Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D17/00—Constructional parts, or assemblies thereof, of cells for electrolytic coating
  • C25D17/008—Current shielding devices
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D15/00—Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/02—Electroplating of selected surface areas
  • C25D5/022—Electroplating of selected surface areas using masking means
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/16—Electroplating with layers of varying thickness
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
  • C25D5/605—Surface topography of the layers, e.g. rough, dendritic or nodular layers
  • C25D5/611—Smooth layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
  • C25D5/623—Porosity of the layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/67—Electroplating to repair workpiece
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/005—Repairing methods or devices

Definitions

• the invention relates to a method for depositing a metal matrix composite coating containing particles, for the repair of a metal blade, in particular but not exclusively a distributor blade of a turbine. gas.
• the invention relates to a process for depositing a MiCrAIM 2 type coating, Mi being chosen from Ni, Co and Fe or a mixture, and M 2 being chosen from Y, Si, Ti, Hf, Ta, Nb, Mn, Pt and rare earths.
• thermal insulation coatings for lowering the temperature of the metal of the rooms cooled by internal convection.
• thermal barrier coatings consist of a yttria-stabilized zirconia-based ceramic layer deposited on a metal bonding layer to provide adhesion to the ceramic coating while protecting the ceramic coating. metal of the piece of oxidation.
• the link layer can be of several types. There may be mentioned sub-layers of MCrAIY type (where M denotes nickel or cobalt). There may be mentioned aluminide sub-layers (NiAl) of intermetallic structure, compounds defined at 50 atomic% of nickel and aluminum. These aluminides can be modified with a precious metal such as platinum. Coatings aluminides are composed of an outer layer formed as well as a layer diffused inside the substrate. All these undercoating systems have the common denominator of being aluminoformers, that is to say that they form by oxidizing an adherent protective alumina film which insulates the metal from the part of the oxidizing environment.
• the removal of the thermal barrier is conventionally carried out by sanding.
• the sanding operation is an aggressive operation both with respect to the ceramic layer and the metal sub-layer.
• the under layer is then removed by chemical dissolution in an acid bath. This operation is difficult because it leads to the dissolution of the diffused layer of the aluminide coating and effectively leads to the decrease of the wall thicknesses of the part. This reduction of the walls of the parts leads, especially on the distributors, to increase the passage section.
• a sector is a part comprising one or more vanes mounted on interconnected platforms.
• the crowning of sectors is, for the most part, the distributor.
• the cross section of a sector is, in the strict sense, the area, measured perpendicularly to the direction of the flow, passage of the flow through the distributor sector between two adjacent blades.
• the passage section more simply designates the passage width of the flow through the dispenser sector. This passage section is conventionally considered at the location, between the edge of attack and the trailing edge, for which its value is the lowest and which corresponds to the narrowest passage of the flow.
• the traditional technology is soldering solder sintered made of superalloy and a solder. This technology is not the most suitable because it has a number of disadvantages.
• sintered and solder powders are, by definition, made of so-called "melting" elements which form compounds having a melting point close to the operating temperature of the parts. It is therefore not recommended to use such materials on large surfaces exposed to extreme temperatures. As a result, the mechanical characteristics of the brazed zones are much lower than those of the bare substrate.
• the deposition by brazing systematically generates a rim forming a step, that is to say a material thickness, all along the recharged area.
• the presence of this step may disturb the flow of air flow (in the air stream), a subsequent machining is necessary to recover the good aerodynamic profile.
• the trailing edge of the dispenser is not thick enough to be brazed: in fact, the brazing is accompanied by the diffusion of the elements on thicknesses up to 300pm and which therefore alter the substrate integrity on this thickness.
• the method is a process for the electrolytic deposition of a metal matrix composite coating containing particles, for the repair of a metal blade, implementing the following steps:
• an anode made in a metal is provided and the anode is connected to a current source
• a solution is provided, forming an electrolytic bath, comprising insoluble particles
• a support made of an electrically non-conductive material having a reference wall and capable of receiving said blade in a working position with respect to the reference wall is provided,
• said blade is mounted on said support in said working position
• said anode is placed facing the critical zone and said support is equipped, for each blade, with means for controlling the current lines so as to obtain a coating on the surface to be coated with said blade.
• variable thickness which is predetermined and substantially constant for the critical zone and which gradually decreases to a substantially zero value along the edges of said coating.
• These current line control means preferably comprise one or more screen portions on the surface of said support which is opposite the surface to be coated with the blade.
• the method according to the present invention makes it possible to simultaneously process several pieces.
• the electroplating technique disturbs the substrate less, since, unlike a soldering process, only a few microns are scattered.
• said surface to be coated extends in the longitudinal direction between the foot and the apex of the blade.
• a non-conductive support is constructed to carry an anode facing said surface to be coated.
• the shape of the anode can be chosen to control the flow of current to the critical zone and create the maximum cladding thickness at the throttling point and a smooth transition between the coated and uncoated areas.
• the shape of the anode can be chosen from a large number of profiles including but not limited to a rod, a bar, a plate, or a configuration according to the shape of the aerodynamic profile.
• the non-conductive medium defines the position of the anode relative to the surface to be coated and may be adapted to control the current lines extending between the anode and the surface to be coated.
• said current line control means comprise a longitudinal portion of the support adapted to face said surface to be coated with said blade, said portion delimiting a location for the anode extending longitudinally and facing the critical zone, the profile and the position, with respect to the surface to be coated, of the longitudinal portion of the support and the anode being chosen to limit and orient the streamlines.
• the blade or blades are turbomachine valve blades.
• the invention also relates to a blade restoration process, comprising the following steps:
• the invention also relates to an assembly for the electrolytic deposition of a coating on a blade, specially adapted for the implementation of the method which is the subject of the invention.
• an assembly for the electrolytic deposition of a coating on a blade comprising:
• a support made of an electrically non-conductive material having a reference wall and adapted to receive said blade in a working position with respect to the reference wall, said support further comprising, for each blade, a longitudinal portion adapted to face said surface to be coated with said blade, said portion delimiting a location extending in the longitudinal direction and facing the critical zone, an anode being housed in said location, the profile and the position, with respect to the surface to be coated, the longitudinal portion of the support and the anode being chosen to limit and orient the current lines so as to obtain, on the surface to be coated with said blade, a coating having a variable thickness, which is predetermined for the critical zone and which gradually decreases to a substantially zero value along the edges of said coating.
• the longitudinal portion comprises a working wall which faces the surface to be coated and which has a profile with a shape adapted so that the current lines allow deposition of the coating on the surface to be coated with the desired characteristics, in particular as regards its thickness.
• FIG. 1 is a sectional view perpendicular to the axis of the two vanes of a distributor sector, indicating the measuring locations of the passage section,
• FIG. 2 is an enlarged sectional view of a blade coated according to the method of the present invention
• FIG. 3 is an enlargement of zone III of FIG. 2,
• FIG. 4 is an enlargement of the area IV of FIG. 2,
• FIG. 5 is a sectional micrographic view corresponding to zone III of FIG. 3, on which appears the gradual variation of the thickness of the coating along one of its edges,
• FIG. 6 is a sectional micrographic view corresponding to the critical zone of FIG. 3, on which appears the predetermined and substantially constant thickness of the coating for the critical zone, and
• FIG. 7 is a diagram showing a possible example of an assembly according to the invention, comprising the support forming the tooling and the blades mounted on said support for implementing the method according to the invention.
• the distributor sector 100 partially visible in Figure 1 comprises two substantially parallel platforms and substantially cylindrical about the axis of the distributor 100 (only one of the two platforms 110 is visible in Figure 1).
• These platforms 110 have a contour in the form of a quadrilateral, in this case a parallelogram.
• the parallelogram there are two opposite sides forming contact surfaces 111, 112 respectively directed towards the two sectors of distributors 200 and 300 disposed on either side of the sector 100 measured (relative mounting position).
• the contact surfaces 111, 112 are designed to keep the adjacent distributor sectors, for example the sectors 100, 200, 300, in the relative position of contact in FIG. 1.
• the other two sides of the parallelogram form lateral faces 113, 114 delimiting the two outer circles of the ring formed by the distributor.
• the distributor sector 100 further comprises two vanes 120, 130.
• Each of these blades has an aerodynamic profile and comprises an extrados 121, 131, and a lower surface 122, 132.
• each of the vanes 110, 120 is an end vane.
• each of these vanes is caused to be disposed vis-a-vis with an end vane of the adjacent distributor sector, in relative mounting position.
• the extrados 121 is vis-à-vis the intrados 232 of the blade 230
• the intrados 132 is vis-à-vis the upper surface 321 of the blade 320.
• the blades 230 and 320 are standard blades, which are the reference vanes for the measurement of the passage sections of the distributor 100.
• inter-blade passages 101, 102, 103 Between the different vanes 230, 120, 130, 320 are formed respectively inter-blade passages 101, 102, 103
• the inter-blade passage 102 is formed between the blades 120 and 130 of the sector 100.
• the inter-blade passages 101 and 103 are formed between, on the one hand, a blade (120 or 130) of the sector 100 considered, and on the other hand the reference blade vis-a-vis, 230 or 320.
• the distance between the blades varies as a function of the position in the channel.
• This plane corresponds respectively to the planes PI, P2, P3 for the inter-vane passages 101, 102, 103; the distance between the blades in these sections is respectively D1, D2, D3, these three distances corresponding to the three measurements made on the measuring bench.
• the surface to be coated with said blade 120 (or 130) is the extrados wall 121 (or 131).
• FIG. 2 it is the section of the blade 120 which is shown in a transverse plane orthogonal to the longitudinal direction along which extends the blade 120.
• the coating 20 obtained by the method of the invention extends over the upper surface 121 only, essentially over the entire surface of this extrados 121, on the one hand between the two longitudinal ends which are mounted on the platforms and secondly between the leading edge 124 and the trailing edge 123,
• the coating 20 has a relatively constant average thickness E over its entire surface, with the exception of the edge at which the thickness of the coating 20 decreases progressively from the average value E to a value substantially zero
• the average thickness E of the coating is between 10 and 11
• the critical zone 21 is the measuring zone of the passage section so that the repair method according to the invention allows the restoration of the passage section of the blade 120 by reloading.
• said coating 20 has a precise and constant predetermined thickness at the location of a critical zone 21 which in this example corresponds to the location of the measurement of the passage section (distance D2 in FIG. ) and which is called the neck of the extrados wall 121.
• said coating 20 has, for the critical zone 21, a thickness E1 of between 10 and 500 microns and in particular between 10 and 300 microns.
• this thickness E1 is constant for the entire critical zone 21.
• critical zone 21 extends over the width
• the coating may have a thickness that begins to decrease outside the critical zone 21 or neck just after this critical zone 21.
• blade 120 is a nickel-cobalt-based superalloy blade, and in particular may be of standard AMI (or NiTa8Cr8CoWA) type with a low sulphide content, ReneNS, DSR142, Renel25 (or NiColOCr9WAITaTiMo ), IN100 (or NiCol5CrlOAITi), or CMSX4 alloy.
• AMI or NiTa8Cr8CoWA
• ReneNS ReneNS
• DSR142 Renel25
• Renel25 or NiColOCr9WAITaTiMo
• IN100 or NiCol5CrlOAITi
• CMSX4 alloy or CMSX4 alloy.
• the coating 20 consists of a metal matrix composite containing particles, which is of the MiCrAIM 2 type, Mi being chosen from Ni, Co and Fe or a mixture, M 2 being chosen from Y, Si, Ti, Hf, Ta , Nb, Mn, Pt and rare earths.
• Rare earth means the elements belonging to the group of lanthanides (lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium), scandium, yttrium, zirconium and hafnium.
• lanthanides lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium
• scandium yttrium, zirconium and hafnium.
• a solution is used for forming the electrolyte, the particles of which are particles of CrAlM 2 , M 2 being chosen from Y, Si, Ti, Hf, Ta, Nb, Mn and Pt. and rare earths.
• an anode made of a metal M u M x is chosen from Ni, Co and Fe or a mixture of these metals.
• NiCrAlY In order to obtain a deposit of NiCrAlY, it is necessary to produce a composite deposit comprising on the one hand nickel and on the other hand particles of CrAIY (Ni can be replaced by Co). NiCrAIY coatings are produced by the controlled coding of CrAIY powder present in a conventional electrolytic bath with nickel from the anode.
• the metal anode in our example Ni
• the metal anode is oxidized and releases Ni 2+ ions into the solution.
• These ions move in the solution always under the effect of the potential difference and move towards the cathode by mixing in the passage with the dispersed particles present in the solution.
• the set formed by ions and particles then migrates towards the cathode and ends up reaching its surface where it is deposited (Ni 2+ then reduced to metallic Ni) thus forming on the cathode a coating of NiCrAlY in which the particles of CrAIY are finely dispersed within a matrix of Ni.
• a thermal treatment of the distributor sector is carried out by placing it in a vacuum chamber for a time and at a temperature adapted to the material forming the substrate, according to a typical example for two hours at a temperature of 1080 ° C.
• FIG. 7 schematically showing an example of a co-deposition installation 10 making it possible to implement the method according to the invention.
• the installation 10 comprises a support 12 made of a non-electrically conductive material having a reference wall 14 and adapted to receive said blade 120, 130 in a working position with respect to the reference wall 14 .
• said support 12 is able to receive two vanes 120 and 130 in a working position with respect to the reference wall 14. In this case, it is a question of mounting a distributor sector.
• 100 complete formed two platforms (only the platform 110 is visible in Figure 7) between which extend the two blades 120 and 130. Without departing from the scope of the present invention, it is possible to provide that the support 12 is capable of receiving more than two blades in a working position with respect to the reference wall 14.
• the reference wall 14 of the support 12 is slid against one of the two lateral faces 113, 114 of the platform 110 of the distributor sector.
• the support 12 is equipped, for each blade to be coated, control means of the current lines to guide them, guiding and concentrating, towards the surface to be coated with said blade.
• the support 12 comprises, for each blade 120, 130 of the sector 100, a longitudinal portion 15 equipped with a working wall 17 extending opposite the entire extrados wall 131 of the corresponding blade 130, between its two longitudinal ends attached to the platforms, from the leading edge to the trailing edge.
• the support 12 of FIG. 7 comprises two identical and parallel longitudinal portions 15 which firstly limit and direct the current lines in the zone 13 extending between the working wall 17 and the surface to be coated (wall extrados 131). Secondly, the longitudinal portion 15 which lies between the two blades 120, 130 of the sector 100 forms a screen for the intrados wall 132 of the other blade 130, which is on the opposite side to the working wall 17 of this longitudinal portion 15.
• the working wall 17 is equipped, at the location 16, with an anode 19 connected to a current source.
• This anode 19 is for example formed of a cylinder of a few millimeters in diameter made of a metal Mi, Mi being chosen from Ni, Co and Fe or a mixture, in order to supply this element or these elements to the solution and to form the coating 20 of type iCrAIM 2 .
• the shape of the anode can be chosen from a large number of profiles including but not limited to a rod, a bar, a plate, or a configuration according to the shape of the aerodynamic profile.
• This anode 19 is fixed to the longitudinal portion 15 which carries it.
• the profile and the position of the longitudinal portion 15 of the support 12 and the anode 19 with respect to the surface to be coated being selected so as to limit and orient the streamlines.
• the anode 19 is connected to a current source in order to generate a potential difference between the cathode (blade 130) and the anode 19.
• the profile of the working wall 17 of the portion 15 which has a general shape complementary to the shape of the profile of the extrados wall 121, 131, and at the distance between this wall 14 and the extrados wall 121, 131, it is possible to orient the field lines optimally to form the coating 20 on the extrados wall 121, 131.
• the areas of the blade 120, 130 which are not to be coated, in particular at the locations of the holes and bores, are masked beforehand.
• fields for example plastic are placed to cover the areas of the dispenser sector (or any part to be coated in general) not to cover for the duration of the electrolytic co-deposition (for example the plates -Internal and external forms of the distributor sector). It is also possible to use wax which is placed in the zones not to be covered, and in particular at the entrance of the holes and bores, in order to prevent the coating, by reaching them, from modifying their size or obstructing them.
• controlled stirring of the powder in the electrolytic bath is provided.
• a circulation in the solution is established with an upward circulation in a first space of the solution and a downward circulation in a second space of the solution, the support 12 being placed in said second space.
• a rotation of the support 12 is instituted around an axis having a horizontal component.
• EP 0 355 051 and EP 0 724 658 for the conditions of movement of the electrolyte and the part in the electrolyte, as well as for the galvanic parameters.
• a coating having any composition of MCrAIY, or more generally MiCrAIM 2 , while having controlled thicknesses, in particular in the critical zone and along the edges.
• Such coatings obtained by electrodeposition also have the other advantage of being very slightly rough (Ra of the order of 1 to 2 ⁇ m), of not being porous and of making a strong (metallic) bond between the substrate and the substrate. coating.
• such a method has the advantage of not generating thermal stress in the substrate.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Electroplating Methods And Accessories (AREA)
• Electroplating And Plating Baths Therefor (AREA)

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• 2009
  • 2009-12-29 FR FR0959633A patent/FR2954780B1/fr active Active
• 2010
  • 2010-12-28 SG SG2012047486A patent/SG181957A1/en unknown
  • 2010-12-28 US US13/519,350 patent/US9464363B2/en active Active
  • 2010-12-28 RU RU2012132466/02A patent/RU2567143C2/ru active
  • 2010-12-28 BR BR112012016144-0A patent/BR112012016144B1/pt active IP Right Grant
  • 2010-12-28 JP JP2012546495A patent/JP5788410B2/ja active Active
  • 2010-12-28 WO PCT/FR2010/052928 patent/WO2011080485A1/fr not_active Ceased
  • 2010-12-28 CA CA2785387A patent/CA2785387C/fr active Active
  • 2010-12-28 CN CN201080060267.XA patent/CN102762778B/zh active Active
  • 2010-12-28 EP EP10808935.0A patent/EP2519663B1/de active Active

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