Holding tool for preform sintering

Abstract

The invention relates to a device for sintering preforms, comprising a sintering furnace provided with a load, characterized in that the load comprises a rotating preform (10) arranged around at least one holding tool (100), the holding tool (100) comprising a disc (110) and a crown (120) present on the periphery of the disc (110), the crown (120) is made of a compressible material that can be eliminated by thermal oxidation, a portion of the preform (10) being in contact with the crown (120) prior to sintering.

Description

Technical Field

[0001] The present invention relates to the production of rotating parts made of composite materials, in particular oxide / oxide type composite materials, and more particularly to the maintenance of fiber preforms used to form such parts during high temperature treatments, in particular carried out during debinding or sintering steps. In particular, the present invention relates to the production of parts used to constitute all or part of the rear body parts of civil aviation engines, such as the exhaust cone. Background Art

[0002] In order to manufacture composite parts, especially parts of oxide / oxide type composite materials, it is known that a fiber preform is produced to be impregnated with one or more matrix precursors and then subjected to a sintering operation to densify the fiber preform. Impregnation of the fiber preform can be performed in a well-known manner by placing the fiber preform in a mold and injecting a slurry containing a liquid phase loaded with matrix precursor particles into the preform. The filter disposed in the mold allows the liquid phase of the slurry to be discharged while retaining the matrix precursor particles in the preform. This method is particularly described in documents US2017334791A1 and US2021046671A1. Then, the matrix precursor particles present in the fiber preform are sintered to form a matrix in the pores of the preform.

[0003] An organic binder (eg PVA) may be added to the liquid phase of the slurry to ensure that the impregnated preform is retained after drying and prior to sintering.

[0004] However, it is worth noting that the preform thus impregnated may deform during the high temperature treatments required for the debinding or sintering operations. In fact, since the matrix precursor particles are not bound inside the preform and have not yet formed a matrix, the strength of the impregnated preform is greatly reduced and it may in particular become oval. The risk of deformation is even more pronounced for parts of very thin thickness and / or elongated shapes.

[0005] In order to overcome these unwanted deformations, one considers integrating stiffeners into the component, or thickening the parts of the component most susceptible to the risk of deformation. However, these methods have many disadvantages and in particular lead to an undesirable increase in the mass of the component. Summary of the invention

[0006] In order to overcome the above-mentioned disadvantages, the present invention proposes a device for sintering a rotating preform, which includes a sintering furnace provided with a load. The device is characterized in that the load includes a rotating preform arranged around at least one holding tool, the holding tool includes a disk and a crown present at the periphery of the disk, the crown is made of a compressible material that can be eliminated by thermal oxidation, and a part of the preform is in contact with the crown before sintering.

[0007] This device ensures that the shape of the fiber preform is maintained during the sintering and possible debonding steps, without increasing the mass of the final part obtained. The presence of a layer of compressible material between the disk and the preform allows compensation of radial thermal expansions between the disk and the preform, ensuring that the contact between the tool and the preform is maintained when the preform is not self-supporting or when its strength decreases, in particular before the start of sintering.

[0008] "Material capable of being eliminated by thermal oxidation" means here: a material that, when exposed to high temperatures, decomposes a large part of its volume by oxidation. Thus, a crown made of such a material is able to hold the fiber preform during possible debonding operations and preferably until the start of sintering, and can then decompose sufficiently by oxidation to allow a gap to be created between the part obtained by sintering and the holding tool whose edges are oxidized. Thus, after the sintering step, the part obtained can be easily separated from the holding tool. Moreover, when the part cools after the sintering operation and therefore sees a reduction in its diameter due to thermal contraction, a large part of the crown disappears by oxidation, which allows avoiding contacts between the cooled part and the oxidized holding tool, which also limits the risks of damaging the part.

[0009] According to one embodiment of the invention, the compressible material is expanded graphite.

[0010] Expanded graphite is a particularly compressible material and is able to absorb significant differences in thermal expansion. In addition, expanded graphite has oxidizing properties that are particularly suitable for the atmosphere of the sintering furnace. In fact, in the non-inert and oxidizing atmosphere of the sintering furnace, expanded graphite does not significantly oxidize in a temperature range that is too low to sinter, but oxidizes rapidly in a temperature range that is high enough to allow sintering.

[0011] According to another embodiment of the invention, the disk is made of a single piece of ceramic.

[0012] The disc is therefore easy to manufacture while having a coefficient of thermal expansion close to that of the preform. In fact, the manufacturing cost and time of a monolithic ceramic disc is lower than that of a disc made of a ceramic matrix composite material.

[0013] According to another embodiment of the invention, at least one holding tool is arranged at an end of the preform along its axis of rotation.

[0014] According to another embodiment of the present invention, the rotated preform contains matrix precursor particles in its pores.

[0015] The invention also relates to a method for manufacturing a composite material rotating component, the method comprising the following steps:

[0016] - impregnating the spun fiber preform with at least the matrix precursor particles,

[0017] - placing a rotating fiber preform containing matrix precursor particles around at least one holding tool comprising a crown made of compressible material and a concentric disk, the crown comprising a first face in contact with the periphery of the disk and a second face opposite to the first face in contact with the inner face of the preform,

[0018] - sintering the fiber preform containing the matrix precursor particles so as to form a matrix in the pores of said fiber preform, thereby obtaining a composite part, the majority of the compressible material of the crown being decomposed by oxidation at the end of the sintering step,

[0019] - Removing the holding tool from the composite part obtained.

[0020] According to one embodiment of the invention, the compressible material is expanded graphite.

[0021] According to another embodiment of the invention, the step of impregnating the fiber preform further comprises: impregnating said preform with a binder, the method further comprising: a step of debinding the rotated fiber preform arranged around the holding tool before the sintering step.

[0022] According to another embodiment of the invention, a positioning and centering device is used during the step of placing the fiber preform around the holding tool, the positioning device comprising at least one rod and a support on which rests the end of the fiber preform that is furthest from the portion of the fiber preform that is in contact with the holding tool along its axis of rotation, the support being fixed to the rod during the placing step and the holding tool being fixed to the rod by their center.

[0023] The use of such a positioning device makes it easier to mount the holding tool in the fiber preform and ensures satisfactory centering, while limiting the risk of damaging said preform during this mounting operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic perspective view of a rotated fiber preform.

[0025] Figure 2 Is set with Figure 1Schematic cross-sectional view of an impregnation tool for a preform.

[0026] Figure 3 Is installed in Figure 1 and Figure 2 Schematic exploded perspective view of a holding tool for an impregnated fiber preform.

[0027] Figure 4 is used to Figure 3 Schematic cross-sectional view of a device for positioning a holding tool in a fiber preform.

[0028] Figure 5 is a schematic cross-sectional view of a sintering device according to the present invention, the sintering device comprising Figure 3 A holding tool holds the impregnated fiber preform.

[0029] Figure 6 yes Figure 5 Schematic cross-sectional view of an apparatus comprising a composite component obtained by sintering an impregnated fiber preform. DETAILED DESCRIPTION

[0030] According to the invention, the method for producing a component made of a thermostructural composite material, preferably of the oxide / oxide type, begins with the production of a fiber preform for forming the fiber reinforcement of the component.

[0031] Figure 1 An example of a fiber preform 10 is shown in FIG. The preform 10 has a shape of revolution with an axis of revolution X. Thus, the preform 10 comprises an outer face 10a and an inner face 10b. In particular, the fiber preform 10 may have a cylindrical, truncated cone, spherical shape or a combination of these shapes. The fiber preform 10 may have a maximum cross section with a diameter greater than 700 mm.

[0032] Therefore, the fiber preform 10 can be produced at least in part by stacking layers or pleats obtained by two-dimensional (2D) weaving. The fiber preform 10 can also be produced at least in part by stacking layers or pleats obtained by three-dimensional (3D) weaving. Here, "two-dimensional weaving" refers to a traditional weaving method in which each weft thread passes from one side of a single layer of warp yarn to the other side, and vice versa. Here, "three-dimensional weaving" refers to weaving in which the warp threads pass through several layers of weft threads or the weft threads pass through several layers of warp threads. The preform 10 can also be produced at least in part by a sheet of unidirectional (UD) fibers.

[0033] The fiber preform 10 can be obtained by laying down a tape or by automated fiber placement (AFP), by draping or by filament winding.

[0034] Finally, the preform 10 may be obtained at least partially by weaving or knitting.

[0035] The fiber preform 10 may be formed of fibers made of one of the following materials: alumina, mullite, silica, aluminosilicate, borosilicate, silicon carbide, carbon, or a mixture of several of these materials.

[0036] When producing the fiber preform 10, it is impregnated with one or more matrix precursors. Preferably, the fiber preform 10 is impregnated with a slurry. The fiber preform 10 can be impregnated with the slurry by placing the preform 10 in a mold closed by a rigid counter-mold, the mold and the counter-mold defining an internal volume having the shape of the part to be manufactured. Figure 2 As shown in , the impregnation of the fiber preform 10 can also be carried out under a flexible membrane. In a well-known manner, impregnation of the fiber preform 10 under a flexible membrane is particularly suitable for: manufacturing parts of slender shape and low thickness, in particular by allowing better control of the dimensions of the parts.

[0037] exist Figure 2 In the example shown in , the fiber preform 10 is arranged in an impregnation tool 500. The impregnation tool 500 comprises a mold which comprises, on the one hand, an impregnation chamber 501 in which the fiber preform 10 is arranged and, on the other hand, a compacting chamber 502.

[0038] The slurry 5 comprises a liquid phase in which particles 51 of the matrix precursor are dispersed. More specifically, the slurry may correspond to a suspension containing the liquid phase and a powder of the matrix precursor particles. In particular, the liquid phase may consist of water, ethanol or any other liquid in which the desired powder may be suspended. The pH of the liquid phase of the slurry may be adjusted according to the properties of the particles (e.g., water having an acidic pH in the case of aluminum oxide powder).

[0039] An organic binder (e.g., water-soluble PVP or PVA) may also be added. This binder ensures the consistency of the raw materials, possibly after drying and before debinding and sintering.

[0040] For example, the slurry may correspond to an aqueous suspension consisting of aluminum oxide powder having an average particle size (D50) between 0.1 μm and 1 μm and a volume fraction between 5% and 50%, acidified with nitric acid (pH between 1.5 and 4). In addition to aluminum oxide, the refractory oxide particles may also be made of a material chosen from mullite, silicon dioxide, aluminum silicate, aluminum phosphate, zirconium oxide, carbides, borides, nitrides and carbon. According to their basic composition, the refractory oxide particles may also be mixed with particles of aluminum oxide, zirconium oxide, aluminum silicate, rare earth oxides, rare earth disilicates (for example, for environmental barriers or thermal barriers) or any other filler (carbon black, graphite, silicon carbide, etc.) that allows the addition of specific functions in the final material.

[0041] The slurry 5 is used to be injected into the impregnation chamber 501, and the compressed fluid 6 is used to be injected into the compaction chamber 502. Therefore, the impregnation chamber 501 includes: one or more inlet holes 511, which allow the slurry 5 to be introduced into the impregnation chamber 501. The inlet hole 511 of the impregnation chamber 501 can be equipped with a valve. The impregnation chamber 501 can also include: one or more outlet holes 512, which allow the liquid phase of the slurry 5 to be discharged. Similarly, the compaction chamber 502 includes: one or more inlet holes 521 that allow the compressed fluid 6 to be introduced into the compaction chamber 502, and one or more outlet holes 521 that allow the compressed fluid 6 present in the compaction chamber 502 to be sucked in and discharged. The inlet hole and the outlet hole 521 of the compaction chamber 502 can be the same or at least partially the same as the example shown in Figure 2. The inlet hole 521 of the compaction chamber 502 can be equipped with a valve.

[0042] The compressed fluid 6 may be water or oil, for example.

[0043] The impregnation chamber 501 may include a filter layer 540 interposed between the fiber preform 10 and the outlet hole 512 of the impregnation chamber 501. The filter layer 540 allows the matrix precursor particles 51 of the slurry 5 to be retained in the preform 10 while allowing the liquid phase of the slurry 5 to pass through, and the liquid phase of the slurry 5 is discharged through the outlet hole 512 of the impregnation chamber 501.

[0044] The filter layer 540 comprises a first face 540a and a second face 540b opposite to the first face 540a. Preferably, the inner face 10b of the preform 10 rests on the second face 540b of the filter layer 540. Therefore, the shape of the second face 540b of the filter layer 540 is adapted to the shape of the inner face 10b of the preform 10b. Preferably, the filter layer 540 is therefore a rotation volume having an axis of rotation X.

[0045] The filter layer 540 can be made of microporous polytetrafluoroethylene (PTFE), for example, but can also be made of gypsum or paper. To produce the filter layer 540, for example, a material with a pore size between 1 μm and 5 μm can be used. The filter layer 540 can have a pore size between 10 -14 m 2 and 10 -15 m 2 The final penetration rate between .

[0046] A rigid perforated element (not shown) may be inserted between the filter layer 540 and the outlet hole 512 of the impregnation chamber 501. Such a rigid perforated element is particularly described in document US20190134848 A1. The function of the rigid perforated element is to facilitate the discharge of the liquid phase that has passed through the filter layer 540 via the outlet hole 512, regardless of its outlet point at the first face 540a of the filter layer 540. In order to also facilitate the discharge of the liquid phase of the slurry 5, the rigid perforated element may include a cutout or cavity between its openings.

[0047] If applicable, a distribution element (not shown) may optionally be arranged between the filter layer 540 and the rigid perforated element, said distribution element having a permeability greater than that of the filter layer 540. Such a distribution element allows obtaining a more uniform liquid phase flow rate inside the filter layer 540.

[0048] The impregnation chamber 501 and the compaction chamber 502 of the mold are separated by a flexible film 530. The flexible film 530 is placed facing the outer surface 10a of the preform 10. The film 530 includes a first surface 530a and a second surface 530b opposite to the first surface 530a. The first surface 530a of the film 530 is placed facing the preform 10. The first surface 530a of the film 530 exists on one side of the impregnation chamber 501, and the second surface 530b of the film 530 exists on one side of the compaction chamber 502.

[0049] The membrane 530 may allow pressure to be applied to the slurry 5 present in the impregnation chamber 501 so that the slurry 5 penetrates into the fiber preform 10. The membrane 530 may also allow compaction pressure to be applied to the fiber preform 10 disposed in the impregnation chamber 501. The pressure applied by the membrane 530 is generated by the compressed fluid 6, which deforms the membrane 530 relative to the fiber preform 10 by applying pressure to the membrane 530. If the pressure in the impregnation chamber 501 increases, the pressure applied by the compressed fluid 6 to the membrane 530 may also allow the membrane 530 to be kept in place relative to the fiber preform 10. Therefore, when the compaction chamber 502 is filled with the compressed fluid 6, the first surface 530a of the membrane 530 may be used to contact the fiber preform 10.

[0050] The membrane 530 is made of silicone, for example, or of a rubber-type material. The membrane 530 may be reinforced with glass fiber or polyester fiber. The membrane 530 must be made of a material that withstands the temperature that the membrane 530 may be subjected to during the entire process and the fluid that the membrane 530 will contact. The compressibility of the membrane 530 must be consistent with the dimensional tolerances required by the components.

[0051] The impregnation of the fiber preform 10 can be performed by first injecting the slurry 5 into the impregnation chamber 501 and then injecting the compressed fluid 6 into the compaction chamber 502. The compressed fluid 6 applies pressure to the slurry 5 through the membrane 530. The compressed fluid 6 applies pressure to the entire membrane 530, thereby applying pressure to the entire slurry 5 above the preform 10.

[0052] Preferably, the pressure applied by the membrane 530 to the slurry 5 and the fiber preform 10 is reduced so as to allow the slurry 5 to penetrate into the preform 10 and to compact the preform 10 sufficiently to allow the liquid phase of the slurry 5 to be discharged through the filter layer 540 without deteriorating the fiber preform 10. In conjunction with the pressure applied to the slurry by the compressed fluid 6, pumping may be performed at the outlet opening 512 of the impregnation chamber 501, for example by a main vacuum pump ( Figure 2 The impregnation tool 500 may also be equipped with a heating device, such as a resistance element integrated into the wall, in order to increase the temperature in the compacting chamber 502 and facilitate the discharge of the liquid phase of the slurry by evaporation. The filter layer 540 allows the matrix precursor particles 51 present in the slurry 5 to be retained in the pores of the preform 10, thereby gradually depositing the particles 51 in the fiber preform 10. These particles 51 allow the formation of a matrix after sintering.

[0053] According to a variant, the impregnation of the fibrous structure 10 can be performed by first injecting the compressed fluid 6 and then injecting the slurry 5, for example according to the method described in document US2021046671 A1. The injection of the compressed fluid 6 and the slurry 5 can also be performed simultaneously or at least partially simultaneously. In addition, the injection of the slurry can be completed before the injection of the compressed fluid is completed, or the injection of the compressed fluid can be completed before the injection of the slurry is completed.

[0054] The impregnation of the fiber preform 10 can also be carried out with several slurries.The impregnation of the fiber preform 10 can also be carried out using an infusion type technique (injection molding technique known as "RTM" or submicron powder suction technique known as "APS").

[0055] When the fiber preform 10 is properly impregnated, it can be removed from the impregnation tool 500. The impregnated fiber preform 10 can be removed from the impregnation tool 500 after a drying phase (preferably at a temperature greater than 60° C. and less than 90° C.), which allows draining off the remainder of the liquid phase still present. Figure 3 As shown in FIG. 1 , the pores of the fiber preform 10 are partially filled with matrix precursor particles 51 .

[0056] The fiber preform can also be made from preimpregnated layers or stacks as described above. Thus, the fiber preform can be made, for example, in a well-known manner by draping layers or stacks obtained by preimpregnation with a slurry as described above, by two-dimensional weaving or three-dimensional weaving, or by automatically placing preimpregnated fibers or fiber textures. This fiber preform is then placed in an autoclave and demoulded in preparation for sintering.

[0057] like Figure 3 As shown in FIG. 1 , before sintering the fiber preform 10 comprising the matrix precursor particles 51 and, if necessary, debonding, the fiber preform 10 is arranged around at least one holding tool 100 .

[0058] Each holding tool 100 comprises at least one disk 110 and a crown 120. The disk 110 and the crown 120 are concentric. The disk 110 comprises two opposite circular faces 110a and 110b and a side face 110c connecting the upper circular face 110a to the lower circular face 110b. The geometry of the side face 110c of the disk 110 may be adapted to the portion of the inner face 10b in contact with the tool 100. Thus, the side face 110c of the disk 110 may be cylindrical or frustoconical.

[0059] When the holding tool 100 is arranged in the fiber preform 10, the rotation axis of the general shape of the disk 110 may coincide with the rotation axis X of the preform 10. More generally, when the holding tool 100 is arranged in the fiber preform 10, the rotation axis of the general shape of the holding tool 100 may coincide with the rotation axis X of the preform 10. Therefore, preferably, when the holding tool 100 is deposited inside the preform 10, it extends perpendicularly to the rotation axis X of the preform 10.

[0060] Preferably, the holding tool 100 is arranged at one end of the fiber preform 10 along the axis of rotation X. In particular, the holding tool 100 is preferably arranged at the end of the fiber preform 10 of the largest radius along the axis of rotation X. In fact, the ends of the preform 10 along its axis of rotation X are more fragile and more sensitive to deformations, especially when they have a large radius: it is therefore more sensible to place the holding tool at these sensitive parts of the preform 10.

[0061] The disk 110 may include one or more through holes 111 and 112. Thus, the through hole 112 opens on the one hand into the upper circular face 110a of the disk 110 and on the other hand into the lower circular face 110b of the disk 110. The through holes 111 and 112 may be used as gripping or attachment areas to facilitate the manipulation of the tool 100. The disk 110 may include a through hole 111, which is centered on the rotation axis of the disk 110, that is, on the rotation axis of the side 110c of the disk 110. Thus, the rotation axis of the through hole 111 coincides with the rotation axis of the disk 110, that is, with the rotation axis of the side 110c of the disk 110. The disk 110 may then have an annular shape. The through holes 111 and 112 also allow the weight of the disk 110 to be reduced. As Figure 3 As shown in , the through holes 112 of the disk 110 that do not include the rotation axis of the disk 110 are preferably arranged angularly around the axis of the disk 110 in a regular manner. The through holes 112 of the disk 110 that do not include the rotation axis of the disk 110 preferably have the same size, and their axes are located at the same distance from the axis of the disk 110. Such regularity of placement and size of the through holes of the disk 110 allows to maintain a regular thermal expansion of the disk 110 in the radial direction. The through holes 112 of the disk 110 that do not include the rotation axis of the disk 110 may have a diameter greater than 50 mm.

[0062] The crown 120 comprises a first face 120a arranged to be in contact with the side of the disk 110. Thus, the crown 120 comprises a first face 120a arranged to be in contact with the periphery of the disk 110. The crown 120 also comprises a second face 120b opposite to the first face 120a of the crown 120 and intended to be in contact with the fiber preform 10 containing the particles 51. More precisely, the second face 120b of the crown 120 is intended to be in contact with a reduced portion of the inner face 10b of the preform 10 containing the particles 51. When the holding tool is mounted in the fiber preform 10, the crown 120 comprises a first face 120a in contact with the periphery of the disk 110 and a second face 120b opposite to the first face 120a, the second face being in contact with a portion of the inner face 10b of the preform 10. Thus, the geometry of the second face 120b of the crown 120 is adapted to the portion of the inner face 10b in contact with the second face 120b. Therefore, the second face 120b of the crown 120 may be cylindrical or frustoconical, for example.

[0063] Preferably, the disk 110 is made of a monolithic ceramic. Monolithic ceramic is understood to mean a ceramic without fiber reinforcement, the porosity of which may be between 0% and 81%, and preferably between 10% and 40%. The higher the porosity of the monolithic ceramic, the easier it is to process the disk 110, the lighter it is, and the lower its cost.

[0064] The disk 110 may be made of mullite. If the disk 110 is made of mullite, it may contain 60% to 80% of alumina, and preferably 65% ​​to 70% of alumina. In fact, a disk 110 made of mullite with such a percentage of alumina allows to reduce the thermal expansion of said disk 110 and thus the compression of the crown 120, while ensuring that the contact between the tool 100 and the preform 110 is maintained until high temperatures are reached, and in particular temperatures above the sintering start temperature. Mullite also has the advantage of being inexpensive.

[0065] The disk 110 is preferably made of alumina. In fact, the thermal expansion coefficient of the disk 110 made of alumina is almost the same as that of the preform to be retained, which allows the thickness of the crown 120 to be limited.

[0066] The disk 110 may also be made of a ceramic matrix composite material of the CMC type (for example, of the C / SiC or SiC / SiC type). In particular, if the part to be manufactured is a part made of a composite material of the C / SiC type, a disk made of a composite material of the C / SiC type may be selected, and if the part to be manufactured is a part made of a composite material of the SiC / SiC type, a disk made of a composite material of the SiC / SiC type may be selected.

[0067] Preferably, the thermal expansion coefficient of the material of the disk 110 is close to the thermal expansion coefficient of the fiber preform 10. Therefore, preferably, the value of the linear thermal expansion coefficient of the material of the disk 110 in the radial direction is between 90% and 110% of the value of the thermal expansion coefficient of the material of the preform 10 in the radial direction. In particular, the linear thermal expansion coefficient of the material of the disk 110 may be between 5×10 -6 K -1 and 8×10 -6 K -1 between, and preferably between 6×10 -6 K -1 and 7.5×10 -6 K -1 In fact, these values ​​promote a reduction in the expansion of the material of the disk 110 so as to limit the compression of the crown 120 relative to the preform 10 while ensuring that the contact between the tool 100 and the preform 110 is maintained until high temperatures are reached, and in particular temperatures above the sintering start temperature.

[0068] The material of the crown 120 is a compressible material, that is to say a material capable of being compressed by at least 20% when the disk 110 expands and presses the compressible material against the inner face 10b of the fiber preform 10. Preferably, the compressible material of the crown 120 is capable of being compressed by at least 30% when the disk 110 expands and presses the compressible material against the inner face 10b of the fiber preform 10.

[0069] Therefore, the crown 120 is preferably made of expanded graphite, for example in the form of a flexible graphite sheet. Expanded graphite also has the advantage that it can be easily wrapped around the disc 110. The crown 120 may also be made of felt, such as carbon felt.

[0070] The crown 120 mounted as described above between the disk 110 and the inner face 10b of the preform 10 may have a thickness in the radial direction of between 2 mm and 15 mm, depending on the thermal expansion of the disk 110 and the preform 10. The thickness of the crown 120 is determined in a well-known manner by calculating the thermal expansion of the preform 10, the crown 120 and the disk 110, so as to ensure at least the contact between the crown 120 and the inner face 10b of the preform 10 until the sintering step begins. In particular, if the disk 110 is made of mullite, the crown 120 may have a thickness in the radial direction of between 5 mm and 15 mm, depending on the thermal expansion of the disk 110 and the preform 10. If the disk 110 is made of alumina, the crown 120 may have a thickness in the radial direction of between 2 mm and 12 mm, depending on the thermal expansion of the disk 110 and the preform 10.

[0071] Preferably, the compressible material of the crown 120 is capable of decomposing by oxidation in an oxidizing atmosphere and at high temperatures. In particular, the compressible material of the crown 120 can be configured to decompose mostly by oxidation during the sintering step in air. In particular, the compressible material of the crown 120 can be configured to decompose mostly by oxidation at temperature values ​​between 600° C. and 1200° C. In addition, the compressible material of the crown 120 can be configured to be mostly not changed by oxidation during the debonding step. In particular, the compressible material of the crown 120 can be configured to be mostly not changed by oxidation at up to 400° C. (and preferably up to 600° C.). A compressible material made of expanded graphite can meet these characteristics. Expanded graphite does not oxidize under an inert atmosphere, such as during a pyrolysis operation or during a chemical infiltration operation in the gas phase. Expanded graphite has very slow oxidation kinetics in an atmosphere with a very low oxygen content until the sintering temperature is reached.

[0072] Preferably, the materials of the disk 110 and the crown 120 are chosen so that: when the holding tool 100 is placed on the inner face 10b of the preform 10, the crown 120 is hardly compressed at room temperature and hardly compressed during a possible debonding of said preform 10. Thus, when said preform 10 has a weak strength and therefore an increased risk of deformation, the tool 100 exerts a very low pressure on the preform 10 when it is placed to limit the risk of damage to said preform 10, and exerts a very low pressure on the preform 10 during a possible debonding of said preform 10.

[0073] Several holding tools 100 as described above may be provided in the fiber preform 10 , provided that their placement in said preform 10 is possible, taking into account variations in the cross section of said preform.

[0074] In order to facilitate the positioning of the holding tool 100 inside the preform 10 and avoid damaging the preform, additional positioning means 200 may be used, such as Figure 4 In particular, this additional positioning device 200 allows ensuring a good alignment between the holding tool 100 and the fiber preform 10 .

[0075] exist Figure 4 In the example shown in , the additional positioning device 200 comprises a rod 220 and a foot 250, which is used to support the mass of the positioning device 200 when the positioning device 200 is installed together with the fiber preform 10 and the holding tool 100. The foot 250 comprises: a hole or inner hole 251, which allows the rod 220 to be fixed. The rod 220 is preferably threaded. If the rod 220 is threaded, the inner hole 251 of the foot 250 is preferably threaded.

[0076] The positioning device 200 may also include a support 240 including a central through hole or bore 241 which may or may not be threaded. Thus, the support 240 of the device 200 can be fixed to a rod 220 which passes through the support 240 via the central bore 241. Preferably, the support 240 is held at a non-zero distance from the foot 250, for example by means of a nut. The support 240 is intended to accommodate one end of the fiber preform 10 along its axis of rotation X and to be in contact with the end. Preferably, the support 240 is intended to accommodate the end of the fiber preform 10 which is farthest from the portion of the fiber preform 10 which accommodates the holding tool 100 along its axis of rotation X, so as to facilitate the assembly of the positioning device 200, the holding tool 100 and the preform 10. Preferably, the support 240 is intended to accommodate the end of the fiber preform 10 which has the smallest radius along its axis of rotation X. The support 240 may be in contact with the outer surface 10a of the fiber preform 10. The support 240 may be produced by additive manufacturing to obtain a shape of the support 240 that is as suitable as possible for the end of the preform 10 in contact with the support 240 when the preform 10 is mounted with the positioning device 200.

[0077] Preferably, one of the through holes 111 of the disk 110 allows the rod 220 of the positioning device 200 to pass through. The through hole 111 that allows the rod 220 to pass through may be threaded. Preferably, the axis of the through hole 111 coincides with the axis of the disk 110.

[0078] The positioning device 200 may also include at least one pressure plate 230, which includes a central through hole or inner hole 231, which may be threaded or not. Therefore, the pressure plate 230 of the device 200 can be fixed to the rod 220, and the rod 220 passes through the pressure plate 230 via the inner hole 231. The pressure plate 230 can be used to fix the holding tool 100 to the rod 220 of the positioning device 200, or to hold the holding tool 100 during the positioning process. To this end, the pressure plate 230 includes an assembly surface 232, which is used to contact the upper circular surface 110a of the disk 110 of the holding tool 100. Therefore, preferably, the positioning device 200 includes: a pressure plate 230 for each holding tool 100.

[0079] The through hole 112 of the disc 110, which is different from the hole 111 that allows the rod 220 to pass through, can facilitate assembly with the positioning device 200 by allowing access to the pressure plate 230 or the nut. Therefore, preferably, the through hole 112 of the disc 110, which is different from the hole 111, has a size sufficient to allow a hand or a suitable tightening tool to pass through.

[0080] The positioning device 200 may also include a plate 210 including a central hole or inner hole 211, which may or may not be threaded. The central hole 211 is configured to allow the rod 220 to pass through. Figure 4 , in particular, the plate 210 is fixed to the rod 220 by means of a nut. The plate 210 comprises an assembly face 213 for at least partially contacting the end of the fiber preform 10 opposite to the support 240. Preferably, the assembly face 213 of the plate 110 is also for contacting the lower circular face 110b of the disk 110 of the holding tool 100. Preferably, the plate 210 of the positioning device 200 comprises one or more through holes 212. The through holes 212 are arranged so that: when the fiber preform 10 is mounted together with the positioning device 200, the through holes 212 of the plate 210 are arranged in the extension of the through holes 112 of the holding tool 100.

[0081] like Figure 4 As shown in , when the preform 10 , the holding tool 100 and the positioning device 200 are mounted together, the platen 230 is present between the support 240 and the plate 210 , and each holding tool 100 is present between at least one platen 230 and the plate 210 .

[0082] When the holding tool 100 has been correctly installed in the fiber preform 10 by means of the positioning device 200, the assembly comprising the positioning device 200, the holding tool 100 and the fiber preform 10 can be turned over. The positioning device 200 allows the fiber preform 10 to be turned over without direct manipulation, which is advantageous because the fiber preform 10 has not yet been sintered and is therefore fragile and sensitive to deformation. Then, when the rotation is completed, the fiber preform 10 is preferably supported by the plate 210. When the rotation is completed, the positioning device 200 can be completely or partially removed. Preferably, when the rotation is completed, the plate 210 remains in contact with the preform 10, and the rest of the positioning device 200 is removed, and in particular the rod 220, the pressure plate 230, the support 240 and the foot 250 (if used) are removed.

[0083] Preferably, the plate 210 comprises: one or more through holes 212 different from the central through hole 211 allowing the rod 220 to pass. When the assembly face of the plate 210 is in contact with the holding tool 100, at least a portion of the through holes 212 of the plate 210 is located in the extension of at least a portion of the through holes 112 of the holding tool 100. In fact, the plate 210 can be held as a support for the preform 10 during the sintering process and, where appropriate, the debonding operation. Therefore, such through holes 212 on the plate 210 can allow the combustion gases to pass during the sintering process, or allow any defects that need to be discharged during the sintering or debonding process to pass. Then, the material of the plate 210 can have properties compatible with the sintering or debonding steps, for example by having chemical inertness and thermal expansion suitable for such a method. The plate 210 may have been previously treated to stabilize its material and avoid interfering with the sintering step.

[0084] Then, if Figure 5 As shown in the figure, the fiber preform 10 held by the holding tool 100 is arranged in the sintering furnace 300. As mentioned above, the fiber preform 10 is preferably placed on the plate 210 in the sintering furnace. The sintering furnace 300 includes: at least one chamber 310, in which the fiber preform 10 held by the holding tool 100 is arranged, whether or not it is placed on the plate 210 of the positioning device 200. The sintering furnace 300 includes a heating device 320. The sintering furnace 300 can be a gas furnace operating at atmospheric pressure, which is heated by one or more gas burners. The gas generated by the burner is extracted by an extractor after the furnace has been heated, so as to leave space for the gas continuously formed due to combustion.

[0085] like Figure 5 and Figure 6As shown in , the sintering furnace 300 may optionally include one or more gas inlet holes 311 opening into the chamber 310 and one or more gas outlet holes 312 from the chamber 310. The gas inlet holes and the gas outlet holes may at least partially coincide.

[0086] The atmosphere in the chamber 310 of the sintering furnace 300 generally includes oxygen which allows obtaining, by oxidation, the decomposition of the compressible material of the crown 120. However, it is preferred to limit the oxygen content in the atmosphere of the chamber 310 of the sintering furnace 300 so as to limit the oxidation kinetics of the compressible material of the crown 120 and not to oxidize said compressible material of the crown 120 prematurely, and in particular not to oxidize a large part of the compressible material of the crown 120 before the matrix precursor particles in the preform 10 begin to sinter.

[0087] The temperature in the sintering furnace 300 receiving the fiber preform 10 may be gradually increased.

[0088] If the fiber preform 10 comprises a binder, the increase in the temperature of the sintering furnace 300 allows debinding the preform before reaching a temperature allowing sintering of said preform 10. During debinding of the fiber preform 10, the temperature of the chamber 310 of the furnace 300 is, for example, between 200°C and 450°C.

[0089] The temperature of the chamber 310 of the furnace 300 is further increased until a temperature is reached that allows sintering of the preform 10. During the sintering of the fiber preform 10, in particular during the sintering of the matrix precursor particles present in the fiber preform 10, the temperature of the chamber 310 of the furnace 300 is, for example, between 1000° C. and 1200° C. Figure 6 As shown in , the sintering step allows the formation of a matrix in the pores of the preform 10, thereby obtaining a part 1 made of composite material. The part 1 made of composite material comprises an outer face 1a having a geometry substantially identical to that of the outer face 10a of the preform 10 and an inner face 1b having a geometry substantially identical to that of the inner face 10b of the preform 10.

[0090] After debonding, the debonded fiber preform 10 is particularly fragile and sensitive to deformation. Therefore, during the debonding of the preform 10, and preferably at least until the start of sintering of said preform 10, it is important to protect the compressible material of the crown 120. In fact, when sintering begins, the matrix precursor particles present in the pores of the preform are sintered and a matrix begins to form in said pores of the preform, thereby improving its strength and retention. Therefore, preferably, oxidation of the compressible material of the crown 120 must be very limited during debonding, relatively low until the start of the sintering operation, and become significant during the sintering operation. Preferably, as Figure 6As shown in , when the sintering operation is completed, most of the compressible material of the crown 120 has disappeared, so as to facilitate the removal of the holding tool 100 from the composite part 1 and avoid the risk of contact between the disk 110 and its inner face 1b during the cooling of the composite part 1. In particular, under the atmospheric conditions of the sintering furnace 300, the compressible material can decompose by oxidation with very slow kinetics from 400° C., then can decompose by oxidation with faster kinetics from a temperature between 600° C. and 700° C., and finally decompose with very fast kinetics from 900° C. As mentioned above, a compressible material with this property can be, for example, expanded graphite.

[0091] The contact between the holding tool 100 and the inner face 10 b of the preform 10 may also be maintained throughout the sintering step.

[0092] Preferably, the compressible material is selected so as not to alter the fiber preform 10 or the chamber 310 of the furnace 300 during its decomposition.

[0093] The debinding step can be carried out in an apparatus different from the sintering apparatus in which, according to the invention, the load comprising the fiber preform and the holding tool is transported at the end of the debinding step.

[0094] Thus, the sintering step allows the formation of a matrix in the pores of the fiber preform 10 to obtain the desired composite material component. The device and method of the present invention are particularly suitable for producing a component that is used to constitute all or part of the rear body component of an aircraft engine or all or part of the combustion chamber. In general, the maximum cross-sectional diameter of the composite rotating component can be greater than 700 mm.

[0095] The expression "between... and..." should be understood as including the upper limit and the lower limit.

Claims

1. A device for sintering a rotating preform, the device comprising a sintering furnace (300) provided with a load, the device being characterized in that the load comprises a rotating preform (10), the rotating preform being arranged around at least one holding tool (100), the holding tool (100) comprising a disk (110) and a crown (120) present on the periphery of the disk (110), the crown (120) being made of a compressible material that can be eliminated by thermal oxidation, a portion of the preform (10) being in contact with the crown (120) before sintering.

2. The device according to claim 1, wherein: The compressible material is expanded graphite.

3. The device according to claim 1 or 2, wherein: The disk (110) is made of a single piece of ceramic.

4. The device according to any one of claims 1 to 3, wherein: At least one holding tool (100) is arranged at one end of the preform (10) along its axis of rotation (X).

5. The device according to any one of claims 1 to 4, wherein: The rotated preform (10) contains matrix precursor particles (51) in its pores.

6. A method for manufacturing a composite rotating component, the method comprising the steps of: impregnating a spun fiber preform (10) with at least one or more matrix precursor particles (51), placing the rotated fiber preform (10) containing the matrix precursor particles (51) around at least one holding tool (100), the holding tool (100) comprising a disk (110) and a crown (120) present on the periphery of the disk (110), the crown (120) being made of a compressible material capable of being eliminated by thermal oxidation, a portion of the preform (10) being in contact with the crown (120), sintering the fiber preform (10) containing the matrix precursor particles (51) so as to form a matrix in the pores of the fiber preform (10) to obtain a composite material part (1), the majority of the compressible material of the crown (120) being decomposed by oxidation at the end of the sintering step, The holding tool (100) is removed from the composite component (1) obtained.

7. The method according to claim 6, wherein: The compressible material is expanded graphite.

8. The method according to claim 6 or 7, wherein: The step of impregnating the fiber preform (10) further comprises: impregnating the preform (10) with a binder, and the method further comprises: a step of debinding the rotated fiber preform (10) arranged around the holding tool (100) before the sintering step.

9. The method according to any one of claims 6 to 8, wherein: In the step of placing the fiber preform (10) around the holding tool (100), a positioning and centering device (200) is used, the positioning device (200) comprising at least one rod (220) and a support (240), the end of the fiber preform (10) farthest from the part of the fiber preform (10) in contact with the holding tool (100) along its rotation axis (X) resting on the support (240), in the placing step, the support (240) is fixed to the rod (220), and the holding tool (100) is fixed to the rod (220) by their center.

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