Holding tool for sintering of preforms

Abstract

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

Description

Technical Field

[0001] This invention relates to the production of rotating components made of composite materials, particularly oxide / oxide-type composite materials, and more specifically, to the maintenance of fiber preforms used to form such components during high-temperature treatment (particularly during debonding or sintering steps). In particular, this invention relates to the production of components constituting all or part of the rear main body components of civil aircraft engines, such as exhaust cones. Background Technology

[0002] To manufacture composite material parts, particularly oxide / oxide-based composite materials, it is known to produce fiber preforms by impregnating them with one or more matrix precursors, followed by a sintering operation to densify the fiber preforms. Impregnation of the fiber preforms can be performed in a well-known manner, wherein the fiber preform is placed in a mold and a slurry comprising a liquid phase loaded with matrix precursor particles is injected into the preform. A filter disposed in the mold allows the liquid phase of the slurry to be drained while retaining the matrix precursor particles in the preform. This method is specifically described in US2017334791A1 and US2021046671A1. The matrix precursor particles present in the fiber preform are then sintered, thereby forming a matrix within the pores of the preform.

[0003] Organic binders (such as PVA) can be added to the liquid phase of the slurry to ensure that the impregnated preforms remain intact after drying and before sintering.

[0004] However, it is worth noting that such impregnated preforms may deform during the high-temperature processing required for debonding or sintering. In fact, because the matrix precursor particles are not bonded within the preform and have not yet formed a matrix, the strength of the impregnated preform is significantly reduced, and it is particularly likely to become elliptical. The risk of deformation is even more pronounced for parts that are very thin and / or elongated in shape.

[0005] To overcome these unwanted deformations, people have considered integrating stiffeners into the component or thickening the parts of the component most susceptible to deformation. However, these methods have many drawbacks, and in particular, lead to an undesirable increase in component mass. Summary of the Invention

[0006] To overcome the above-mentioned drawbacks, the present invention proposes an apparatus for sintering rotary preforms, the apparatus comprising a sintering furnace provided with a load, characterized in that the load comprises a rotary preform disposed around at least one holding tool, the holding tool comprising a disc and a crown present around the disc, the crown being made of a compressible material that can be eliminated by thermal oxidation, a portion of the preform contacting the crown prior to sintering.

[0007] This device ensures that the shape of the fiber preform is maintained during sintering and possible debonding steps without increasing the mass of the final part obtained. A compressible material layer exists between the disc and the preform, which allows for compensation of radial thermal expansion between the disc and the preform to ensure contact between the tool and the preform is maintained even when the preform cannot self-support or when its strength decreases (especially before sintering begins).

[0008] "Materials that can be eliminated by thermal oxidation" refers here to materials whose majority of volume decomposes through oxidation when exposed to high temperatures. Therefore, crowns made of such materials can hold the fibrous preform during potentially debonding operations and preferably until the start of sintering, and can then be sufficiently decomposed by oxidation to allow a gap to be created between the part obtained by sintering and its oxidized retaining tool. Thus, the resulting part can be easily separated from the retaining tool after the sintering step. Furthermore, as the part cools after the sintering operation and thus its diameter decreases due to thermal shrinkage, most of the crown disappears due to oxidation, allowing contact between the cooled part and the oxidized retaining tool to be avoided, which also limits the risk of damage to the part.

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

[0010] Expanded graphite is a particularly compressible material and can absorb significant differences in thermal expansion. Furthermore, expanded graphite possesses oxidation properties particularly well-suited to sintering furnace atmospheres. In fact, in the non-inert and oxidizing atmosphere of a sintering furnace, expanded graphite does not oxidize significantly at temperatures too low for sintering, but oxidizes rapidly at temperatures high enough to allow sintering.

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

[0012] Therefore, the disc is easy to manufacture and has a coefficient of thermal expansion close to that of a preform. In fact, the manufacturing cost and time required for a single ceramic disc are lower than those for discs made from ceramic matrix composites.

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

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

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

[0016] - The rotating fiber preform is impregnated with at least matrix precursor particles.

[0017] - A rotating fiber preform containing matrix precursor particles is placed around at least one retaining tool, the retaining tool comprising a crown made of a compressible material and a concentric disk, the crown comprising a first surface contacting the periphery of the disk and a second surface opposite the first surface and contacting the inner surface of the preform.

[0018] - Sintering a fiber preform containing matrix precursor particles to form a matrix within the pores of the fiber preform yields a composite component. Most of the compressible material in the crown decomposes through oxidation at the end of the sintering step.

[0019] - Remove the retaining tool from the obtained composite part.

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

[0021] According to another embodiment of the invention, the step of impregnating the fiber preform further includes: impregnating the preform with an adhesive, and the method further includes: a step of debonding the rotating fiber preform disposed around the holding tool prior to 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 includes at least one rod and a support member, with the end of the fiber preform furthest from the portion of the fiber preform in contact with the holding tool along its axis of rotation resting on the support member. During the placement step, the support member is fixed to the rod, and the holding tool is fixed to the rod through their center.

[0023] The use of this positioning device makes it easier to install the retaining tool in the fiber preform and ensures satisfactory alignment, while limiting the risk of damaging the preform during the installation operation. Attached Figure Description

[0024] Figure 1 This is a schematic three-dimensional view of a rotating fiber preform.

[0025] Figure 2 Is it set? Figure 1A schematic cross-sectional view of the impregnation tool for the preform.

[0026] Figure 3 It is installed in Figure 1 and Figure 2 A schematic exploded perspective view of the retaining tool in the impregnated fiber preform.

[0027] Figure 4 It is used to Figure 3 A schematic cross-sectional view of a device for positioning a retaining tool in a fiber preform.

[0028] Figure 5 This is a schematic cross-sectional view of a sintering apparatus according to the present invention, the sintering apparatus comprising: Figure 3 The retaining tool holds the impregnated fiber preform.

[0029] Figure 6 yes Figure 5 A schematic cross-sectional view of the device, which includes composite material components obtained by sintering impregnated fiber preforms. Detailed Implementation

[0030] According to the present invention, a method for manufacturing a component made of a thermal structural composite material, preferably an oxide / oxide-type thermal structural composite material, 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. The preform 10 has a rotational shape with a rotation axis X. Therefore, the preform 10 includes an outer surface 10a and an inner surface 10b. In particular, the fiber preform 10 can have a cylindrical, truncated conical, spherical, or combination of these shapes. The fiber preform 10 can have a maximum cross-section with a diameter greater than 700 mm.

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

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

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

[0035] The fiber preform 10 can be formed from fibers made of one of the following materials: alumina, mullite, silicon dioxide, 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 a slurry by placing it in a mold closed by a rigid die, the mold and the die defining an internal volume having the shape of the part to be manufactured. Figure 2 As shown, the impregnation of the fiber preform 10 can also be performed under a flexible membrane. Impregnating the fiber preform 10 under a flexible membrane in a well-known manner is particularly suitable for manufacturing elongated shapes and low-thickness parts, especially by allowing for better control over the dimensions of the parts.

[0037] exist Figure 2 In the example shown, the fiber preform 10 is disposed in an impregnation tool 500. The impregnation tool 500 includes a mold that includes an impregnation chamber 501 on one side, in which the fiber preform 10 is disposed, and a compaction chamber 502 on the other side.

[0038] The slurry 5 comprises a liquid phase in which matrix precursor particles 51 are dispersed. More specifically, the slurry may correspond to a suspension containing the liquid phase and matrix precursor particle powder. 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 can be adjusted according to the properties of the particles (e.g., in the case of alumina powder, the pH is acidic water).

[0039] Organic binders (e.g., water-soluble PVP or PVA) can also be added. This binder ensures the consistency of the raw materials, potentially both after drying and before debonding and sintering.

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

[0041] Slurry 5 is injected into impregnation chamber 501, and compressed fluid 6 is injected into compaction chamber 502. Therefore, impregnation chamber 501 includes one or more inlet ports 511 that allow slurry 5 to be introduced into it. The inlet ports 511 of impregnation chamber 501 may be equipped with valves. Impregnation chamber 501 may also include one or more outlet ports 512 that allow the liquid phase of slurry 5 to be discharged. Similarly, compaction chamber 502 includes one or more inlet ports 521 that allow compressed fluid 6 to be introduced into it, and one or more outlet ports 521 that allow the compressed fluid 6 present in compaction chamber 502 to be drawn in and discharged. The inlet ports and outlet ports 521 of compaction chamber 502 may be the same as or at least partially the same as the example shown in Figure 2. The inlet ports 521 of compaction chamber 502 may be equipped with valves.

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

[0043] The impregnation chamber 501 may include a filter layer 540 inserted between the fiber preform 10 and the outlet orifice 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 be discharged via the outlet orifice 512 of the impregnation chamber 501.

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

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

[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 specifically described in document US20190134848 A1. The function of this rigid perforated element is to facilitate the discharge of liquid phase that has passed through the filter layer 540 via the outlet hole 512, regardless of its outlet point at the first surface 540a of the filter layer 540. To further facilitate the discharge of liquid phase from the slurry 5, the rigid perforated element may include cuts or cavities between its openings.

[0047] If applicable, a dispensing element (not shown) may optionally be disposed between the filter layer 540 and the rigid perforated element, the dispensing element having a permeability greater than that of the filter layer 540. Such a dispensing element allows for a more uniform liquid flow rate within the filter layer 540.

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

[0049] The membrane 530 allows pressure to be applied to the slurry 5 present in the impregnation chamber 501, causing the slurry 5 to penetrate into the fiber preform 10. The membrane 530 also allows 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 a 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 to the membrane 530 by the compressed fluid 6 also allows the membrane 530 to be held 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 can be used to contact the fiber preform 10.

[0050] Membrane 530 may be made of, for example, silicone resin or a rubber-type material. Membrane 530 may be reinforced with glass fiber or polyester fiber. Membrane 530 must be made of a material that can withstand the temperatures it may experience throughout the process and the fluids it will come into contact with. The compressibility of membrane 530 must conform to the dimensional tolerances required for the component.

[0051] Impregnation of the fiber preform 10 can be performed by first injecting slurry 5 into impregnation chamber 501, and then injecting compressed fluid 6 into compaction chamber 502. The compressed fluid 6 applies pressure to the slurry 5 through 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 membrane 530 to the slurry 5 and fiber preform 10 is reduced so that the slurry 5 penetrates into the preform 10 and sufficiently compacts the preform 10 to allow the liquid phase of the slurry 5 to drain through filter layer 540 without deteriorating the fiber preform 10. Combined with the pressure applied to the slurry by compressed fluid 6, pumping can be performed at the outlet port 512 of impregnation chamber 501, for example by a main vacuum pump. Figure 2 Pumping is performed (not shown). This pump is optional. Furthermore, the impregnation tool 500 may be equipped with a heating device, such as a resistive element integrated into the wall, to increase the temperature in the compaction chamber 502 and facilitate the removal 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 within the pores of the preform 10, thereby gradually depositing the particles 51 into the fiber preform 10. These particles 51 allow the matrix to form after sintering.

[0053] According to one variant, impregnation of the fiber structure 10 can be performed first by injecting a compressed fluid 6, followed by injecting a 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. Furthermore, 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] Impregnation of the fiber preform 10 can also be performed using several slurries. Impregnation of the fiber preform 10 can also be performed using infusion technology (injection molding technology known as "RTM" or submicron powder suction technology known as "APS").

[0055] Once the fiber preform 10 has been 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 the drying stage (preferably at a temperature greater than 60°C and less than 90°C), which allows the drainage of any remaining liquid phase. Therefore, as... Figure 3 As shown, the pores of the fiber preform 10 are partially filled by matrix precursor particles 51.

[0056] Fiber preforms can also be made from pre-impregnated layers or laminates as described above. Therefore, fiber preforms can be made, for example, in a well-known manner, by draping layers or laminates obtained by pre-impregnating with slurry, two-dimensional or three-dimensional weaving, or by automatically placing pre-impregnated fibers or fiber textures as described above. Such fiber preforms are then placed in an autoclave and demolded for sintering.

[0057] like Figure 3 As shown, the fiber preform 10, which contains matrix precursor particles 51, is disposed around at least one retaining tool 100 before sintering.

[0058] Each retaining tool 100 includes at least one disc 110 and a crown 120. The disc 110 and the crown 120 are concentric. The disc 110 includes two opposing circular surfaces 110a and 110b and a side surface 110c that connects the upper circular surface 110a to the lower circular surface 110b. The geometry of the side surface 110c of the disc 110 can be adapted to the portion of the inner surface 10b that contacts the tool 100. Therefore, the side surface 110c of the disc 110 can be cylindrical or truncated conical.

[0059] When the retaining tool 100 is disposed in the fiber preform 10, the axis of rotation of the generally shaped disc 110 can coincide with the axis of rotation X of the preform 10. More generally, when the retaining tool 100 is disposed in the fiber preform 10, the axis of rotation of the generally shaped retaining tool 100 can coincide with the axis of rotation X of the preform 10. Therefore, preferably, when the retaining tool 100 is deposited inside the preform 10, it extends perpendicular to the axis of rotation X of the preform 10.

[0060] Preferably, the retaining tool 100 is disposed at one end of the fiber preform 10 along the axis of rotation X. In particular, the retaining tool 100 is preferably disposed at the end of the fiber preform 10 with 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 deformation, especially when they have a large radius; therefore, it is more sensible to place the retaining 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 one side of the upper circular surface 110a of the disk 110 and on the other side of the lower circular surface 110b of the disk 110. The through holes 111 and 112 can serve as gripping or attachment areas to facilitate the manipulation of the tool 100. The disk 110 may include a through hole 111 centered on the axis of rotation of the disk 110, that is, centered on the axis of rotation of the side surface 110c of the disk 110. Therefore, the axis of rotation of the through hole 111 coincides with the axis of rotation of the disk 110, that is, coincides with the axis of rotation of the side surface 110c of the disk 110. The disk 110 may then have an annular shape. The through holes 111 and 112 also allow for weight reduction of the disk 110. Figure 3 As shown, the through holes 112 of the disk 110, excluding the axis of rotation of the disk 110, are preferably arranged at an angle in a regular manner around the axis of the disk 110. The through holes 112 of the disk 110, excluding the axis of rotation 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. This regularity in the placement and size of the through holes of the disk 110 allows for regular thermal expansion of the disk 110 in the radial direction. The through holes 112 of the disk 110, excluding the axis of rotation of the disk 110, can have a diameter greater than 50 mm.

[0062] The crown 120 includes a first surface 120a configured to contact the side of the disc 110. Therefore, the crown 120 includes a first surface 120a configured to contact the periphery of the disc 110. The crown 120 also includes a second surface 120b opposite to the first surface 120a and configured to contact the fiber preform 10 containing particles 51. More specifically, the second surface 120b of the crown 120 is configured to contact a reduced portion of the inner surface 10b of the preform 10 containing particles 51. When a retaining tool is mounted in the fiber preform 10, the crown 120 includes a first surface 120a contacting the periphery of the disc 110 and a second surface 120b opposite to the first surface 120a, the second surface contacting a portion of the inner surface 10b of the preform 10. Therefore, the geometry of the second surface 120b of the crown 120 is adapted to the portion of the inner surface 10b that contacts the second surface 120b. Therefore, the second surface 120b of the crown 120 can be, for example, cylindrical or truncated conical.

[0063] Preferably, the disc 110 is made of monolithic ceramic. Monolithic ceramic is understood to refer to ceramic without fiber reinforcement, and its porosity can be between 0% and 81%, and preferably between 10% and 40%. The higher the porosity of the monolithic ceramic, the easier the disc 110 is to process, the lighter its weight, and the lower its cost.

[0064] The disc 110 can be made of mullite. If the disc 110 is made of mullite, it can contain 60% to 80% alumina, and preferably 65% ​​to 70% alumina. In fact, a disc 110 made of mullite with this percentage of alumina allows for reduced thermal expansion of the disc 110, thereby reducing compression of the crown 120, while ensuring that contact between the tool 100 and the preform 110 is maintained until high temperatures, and particularly above the sintering start temperature. Mullite also has the advantage of being inexpensive.

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

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

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

[0068] The crown 120 is made of a compressible material, that is, a material that can be compressed by at least 20% when the disc 110 expands and presses the compressible material against the inner surface 10b of the fiber preform 10. Preferably, the compressible material of the crown 120 can be compressed by at least 30% when the disc 110 expands and presses the compressible material against the inner surface 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 of being easily wound around the disc 110. The crown 120 may also be made of felt, such as carbon felt.

[0070] As described above, the crown 120, mounted between the disc 110 and the inner surface 10b of the preform 10, can have a thickness between 2 mm and 15 mm in the radial direction, depending on the thermal expansion of the disc 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 disc 110, thereby ensuring at least contact between the crown 120 and the inner surface 10b of the preform 10 until the sintering step begins. Specifically, if the disc 110 is made of mullite, the crown 120 can have a thickness between 5 mm and 15 mm in the radial direction, depending on the thermal expansion of the disc 110 and the preform 10. If the disc 110 is made of alumina, the crown 120 can have a thickness between 2 mm and 12 mm in the radial direction, depending on the thermal expansion of the disc 110 and the preform 10.

[0071] Preferably, the compressible material of the crown 120 is capable of decomposition by oxidation under an oxidizing atmosphere and high temperature. Specifically, the compressible material of the crown 120 can be configured to decompose mostly by oxidation during the sintering step in air. Specifically, the compressible material of the crown 120 can be configured to decompose mostly by oxidation at temperatures between 600°C and 1200°C. Furthermore, the compressible material of the crown 120 can be configured to remain largely unchanged by oxidation during the debinding step. Specifically, the compressible material of the crown 120 can be configured to remain largely unchanged by oxidation at temperatures up to 400°C (and preferably up to 600°C). Compressible materials made of expanded graphite can satisfy these characteristics. Expanded graphite does not oxidize in an inert atmosphere, such as during pyrolysis operations or during chemical infiltration operations in the gas phase. In atmospheres with very low oxygen content, expanded graphite exhibits very slow oxidation kinetics until the sintering temperature is reached.

[0072] Preferably, the materials of the disc 110 and the crown 120 are selected such that: when the retaining tool 100 is placed on the inner surface 10b of the preform 10, the crown 120 is almost uncompressed at room temperature, and is almost uncompressed during possible debonding of the preform 10. Therefore, when the preform 10 has weak strength and thus an increased risk of deformation, the tool 100 applies very low pressure to the preform 10 during its placement to limit the risk of damage to the preform 10, and applies very low pressure to the preform 10 during possible debonding.

[0073] The aforementioned retaining tools 100 may be provided in the fiber preform 10, provided that placement in the preform 10 is possible, while taking into account variations in the cross-section of the preform.

[0074] To facilitate positioning the retaining tool 100 inside the preform 10 and to avoid damaging the preform, an additional positioning device 200 can be used, such as... Figure 4 As shown in the diagram. In particular, the additional positioning device 200 allows for ensuring good alignment between the tool 100 and the fiber preform 10.

[0075] exist Figure 4 In the example shown, the additional positioning device 200 includes a rod 220 and a foot 250. When the positioning device 200 is mounted with the fiber preform 10 and the retaining tool 100, the foot 250 supports the mass of the positioning device 200. The foot 250 includes a hole or inner bore 251 that allows the rod 220 to be secured. The rod 220 is preferably threaded. If the rod 220 is threaded, the inner bore 251 of the foot 250 is preferably threaded.

[0076] The positioning device 200 may further include a support 240, which includes a central through-hole or inner hole 241, which may or may not be threaded. Thus, the support 240 of the device 200 can be secured to a rod 220 that passes through the support 240 via the central inner hole 241. Preferably, the support 240 is held, for example, by means of a nut, at a non-zero distance from the foot 250. The support 240 is used to receive and contact one end of the fiber preform 10 along its axis of rotation X. Preferably, the support 240 is used to receive the end of the fiber preform 10 along its axis of rotation X that is furthest from the portion of the fiber preform 10 that houses the retaining tool 100, to facilitate the assembly of the positioning device 200, the retaining tool 100, and the preform 10. Preferably, the support 240 is used to receive the end of the fiber preform 10 having a minimum radius along its axis of rotation X. The support member 240 can contact the outer surface 10a of the fiber preform 10. The support member 240 can be produced by additive manufacturing to obtain the shape of the support member 240, which is as suitable as possible to the end of the preform 10 that contacts the support member 240 when the preform 10 is assembled 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 allowing 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 further include at least one pressure plate 230, which includes a central through hole or inner hole 231, which may or may not be threaded. Therefore, the pressure plate 230 of the device 200 can be fixed to a rod 220, which passes through the pressure plate 230 via the inner hole 231. The pressure plate 230 can be used to fix a retaining tool 100 to the rod 220 of the positioning device 200, or to retain the retaining tool 100 during positioning. For this purpose, the pressure plate 230 includes an assembly surface 232 for contacting the upper circular surface 110a of the disc 110 of the retaining tool 100. Therefore, preferably, the positioning device 200 includes a pressure plate 230 for each retaining tool 100.

[0079] The through-hole 112 of the disc 110, which is different from the hole 111 through which the rod 220 passes, facilitates 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, is sized to allow a hand or a suitable tightening tool to pass through.

[0080] The positioning device 200 may also include a plate 210 with 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 As shown, plate 210 is specifically secured to rod 220 by means of a nut. Plate 210 includes an assembly surface 213 for at least partially contacting the end of fiber preform 10 opposite to support 240. Preferably, the assembly surface 213 of plate 210 also contacts the lower circular surface 110b of disc 110 of retaining tool 100. Preferably, plate 210 of positioning device 200 includes one or more through holes 212. The through holes 212 are configured such that when fiber preform 10 is mounted with positioning device 200, the through holes 212 of plate 210 are located in an extension of through hole 112 of retaining tool 100.

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

[0082] Once the retaining tool 100 has been correctly installed in the fiber preform 10 using the positioning device 200, the assembly including the positioning device 200, retaining tool 100, and fiber preform 10 can be flipped. The positioning device 200 allows the fiber preform 10 to be flipped without direct manipulation, which is advantageous because the fiber preform 10 is not yet sintered and is therefore fragile and sensitive to deformation. The fiber preform 10 is then preferably supported by the plate 210 upon completion of the rotation. The positioning device 200 can be completely or partially removed upon completion of the rotation. Preferably, the plate 210 remains in contact with the preform 10 upon completion of the rotation, and the remainder of the positioning device 200 is removed, particularly the rod 220, pressure plate 230, support 240, and foot 250 (if used).

[0083] Preferably, plate 210 includes one or more through holes 212 different from the central through hole 211 through which rod 220 passes. When the assembled surface of plate 210 contacts retaining tool 100, at least a portion of the through holes 212 of plate 210 is located in an extension of at least a portion of the through holes 112 of retaining tool 100. In fact, plate 210 can be held as a support for preform 10 during sintering and, where appropriate, during debonding. Thus, such through holes 212 on plate 210 allow combustion gases to pass through during sintering or allow any defects that need to be discharged during sintering or debonding to pass through. The material of plate 210 can then have properties compatible with the sintering or debonding steps, for example, by having chemical inertness and thermal expansion suitable for this method. Plate 210 may have been pretreated to stabilize its material and avoid interfering with the sintering steps.

[0084] Then, as Figure 5 As shown, a fiber preform 10 held by a holding tool 100 is disposed in a sintering furnace 300. As described above, the fiber preform 10 is preferably rested on a 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 disposed, regardless of whether it is rested on the plate 210 of the positioning device 200. The sintering furnace 300 includes a heating device 320. The sintering furnace 300 may be a gas-fired furnace operating at atmospheric pressure, heated by one or more gas burners. Gases generated by the burners are extracted by an extractor after the furnace has been heated to make room for gases continuously generated by combustion.

[0085] like Figure 5 and Figure 6As shown, 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 gas outlet holes may at least partially overlap.

[0086] The atmosphere in chamber 310 of the sintering furnace 300 typically includes oxygen, which allows for the decomposition of the compressible material of the crown 120 by oxidation. However, preferably, the oxygen content in the atmosphere of chamber 310 of the sintering furnace 300 is limited, thereby limiting the oxidation kinetics of the compressible material of the crown 120 and preventing premature oxidation of the compressible material of the crown 120, and particularly preventing the oxidation of a large portion of the compressible material of the crown 120 before the matrix precursor particles in the preform 10 begin sintering.

[0087] The temperature in the sintering furnace 300 that receives the fiber preform 10 can be gradually increased.

[0088] If the fiber preform 10 includes an adhesive, the temperature rise in the sintering furnace 300 allows for debonding of the preform 10 before reaching the temperature required for sintering. During the debonding process of the fiber preform 10, the temperature of chamber 310 of the furnace 300 is, for example, between 200°C and 450°C.

[0089] The temperature of chamber 310 in furnace 300 is further increased until it reaches the temperature that allows sintering of the preform 10. During the sintering process of the fiber preform 10, especially during the sintering of the matrix precursor particles present in the fiber preform 10, the temperature of chamber 310 in furnace 300 is, for example, between 1000°C and 1200°C. Figure 6 As shown, the sintering step allows a matrix to be formed in the pores of the preform 10, thereby obtaining a component 1 made of composite material. The component 1 made of composite material includes an outer surface 1a and an inner surface 1b, the geometry of the outer surface 1a being substantially the same as the geometry of the outer surface 10a of the preform 10, and the geometry of the inner surface 1b being substantially the same as the geometry of the inner surface 10b of the preform 10.

[0090] After debonding, the debonded fiber preform 10 is particularly fragile and sensitive to deformation. Therefore, it is important to protect the compressible material of the crown 120 during the debonding of the preform 10, and preferably at least until the sintering of the preform 10 begins. 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 the pores of the preform, thereby improving its strength and retention. Therefore, preferably, the 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, when the sintering operation is complete, most of the compressible material of the crown 120 has disappeared, facilitating the removal of the retaining tool 100 from the composite component 1 and avoiding the risk of contact between the disc 110 and its inner surface 1b during the cooling of the composite component 1. Specifically, under the atmospheric conditions of the sintering furnace 300, the compressible material can decompose from 400°C with very slow kinetics via oxidation, then from a temperature between 600°C and 700°C with faster kinetics via oxidation, and finally from 900°C with very fast kinetics. As described above, a compressible material with these properties could be, for example, expanded graphite.

[0091] The contact between the tool 100 and the inner surface 10b of the preform 10 can also be maintained throughout the sintering process.

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

[0093] The debinding step can be carried out in a different apparatus than the sintering apparatus. According to the invention, in the sintering apparatus, a load comprising fiber preforms and holding tools is transported at the end of the debinding step.

[0094] Therefore, the sintering step allows a matrix to be formed within the pores of the fiber preform 10 to obtain the desired composite material component. The apparatus and method of the present invention are particularly suitable for producing a component that constitutes all or part of the rear main body component of an aero-engine or all or part of the combustion chamber. Generally, the maximum cross-sectional diameter of the composite rotating component can be greater than 700 mm.

[0095] The phrase “between… and…” should be understood to include both an upper and lower limit.

Claims

1. An apparatus for sintering a rotary fiber preform, the apparatus comprising a sintering furnace (300) provided with a load, the apparatus characterized in that the load comprises a rotary fiber preform (10) disposed around at least one retaining tool (100), the retaining tool (100) comprising a disc (110) and a crown (120) present on the periphery of the disc (110), the crown (120) being made of a compressible material that can be eliminated by thermal oxidation, a portion of the rotary fiber preform (10) being in contact with the crown (120) prior to sintering.

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

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

4. The apparatus according to claim 1 or 2, wherein, At least one retaining tool (100) is disposed at one end of the rotating fiber preform (10) along its axis of rotation (X).

5. The apparatus according to claim 1 or 2, wherein, The rotating fiber preform (10) contains matrix precursor particles (51) in its pores.

6. A method for manufacturing a composite material rotating component, the method comprising the following steps: The rotating fiber preform (10) is impregnated with at least one or more matrix precursor particles (51). The rotary fiber preform (10) containing the matrix precursor particles (51) is placed around at least one retaining tool (100), the retaining tool (100) comprising a disc (110) and a crown (120) present on the periphery of the disc (110), the crown (120) being made of a compressible material that can be eliminated by thermal oxidation, a portion of the rotary fiber preform (10) contacting the crown (120). The rotary fiber preform (10) containing the matrix precursor particles (51) is sintered to form a matrix in the pores of the rotary fiber preform (10), thereby obtaining a composite material component (1). Most of the compressible material of the crown (120) decomposes by oxidation at the end of the sintering step. Remove the retaining tool (100) from the obtained composite material part (1).

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 rotary fiber preform (10) further includes: impregnating the rotary fiber preform (10) with an adhesive, and the method further includes: a step of debonding the rotary fiber preform (10) disposed around the holding tool (100) prior to the sintering step.

9. The method according to claim 6 or 7, wherein, In the step of placing the rotating fiber preform (10) around the retaining tool (100), a positioning and centering device (200) is used, the positioning and centering device (200) comprising at least one rod (220) and a support (240), the end of the rotating fiber preform (10) furthest from the portion of the rotating fiber preform (10) that contacts the retaining tool (100) along its axis of rotation (X) resting on the support (240), the support (240) being secured to the rod (220) in the placement step, and the retaining tool (100) being secured to the rod (220) through their center.

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