US20060213435A1 - Inlet coating for gas turbines - Google Patents

Inlet coating for gas turbines Download PDF

Info

Publication number
US20060213435A1
US20060213435A1 US10/552,213 US55221305A US2006213435A1 US 20060213435 A1 US20060213435 A1 US 20060213435A1 US 55221305 A US55221305 A US 55221305A US 2006213435 A1 US2006213435 A1 US 2006213435A1
Authority
US
United States
Prior art keywords
coating
abradable coating
layer
abradable
casing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/552,213
Inventor
Christian Friedrich
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MTU Aero Engines AG
Original Assignee
MTU Aero Engines GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=33394727&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=US20060213435(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by MTU Aero Engines GmbH filed Critical MTU Aero Engines GmbH
Assigned to MTU AERO ENGINES GMBH reassignment MTU AERO ENGINES GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FREIDRICH, CHRISTIAN
Publication of US20060213435A1 publication Critical patent/US20060213435A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • 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
    • F01D5/12—Blades
    • F01D5/14—Form or construction
    • F01D5/20—Specially-shaped blade tips to seal space between tips and stator
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C23C28/042—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C23C28/044—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material coatings specially adapted for cutting tools or wear applications
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
    • C23C28/322—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
    • C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
    • C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer
    • C23C28/3455—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
    • C23C28/347—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with layers adapted for cutting tools or wear applications
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
    • 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
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • F01D11/12—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator using a rubstrip, e.g. erodible. deformable or resiliently-biased part
    • F01D11/122—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator using a rubstrip, e.g. erodible. deformable or resiliently-biased part with erodable or abradable material
    • 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
    • F01D5/12—Blades
    • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
    • F01D5/288—Protective coatings for blades
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2300/00—Materials; Properties thereof
    • F05D2300/10—Metals, alloys or intermetallic compounds
    • F05D2300/15—Rare earth metals, i.e. Sc, Y, lanthanides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

  • the present invention is directed to an abradable coating for gas turbines according to the definition of the species in claim 1 .
  • Gas turbines such as aircraft engines, typically include a plurality of rotating blades, as well as a plurality of stationary guide vanes, the blades rotating together with a rotor and the blades, as well as the guide vanes being enclosed by a fixed casing of the gas turbine.
  • a fixed casing of the gas turbine To boost the performance of an aircraft engine, it is vitally important that all components and subsystems be optimized. These also include the so-called sealing systems in aircraft engines. Maintaining a minimal gap between the rotating blades and the fixed casing of a high-pressure gas turbine is especially problematic in the context of aircraft engines. Namely, in high-pressure gas turbines, the highest absolute temperatures, as well as the greatest temperature gradients occur. This complicates the task of maintaining the gap between the rotating blades and the fixed casing of the compressor. This has to do, inter alia, with the fact that the shrouds, as are used for turbines, have been eliminated in the case of compressor blades.
  • the blades in the compressor are not provided with a shroud.
  • the ends or tips of the rotating blades are subjected to a direct frictional contact with the fixed casing when rubbing into the same.
  • Such a rubbing of the blade tips into the casing is caused by manufacturing tolerances produced when a minimal radial gap is set. Since the frictional contact of the tips of the rotating blades against the casing causes material to be ablated from the tips of the rotating blades, the gap can become undesirably enlarged over the entire periphery of the casing and rotor.
  • it is already known from related art methods to hardface the ends or tips of the rotating blades with a hard coating or with abrasive particles.
  • the EP 0765 951 B 1 describes an abradable coating for a gas turbine whose outer layer or top layer of the abradable coating, which is in contact with the tips of the blades, is produced from zirconium dioxide. Another abradable coating is known from the U.S. Pat. No. 4,936,745.
  • the object of the present invention is to devise a novel type of abradable coating for gas turbines.
  • the abradable coating according to the present invention for gas turbines is used for sealing a radial gap between a fixed casing of the gas turbine and rotating blades of the same.
  • the abradable coating is applied to the casing.
  • the abradable coating is at least single-layered, at least one outer layer of the abradable coating being fabricated from a material having a magnetoplumbite structure, preferably from lanthanum hexaaluminate. Accordingly, the present invention provides for the outer layer of the abradable coating, which first comes in contact with the rotating blades, to no longer be produced from zirconium dioxide, but preferably from lanthanum hexaaluminate.
  • the abradable coating is multi-layered, the outermost layer of the abradable coating, which is first able to be contacted by ends of the blades, being fabricated from lanthanum hexaaluminate.
  • at least one additional, interior layer is disposed between the outer layer of lanthanum hexaaluminate and the casing.
  • a first interior layer is formed as an adhesion-promoting layer;
  • a second interior layer is produced from zirconium dioxide and is disposed between the first interior layer and the layer of lanthanum hexaaluminate.
  • the second interior layer of zirconium dioxide is provided for increasing the useful life of the abradable coating.
  • FIG. 1 shows a very schematized representation of a blade of a gas turbine, together with a casing of the gas turbine and including an abradable coating applied to the housing;
  • FIG. 2 shows a very schematized representation of a blade of a gas turbine, together with a casing of the gas turbine and including an alternative abradable coating applied to the casing.
  • FIG. 1 illustrates a rotating blade 10 of a gas turbine, which rotates against a fixed casing 11 , in the direction of arrow 12 .
  • An abradable coating 13 is disposed on casing 11 .
  • Abradable coating 13 is used for sealing a radial gap between a tip, i.e., an end 14 of rotating blade 10 and fixed casing 11 .
  • the demands placed on such an abradable coating are very complex.
  • the abradable coating must exhibit optimized wear characteristics, i.e., good chip formation and removability of the abraded material.
  • there should be no transfer of material to rotating blades 10 .
  • abradable coating 13 must exhibit a low frictional resistance.
  • Abradable coating 13 must also not ignite in response to rotating blades 10 rubbing against it.
  • Other demands placed on abradable coating 13 that are mentioned here exemplarily include erosion resistance, temperature resistance, resistance to heat exchange, and corrosion resistance to lubricants and sea water.
  • FIG. 1 illustrates ends 14 of blades 10 coming in contact with abradable coating 13 , thereby releasing ablated material 15 in response to the centrifugal forces occurring during operation of the gas turbine and heating of the gas turbine. This pulverized ablated material 15 must be prevented from causing damage to rotating blades 10 .
  • abradable coating 13 is fabricated from a material having a magnetoplumbite structure; in the illustrated exemplary embodiment, from lanthanum hexaaluminate.
  • the exemplary embodiment of FIG. 1 relates to a single-layered abradable coating 13 , the only layer of abradable coating 13 being produced from the lanthanum hexaaluminate and being directly deposited on casing 11 . Accordingly, the present invention provides for lanthanum hexaaluminate to be used for fabricating the outer layer of abradable coatings, instead of the zirconium dioxide known from the related art.
  • FIG. 2 illustrates a second exemplary embodiment of the present invention.
  • FIG. 2 shows, in turn, a rotating blade 16 , which is rotating in the direction of arrow 17 relative to a fixed housing 18 .
  • An abradable coating 19 is again disposed on casing 18 .
  • abradable coating 19 of the exemplary embodiment according to FIG. 2 is not single-layered, but rather multi-layered.
  • An outer layer 20 of abradable coating 19 which first makes contact with blades 16 , is again produced in accordance with the present invention from lanthanum hexaaluminate.
  • Interior layer 21 is provided between outer layer 20 and casing 18 .
  • Interior layer 21 is an adhesion-promoting layer, whose purpose is to improve the adhesion between casing 18 and outer layer 20 .
  • Adhesion-promoting interior layer 20 may be metallic.
  • An additional intermediate layer (not shown) of zirconium dioxide may be placed between the adhesion-promoting, interior layer 21 and outer layer 20 of lanthanum hexaaluminate.
  • the purpose of this intermediate layer of zirconium dioxide is to improve the properties of the laminar structure, in particular, to increase its useful life.
  • the outer layer of a multi-layer abradable coating which first comes in contact with the rotating blades of the gas turbine, should be produced from lanthanum hexaaluminate.
  • FIG. 2 depicts a sealing system for a gas turbine, where an abradable coating 19 according to the present invention that is deposited on casing 18 of the gas turbine is combined with a barrier coating 23 disposed on the blade tips.
  • FIGS. 1 and 2 Underlying both exemplary embodiments of FIGS. 1 and 2 is the principle according to the present invention whereby an outer layer of an abradable coating, which comes in contact with the tips of the rotating blades, is produced from lanthanum hexaaluminate.

Abstract

An abradable coating for gas turbines is provided. The abradable coating is used for sealing a radial gap between a casing (11) of the gas turbine and rotating blades (10) of the same. The abradable coating (13) is applied to the casing. The abradable coating (13) is at least single-layered, at least one outer layer of the abradable coating (13) being produced from a material having a magnetoplumbite structure, preferably lanthanum hexaaluminate.

Description

  • The present invention is directed to an abradable coating for gas turbines according to the definition of the species in claim 1.
  • Gas turbines, such as aircraft engines, typically include a plurality of rotating blades, as well as a plurality of stationary guide vanes, the blades rotating together with a rotor and the blades, as well as the guide vanes being enclosed by a fixed casing of the gas turbine. To boost the performance of an aircraft engine, it is vitally important that all components and subsystems be optimized. These also include the so-called sealing systems in aircraft engines. Maintaining a minimal gap between the rotating blades and the fixed casing of a high-pressure gas turbine is especially problematic in the context of aircraft engines. Namely, in high-pressure gas turbines, the highest absolute temperatures, as well as the greatest temperature gradients occur. This complicates the task of maintaining the gap between the rotating blades and the fixed casing of the compressor. This has to do, inter alia, with the fact that the shrouds, as are used for turbines, have been eliminated in the case of compressor blades.
  • As just mentioned, the blades in the compressor are not provided with a shroud. For that reason, the ends or tips of the rotating blades are subjected to a direct frictional contact with the fixed casing when rubbing into the same. Such a rubbing of the blade tips into the casing is caused by manufacturing tolerances produced when a minimal radial gap is set. Since the frictional contact of the tips of the rotating blades against the casing causes material to be ablated from the tips of the rotating blades, the gap can become undesirably enlarged over the entire periphery of the casing and rotor. To overcome this problem, it is already known from related art methods, to hardface the ends or tips of the rotating blades with a hard coating or with abrasive particles.
  • Another way to ensure that the tips of the rotating blades to not become worn and to provide an optimized sealing action between the ends or tips of the rotating blades and the fixed casing is to coat the casing with a so-called abradable coating. When material is ablated from an abradable coating, the radial gap is not enlarged over the entire periphery, but rather, typically, only in a sickle shape. This makes it possible to avoid a decline in the engine performance. Casings having an abradable coating are generally known from the related art.
  • The EP 0765 951 B 1 describes an abradable coating for a gas turbine whose outer layer or top layer of the abradable coating, which is in contact with the tips of the blades, is produced from zirconium dioxide. Another abradable coating is known from the U.S. Pat. No. 4,936,745.
  • Against this background, the object of the present invention is to devise a novel type of abradable coating for gas turbines.
  • This objective is achieved in that the abradable coating mentioned at the outset is further refined by the features set forth in the characterizing portion of claim 1.
  • The abradable coating according to the present invention for gas turbines is used for sealing a radial gap between a fixed casing of the gas turbine and rotating blades of the same. The abradable coating is applied to the casing. In accordance with the present invention, the abradable coating is at least single-layered, at least one outer layer of the abradable coating being fabricated from a material having a magnetoplumbite structure, preferably from lanthanum hexaaluminate. Accordingly, the present invention provides for the outer layer of the abradable coating, which first comes in contact with the rotating blades, to no longer be produced from zirconium dioxide, but preferably from lanthanum hexaaluminate.
  • In accordance with one advantageous embodiment of the present invention, the abradable coating is multi-layered, the outermost layer of the abradable coating, which is first able to be contacted by ends of the blades, being fabricated from lanthanum hexaaluminate. In this case, at least one additional, interior layer is disposed between the outer layer of lanthanum hexaaluminate and the casing. A first interior layer is formed as an adhesion-promoting layer; a second interior layer is produced from zirconium dioxide and is disposed between the first interior layer and the layer of lanthanum hexaaluminate. The second interior layer of zirconium dioxide is provided for increasing the useful life of the abradable coating.
  • Preferred embodiments of the present invention are derived from the dependent claims and from the following description.
  • The present invention is described in greater detail in the following on the basis of exemplary embodiments, without being limited thereto. Reference is made to the drawing, whose:
  • FIG. 1 shows a very schematized representation of a blade of a gas turbine, together with a casing of the gas turbine and including an abradable coating applied to the housing; and
  • FIG. 2 shows a very schematized representation of a blade of a gas turbine, together with a casing of the gas turbine and including an alternative abradable coating applied to the casing.
  • In a highly schematized view, FIG. 1 illustrates a rotating blade 10 of a gas turbine, which rotates against a fixed casing 11, in the direction of arrow 12. An abradable coating 13 is disposed on casing 11.
  • Abradable coating 13 is used for sealing a radial gap between a tip, i.e., an end 14 of rotating blade 10 and fixed casing 11. The demands placed on such an abradable coating are very complex. Thus, the abradable coating must exhibit optimized wear characteristics, i.e., good chip formation and removability of the abraded material. In addition, there should be no transfer of material to rotating blades 10. Moreover, abradable coating 13 must exhibit a low frictional resistance. Abradable coating 13 must also not ignite in response to rotating blades 10 rubbing against it. Other demands placed on abradable coating 13 that are mentioned here exemplarily include erosion resistance, temperature resistance, resistance to heat exchange, and corrosion resistance to lubricants and sea water.
  • FIG. 1 illustrates ends 14 of blades 10 coming in contact with abradable coating 13, thereby releasing ablated material 15 in response to the centrifugal forces occurring during operation of the gas turbine and heating of the gas turbine. This pulverized ablated material 15 must be prevented from causing damage to rotating blades 10.
  • Along the lines of the present invention, abradable coating 13 is fabricated from a material having a magnetoplumbite structure; in the illustrated exemplary embodiment, from lanthanum hexaaluminate. The exemplary embodiment of FIG. 1 relates to a single-layered abradable coating 13, the only layer of abradable coating 13 being produced from the lanthanum hexaaluminate and being directly deposited on casing 11. Accordingly, the present invention provides for lanthanum hexaaluminate to be used for fabricating the outer layer of abradable coatings, instead of the zirconium dioxide known from the related art.
  • FIG. 2 illustrates a second exemplary embodiment of the present invention. Thus, FIG. 2 shows, in turn, a rotating blade 16, which is rotating in the direction of arrow 17 relative to a fixed housing 18. An abradable coating 19 is again disposed on casing 18.
  • However, in contrast to the exemplary embodiment of FIG. 1, abradable coating 19 of the exemplary embodiment according to FIG. 2 is not single-layered, but rather multi-layered. An outer layer 20 of abradable coating 19, which first makes contact with blades 16, is again produced in accordance with the present invention from lanthanum hexaaluminate.
  • In addition, an interior layer 21 is provided between outer layer 20 and casing 18. Interior layer 21 is an adhesion-promoting layer, whose purpose is to improve the adhesion between casing 18 and outer layer 20. Adhesion-promoting interior layer 20 may be metallic.
  • An additional intermediate layer (not shown) of zirconium dioxide may be placed between the adhesion-promoting, interior layer 21 and outer layer 20 of lanthanum hexaaluminate. The purpose of this intermediate layer of zirconium dioxide is to improve the properties of the laminar structure, in particular, to increase its useful life.
  • It is noted here that three- or multi-layer abradable coatings along the lines of the present invention may, of course, also be provided. In accordance with the present invention, however, the outer layer of a multi-layer abradable coating, which first comes in contact with the rotating blades of the gas turbine, should be produced from lanthanum hexaaluminate.
  • In the exemplary embodiment of FIG. 2, a so-called barrier coating 23 is provided at end 22, i.e., at the tip of rotating blade 16. This barrier coating 23 is essentially produced by hardfacing of the blade tips. In the illustrated exemplary embodiment, barrier coating 23 encompasses a plurality of wedge-shaped elements 24, clearance spaces 25 being formed between adjacent elements 24 of barrier coating 23. In this respect, FIG. 2 depicts a sealing system for a gas turbine, where an abradable coating 19 according to the present invention that is deposited on casing 18 of the gas turbine is combined with a barrier coating 23 disposed on the blade tips.
  • Underlying both exemplary embodiments of FIGS. 1 and 2 is the principle according to the present invention whereby an outer layer of an abradable coating, which comes in contact with the tips of the rotating blades, is produced from lanthanum hexaaluminate.
  • Especially beneficial properties are able to be achieved using an abradable coating of this kind. Thus, particularly good wear characteristics of the abradable coating are obtained. The other demands made of the abradable coating are also fulfilled or influenced in a beneficial way. For example, the temperature stability and useful life of the abradable coatings are improved.
  • Mention is made at this point that the abradable coating according to the present invention is deposited on the metallic surface of the casing using thermal spray-coating processes. The details pertaining to such thermal spray-coating processes are familiar to one skilled in the art whom this technical teaching concerns.

Claims (14)

1-7. (canceled)
8. An abradable coating for application to a casing of a gas turbine, comprising a coating produced from a material having a magnetoplumbite structure.
9. The abradable coating as recited in claim 8, wherein the material is produced from lanthanum hexaaluminate.
10. The abradable coating as recited in claim 8, wherein the abradable coating is a single-layer coating, and wherein the only layer of the single layer coating abradable coating is produced from lanthanum hexaaluminate.
11. The abradable coating as recited in claim 8, wherein the abradable coating is a multi-layered coating, and an outermost layer of the abradable coating is produced from lanthanum hexaaluminate.
12. The abradable coating as recited in claim 11, wherein the multi-layered coating includes an interior layer, disposed between the outer layer of lanthanum hexaaluminate and a casing to which the coating is applied.
13. The abradable coating as recited in claim 12, wherein the interior layer is an adhesion-promoting layer.
14. The abradable coating as recited in claim 12, wherein the multi-layered coating further includes an intermediate layer of zirconium dioxide disposed between the interior layer and the outer layer of lanthanum hexaaluminate.
15. A gas turbine comprising
a plurality of rotating blades,
a casing enclosing the plurality of rotating blades; and
an abradable coating on the casing, the abradable coating sealing a radial gap between the casing and the rotating blades, wherein the coating is produced from a material having a magnetoplumbite structure.
16. The gas turbine as recited in claim 15, wherein the material is produced from lanthanum hexaaluminate.
17. The gas turbine as recited in claim 15, wherein the abradable coating is a single-layer coating, and wherein the only layer of the single layer coating abradable coating is produced from lanthanum hexaaluminate.
18. The gas turbine as recited in claim 15, wherein the abradable coating is a multi-layered coating, and an outermost layer of the abradable coating is produced from lanthanum hexaaluminate.
19. The gas turbine as recited in claim 18, wherein the multi-layered coating includes an interior layer, disposed between the outer layer of lanthanum hexaaluminate and the casing.
20. The gas turbine as recited in claim 19, wherein the interior layer is an adhesion-promoting layer.
US10/552,213 2003-05-17 2004-04-17 Inlet coating for gas turbines Abandoned US20060213435A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10322339A DE10322339A1 (en) 2003-05-17 2003-05-17 Inlet lining for gas turbines
DE10322339.8 2003-05-17
PCT/DE2004/000808 WO2004104378A1 (en) 2003-05-17 2004-04-17 Inlet coating for gas turbines

Publications (1)

Publication Number Publication Date
US20060213435A1 true US20060213435A1 (en) 2006-09-28

Family

ID=33394727

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/552,213 Abandoned US20060213435A1 (en) 2003-05-17 2004-04-17 Inlet coating for gas turbines

Country Status (4)

Country Link
US (1) US20060213435A1 (en)
EP (1) EP1625283B2 (en)
DE (1) DE10322339A1 (en)
WO (1) WO2004104378A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070248764A1 (en) * 2004-05-26 2007-10-25 Mtu Aero Engines Gmbh Heat-Insulating Layer System
US20110127728A1 (en) * 2009-11-27 2011-06-02 Rolls-Royce Deutschland Ltd & Co Kg Sealing rings for a labyrinth seal
US20160008791A1 (en) * 2013-03-07 2016-01-14 Basf Se Nickel hexaaluminate-containing catalyst for reforming hydrocarbons in the presence of carbon dioxide
US20180306048A1 (en) * 2017-04-20 2018-10-25 Safran Aircraft Engines Sealing ring element for a turbine comprising an inclined cavity in an abradable material

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004009752A1 (en) * 2004-02-28 2005-09-15 Mtu Aero Engines Gmbh layer system
DE102006027728A1 (en) 2006-06-16 2007-12-20 Mtu Aero Engines Gmbh thermal barrier
EP2309098A1 (en) * 2009-09-30 2011-04-13 Siemens Aktiengesellschaft Airfoil and corresponding guide vane, blade, gas turbine and turbomachine
FR3026428B1 (en) * 2014-09-30 2019-10-25 Safran Aircraft Engines RADIANT TURBOMACHINE TURBOMACHINE ROTOR BEARD

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4269903A (en) * 1979-09-06 1981-05-26 General Motors Corporation Abradable ceramic seal and method of making same
US4936745A (en) * 1988-12-16 1990-06-26 United Technologies Corporation Thin abradable ceramic air seal
US20020197503A1 (en) * 2001-05-09 2002-12-26 Bilge Saruhan-Brings Thermal-insulating material having an essentially magnetoplumbitic crystal structure
US6602814B1 (en) * 1998-02-20 2003-08-05 Mtu Aero Engines Gmbh Thermal insulating material and method of producing same
US20040012152A1 (en) * 2002-06-10 2004-01-22 Mtu Aero Engines Gmbh Layer system for the rotor/stator seal of a turbomachine

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4299865A (en) † 1979-09-06 1981-11-10 General Motors Corporation Abradable ceramic seal and method of making same
US5704759A (en) † 1996-10-21 1998-01-06 Alliedsignal Inc. Abrasive tip/abradable shroud system and method for gas turbine compressor clearance control

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4269903A (en) * 1979-09-06 1981-05-26 General Motors Corporation Abradable ceramic seal and method of making same
US4936745A (en) * 1988-12-16 1990-06-26 United Technologies Corporation Thin abradable ceramic air seal
US6602814B1 (en) * 1998-02-20 2003-08-05 Mtu Aero Engines Gmbh Thermal insulating material and method of producing same
US20020197503A1 (en) * 2001-05-09 2002-12-26 Bilge Saruhan-Brings Thermal-insulating material having an essentially magnetoplumbitic crystal structure
US20040012152A1 (en) * 2002-06-10 2004-01-22 Mtu Aero Engines Gmbh Layer system for the rotor/stator seal of a turbomachine

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070248764A1 (en) * 2004-05-26 2007-10-25 Mtu Aero Engines Gmbh Heat-Insulating Layer System
US7445851B2 (en) 2004-05-26 2008-11-04 Mtu Aero Engines Gmbh Heat-insulating layer system
US20110127728A1 (en) * 2009-11-27 2011-06-02 Rolls-Royce Deutschland Ltd & Co Kg Sealing rings for a labyrinth seal
US9016692B2 (en) * 2009-11-27 2015-04-28 Rolls-Royce Deutschland Ltd & Co Kg Sealing rings for a labyrinth seal
US20160008791A1 (en) * 2013-03-07 2016-01-14 Basf Se Nickel hexaaluminate-containing catalyst for reforming hydrocarbons in the presence of carbon dioxide
US9475037B2 (en) * 2013-03-07 2016-10-25 Basf Se Nickel hexaaluminate-containing catalyst for reforming hydrocarbons in the presence of carbon dioxide
US20180306048A1 (en) * 2017-04-20 2018-10-25 Safran Aircraft Engines Sealing ring element for a turbine comprising an inclined cavity in an abradable material
US11215066B2 (en) * 2017-04-20 2022-01-04 Safran Aircraft Engines Sealing ring element for a turbine comprising an inclined cavity in an abradable material

Also Published As

Publication number Publication date
EP1625283B1 (en) 2012-05-09
DE10322339A1 (en) 2004-12-02
WO2004104378A1 (en) 2004-12-02
EP1625283A1 (en) 2006-02-15
EP1625283B2 (en) 2015-09-02

Similar Documents

Publication Publication Date Title
US7614847B2 (en) Pattern for the surface of a turbine shroud
US6533285B2 (en) Abradable coating and method of production
JP6340010B2 (en) Seal system for use in a turbomachine and method of making the same
US4936745A (en) Thin abradable ceramic air seal
US7749565B2 (en) Method for applying and dimensioning an abradable coating
CA2657190C (en) Gas turbine with a peripheral ring segment comprising a recirculation channel
EP2281913B1 (en) Lubricated abradable coating
JP6612096B2 (en) Abradable seal and method of forming abradable seal
JPS58113503A (en) Blade of fluid machine and its manufacture
US9062558B2 (en) Blade outer air seal having partial coating
JPH0160680B2 (en)
US20110171010A1 (en) Sealing System Between a Shroud Segment and a Rotor Blade Tip and Manufacturing Method for Such a Segment
US9982358B2 (en) Abrasive tip blade manufacture methods
US20160245110A1 (en) Hard phaseless metallic coating for compressor blade tip
US20170218768A1 (en) Blade of a turbomachine having blade root thermal insulation
US8128349B2 (en) Gas turbine engines and related systems involving blade outer air seals
US10927685B2 (en) Coating to improve oxidation and corrosion resistance of abrasive tip system
EP3456928A1 (en) Turbine engine seal for high erosion environment
US20060213435A1 (en) Inlet coating for gas turbines
US20110171039A1 (en) Blade arrangement of a gas turbine
US8257045B2 (en) Platforms with curved side edges and gas turbine engine systems involving such platforms
US7699581B2 (en) Run-in coating for gas turbines and method for producing same
CN110662884B (en) Turbine blade with recessed tip and dense oxide dispersion strengthened layer
US20130084167A1 (en) Wear-resistant coating and use thereof
US8992169B2 (en) Layer system for rotor/stator seal of a turbomachine and method for producing this type of layer system

Legal Events

Date Code Title Description
AS Assignment

Owner name: MTU AERO ENGINES GMBH, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FREIDRICH, CHRISTIAN;REEL/FRAME:017859/0200

Effective date: 20050822

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION