METHOD FOR PRODUCEING A RUBBERIZED SEALING ELEMENT AND RUBBERIZED SEALING ELEMENT

Description

FIELD OF INVENTION

[0001] The invention is in the field of aeronautics.

[0002] It relates more specifically to a continuous manufacturing process for an abradable sealing element for a turbomachine. This sealing element is preferably intended to be mounted on a rotor wheel housing or a distributor base of a turbine or turbomachine compressor.

[0003] It also concerns this abradable sealing element as well as a turbine or compressor comprising it. STATE OF THE ART

[0004] Typically, a turbomachine comprises, from upstream to downstream, successively a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine and a low-pressure turbine, which are traversed by an airflow.

[0005] There figure 1 The attached figure represents an example of a turbomachine turbine design. The gas flow inside the turbine is from upstream AM to downstream AV in the direction of flow represented by arrow V.

[0006] This turbine comprises several successive stages, each stage including a distributor 1 and a rotor wheel 2. These are arranged inside an annular casing 3, of approximately frustoconical shape, with axis X-X'. The rotor wheel 2 rotates around the axis X-X'. The casing 3 forms an external shell for the turbine.

[0007] Each rotor wheel 2 comprises a disc 20 which carries on its periphery a plurality of radial blades 21. The various discs 20 are assembled together and fixed on a rotating shaft (not shown in the figures) which drives them simultaneously in rotation. Each distributor 1 comprises a plurality of radial blades 10 whose radially external end is fixed to the housing 3.

[0008] A ring, made of several elements of abradable material 30 arranged end-to-end circumferentially, is fixed to the inner face of the housing 3, opposite the radially external end of the rotor blades 21. During turbine operation, the tips of the blades 21 (optionally equipped with blades 210) penetrate the abradable material of the element 30. This ensures the smallest possible, or even zero, clearance, essentially radial, between the tips of the moving blades 21 and the housing 3. This guarantees the aerodynamic performance of the turbine and therefore of the turbomachine.

[0009] For the same aerodynamic performance reasons, an annular distributor foot 12 supports several abradable material elements 11 arranged end-to-end circumferentially. It is positioned at the radially inner end of the fixed blades 10, so as to be opposite an annular flange 22, itself fixed between two adjacent rotor discs 21. This flange 22 is provided with at least one annular shim 23 that penetrates the abradable material 11 during turbine operation.

[0010] The flow path of a turbomachine is characterized by a rapid flow of air and various particles. Therefore, it is desirable that the abradable material of components 30 and 11 be both abradable (i.e., wear preferentially compared to the blades 21 or the nozzles 23) and resistant to erosion by the particles. However, these two properties are antagonistic, which poses problems in the development of abradable materials.

[0011] The compressor of a turbomachine has a similar structure with respect to the abradable elements.

[0012] We already know from US document 2019 / 032504 a high-performance component comprising a support substrate covered with a multi-layer abradable track, as well as its manufacturing process.

[0013] However, this document does not describe the manufacturing process according to the invention, nor an abradable sealing element comprising sub-layers of abradable material having decreasing mechanical wear resistance from the sub-layer closest to the supporting substrate to the one furthest from this supporting substrate. DESCRIPTION OF THE INVENTION

[0014] An object of the invention is therefore to propose an abradable sealing element, which includes a support substrate, covered with a coating which is both abradable and erosion resistant, this abradable element being able to be fixed, preferably, on the inner face of the housing 3, opposite the radially external end of the rotor blades 21 or on the radially internal end of the fixed radial blades 10 of the distributor, more precisely on the distributor foot 12, opposite the wipers 23.

[0015] Another aim of the invention is to propose a method for manufacturing such an abradable sealing element.

[0016] To this end, the invention relates to a continuous manufacturing process for an abradable sealing element for a turbomachine, this sealing element comprising a support substrate covered with a coating comprising at least two successive layers, each layer comprising an underlayer of abradable material and an underlayer of anti-erosion material and the different layers being arranged in a layer stacking direction, such that an underlayer of abradable material is alternated with an underlayer of anti-erosion material.

[0017] According to the invention, this method comprises the steps of: a) place at least one substrate support on a rotating carousel around which are arranged at least two thermal spray torches, one of the two torches allowing the deposit of the underlayer of abradable material and the other of the two torches allowing the deposit of the underlayer of anti-erosion material, b) rotate the carousel so as to bring said substrate support successively in front of one then the other of the two thermal spray torches and to carry out the deposit of the underlayer of anti-erosion material and the deposit of the underlayer of abradable material and repeat this operation of rotating the carousel and depositing the underlayers so as to obtain said abradable sealing element.

[0018] Thanks to these features of the invention, it is possible to manufacture industrially and continuously an abradable sealing element that is highly resistant to erosion.

[0019] According to other advantageous and non-limiting features of the invention, taken alone or in combination: said thermal projection torches are plasma torches; the process consists of arranging N support substrates on the rotating carousel, regularly spaced at an angle of 360° / N, on the periphery of the carousel; the process consists of depositing at least three successive stacked layers on said support substrate, so as to form said coating and the different sub-layers of abradable material of this coating have a decreasing mechanical resistance to wear from the sub-layer of abradable material closest to the support substrate to that furthest from this support substrate according to the direction of stacking of the layers.

[0020] The invention also relates to an abradable sealing element for a turbomachine.

[0021] According to the invention, this element is obtained by the aforementioned process; it comprises a support substrate covered with a coating comprising at least two successive layers, preferably at least three successive layers; each layer comprises an abradable material sub-layer and an erosion-resistant material sub-layer; the different layers are arranged, according to a layer stacking direction, so that an abradable material sub-layer is alternated with an erosion-resistant material sub-layer; and the different abradable material sub-layers exhibit decreasing mechanical wear resistance from the abradable material sub-layer closest to the support substrate to the one furthest from this support substrate, according to a layer stacking direction.

[0022] According to other features of the invention taken alone or in combination: the different stacked layers are in contact with each other; the different underlayers of erosion-resistant material have the same thickness and / or the different underlayers of abradable material have the same thickness; for each layer, the underlayer of abradable material is at least ten times thicker than the underlayer of erosion-resistant material; the thickness of each underlayer of erosion-resistant material is between 1 µm and 50 µm; each underlayer of erosion-resistant material comprises a material selected from iron- or nickel-based materials, such as nickel / chromium / aluminum alloys, or from ceramic materials; each abradable underlayer comprises a material selected from the rare earth group materials.

[0023] The invention also relates to a turbine or turbomachine compressor comprising at least one rotor wheel and a distributor, arranged inside a casing, the rotor wheel comprising a plurality of radial blades, said casing comprising on its inner face at least one abradable sealing element, arranged opposite the radially external ends of said rotor blades.

[0024] According to the invention, said at least one abradable sealing element is an element such as above and said rotor wheel is arranged so that its radial blades come into contact with the layers of the coating of said abradable sealing element.

[0025] Finally, the invention relates to a turbine or turbomachine compressor comprising at least two rotor wheels and a distributor, each rotor wheel comprising a rotor disc provided at its periphery with a plurality of radial blades, the distributor comprising a plurality of radial blades, at least one of said distributor blades supporting at its radially internal end, at least one abradable sealing element.

[0026] According to the invention, said at least one abradable sealing element is an element such as above, a flange provided with at least one annular sealing strip is fixed between said two rotor discs and said sealing strip is arranged so as to come into contact with the layers of the coating of said abradable sealing element. DESCRIPTION OF THE FIGURES

[0027] Other features, purposes and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which: There figure 1 This is an axial cross-sectional view of a portion of a turbine in a turbomachine. figure 2 is a diagram representing an abradable sealing element according to the invention. figure 3 is a graph representing the mechanical resistance to wear R of an example of a coating on the abradable element, as a function of the height H of this coating. figure 4 is a graph representing the mechanical resistance to wear R of another example of a coating on the abradable element, as a function of the height H of this coating. figure 5A is a diagram representing a first step in the continuous manufacturing process according to a first embodiment of the invention. figure 5B is a diagram representing a second step in the continuous manufacturing process according to a first embodiment of the invention. figure 5C is a diagram representing a third step in the continuous manufacturing process according to a first embodiment of the invention. figure 6A is a diagram representing a first step in the continuous manufacturing process according to a second embodiment of the invention. figure 6B is a diagram representing a second step in the continuous manufacturing process according to a second embodiment of the invention. figure 6C is a diagram representing a third step in the continuous manufacturing process according to a second embodiment of the invention. figure 7 is a diagram representing a third embodiment of the continuous manufacturing process according to the invention. figure 8 is a diagram representing the installation enabling the implementation of the process according to the invention.

[0028] Across all figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION

[0029] The invention relates to an abradable element 4, such as that schematically represented on the figure 2 This abradable element 4 is preferably intended to replace at least one of the abradable elements 30 and / or the abradable elements 11 of the turbine of the figure 1 or a compressor not shown in the figures.

[0030] The abradable element 4 comprises a support substrate 40 covered with a coating 5.

[0031] The support substrate 40 preferably has the shape of a sector of a ring curved in an arc of a circle. These different ring sectors are intended to be placed end to end circumferentially, so as to form a complete ring, which is fixed to the inner face of the housing 3. The support substrate 40 could also be a complete ring.

[0032] The concave face of this support substrate is its radially internal face and it is this face which is covered with the coating 5. The support substrate 40 can be made of metal, ceramic or ceramic matrix composite material (CMC).

[0033] The coating 5 comprises at least two successive layers 50, preferably superimposed. Each layer 50 comprises an underlayer of an abradable material 501 and an underlayer of an erosion-resistant material 502, which is more mechanically resistant than the abradable underlayer 501, i.e., which breaks less easily. A preferred embodiment of the invention, described later, comprises at least three successive layers 50.

[0034] Preferably, the stacking of the layers 50 is done so that an anti-erosion sub-layer 502 is the last of the stacking, that is to say, it is located at the end opposite the substrate 40 according to the direction of stacking of the layers.

[0035] The stacking direction of the layers starts from substrate 40 and moves away from it. It is indicated by the arrow ZZ' in figure 2 .

[0036] The first sub-layer in contact with the substrate 40 can be either a sub-layer 501 or 502.

[0037] The technical solution according to the invention consists of alternating abradable underlayers 501 with erosion-resistant underlayers 502 that are more mechanically resistant than the abradable underlayers 501. When a moving part comes into contact (for example, on the figure 2 a rotor blade 21), the penetration of the blade will remove the first anti-erosion underlayer 502 by shearing the abradable underlayer 501 below, and this with a minimum of effort and abrasion for the moving blade 21.

[0038] Erosion by particles circulating in the airflow then removes the residues from the abradable sub-layer 501 and stops at the level of the next anti-erosion sub-layer 502. During turbine operation, the blades 21, or the blades 23, expand further radially towards the abradable element, so that a subsequent layer 50 can in turn be degraded, as just described, and this operation can be repeated.

[0039] The thinner the different sub-layers 501, 502 are, the smaller the residual gap j between the top of the blade 21 and the surface facing the coating 5, and therefore the more the sealing and efficiency of the turbine are guaranteed.

[0040] Advantageously, the different 501 sub-layers of abradable material are of the same thickness to each other.

[0041] Preferably, the different underlayers of anti-erosion material 502 are of the same thickness to each other.

[0042] Preferably also, the abradable material underlayer 501 is thicker than the erosion-resistant material underlayer 502, preferably at least ten times thicker.

[0043] Preferably, the underlayer of erosion control material 502 is less than 0.1 mm thick, and more preferably between 1 µm and 50 µm. This erosion control layer does not alter the abradable nature of the underlayer 501.

[0044] Advantageously, coating 5 comprises between ten and one thousand layers 50.

[0045] The material used for the 502 erosion control underlayer is advantageously chosen from iron- or nickel-based materials, such as nickel / chromium / aluminum alloys (NiCrAl). The material for the 502 erosion control underlayer can also be ceramic.

[0046] The constituent material of the 501 abradable material underlayer is advantageously chosen from materials in the rare earth group.

[0047] According to a first embodiment of the coating 5, the various underlayers of abradable material 501 have the same mechanical resistance to each other, and furthermore, the various underlayers of erosion-resistant material 502 have the same mechanical resistance to each other. Moreover, the erosion-resistant underlayers 502 are more mechanically resistant than the abradable underlayers 501.

[0048] This scenario is illustrated on the figure 3 This diagram represents the evolution of the mechanical wear resistance R of the different sub-layers as a function of the height H of the coating 5, from the radially external zone EXT of the coating (closest to the substrate 40) to the radially internal zone (INT) of this substrate. This diagram shows that the erosion-resistant sub-layers 502 all have a mechanical wear resistance Rb, and that the abradable material sub-layers 501 all have a mechanical wear resistance Ra, with Rb greater than Ra.

[0049] According to a preferred embodiment of the invention, the coating 5 comprises at least two layers 50, preferably at least three layers 50, each comprising the two sub-layers 501 and 502 with a variation in the mechanical wear resistance of the sub-layers 502 over the height H of the coating (see figure 4 Thus, while the mechanical wear resistance of the erosion control material 502 is constant (Rb value), the mechanical wear resistance of the abradable material sublayer 501 varies and increases from the radially inner end (INT) of the coating 5 to its radially outer end (EXT side). Therefore, with each new sublayer 501 of abradable material, the mechanical wear resistance Ra increases; here, with six sublayers, we see that the values ​​Ra1, Ra2, Ra3, Ra4, Ra5, and Ra6 are increasing, all of these values ​​being lower than Rb.

[0050] Thus, having a lower mechanical resistance to wear of the abradable sub-layers 501 in contact with the moving blade 21 can avoid a direct break of an abradable sub-layer 501 (closer to the support substrate 40).

[0051] One way to vary the mechanical resistance to wear of an underlay is to adjust its density. The denser an underlay is, the more mechanically resistant it will be.

[0052] An example of a manufacturing process for the aforementioned abradable element 4 will now be described in connection with the figures 5A à 8 .

[0053] The process according to the invention is an industrial process, which allows the coating 5 to be manufactured continuously, at a high rate, by coating at least one support substrate 40 and preferably several dozen support substrates simultaneously.

[0054] The process according to the invention is implemented in an installation such as, for example, the one shown in the figure 8 This includes a carousel 6 preferably motorized, at least two thermal projection torches 7, 7', all preferably placed in a projection enclosure 8.

[0055] The carousel 6 comprises a base 60, fixed on a rotating platform 61, driven in rotation around a vertical axis Y-Y'. The support substrates 40 are arranged on the external face of the base 60, so that their curved inner face 400 is opposite the projection torches 7, 7'.

[0056] Torches 7 and 7' can, for example, be chosen from air plasma spraying torches, known by the acronym "APS" (which stands for "Air Plasma Spraying"), or high-velocity oxygen-fuel spraying torches, known by the acronym "HVOF" (which stands for "High Velocity Oxygen Fuel"). These different types of torches allow for different powder formulations and thus the application of either the 501 abradable material undercoat or the 502 erosion-resistant material undercoat.

[0057] Advantageously, at least one of the torches 7, 7' can have one or two degrees of freedom, and its movement can optionally be programmed. This torch can, for example, be mounted on a robotic articulated arm so as to pivot, for example, to the left or to the right relative to the rotation axis Y-Y', or up or down relative to the vertical position of the carousel 6 shown in the figure 8 .

[0058] Advantageously, the distance D between the support substrate 40 to be covered and the projection torch 7 or 7' can be adjusted.

[0059] The carousel 6 is driven in rotation (arrow F), either continuously or indexed in 360 / N degrees, where N is the number of support substrates 40 fixed to the carousel, so as to sequentially bring each support substrate 40 in front of a torch 7 or 7'. For example, when six support substrates 40 are distributed on the carousel 6, this sequenced movement will occur sixty degrees at a time.

[0060] One of the torches, for example torch 7, allows the underlayer of abradable material 501 to be deposited and the other, for example torch 7', the layer of anti-erosion material 502.

[0061] In the example shown in the figures, torches 7 and 7' are positioned 180° apart. However, this angular arrangement could be different. Furthermore, as shown, for example, in the figures 5A à 5C , it is possible to place around the carousel 6, a device 80 projecting a jet of cooling air, preferably after the passage of the support substrate 40 in front of the two torches 7 and 7'.

[0062] Advantageously, the substrate 40 is prepared before being fixed to the carousel 6. For example, it can be subjected to mechanical or chemical stripping, followed by a cleaning step to remove the stripping residue; this cleaning can be carried out, for example, in a solvent bath. It is also possible to then apply a bonding undercoat to this substrate 40 for the coating 5, which will be applied later.

[0063] The support substrate 40 can then be fixed onto the carousel 6.

[0064] Advantageously, and as shown in the figures, the support substrate 40 can be fixed to the base 60 by means of a device that also allows one or two degrees of freedom, for example, upward or downward movement, or to the right or left. This makes it possible, for example, to sweep the beam projected by the torch 7 or 7' across the surface of the support substrate 40 to be covered.

[0065] In the example implementation shown on the figures 5A à 5C , a single support substrate 40 is fixed on the carousel 6.

[0066] The carousel 6 is positioned so that the substrate 40 is in front of one of the two torches, for example in front of torch 7 ( figure 5A ). The first underlayer is deposited, for example the abradable material underlayer 501, then the carousel 6 is rotated so as to bring the substrate 40 in front of the other torch 7' and to deposit the other underlayer, here 502 ( figure 5B ). The rotation of the carousel 6 continues and after passing in front of the possible air jet spraying device 80, the substrate 40 is found in front of the first torch 7 ( figure 5C ) to receive a new underlayer of abradable material 501. This cycle is repeated as many times as necessary to obtain the desired number of underlayers 501, 502 on the substrate 40.

[0067] THE figures 6A à 6C illustrate a variant of the process in which two support substrates 40a, 40b are fixed on the carousel 6, preferably at 180° to each other, which makes it possible to increase the production rate.

[0068] Initially, substrate 40a is positioned in front of torch 7 and substrate 40b in front of torch 7'. The underlayer formed by torch 7 (for example 501) is deposited on substrate 40a, while torch 7' is not fed initially, so that substrate 40b remains blank.

[0069] The next step represented at the figure 6B , the carousel 6 has rotated 180°, so that the substrate 40a covered with a first abradable underlayer 501 then receives a first anti-erosion underlayer 502, while the substrate 40b receives a first abradable underlayer 501, deposited directly on the substrate 40b.

[0070] The 180° rotations are continued, so as to bring alternately the two substrates 40a and 40b in front of one or the other of the two torches 7 and 7' and thus obtain the desired number of sub-layers 501 and 502.

[0071] On the figure 7 , we can see a variant embodiment in which six support substrates 40a, 40b, 40c, 40d, 40e and 40f are arranged on the carousel 6.

[0072] For example, up to thirty-two support substrates 40 (or even more) can be placed on a carousel 6. Advantageously, and in order to increase the deposition rates, several pairs of torches 7 and 7' can then be arranged around the carousel 6.

[0073] The deposition parameters of the two torches 7 and 7' are advantageously set so that the thickness of the sub-layer of abradable material 501 is greater than that of the sub-layer of anti-erosion material 502, as previously explained.

[0074] To achieve this, we can adjust various parameters, such as the flow rate of projected material, the deposition speed, or the projection angle.

[0075] The material flow rates can be different. By acting on the ratio between the flow rates of the two sub-layers 501 and 502 and on the ratio between their respective densities, it is therefore possible to obtain different thicknesses.

[0076] As a purely illustrative example, if we deposit an abradable 501 AlSiBN underlayer at a rate of 100g per minute and an anti-erosion AlNi underlayer at a rate of 20g per minute (flow rate ratio of five), knowing that the density of AlSiBN is five times lower than that of AlNi, then we can achieve an anti-erosion material deposit ten times thinner than that of the abradable material layer.

[0077] The deposition speed determines the thickness of the deposited layer when the deposit is made in a single pass (the slower the speed, the thicker the deposit). To obtain a thicker layer, it is also possible to adjust the torches 7 or 7' to make them perform a sweeping and back-and-forth motion before the carousel 6 is set in rotation for the next step.

[0078] Finally, it should be noted that the deposited thickness varies according to the sine of the projection angle. The more acute (grazing) the projection angle is relative to the coated surface, the larger the covered area will be. The deposited thickness will also be less. It is generally preferable not to exceed an angle of 45° relative to the normal to the surface being coated.

[0079] Thanks to these features of the invention, it is possible to continuously produce a large number of abradable sealing elements 4 having a large number of underlayers with different characteristics and thus obtain an overall coating 5 benefiting from all the advantages of each of the underlayers 501, 502, without the disadvantages (namely an abradable material character with good resistance to erosion).

Claims

1. A method for the continuous manufacture of an abradable sealing element (4) for a turbomachine, said sealing element (4) comprising a support substrate (40) coated with a coating (5) comprising at least two successive layers (50), each layer (50) comprising a sublayer of abradable material (501) and a sublayer of anti-erosion material (502), and the various layers (50) being arranged in a layer stacking direction such that a sublayer of abradable material (501) alternates with a sublayer of erosion-resistant material (502), said method being characterized in that it comprises the steps of: - a) positioning at least one support substrate (40, 40a, 40b, 40c, 40d, 40e, 40f) on a rotating carousel (6) around which at least two thermal spraying torches (7, 7') are arranged, one of the two torches (7, 7') being used to deposit the underlayer of abradable material (501) and the other of the two torches being used to deposit the underlayer of erosion-resistant material (502), - b) rotating the carousel (6) so as to bring said support substrate (40, 40a, 40b, 40c, 40d, 40e, 40f) successively in front of first one and then the other of the two thermal spray torches (7, 7') and to deposit the anti-erosion material sublayer (502) and the abradable material sublayer (501), and repeating this operation of rotating the carousel (6) and depositing the sublayers so as to obtain said abradable sealing element (4).

2. A continuous manufacturing process according to claim 1, characterized in that said thermal spray torches (7, 7') are plasma torches.

3. A continuous manufacturing method according to claim 1 or 2, characterized in that it consists of arranging N support substrates (40, 40a, 40b, 40c, 40d, 40e, 40f) on the rotating carousel (6), spaced evenly at an angle of 360° / N around the periphery of the carousel.

4. A continuous manufacturing process according to one of the preceding claims, characterized in that it consists of depositing at least three successive stacked layers (50) on said support substrate (40, 40a, 40b, 40c, 40d, 40e, 40f) in such a way as to form said coating (5), and in that the various sublayers of abradable material (501) of this coating (5) exhibit a mechanical wear resistance that decreases from the sublayer of abradable material (501) closest to the support substrate (40, 40a, 40b, 40c, 40d, 40e, 40f) to the one furthest from said support substrate in the direction of stacking of these layers (50).

5. A continuous manufacturing process according to one of the preceding claims, characterized in that the various sublayers of erosion-resistant material (502) and the various sublayers of abradable material (501) are deposited such that the various sublayers of erosion-resistant material (502) have the same thickness and / or the various sublayers of abradable material (501) have the same thickness.

6. A continuous manufacturing process according to any one of claims 1 through 4, characterized in that the various sublayers of anti-erosion material (502) and the various sublayers of abradable material (501) are deposited such that, for each layer (50), the sublayer of abradable material (501) is at least ten times thicker than the sublayer of erosion-resistant material (502).

7. A continuous manufacturing process according to one of the preceding claims, characterized in that each deposited anti-erosion sublayer (502) comprises a material selected from iron- or nickel-based materials, such as nickel / chromium / aluminum alloys, or from ceramic materials.

8. A continuous manufacturing process according to one of the preceding claims, characterized in that the material constituting the abradable material sublayer (501) is selected from rare earth materials.

9. An abradable sealing element (4) for a turbomachine, characterized in that it is produced by the method according to claim 4, in that it comprises a support substrate (40) coated with a coating (5) comprising at least three successive layers (50), in that each layer (50) comprises a sublayer of abradable material (501) and a sublayer of erosion-resistant material (502), in that the various layers (50) are arranged in a stacking direction such that a sublayer of abradable material (501) alternates with a sub sublayer of erosion-resistant material (502), and in that the various sublayers of abradable material (501) exhibit a mechanical wear resistance that decreases from the sublayer of abradable material closest to the support substrate to the one farthest from said support substrate in the direction of layer stacking.

10. Sealing element (4) according to claim 9, characterized in that the various stacked layers (50) are in contact with one another.

11. A sealing element (4) according to claim 9 or 10, characterized in that the various sublayers of erosion-resistant material (502) have the same thickness and / or in that the various sublayers of abradable material (501) have the same thickness.

12. A sealing element (4) according to one of claims 9 through 10, characterized in that, for each layer (50), the sublayer of abradable material (501) is at least ten times thicker than the sublayer of erosion-resistant material (502).

13. A sealing element (4) according to any one of claims 9 through 12, characterized in that the thickness of each erosion-resistant material sublayer (502) is between 1 µm and 50 µm.

14. A sealing element (4) according to any one of claims 9 through 13, characterized in that each anti-erosion sublayer (502) comprises a material selected from iron- or nickel-based materials, such as nickel / chromium / aluminum alloys, or from ceramic materials.

15. A sealing element according to any one of claims 9 through 14, characterized in that the material of the abradable sublayer (501) is selected from rare earth materials.