Method for localized heat treatment of an aircraft brake disk

Abstract

The invention relates to a method for the localized heat treatment of an aircraft brake disk (1) based on carbon-carbon composite, the disk (1) being provided with two friction faces each located on one side of the disk (1), the method being characterized in that it comprises: - placing an electrode (11), on each side of the disk (1), in electrical contact with a region to be treated (17) of the disk (1), an electrical insulator (14) being arranged on at least one friction face, in a vicinity of the region to be treated (17); and - generating an electric current between the two electrodes (11) so as to heat the region to be treated (17) by Joule heating.

Description

[0001] DESCRIPTION

[0002] TITLE: Localized heat treatment process for an aircraft brake disc

[0003] The invention relates to parts comprising a composite material having a carbon fiber-reinforced matrix, and in particular a carbon / carbon composite material (with a carbon matrix), a C / C-SiC composite material (with a C-SiC matrix), a C / SiC composite material (with a SiC matrix), or a C / ceramic composite material (with a ceramic matrix), especially friction parts such as aircraft brake discs. More particularly, the invention relates to a method for localized heat treatment of an aircraft brake disc, as well as a device for implementing the method.

[0004] Ceramic matrix composites, or CMCs, are composite materials characterized by a set of ceramic fibers embedded in a ceramic matrix. Both the fibers and the matrix can be made of any known ceramic, including carbon.

[0005] Carbon / carbon composite, or C / C, is a composite material comprising an addition of carbon fibers in a carbon matrix, typically graphitizable carbon.

[0006] Currently, the final properties of ceramic matrix composites (C / C) are intrinsically linked to their manufacturing processes. The composite's final properties represent a compromise between the complexity of the manufacturing process and the precision of the material properties. Industrial processes for manufacturing these C / C materials only allow for work at scales on the order of a single part or larger. Aircraft brake discs, for example, are mass-produced, and their properties are averaged across the disc, with the exception of surface treatments such as external anti-oxidation coatings (AOCs) or the machining stage. Given the manufacturing processes typically used, it is therefore not currently possible to locally adjust the material properties according to the specific stresses experienced by the part.

[0007] Three cases can illustrate this problem.

[0008] The first case involves the application of an internal or external anti-oxidation coating (AOC) by painting and diffusion into the pores, followed by curing. Curing is achieved by heating the entire part, unless an industrial solution for localized heating only in the areas of the internal or external AOC coating is available. Heating an entire disc requires more energy and a suitable chemical environment (neutral gas) to prevent part degradation. A large-volume, sealed oven is used.

[0009] A second case concerns the lugs / notches of aircraft brake discs. These are areas prone to damage because they are subjected to significant mechanical stresses. Currently, it is not possible to specifically reinforce these areas without modifying the entire disc, which can result in reduced braking performance, increased wear, or a significant increase in manufacturing costs.

[0010] A final case involves impregnating an aircraft brake disc to load the part with ceramics. This added filler reduces cold friction wear but slightly increases oxidation at high temperatures. The lugs and non-friction areas (areas not intended to rub against a corresponding friction area of ​​an adjacent disc) are also ceramic-loaded because it is not possible to load only the friction faces of the disc. Under these conditions, the behavior of the non-friction areas is therefore degraded (sensitivity to oxidation) in favor of the cold wear resistance of the friction areas.

[0011] The invention aims to remedy these drawbacks by proposing a localized high-temperature process that allows adjustment of the properties of the different functional areas of the disk.

[0012] The invention relates to the localized heat treatment of an aircraft brake disc comprising a composite material with a carbon fiber-reinforced matrix, the disc being provided with two friction surfaces, each located on one side of the disc. The method according to the invention comprises:

[0013] - electrical contact of an electrode, on each side of the disc, with a treatment area of ​​the disc, an electrical insulator being placed on at least one friction face, preferably on each friction face, in the vicinity of the treatment area, and

[0014] - the generation of an electric current between the two electrodes, so as to heat the said area to be treated by Joule effect.

[0015] Thus, passing an electric current through the area to be treated, combined with the presence of electrical insulation around the area, allows for localized heat treatment, limited to that specific zone. Only the treated area is heated, and not the entire disc, which reduces treatment time and associated costs. The heating kinetics can be controlled, with rapid heating, particularly "flash" heating, such as that obtained during flash sintering, to limit heat diffusion.

[0016] The electrical insulator is placed in the vicinity of the area to be treated, advantageously in such a way as to insulate the other parts of the disk outside the area to be treated.

[0017] The composite material having a matrix reinforced by carbon fibers can be a carbon / carbon (C / C) composite material, a C / C-SiC composite material, a C / SiC composite material, or a C / ceramic composite material.

[0018] Each friction face may include a friction zone, a fixation zone and a free zone, and the area to be treated may include a part of each friction zone, a part of each fixation zone, or a part of each free zone.

[0019] Each friction zone can extend radially between a mounting zone and a free zone. A free zone is an area adjacent to a friction zone that is neither a friction zone nor a mounting zone. A mounting zone is an area intended to be attached to a landing gear axle, in the case of a stator disc, or an area intended to be attached to a landing gear wheel rim, in the case of a rotor disc. One or more zones to be treated can be considered, extending through the entire thickness of the disc or not; for example, a zone to be treated that includes two opposing friction surfaces. For this purpose, two electrical contact zones for the electrodes can be implemented, symmetrical with respect to the disc's plane of symmetry; for example, two electrical contact zones belonging to the two friction zones, the two mounting zones, or the two free zones.

[0020] The disc can be a stator disc, with each mounting area being a radially internal area intended to be attached to an axle of a landing gear, and each free area being a radially external area.

[0021] The disc can be a rotor disc, with each attachment area being a radially external area intended to be attached to a wheel rim of a landing gear, and each free area being a radially internal area.

[0022] The area to be treated can be coated with an anti-oxidation agent or an anti-oxidation precursor mixture before Joule heating. In this case, Joule heating can be carried out at a temperature between 500 and 1000°C, for a duration of between 2 seconds and one hour.

[0023] The area to be treated may include a portion of each fixing zone, and each fixing zone may be coated with resin before Joule heating of the area to be treated. In this case, Joule heating may be carried out at a temperature between 200 and 1000°C, for a duration of between 5 minutes and four hours.

[0024] The area to be treated may include a portion of each fixation zone, and ceramic fillers (such as borides, carbides, oxides, refractory metals (Ta, W)) or a ceramic precursor may be introduced into the area to be treated prior to Joule heating of the area to be treated.

[0025] The disc may include an inner zone located within its thickness, and the area to be treated may include a portion of this inner zone. In particular, the area to be treated may include a portion of the inner zone and a portion of each of the friction zones. The invention also relates to a disc obtained by the process described above.

[0026] The invention also relates to a device for implementing a localized treatment process described above. The device comprises a hermetically sealed enclosure under a neutral gas atmosphere, inside which is placed an aircraft brake disc comprising a composite material having a matrix reinforced by carbon fibers, the disc being provided with two friction faces, each located on one side of the disc, and the device may further comprise two electrodes connected to an electric current generator and adapted to be applied, each on one side of the disc, to a treatment area of ​​the disc, an electrical insulator being disposed on at least one friction face in the vicinity of the treatment area.

[0027] Other features and advantages of the present invention will become apparent from the detailed description below, of a non-limiting example of implementation, made with reference to the accompanying figures in which:

[0028] [Fig. 1] is a schematic front view of an aircraft brake stator disc,

[0029] [Fig. 2] is a cross-sectional view AA of the disk of [Fig. 1],

[0030] [Fig. 3] is a schematic front view of an aircraft brake rotor disc,

[0031] [Fig. 4] is a BB cross-sectional view of the disk from [Fig. 3],

[0032] [Fig. 5] is a schematic exploded perspective view of a device enabling the implementation of a method according to the invention for the localized treatment of an aircraft brake disc,

[0033] [Fig. 6] is a schematic half-view of the device applied to a stator disk,

[0034] [Fig. 7] is a schematic view of the device applied to a rotor disk,

[0035] [Fig. 8] is a schematic half-view of the device during a first step of a process according to the invention for localized treatment of an aircraft brake disc,

[0036] [Fig. 9] is a schematic half-view of the device during a second step of a method according to the invention for localized treatment of an aircraft brake disc, [Fig. 10] is a schematic half-view of the device during a third step of a method according to the invention for localized treatment of an aircraft brake disc,

[0037] [Fig. 11] is a schematic half-view of the device during a fourth step of a method according to the invention for localized treatment of an aircraft brake disc, and

[0038] [Fig. 12] is a schematic half-view of the device during a fifth step of a method according to the invention for localized treatment of an aircraft brake disc.

[0039] Aircraft brake discs are stacked one on top of the other, forming what is known as a "heat sink" due to the high temperatures they can reach (up to 2,000°C). Half of these discs are attached to a wheel (or rim) of the landing gear and rotate with it: these are the rotor discs. The other half are attached to the aircraft via the axle and do not rotate: these are the stator discs. The rotor and stator discs are mounted alternately. It is the friction between the discs that provides the braking force.

[0040] As illustrated in Figures 1 and 2, a stator disc 1 comprises two friction faces 2. On each of its two friction faces 2, the stator disc 1 is provided with a friction zone 3, designed to rub against a corresponding friction zone 30 of a rotor disc 10 (as shown in Figures 3 and 4), a free radially external zone 4 (not subject to friction), and a radially internal mounting zone 5 surrounding a central annular opening 6. The radially internal mounting zone 5 includes notches / grooves defining slots that are designed to engage with load-bearing bars of the landing gear axle. The friction zone 3, the free radially external zone 4, and the radially internal mounting zone 5 are annular in shape.

[0041] Brake discs, whether stator discs 1 or rotor discs 10, are generally annular in shape, with a thickness in an axial direction and a diameter in a radial direction, relative to an axis X around which the wheel rotates. An axle is configured to pass through the opening 6. Each brake disc 1 has two friction faces 2: one facing axially to an end plate and the other facing axially to a pressure plate. A line normal to each of the friction faces 2 is parallel to the axis X around which the wheel rotates, such that a plane in which each brake disc lies is orthogonal to the axis X around which the wheel rotates.

[0042] As can be seen in Figure 2, the two friction zones 3 of the stator disk 1 (each friction zone 3 being associated with a friction face 2 of the stator disk 1) axially surround an inner zone 7 which is the core of the disk.

[0043] As illustrated in Figures 3 and 4, a rotor disc 10 also includes two friction faces 20. On each of its two friction faces 20, the rotor disc 10 has a friction zone 30, designed to rub against a corresponding friction zone 3 of a stator disc 1 (as shown in Figures 1 and 2), a free radially internal zone 40 (not subject to friction) surrounding a central annular opening 60, and a radially external mounting zone 50. The friction zone 30, the free radially internal zone 40, and the radially external mounting zone 50 are annular in shape. The radially external mounting zone 50 includes notches / grooves defining slots that are designed to fit onto load-bearing bars of the wheel rim. The friction zone 30, the free radially internal zone 40, and the external radially fixed zone 50 are annular in shape.

[0044] As can be seen in Figure 4, the two friction zones 30 of the friction faces 20 axially surround an inner zone 70 which is the core of the rotor disk 10.

[0045] For the implementation of the localized heat treatment process according to the invention, the disc, whether it is a stator disc 1 or a rotor disc 10, is positioned in an external tube 8 made of refractory graphite which acts as a reaction chamber and mold. An internal tube 9 made of refractory graphite can be arranged in the central annular opening 6 of the disc 1, for example in the case where it is necessary to heat the inner zone 7, 70 of the disc 1, 10 (Figures 5 to 7).

[0046] Figure 6 shows a device comprising a stator disk 1, while Figure 7 shows a device comprising a rotor disk 10.

[0047] Two flat graphite electrodes 11 are positioned in contact with the friction faces 2, 20 of the disc. A current is created between these two friction faces 2, 20 by applying a voltage differential. Under the effect of the current, the disc is rapidly heated throughout its volume. An axial force can also be maintained on the disc throughout the heating phase. For this purpose, the two flat electrodes 11 can also be used to transfer the pressing force to the disc.

[0048] The disc, outer tube 8, inner tube 9 and electrodes 11 are arranged inside a hermetically sealed enclosure 12, into which an inert gas, such as nitrogen, is injected via an inert gas inlet 13.

[0049] An electrical insulating layer 14, for example pyrolytic boron nitride, can be placed between the outer graphite tube 8 and the disc to be treated to prevent leakage currents to the tooling and maximize volumetric heating (Figures 8 to 11). Electrical insulation is all the more important when the material of the disc being treated is a poor electrical conductor, as is the case with ceramic fillers. Using an electrical insulator 14 on part of the friction faces 2 limits the current flow in the inner zone 7 of the disc or to the outer or inner zones of the disc. The heating is then heterogeneous, with temperature fields corresponding to the electrical path within the disc 1.

[0050] To heat the outer area of ​​the disc (i.e. the radially outer free area 4 in the case of a stator disc or the radially outer fixing area 50 in the case of a rotor disc), the outer graphite tube 8 is not insulated and the friction areas 3 and the flat part of the inner diameter (the fixing area 5 in the case of a stator disc or the free area 4 in the case of a rotor disc) are insulated.

[0051] To heat the inner zone of the disk (i.e., the radially inner mounting zone 5 in the case of a stator disk or the radially inner zone 40 in the case of a rotor disk), the outer graphite tube 8 is insulated, and the friction zones 3 and the flat portion of the outer zone (i.e., the radially inner mounting zone 5 in the case of a stator disk or the radially inner free zone 40 in the case of a rotor disk) are insulated. The inner graphite tube 9, with a diameter equivalent to the diameter of the central opening 6, can be added to provide a heating element. To heat the inner zone 7 of the disk and the friction zones 3, the graphite housing and the flat portions of the areas that are not friction zones (i.e., the mounting zone 5 and the free zone 4) are insulated.

[0052] Heating using electrodes 11 further reduces structural changes and high-temperature chemical reactions between the fillers, carbon fibers, and carbon matrix, compared to wall heating, which is slower.

[0053] Due to its composition and structure, a C / C disc is an excellent electrical conductor, which can easily be heated by Joule heating. Localized treatment of the disc advantageously includes the application of an electrical insulator such as, by way of non-exhaustive example: glass for heat treatment below 1200°C,

[0054] - Pure quartz / silica for heat treatment between 1200°C and 1600°C,

[0055] - boron nitride for heat treatment under a neutral atmosphere, silicon nitride, metallic nitrides (such as TiN, AIN),

[0056] - oxides (such as alumina, mullite, HfC>2, ZrC>2).

[0057] The thickness of the electrical insulation layer is advantageously chosen by taking into account the breakdown voltage of the insulation and the experimental conditions (such as voltage or pressure).

[0058] It is also possible to consider using an electrode with a shape adapted to the geometry of the area to be treated.

[0059] It is also possible to combine the two previous aspects by developing a "hybrid" tooling system incorporating conductive zones (electrodes) and insulating zones (press force application) adapted to the geometry of the workpiece being processed. Heat dissipation zones (cooling / heat sinks) can be added to the tooling to accentuate thermal gradients and / or protect functional areas that should not be heated.

[0060] The manufacture of an aircraft brake disc based on carbon / carbon composite material generally includes the following steps: the manufacture of a preform including needle punching of oxidized polyacrylonitrile fibers, a carbonization step, matrix deposition, final heat treatment, and machining.

[0061] In particular, the manufacture of such discs usually involves a step of creating a fibrous preform in carbon fibers having a shape close to that of a disc to be manufactured and intended to constitute the fibrous reinforcement of the composite material, and the densification of the preform by a carbon matrix.

[0062] A well-known process for producing a carbon fiber preform involves layering fibrous layers of carbon precursor fibers, for example oxidized polyacrylonitrile (PAN), linking the layers together, for example by needle punching, and carrying out a carbonization heat treatment to transform the precursor into carbon.

[0063] The densification of the preform with a carbon matrix can be carried out by chemical vapor infiltration (CVI). Preforms are placed in a chamber into which a gaseous phase containing one or more carbon precursors, such as methane and / or propane, is introduced. The temperature and pressure within the chamber are controlled to allow the gaseous phase to diffuse into the preforms and form a solid pyrolytic carbon (PyC) deposit through the decomposition of the precursor(s).

[0064] Densification by a carbon matrix can also be carried out by liquid means, i.e. by impregnation of the preform with a carbon precursor, typically a resin, and pyrolysis of the precursor, several cycles of impregnation and pyrolysis being usually carried out.

[0065] We also know of a densification process called "heat-action" in which a preform of a disk to be densified is immersed in a bath of carbon precursor, for example toluene, and is heated, for example by coupling with an inductor, so that the precursor vaporized in contact with the preform diffuses within it to form a PyC deposit by decomposition.

[0066] A non-exhaustive list of examples of implementation of the process according to the invention is described below. Example 1: Heat treatment of an external anti-oxidation coating

[0067] An anti-oxidation coating (AOC) is applied to a carbon / carbon composite disc using either a liquid (brush, spray gun) or solid (thermal spray) method. The AOC can be applied to exposed areas (internal or external).

[0068] The coating is then consolidated / sintered / crystallized using the localized treatment process described above. This treatment can also produce a specific phase (chemical reaction between several components, crystallization, etc.). The Joule heating temperature can range from 500 to 1000°C, under a protective atmosphere (nitrogen, argon, or another inert gas), for a duration ranging from a few seconds to one hour.

[0069] Example 2: Reinforcement of a fixing area

[0070] A preform is created by needle punching pre-oxidized polyacrylonitrile fibers, followed by a carbonization heat treatment. The preform can then be densified with a carbon matrix by CVI, heat treatment, or resin impregnation and pyrolysis.

[0071] The fastening zone is then reinforced by locally increasing its density. For this purpose, the fastening zone (lugs / notches) is impregnated with a high-carbon resin, such as phenolic resins, furfural, tars, coke, pitch, asphaltenes, cyanates and their derivatives, or benzoxazines. Rapid, localized heating of the fastening zone is then carried out using the localized treatment process described above, in order to pyrolyze the resin and subsequently manage the effluent gases. Pyrolysis can be performed at a temperature between 200 and 1000°C, for a duration of between 5 minutes and 4 hours. The higher the temperature, the shorter the duration (typically 4 hours at 200°C). The temperature ramp must be maximized while ensuring proper evacuation of the gaseous byproducts. Purification, which is optional, can be carried out at a temperature between 800 and 1500°C.A graphitization step (baking carbon to obtain graphite) can be carried out at a temperature between 1500 and 2500°C, for a duration of between 2 minutes and 10 hours. Resin residues present on the friction areas / core of the disc are then removed by rinsing in a suitable solvent, followed by a final heat treatment and machining, and then the application of a protective anti-oxidation coating.

[0072] Example 3: Graphitization heat treatment of the disk core or free areas to increase oxidation resistance

[0073] The disk (stator disk or rotor disk) is arranged in the hermetically sealed enclosure under a neutral gas (nitrogen N2, for example). A conductive layer 15 for electrical contact is arranged in the middle of the friction zones 3 of the friction faces 2. The conductive layers 15 are preferably arranged symmetrically with respect to the plane of symmetry of the disk passing through the disk, and which is perpendicular to the X-axis of the disk 1. The electrical contact layers 15 may belong to the disk 1 or to the flat electrodes 11. In addition, a layer of electrical insulation 14 is arranged on the rest of the surface of the disk 1, that is to say, in particular on the areas that are not friction zones, so as to electrically insulate the rest of the disk from the flat electrodes 11 (Figure 8).

[0074] The flat graphite electrodes 11 are brought together so as to make contact with the electrical contact layers 15 and the electrical insulating layer 14 (figure 9).

[0075] An electric current is created between the two faces by applying a potential difference using a voltage or current generator G. Under the effect of the current, the disk is heated by Joule effect at very high speed in its volume, in the hot zone 16 (figure 10).

[0076] The two flat electrodes 11 are then removed (Figure 11) and the disk 1 is removed from the enclosure 12 (Figure 12). The disk 1 thus presents a heat-treated area 17 located mainly in the inner area 7 of the disk (Figure 12).

[0077] Example 4: Local addition of charges

[0078] A preform is created by needle-punching oxidized polyacrylonitrile fibers, followed by a carbonization heat treatment. The preform is then densified with a carbon matrix. Partial densification is achieved (density between 0.5 and 1.6). Ceramic fillers or a ceramic precursor are introduced locally into the fixation zone (the pins / notches). A Joule heating treatment according to the invention is then carried out at a temperature between 600 and 1700°C, localized to the fixation zone. The mass fraction of filler added is between 1 and 20%.

[0079] The rest of the piece is then densified by CVI or PI P (“Polymer Impregnation and Pyrolysis” in English).

[0080] A final heat treatment and machining followed by the application of an anti-oxidation protective coating complete the process.

[0081] The filler can be introduced using various suitable methods. For example, but not exhaustively, a liquid precursor or a filler dispersion can be added by vacuum or pressure impregnation, preparation of the material by washing with a surfactant then localized application followed by vacuuming to allow the filler to penetrate.

[0082] Localized introduction of the ceramic filler can be achieved by impregnating a ceramic precursor via the sol / gel process. The partially densified material can be impregnated under vacuum with the precursor sol. Gelation of the core is achieved by localized heating of the part to a temperature between 50 and 120°C, depending on the impregnation solvent. The ungelled precursor is then removed by rinsing. Excess precursor can be removed using one or a combination of the following techniques: ultrasonic solvent bath, rinsing with a surfactant or precursor chelating agent solution, or rinsing with a solvent introduced into the material by forced flow (convection / pressure or vacuum). Pyrolysis / conversion of the precursor to ceramic is achieved by applying Joule heating at a temperature between 500 and 1600°C for a duration ranging from 3 seconds to 20 minutes.

[0083] The invention thus enables a localized method for adjusting the properties of the aircraft brake disc, allowing the material present in each functional area to be adapted to the stresses it faces during its life cycle: - for the fastening area (lugs / notches): mechanical properties, oxidation (catalytic and thermal), thermal conductivity,

[0084] - For the friction zone: tribological behavior, wear resistance and, secondarily, oxidation resistance; - For the free zone: oxidation (catalytic and thermal), emissivity

[0085] (radiation),

[0086] - for the core of the disk: heat capacity, diffusivity / conductivity.

[0087] The process allows control of the temperature fields within the disk, the mechanical pressure applied to the disk, and the chemical environment in which the disk is placed (neutral gas, precursor, oxidant).

Claims

Demands 1. A method for localized heat treatment of an aircraft brake disc (1, 10) comprising a composite material having a carbon fiber reinforced matrix, the disc (1, 10) being provided with two friction faces (2, 20) each located on one side of the disc (1, 10), the method being characterized in that it comprises: - electrical contact of an electrode (11) on each side of the disc (1, 10), with a treatment zone (17) of the disk (1, 10), an electrical insulator (14) being disposed on at least one friction face (2, 20), in a neighborhood of the treatment zone (17), and - the generation of an electric current between the two electrodes (11), so as to heat by Joule effect the said area to be treated (17).

2. A method according to claim 1, characterized in that the composite material comprising a matrix reinforced by carbon fibers is a carbon / carbon (C / C) composite material, a C / C-SiC composite material, a C / SiC composite material, or a C / ceramic composite material.

3. Method according to claim 1 or 2, characterized in that each friction face (2, 20) comprises a friction zone (3, 30), a fixing zone (5, 50) and a free zone (4, 40), and in that the area to be treated (17) comprises a part of each friction zone (3, 30), a part of each fixing zone (5, 50), or a part of each free zone (4, 40).

4. Method according to claim 3, characterized in that each friction zone (3, 30) extends radially between a fixing zone (5, 50) and a free zone (4, 40).

5. Method according to claim 4, characterized in that the disk (1, 10) is a stator disk (1), each fixing zone (5) being a radially internal zone intended to be fixed to an axle of a landing gear, and each free zone (4) being a radially external zone.

6. A method according to claim 4, characterized in that the disc (1, 10) is a rotor disc (10), each mounting zone (50) being a radially external intended to be fixed to a wheel rim of a landing gear, and each free area (40) being a radially internal area.

7. A method according to any one of claims 1 to 6, characterized in that the area to be treated (17) is coated with an anti-oxidation protection or an anti-oxidation protection precursor mixture before heating the area to be treated by Joule effect.

8. A method according to any one of claims 3 to 6, characterized in that the area to be treated (17) comprises a part of each fixing zone (5, 50), and in that each fixing zone (5, 50) is coated with resin before heating the area to be treated (17) by Joule effect.

9. A method according to any one of claims 3 to 6, characterized in that the area to be treated (17) comprises a part of each fixing area (5, 50), and in that ceramic fillers or a ceramic precursor are introduced into the area to be treated (17) before heating the area to be treated (17) by Joule effect.

10. A method according to any one of claims 1 to 9, characterized in that the disc (1, 10) comprises an inner zone (7, 70) located in the thickness of the disc (1, 10) and in that the area to be treated (17) comprises a part of the inner zone (7, 70).

11. Device for implementing a localized treatment process according to any one of claims 1 to 10, characterized in that it comprises a hermetically sealed enclosure (12) under a neutral gas atmosphere, inside which is disposed an aircraft brake disc (1, 10) comprising a composite material having a matrix reinforced by carbon fibers, the disc (1, 10) being provided with two friction faces (2, 20) each located on one side of the disc (1, 10), and in that the device further comprises two electrodes (11) connected to an electric current generator and suitable for being applied each on one side of the disc (1, 10) to a treatment area (17) of the disc, an electrical insulator (14) being disposed on at least one friction face (2, 20) in a vicinity of the treatment area (17).

Images