which comprise either alumina or zircon, or electro-fused silica. Each of these compounds has at least one particular disadvantage. By way of example, alumina is not compatible with certain constituent alloys of the precision metal parts to be produced, electro-fused silica lacks refractoriness, and zircon, in addition to being radioactive, loses stability as it becomes more stable. that the temperature of the molten alloy increases.
L'invention a notamment pour but d'apporter une solution simple, efficace et économique à ces problèmes.  The invention aims in particular to provide a simple, effective and economical solution to these problems.
A cet effet, l'invention propose, un procédé de fabrication de moule carapace à plusieurs couches dont au moins une couche de contact, à partir d'un modèle de pièce à fabriquer en cire ou autre matériau semblable, le procédé comprenant une étape de trempage du modèle dans une barbotine de contact formant la couche de contact et comprenant un liant et une poudre, la poudre comprenant un composite mullite-zircone.  For this purpose, the invention proposes a method of manufacturing a multi-layered shell mold, including at least one contact layer, from a model of a piece to be made of wax or other similar material, the method comprising a step of dipping the model in a contact slip forming the contact layer and comprising a binder and a powder, the powder comprising a mullite-zirconia composite.
L'utilisation d'une poudre composite mullite-zircone permet de limiter les interactions chimiques entre le moule carapace et l'alliage métallique introduit par coulée dans le moule carapace. Le composite précité est de préférence essentiellement ou quasi exclusivement formé de mullite et de zircone. Bien évidemment, on comprend qu'il pourra comprendre des impuretés en quantité négligeable. Ces impuretés peuvent être du calcium ou du sodium, notamment. Selon une caractéristique de l'invention, le liant peut être inorganique ou organique ou encore être un mélange de composés organiques et inorganiques. The use of a mullite-zirconia composite powder makes it possible to limit the chemical interactions between the carapace mold and the metal alloy introduced by casting into the shell mold. The aforementioned composite is preferably substantially or almost exclusively formed of mullite and zirconia. Of course, it is understood that it may include impurities in negligible amount. These impurities can be calcium or sodium, in particular. According to one characteristic of the invention, the binder can be inorganic or organic or be a mixture of organic and inorganic compounds.
La poudre composite mullite-zircone permet notamment de réaliser une barbotine de contact ayant une bonne stabilité rhéologique, une bonne inertie chimique vis-à-vis de l'alliage fondu et dont on maîtrise la fabrication.  The mullite-zirconia composite powder makes it possible, in particular, to produce a contact slip having good rheological stability, good chemical inertness with respect to the molten alloy and whose production is controlled.
On rappelle qu'un composite est un matériau composé de plusieurs composants élémentaires dont l'association confère à l'ensemble des propriétés qu'aucun des composants pris séparément ne possède.  It is recalled that a composite is a material composed of several elementary components, the combination of which confers on the set of properties that none of the components taken separately possesses.
La poudre composite mullite-zircone peut être obtenue par synthèse chimique à l'aide d'un précurseur de la mullite tels que l'alumine et /ou la silice et d'un précurseur de la zircone tel que le zircon. Les grains de la poudre sont alors formés d'un agrégat de mullite et de zircone.  The mullite-zirconia composite powder can be obtained by chemical synthesis using a mullite precursor such as alumina and / or silica and a precursor of zirconia such as zircon. The grains of the powder are then formed of an aggregate of mullite and zirconia.
De préférence, les grains de la poudre composite mullite-zircone ont une taille moyenne comprise entre 5 et 20 μιτι et une distribution de la taille s'étalant entre une taille sous-micronique jusqu'à une taille de 100 μιτι.  Preferably, the grains of the mullite-zirconia composite powder have an average size of between 5 and 20 μιτι and a size distribution ranging between a submicron size up to a size of 100 μιτι.
Selon une autre caractéristique, la couche de contact peut avoir une épaisseur inférieure ou égale à 1 mm. Il est souhaitable de limiter l'épaisseur de la couche de contact pour éviter d'affaiblir mécaniquement le moule carapace du fait de la présence de zircone.  According to another characteristic, the contact layer may have a thickness less than or equal to 1 mm. It is desirable to limit the thickness of the contact layer to avoid mechanically weakening the shell mold due to the presence of zirconia.
Pour obtenir une barbotine de contact de bonne qualité, le taux de zircone dans la poudre est compris entre 5% et 90% en masse et, de préférence entre 10% et 50% en masse et encore plus préférentiellement entre 30% et 50%.  To obtain a good quality contact slip, the zirconia content in the powder is between 5% and 90% by weight and preferably between 10% and 50% by weight and even more preferably between 30% and 50%.
Avantageusement, le liant est de la silice colloïdale.  Advantageously, the binder is colloidal silica.
Pour favoriser le mouillage de la couche de contact sur la surface du modèle, la barbotine de contact comprend également au moins un agent mouillant et/ou au moins un agent anti-moussant.  To promote the wetting of the contact layer on the surface of the model, the contact slip also comprises at least one wetting agent and / or at least one anti-foaming agent.
Pour réaliser un moule résistant permettant la fabrication d'une pièce de précision, le procédé comprend, à la suite du trempage du modèle dans la barbotine de contact, des étapes dans lesquelles : - on sable le modèle, To produce a resistant mold for the manufacture of a precision part, the method comprises, following the dipping of the model in the contact slip, steps in which: - we sand the model,
- on sèche le modèle sablé,  - we dry the sandblasted model,
- on trempe le modèle sablé et séché dans une deuxième barbotine qui peut être de préférence dépourvue de zircone afin de lui conférer une meilleure résistance mécanique, the sanded and dried model is quenched in a second slip which may preferably be devoid of zirconia so as to give it better mechanical strength,
- on enduit le modèle trempé dans la deuxième barbotine d'un matériau de renfort, the model dipped in the second slip is coated with a reinforcing material,
- on sèche le modèle enduit du matériau de renfort, et  the model coated with the reinforcing material is dried, and
- on réalise un traitement thermique sur le modèle enduit du matériau de renfort et séché.  - Heat treatment is carried out on the model coated with the reinforcing material and dried.
Avantageusement, les étapes de trempage dans la deuxième barbotine, d'enduction dans le matériau de renfort et de séchage du modèle enduit du matériau de renfort et séché sont réitérées.  Advantageously, the steps of dipping in the second slip, coating in the reinforcing material and drying of the model coated with the reinforcing material and dried are repeated.
La succession d'étapes de ce procédé et, le cas échéant, la réitération de certaines étapes permettent d'obtenir un moule de bonne qualité qui résistera à la fabrication d'une pièce de précision et offrira un bon état de surface extérieure à la pièce de précision fabriquée.  The succession of steps of this process and, if necessary, the reiteration of certain steps make it possible to obtain a mold of good quality that will withstand the manufacture of a precision part and will offer a good state of external surface to the piece manufactured precision.
Ce procédé, préalablement au trempage du modèle dans la barbotine de contact, comprend une phase de réalisation de la barbotine de contact comprenant les sous-étapes où :  This method, prior to soaking the model in the contact slip, comprises a step of producing the contact slip comprising the substeps where:
- on introduit le liant dans récipient,  the binder is introduced into a container,
- on ajoute la poudre composite mullilte-zircone dans le mélangeur,  the molar zirconia composite powder is added to the mixer,
- on laisse le mélange de liant colloïdal minéral et de poudre composite se stabiliser.  the mixture of inorganic colloid binder and of composite powder is allowed to stabilize.
Avantageusement, la phase de réalisation de la barbotine de contact comprend également une sous-étape d'ajout de l'anti-moussant et/ou de l'agent mouillant.  Advantageously, the phase of producing the contact slip also comprises a sub-step of adding the anti-foaming agent and / or the wetting agent.
En outre, l'invention concerne également l'utilisation d'un moule selon le procédé qui vient d'être décrit, pour la fabrication d'une pièce de turbomachine coulée et solidifiée. L'invention sera mieux comprise et d'autres détails, caractéristiques et avantages de l'invention apparaîtront à la lecture de la description suivante faite à titre d'exemple non limitatif en référence aux dessins annexés dans lesquels : In addition, the invention also relates to the use of a mold according to the method which has just been described for the manufacture of a cast and solidified turbine engine part. The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of non-limiting example with reference to the accompanying drawings in which:
- la figure 1 est un ordinogramme montrant les étapes de réalisation d'un moule de fonderie à cire perdue selon l'invention, et  FIG. 1 is a flowchart showing the steps for producing a lost wax foundry mold according to the invention, and
- la figure 2 est une vue schématique en coupe d'un moule de fonderie préalablement à une étape de traitement thermique.  - Figure 2 is a schematic sectional view of a foundry mold prior to a heat treatment step.
- les figures 3 et 4 sont des images obtenues en microscopie électronique à balayage des grains de deux composites mullite-zirone différents pouvant l'un et l'autre être utilisés dans le procédé selon l'invention ;  FIGS. 3 and 4 are images obtained by scanning electron microscopy of the grains of two different mullite-zirone composites, both of which can be used in the process according to the invention;
- la figure 5 est une illustration de différents grains d'une poudre du composite mullite-zircone.  FIG. 5 is an illustration of different grains of a powder of the mullite-zirconia composite.
On a représenté, sur la figure 1 , un ordinogramme montrant les étapes de la fabrication d'un moule 1 à cire perdue pour la fabrication de pièces de précision. Le nom « moule à carapace » est également utilisé pour appeler ce type de moule, toutefois, dans la suite de la description, nous utiliserons le terme simplifié de moule 1 .  There is shown in FIG. 1 a flow chart showing the steps of manufacturing a lost wax mold 1 for the manufacture of precision parts. The name "shell mold" is also used to call this type of mold, however, in the rest of the description, we will use the simplified term of mold 1.
Le moule 1 , schématiquement représenté en coupe sur la figure The mold 1, schematically represented in section in the figure
2 comprend une pluralité de couches 2, 3, 4, 5, superposées les unes sur les autres et recouvrant un modèle 6 en cire ou dans un matériau semblable, c'est-à-dire un matériau ayant des caractéristiques similaires et facilement éliminable. 2 comprises a plurality of layers 2, 3, 4, 5 superimposed on each other and covering a model 6 of wax or a similar material, that is to say a material having similar characteristics and easily removable.
Le procédé de réalisation du moule 1 comprend les étapes 100 à The method for producing the mold 1 comprises steps 100 to
700 qui vont maintenant être décrites. 700 that will now be described.
Dans une première étape 100, on réalise le modèle 6, en cire, de la pièce de précision à fabriquer.  In a first step 100, the model 6, in wax, is made of the precision part to be manufactured.
Pour permettre la réalisation d'une pièce de précision parfaite, le modèle 6 est réalisé aux dimensions exactes de la pièce de précision et comprend un état de surface 7 extérieure de grande qualité. Ainsi, seules quelques légères aspérités peuvent être visibles ou détectables sur la surface 7 extérieure du modèle 6 de sorte que la pièce de précision finale n'aura besoin que d'une passe (c'est-à-dire une opération d'usinage) de finition visant à rectifier la surface externe de la pièce de précision obtenue. To enable the realization of a perfect precision part, the model 6 is made to the exact dimensions of the precision part and includes a high quality external surface condition. Thus, only some slight asperities may be visible or detectable on the outer surface of the model 6 so that the final precision part will need only a finishing pass (ie machining operation) to to grind the outer surface of the precision piece obtained.
Avantageusement, le modèle 6 aura un état de surface tel, qu'une passe de finition ne sera pas nécessaire et la pièce de précision pourra être utilisée directement à la sortie du moule.  Advantageously, the model 6 will have a surface condition such that a finishing pass will not be necessary and the precision piece can be used directly at the exit of the mold.
Par exemple, la pièce de précision à fabriquer sera une aube de turbomachine qui doit avoir une surface extérieure dépourvue d'aspérités de sorte à :  For example, the precision part to be manufactured will be a turbomachine blade that must have an outer surface free of asperities so as to:
- limiter le risque de cassure de l'aube qui est soumise à une force centrifuge importante en utilisation, ou encore  to limit the risk of breakage of the blade which is subjected to a large centrifugal force in use, or
- limiter les perturbations d'un flux d'air s'écoulant sur la surface extérieure de l'aube.  - Limit the disturbances of a flow of air flowing on the outer surface of the blade.
Dans une deuxième étape 200, on trempe le modèle dans une barbotine de contact afin de former, autour du modèle 6, une couche 2 de contact pouvant avoir une épaisseur inférieure ou égale à 1 mm.  In a second step 200, the model is immersed in a contact slip to form, around the model 6, a contact layer 2 may have a thickness less than or equal to 1 mm.
La couche 2 de contact a un rôle essentiel dans l'utilisation du moule 1 puisque c'est elle qui donnera à la pièce de précision produite sa surface extérieure. Il est ainsi nécessaire que la barbotine de contact soit dense et résistante à la fois, et que sa viscosité et son pouvoir couvrant soient maîtrisés.  The contact layer 2 has an essential role in the use of the mold 1 since it is it that will give the precision piece produced its outer surface. It is thus necessary that the contact slip is dense and resistant at the same time, and that its viscosity and its covering power are controlled.
La viscosité et la densité sont nécessaires de sorte que lors du trempage, la barbotine de contact épouse parfaitement le modèle 6 en cire, et plus précisément la surface 7 extérieure du modèle 6 en cire sans créer, entre la barbotine de contact et la surface 7 extérieure du modèle 6, de bulles d'air qui formeraient, sur une surface 8 interne du moule 1 , une cavité propice à la création d'aspérité sur la surface extérieure de la pièce de précision.  The viscosity and the density are necessary so that during soaking, the contact slip conforms perfectly to the model 6 in wax, and more specifically the outer surface 7 of the model 6 in wax without creating, between the contact slip and the surface 7 6, air bubbles which would form, on an internal surface 8 of the mold 1, a cavity that is favorable for the creation of roughness on the outer surface of the precision piece.
En revanche, la résistance de la barbotine de contact sera nécessaire, pour que la couche 2 de contact ne se déforme pas lors de la fabrication de la pièce de précision. Pour répondre à ce double critère de viscosité et de résistance, la barbotine de contact est composée d'un liant inorganique et/ou organique et d'une poudre, en l'espèce un composite mullite-zircone. On the other hand, the resistance of the contact slip will be necessary so that the contact layer 2 does not deform during the manufacture of the precision part. To meet this double criterion of viscosity and strength, the contact slip is composed of an inorganic and / or organic binder and a powder, in this case a mullite-zirconia composite.
De préférence, le liant est un liant colloïdal minéral tel que de la silice colloïdale dans une quantité massique comprise entre 10% et 40 % et, de préférence, entre 20% et 30%.  Preferably, the binder is a mineral colloidal binder such as colloidal silica in a mass quantity of between 10% and 40% and preferably between 20% and 30%.
A titre d'exemples non limitatifs, le liant inorganique peut être du silicate de soude ou encore du silicate éthyle et le liant organique comprend de l'eau.  As non-limiting examples, the inorganic binder may be sodium silicate or ethyl silicate and the organic binder comprises water.
La poudre comprend, en masse, un taux de zircone compris entre The powder comprises, by mass, a zirconia content between
5% et 90% et, de préférence, compris entre 10% et 50% et encore plus préférentiellement entre 30% et 50%. 5% and 90% and preferably between 10% and 50% and even more preferably between 30% and 50%.
Selon un mode préféré de réalisation, la répartition massique des éléments composant la barbotine de contact est la suivante :  According to a preferred embodiment, the mass distribution of the elements making up the contact slip is as follows:
- liant (silice colloïdale) : 29,8% ;  binder (colloidal silica): 29.8%;
- poudre composite (mullite-zircone) : 70,0% ;  composite powder (mullite-zirconia): 70.0%;
- agent mouillant, anti-moussant et autres additifs : 0,2%.  - wetting agent, anti-foaming and other additives: 0.2%.
La répartition massique est ici donnée à titre d'exemple, étant entendu qu'une variation de la répartition massique comprise entre 0,1 % et 10% est possible.  The mass distribution is here given by way of example, it being understood that a variation of the mass distribution of between 0.1% and 10% is possible.
A titre d'exemples, les autres additifs pouvant être ajoutés peuvent être un agent bactéricide pour limiter les bactéries et augmenter la stabilité de la barbotine, ou d'autres liants organiques permettant de garantir un dépôt uniforme et résistant de la couche 2 de contact sur le modèle 6 en cire.  By way of example, the other additives that may be added may be a bactericidal agent to limit the bacteria and increase the stability of the slip, or other organic binders to ensure a uniform and resistant deposit of the contact layer 2 on the model 6 in wax.
Avantageusement, la barbotine de contact comprend également un agent mouillant et un agent anti-moussant.  Advantageously, the contact slip also comprises a wetting agent and an anti-foaming agent.
La confection de la barbotine de contact peut être réalisée comme suit :  The preparation of the contact slip can be carried out as follows:
- on introduit et mélange le liant colloïdal minéral et l'agent mouillant dans un récipient, en l'espèce un mélangeur, - on ajoute ensuite la poudre composite mullite-zircone dans le mélangeur, the inorganic colloidal binder and the wetting agent are introduced and mixed in a container, in this case a mixer, the mullite-zirconia composite powder is then added to the mixer,
- on ajoute l'anti-moussant,  the anti-foaming agent is added,
- on maintient le mélangeur en marche pendant une durée comprise entre 1 heure et 48 heures, et de préférence pendant une durée de 24 heures,  the mixer is kept running for a period of between 1 hour and 48 hours, and preferably for a period of 24 hours,
- on transfère le mélange obtenu dans un récipient permettant de réaliser le trempage du modèle, par exemple une cuve de trempée, et  the resulting mixture is transferred into a container for soaking the model, for example a quench tank, and
- on laisse le mélange se stabiliser pendant une durée comprise entre 24 heures et 48 heures, et de préférence pendant une durée de 24 heures.  the mixture is allowed to stabilize for a period of between 24 hours and 48 hours, and preferably for a period of 24 hours.
A la suite de ces étapes, le mélange dans la cuve de trempé est alors la barbotine de contact.  Following these steps, the mixture in the quench tank is then the slip contact.
La composition de la barbotine de contact présente de nombreux avantages par rapport à la barbotine de l'art antérieur, parmi lesquels une meilleure durée de vie, une bonne stabilité chimique, un temps de fabrication réduit, une formulation non radioactive et une qualité accrue du moule obtenu.  The composition of the contact slip has many advantages over the slip of the prior art, including improved service life, good chemical stability, reduced manufacturing time, non-radioactive formulation and improved quality of the sealant. mold obtained.
A titre d'exemple, par rapport à la barbotine de l'art antérieur, la barbotine de contact selon l'invention offre :  By way of example, with respect to the slip of the prior art, the slip of contact according to the invention offers:
- un temps de fabrication divisé au minimum par deux,  - a manufacturing time divided by at least two,
- une densité supérieure d'au moins 16%,  - a density greater than or equal to 16%,
- une viscosité inférieure d'au moins 60% à la fin de la fabrication et d'environ 50% trente jours après la fin de la fabrication, et a viscosity of at least 60% lower at the end of manufacture and about 50% thirty days after the end of manufacture, and
- un meilleur recouvrement du modèle 6 en cire, notamment dans ses formes complexes, par exemple des renfoncements ou des rainures. - Better recovery of the model 6 in wax, especially in its complex shapes, for example recesses or grooves.
Dans une troisième étape 300, le modèle 6 trempé dans la barbotine de contact, est sablé puis séché. Le sablage est réalisé de manière peu agressive avec une poudre qui n'affectera pas la couche 2 de contact et notamment l'état de la surface 8 interne du moule 1 . In a third step 300, the model 6 dipped in the contact slip, is sandblasted and then dried. Sandblasting is done in a way little aggressive with a powder that will not affect the contact layer 2 and in particular the state of the inner surface 8 of the mold 1.
Le sablage permet notamment de renforcer la couche 2 de contact et de faciliter l'accrochage d'une deuxième couche du moule 1 .  The sandblasting makes it possible in particular to reinforce the layer 2 of contact and to facilitate the attachment of a second layer of the mold 1.
Dans une quatrième étape 400, on trempe le modèle 6 entouré de la couche 2 de contact sablée et séchée, dans une deuxième barbotine pouvant être de même composition que la barbotine de contact ou de composition différente.  In a fourth step 400, the model 6 is immersed surrounded by the sanded and dried contact layer 2, in a second slip may be of the same composition as the contact slip or different composition.
Dans une cinquième étape 500, le modèle, sorti de la deuxième barbotine, est sablé puis séché.  In a fifth step 500, the model, taken out of the second slip, is sanded and then dried.
A la fin de l'étape 500, on obtient un modèle 6 sur lequel sont superposées la couche 2 de contact et une première couche 3 de renfort.  At the end of step 500, a model 6 is obtained on which are superimposed the contact layer 2 and a first reinforcing layer 3.
Comme cela est représenté sur l'ordinogramme de la figure 1 par la flèche en traits pointillés, les étapes 400 et 500 peuvent être réitérées en fonction de l'épaisseur à donner au moule 1 .  As shown on the flowchart of FIG. 1 by the dashed arrow, steps 400 and 500 can be repeated according to the thickness to be given to mold 1.
Dans l'exemple de moule 1 illustré sur la figure 2, une deuxième couche 4 de renfort et une troisième couche 5 de renfort ont été superposées sur la première couche de renfort.  In the mold example 1 illustrated in FIG. 2, a second reinforcing layer 4 and a third reinforcing layer 5 have been superimposed on the first reinforcing layer.
Toutefois, cet exemple de moule 1 n'est nullement limitatif et un nombre supérieur ou inférieur de couches 3 de renfort pourrait être prévu.  However, this example of mold 1 is not limiting and a higher or lower number of reinforcement layers 3 could be provided.
Dans une sixième étape 600, le modèle 6 en cire est fondu de sorte qu'il ne reste que le moule 1 .  In a sixth step 600, the model 6 in wax is melted so that only the mold 1 remains.
Enfin, dans une septième (et dernière) étape 700, le moule 1 , comprenant un nombre adéquat de couches de renfort (ici trois couches 3, 4, 5 de renfort) subit un traitement thermique, en l'espèce une cuisson dans un four, afin de solidifier le moule 1 .  Finally, in a seventh (and last) step 700, the mold 1, comprising an adequate number of reinforcement layers (here three layers 3, 4, 5 of reinforcement) undergoes a heat treatment, in this case a baking in an oven in order to solidify the mold 1.
Toutefois, d'une manière générale, l'élimination du modèle 6 en cire (également appelée étape de décirage) est effectuée avant le traitement thermique du moule 1 . Il est également possible que le modèle 6 en cire soit éliminé lors de l'étape 700 de traitement thermique, la température pour consolider le moule 1 étant suffisante pour faire fondre la cire du modèle 6, les étapes 600 et 700 étant alors combinées en une seule étape. However, in general, the elimination of the model 6 in wax (also called dewaxing step) is carried out before the heat treatment of the mold 1. It is also possible that the model 6 in wax is eliminated during the heat treatment step 700, the temperature for consolidate the mold 1 being sufficient to melt the wax of the model 6, the steps 600 and 700 then being combined in a single step.
Lorsque le moule 1 est terminé, une matière, par exemple un alliage métallique pour la fabrication des aubes, peut être coulé dans le moule 1 , contre la surface interne 8. A l'issue de son refroidissement, ce matériau coulé forme alors la pièce de précision à fabriquer.  When the mold 1 is finished, a material, for example a metal alloy for the manufacture of the blades, can be cast in the mold 1, against the inner surface 8. After cooling, this cast material then forms the part precision to manufacture.
Pour retirer la pièce de précision du moule 1 , on peut éliminer le moule 1 par voie mécanique (cassage du moule 1 ), par voie chimique (dissolution du moule 1 ), ou par une combinaison mécanique et chimique.  To remove the precision part of the mold 1, the mold 1 can be removed mechanically (breaking the mold 1), chemically (dissolution of the mold 1), or by a mechanical and chemical combination.
Un autre avantage offert par le choix d'une poudre composite mullite-zircone pour la barbotine de contact est que la couche 2 de contact présente un faible (voire inexistant) risque de réaction chimique avec une variété importante de matériaux pouvant être coulés pour former la pièce de précision.  Another advantage offered by the choice of a mullite-zirconia composite powder for the contact slip is that the contact layer 2 has a low (or nonexistent) risk of chemical reaction with a large variety of materials that can be cast to form the precision piece.
En outre, le composite mullite-zircone assure une bonne facilité de mise en œuvre de la barbotine et permet de recouvrir les modèles 6 en cire à géométries complexes et notamment de se loger dans les rainures et autres cavités peu accessibles de sorte que tous les détails des modèles 6 en cire sont reproduits sur la couche 2 de contact.  In addition, the mullite-zirconia composite assures a good ease of implementation of the slip and makes it possible to cover the wax models 6 with complex geometries and in particular to lodge in the grooves and other inaccessible cavities so that all the details wax models 6 are reproduced on the contact layer 2.
Enfin le composite mullite-zircone offre l'avantage de ne pas être radioactif, et donc manipulable sans équipement spécifique.  Finally the mullite-zirconia composite offers the advantage of not being radioactive, and therefore manipulable without specific equipment.
On se réfère maintenant aux figures 3 et 4 qui représentent deux images obtenues en microscopie électronique à balayage des grains de deux composites mullite-zirone différents pouvant l'un et l'autre être utilisés dans le procédé selon l'invention. Le composite mullite-zircone peut être obtenu par synthèse par fusion (figure 3) ou par synthèse par frittage réactif à l'état solide (figure 4) suivi dans l'un et l'autre des cas par une solidification par refroidissement. Les blocs de composite mullite-zircone obtenus subissent ensuite une micronisation ou un broyage ultra-fin.  Referring now to Figures 3 and 4 which show two images obtained by scanning electron microscopy grains of two different mullite-zirone composites can both be used in the method according to the invention. The mullite-zirconia composite can be obtained by melt synthesis (FIG. 3) or by solid state reactive sintering synthesis (FIG. 4) followed in either case by cooling solidification. The mullite-zirconia composite blocks obtained then undergo micronization or ultrafine grinding.
Sur l'image de la figure 3, on peut distinguer plusieurs grains 9 de la poudre composite mullite-zircone, la mullite étant indiquée par la référence 10 et la zircone par la référence 1 1 . Sur l'image de la figure 4, on ne distingue pas la mullite de la zircone au sein d'un grain 9 du fait d'une plus grande homogénéité de la répartition de la mullite et de la zircone au sein d'un grain de la poudre composite mullite-zircone. In the image of FIG. 3, several grains 9 can be distinguished from the mullite-zirconia composite powder, the mullite being indicated by the reference 10 and zirconia by the reference 1 1. In the image of FIG. 4, the mullite of zirconia can not be distinguished within a grain 9 because of a greater homogeneity of the distribution of mullite and zirconia within a grain of the mullite-zirconia composite powder.
La figure 5 est une illustration schématique de plusieurs grains d'une poudre composite mullite-zircone montrant la diversité des formes de grains. De préférence, les grains de la poudre composite mullite-zircone ont une taille moyenne comprise entre 5 et 20 μιτι et une distribution de la taille s'étalant entre une taille sous-micronique jusqu'à une taille de 100 μιτι.  Figure 5 is a schematic illustration of several grains of a mullite-zirconia composite powder showing the diversity of grain shapes. Preferably, the grains of the mullite-zirconia composite powder have an average size of between 5 and 20 μιτι and a size distribution ranging between a submicron size up to a size of 100 μιτι.

Claims

REVENDICATIONS
1 . Procédé de fabrication de moule (1 ) carapace à plusieurs couches (2, 3, 4, 5) dont au moins une couche (2) de contact, à partir d'un modèle (6) de pièce à fabriquer en cire ou autre matériau semblable, le procédé comprenant une étape de trempage du modèle (6) dans une barbotine de contact formant la couche (2) de contact et comprenant un liant et une poudre, caractérisé en ce que la poudre comprend un composite mullite-zircone. 1. A method of manufacturing a multi-layered shell (1, 3, 4, 5) having at least one contact layer (2) from a model (6) of a piece to be made of wax or other material similar, the method comprising a step of dipping the model (6) in a contact slip forming the contact layer (2) and comprising a binder and a powder, characterized in that the powder comprises a mullite-zirconia composite.
2. Procédé selon la revendication 1 , dans lequel le taux de zircone dans la poudre est compris entre 5% et 90% en masse.  2. The method of claim 1, wherein the zirconia content in the powder is between 5% and 90% by weight.
3. Procédé selon la revendication précédente, dans lequel le taux de zircone dans la poudre est compris entre 10% et 50% en masse.  3. Method according to the preceding claim, wherein the zirconia content in the powder is between 10% and 50% by weight.
4. Procédé selon la revendication 2 ou 3, dans lequel le taux de zircone dans la poudre est compris entre 30% et 50% en masse.  4. The method of claim 2 or 3, wherein the zirconia content in the powder is between 30% and 50% by weight.
5. Procédé selon l'une des revendications précédentes, dans lequel les grains de la poudre composite mullite-zircone ont une taille moyenne comprise entre 5 et 20 μιτι.  5. Method according to one of the preceding claims, wherein the grains of the composite mullite-zirconia powder have an average size of between 5 and 20 μιτι.
6. Procédé selon l'une des revendications précédentes, dans lequel la couche de contact a une épaisseur inférieure ou égale à 1 mm.  6. Method according to one of the preceding claims, wherein the contact layer has a thickness less than or equal to 1 mm.
7. Procédé selon l'une quelconque des revendications précédentes, dans lequel le liant est de la silice colloïdale.  7. A process according to any one of the preceding claims, wherein the binder is colloidal silica.
8. Procédé selon l'une quelconque des revendications précédentes, dans lequel la barbotine de contact comprend également au moins un agent mouillant et/ou au moins un agent anti-moussant.  8. A method according to any one of the preceding claims, wherein the contact slip also comprises at least one wetting agent and / or at least one anti-foaming agent.
9. Procédé selon l'une quelconque des revendications précédentes, qui comprend, à la suite du trempage du modèle (6) dans la barbotine de contact, les étapes dans lesquelles :  9. Process according to any one of the preceding claims, which comprises, following the dipping of the model (6) in the contact slip, the steps in which:
- on sable le modèle (6),  - we sand the model (6),
- on sèche le modèle (6) sablé, - on trempe le modèle (6) sablé et séché dans une deuxième barbotine, de préférence dépourvue de zircone, - We dry the model (6) sandblasted, the sanded and dried model (6) is quenched in a second slip, preferably devoid of zirconia,
- on enduit le modèle (6) trempé dans la deuxième barbotine d'un matériau de renfort,  - The model (6) dipped in the second slip is coated with a reinforcing material,
- on sèche le modèle (6) enduit du matériau de renfort, et  the model (6) coated with the reinforcing material is dried, and
- on réalise un traitement thermique sur le modèle (6) enduit du matériau de renfort et séché.  - Heat treatment is carried out on the model (6) coated with the reinforcing material and dried.
10. Procédé selon la revendication précédente, dans lequel les étapes de trempage dans la deuxième barbotine, d'enduction dans le matériau de renfort et de séchage du modèle (6) enduit du matériau de renfort et séché sont réitérées.  10. Method according to the preceding claim, wherein the steps of dipping in the second slip, coating in the reinforcing material and drying of the model (6) coated with the reinforcing material and dried are repeated.
1 1 . Procédé selon l'une quelconque des revendications précédentes, lequel, préalablement au trempage du modèle (6) dans la barbotine de contact, comprend une phase de réalisation de la barbotine de contact comprenant les étapes où :  1 1. Process according to any one of the preceding claims, which, prior to dipping of the model (6) in the contact slip, comprises a step of producing the contact slip comprising the steps:
- on introduit le liant colloïdal minéral dans un récipient, en l'espèce un mélangeur,  the inorganic colloidal binder is introduced into a container, in this case a mixer,
- on ajoute la poudre composite mullite-zircone dans le mélangeur,  the mullite-zirconia composite powder is added to the mixer,
- on laisse le mélange de liant colloïdal minéral et de poudre se stabiliser.  the mixture of inorganic colloidal binder and powder is allowed to stabilize.
12. Procédé selon la revendication précédente lorsqu'elle dépend de la revendication 7, dans lequel la phase de réalisation de la barbotine de contact comprend également une étape d'ajout de l'anti- moussant et/ou de l'agent mouillant.  12. Method according to the preceding claim when it depends on claim 7, wherein the phase of producing the contact slip also comprises a step of adding the anti-foaming agent and / or the wetting agent.
13. Utilisation d'un moule (1 ) obtenu selon le procédé de l'une quelconque des revendications précédentes pour la fabrication d'une pièce de turbomachine coulée et solidifiée.  13. Use of a mold (1) obtained by the method of any one of the preceding claims for the manufacture of a cast and solidified turbine engine part.
EP17754752.8A 2016-07-22 2017-07-21 Process for manufacturing a shell mold Active EP3487649B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1657022A FR3054149B1 (en) 2016-07-22 2016-07-22 PROCESS FOR PRODUCING CARAPACE MOLD
PCT/FR2017/052030 WO2018015701A1 (en) 2016-07-22 2017-07-21 Process for manufacturing a shell mold

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EP3487649A1 true EP3487649A1 (en) 2019-05-29
EP3487649B1 EP3487649B1 (en) 2021-09-22

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US (1) US10987723B2 (en)
EP (1) EP3487649B1 (en)
CN (1) CN109475928B (en)
BR (1) BR112019001244B1 (en)
CA (1) CA3031321A1 (en)
FR (1) FR3054149B1 (en)
RU (1) RU2753188C2 (en)
WO (1) WO2018015701A1 (en)

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US4196769A (en) * 1978-03-20 1980-04-08 Remet Corporation Ceramic shell mold
FR2667523B1 (en) * 1990-10-03 1993-07-09 Snecma SOLUBLE SHELL MOLD FOR FOUNDRY AND DISPOSAL PROCESS.
JP2718460B2 (en) * 1991-01-16 1998-02-25 工業技術院長 Easily collapsible mold and method for producing the same
US5927379A (en) * 1996-09-26 1999-07-27 Pcc Structurals, Inc. Infiltration method for producing shells useful for investment casting
US6814131B2 (en) * 2000-11-10 2004-11-09 Buntrock Industries, Inc. Investment casting mold and method of manufacture
DE60311824T2 (en) * 2002-08-20 2007-10-31 Ex One Corp. casting process
US6951239B1 (en) * 2004-04-15 2005-10-04 United Technologies Corporation Methods for manufacturing investment casting shells
DE102007012660B4 (en) * 2007-03-16 2009-09-24 Chemex Gmbh Core-shell particles for use as filler for feeder masses
CN101301677A (en) * 2008-06-03 2008-11-12 西安交通大学 Method for quickly and precisely casting complex parts
US8033320B2 (en) * 2008-07-25 2011-10-11 General Electric Company High emittance shell molds for directional casting
CN102527937A (en) * 2012-03-15 2012-07-04 哈尔滨工业大学 Method for preparing fiber-reinforced thin-wall shell for casting titanium alloy smelting mold
CN104550736A (en) * 2013-10-22 2015-04-29 青岛五洋铸机有限公司 Preparation method of boron nitride ceramic shell used for precision casting of titanium and titanium alloy
CN105039751B (en) * 2015-07-30 2017-09-26 何明亮 The preparation method of zircaloy contact material, the filter medium using the material and running channel

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RU2019103466A3 (en) 2020-12-07
RU2019103466A (en) 2020-08-24
CN109475928A (en) 2019-03-15
US10987723B2 (en) 2021-04-27
BR112019001244B1 (en) 2022-08-09
CN109475928B (en) 2022-01-07
US20190329317A1 (en) 2019-10-31
FR3054149A1 (en) 2018-01-26
EP3487649B1 (en) 2021-09-22
RU2753188C2 (en) 2021-08-12
WO2018015701A1 (en) 2018-01-25
BR112019001244A2 (en) 2019-04-30
FR3054149B1 (en) 2019-04-05
CA3031321A1 (en) 2018-01-25

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