Classifications

• • 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
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
• • 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
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
  • C23C4/11—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
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying

Definitions

• TITLE METHOD FOR MAKING HEAT BARRIER COATINGS, COATINGS AND STRUCTURE OBTAINED THEREBY AS WELL AS COMPONENTS COATED THEREWITH
• the present invention relates to the development of a thick TBC coating, for application on gas turbine components, mainly on heat shields, combustion chambers and turbine wall covering panels , and the method for making it. Nevertheless, protection is not only requested hereby for such application, but for any TBC deposition application, such as in the automotive industry (combustion engines) .
• the present invention relates to coatings, typically of ceramic material, deposited on a previously deposited layer used as a bond coat, said layers being obtained by Thermal Spray processes, such as:
• these coatings improve corrosion and heat-oxidation resistance of components, such as gas turbines and aeronautical engines .
• the above mentioned deposits may be, for instance, of a metal material obtained from a M-CrAlY alloy (where M means Ni, Co, Fe or a combination thereof) followed by yttria partially stabilized zirconia (YPSZ) coatings .
• M means Ni, Co, Fe or a combination thereof
• YPSZ yttria partially stabilized zirconia
• TBC thermal barrier coatings
• thin TBCs are defined as coatings of a thickness from 200 to 800 ⁇ m
• thick TBCs are ceramic coatings of a thickness greater than 1 mm, generally in a range from 1,2 to 3 mm.
• the present invention relates to the particular method for depositing thick coatings, i.e. the particular handling/pivoting of the torch relative to the surface on which the coating has to be deposited, to obtain an improved coating microstrueture as compared with currently available ones.
• the present invention applies to both thick and thin coatings .
• the structure so obtained improves resistance of the coating to thermal cycling fatigue (TFC) , and thereby increases the performances of the components coated thereby (reduced operating temperatures and extended life of the component) .
• TFC thermal cycling fatigue
• the principle of thermal spray technologies consists in supplying energy to the material to be deposited until it melts, and transfer it to the substrate to be coated.
• Energy may be supplied to the material to be deposited from various sources : energy deriving from combustion between oxygen and a fuel, either in gas form (propane, acetylene, hydrogen) or in liquid form (kerosene) or deriving from recombination of ions in a plasma.
• Thermal spray technologies include :
• the coating results from successive deposition of various numbers of layers which join together to form the coating (passes) .
• Figure 1 shows a component to be coated according to the present method, namely a part of combustion chamber
• Figure 2 shows the structure of a thermal barrier
• Figure 3 is an exemplary micrograph of the thermal barrier obtained by the present method, showing that porosity is variable
• FIG. 4 is a schematic view of the system for thermal spray deposition of the coating, showing the changing angle of incidence of the torch relative to the surface to be coated.
• numeral 5 designates a component to be coated by TBC as described above; the component 5 may be part of a gas or aeronautical turbine .
• the surface 3 is the one to be coated with the thick TBC.
• thermal barrier coating system 11 according to the inventive specifications is shown, which barrier 11 is laid over the surface 3 of the component 5.
• the thermal barrier coating system (TBC) 11 has a substrate 15 acting as a binder and/or a plurality of other layers designed for other possible purposes, such as: corrosion resistance, adhesion, diffusion barrier.
• the substrate 15 is preferably deposited on the surface 3 of the component 5 using a conventional well- known process. Then, the coating 15 is deposited on said substrate 15 to act as a thermal battier, using the method as described below.
• This microstrueture has pores 23 of varying sizes according to the deposition technologies and the parameters being used.
• Such porosities are characterized by a highly homogeneous arrangement, as ensured by the inventive deposition system.
• the dispersion of the pores 21 and 23 is shown, whose number changes depending on the energy supplied during deposition. Therefore, the structure exhibits a variable porosity with fine pores evenly dispersed in the body of the coating obtained by the method of the present invention.
• High ceramic cohesion areas 21 are also visible.
• Figure 4 a schematic view of one of the combinations of the method for depositing the coating 13 is shown, which is carried out through successive passes at different angles of incidence of the torch 33.
• a cylindrical component to be coated was pivoted about its own axis and the torch was displaced over a rectilinear path along a straight line parallel to the axis of rotation of the component to be coated.
• the torch tilt relative to an ideal surface tangent to the one to be coated may be described as follows: the torch 33 carries out a first deposition step at a certain angle ⁇ relative to the surface 3 to be coated; then, the torch 33 is pivoted to such a position as to form a second angle of incidence ⁇ , other than ⁇ , to carry out another deposition step on the coating that has just been laid at a tilt angle CC; finally, the torch 33 is positioned/pivoted to form a third angle of incidence ⁇ and a further deposition step is carried out.
• a constant tilt pass may be repeated n times, which means that the cycle may include:
• the above cycle may be repeated a desired number of times .
• the succession of the various passes at different tilts provides a coating microstrueture composed of fine pores evenly dispersed in the coating structure.
• the number of pores increases with the energy used during the deposition.
• the scope of the present invention encompasses both the mechanical component 1 (such as the gas or aeronautical turbine) having thick TBC coatings
• ceramic material such as yttrium oxide stabilized zirconia, obtained by a Thermal Spray process, deposited on the bond coat surface of the component, and the method for making it, in which the thermal coating 13 is obtained with three or more different tilts of the deposition torch 22, at different and well-defined angles relative to the surface to be sprayed.
• angles ⁇ , ⁇ and ⁇ are preferably as follows :
• the order in which the torch 33 is tilted to form the various incidence angles ⁇ , ⁇ and ⁇ for deposition of the coating within each cycle can change and different combinations from the above may be provided.
• the present method allows the head 33 to operate at angles in a range from 30° to 150° relative to the tangent to the surface 3 to be coated.
• the torch 33 is tilted at least at three different angles, by carrying out a deposition step for each of them, a required number of passes being performed for each angle.
• the scope of the present invention obviously encompasses all the coatings obtained with the above method, for any substrate and component (not necessarily a part of a gas turbine or an aeronautical engine) coated with the TBC.
• the coating 13 may be composed of zirconia, possibly stabilized with other materials (e.g. ceria, dysprosia, ytterbia, Ca or Mg oxide) or other ceramic materials (alumina, titania, spinels, perovskite, etc.) .
• other materials e.g. ceria, dysprosia, ytterbia, Ca or Mg oxide
• ceramic materials alumina, titania, spinels, perovskite, etc.
• the invention as described herein provides an essential contribution to the thermal cycling fatigue resistance of TBC coatings, particularly thanks to the structure of the coating.
• the higher the porosity the higher the thermal cycling fatigue resistance.
• thermal cycling fatigue resistance is obtained regardless of the porosity (from 11% to 28% in the tests) .
• four different porosity levels were obtained using the same structure with fine pores evenly dispersed over the coating body.
• the above deposition method applies to deposition of thermal barriers and of ceramic materials in general, regardless of the parameters being used to supply enough energy to the powder for such powder to be melted.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Plasma & Fusion (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Physics & Mathematics (AREA)
• Coating By Spraying Or Casting (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Dowels (AREA)
• Building Environments (AREA)
• Road Signs Or Road Markings (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (7)

Cited By (5)

Families Citing this family (1)

Citations (4)

• 2006
  • 2006-10-05 IT IT000087A patent/ITPR20060087A1/it unknown
• 2007
  • 2007-09-28 DE DE602007010327T patent/DE602007010327D1/de active Active
  • 2007-09-28 EP EP07820675A patent/EP2069080B1/en active Active
  • 2007-09-28 ES ES07820675T patent/ES2355859T3/es active Active
  • 2007-09-28 PL PL07820675T patent/PL2069080T3/pl unknown
  • 2007-09-28 AT AT07820675T patent/ATE486975T1/de not_active IP Right Cessation
  • 2007-09-28 WO PCT/EP2007/060287 patent/WO2008040678A1/en active Application Filing

Patent Citations (4)

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