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
  • C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
• • 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
• • 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
  • C23C4/18—After-treatment
• • 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

Definitions

• the invention relates to a component made of a base material based on nickel or cobalt with a protective layer against oxidation, corrosion and thermal fatigue.
• High-temperature resistant superalloys based on nickel or cobalt were developed for use in turbine construction.
• the blade material is exposed to particularly high loads, which not only withstand the high temperatures (above 950 ° C) in the turbine, but also must have a high creep resistance.
• the blade material made of superalloys in particular is grown in large crystalline form and partly with a columnar structure using appropriate casting and crystallization techniques.
• grain boundary deposits of easily oxidizable alloy additives such as vanadium or titanium are disadvantageously formed for the corrosion resistance. This adversely affects the surface properties, such as resistance to oxidation and corrosion, and the resistance to thermal fatigue.
• Diffusion processes have a disadvantage due to the different concentration on both sides of the boundary layer between the surface of the layer and the coating, which lead to diffusion pores in the region near the boundary layer, so that the protective layer flakes off at locations of high diffusion pore density when thermal stresses are superimposed.
• the MCrAlX, Y layers tend to suffer from thermal fatigue, since there is a mismatch in the thermal expansion behavior between the base material alloy and the MCrAlYX layer and the MCrAlX, Y layers are very ductile compared to the base material.
• the components of the base material such as vanadium and titanium, which are sensitive to oxidation and corrosion are avoided, and stable oxide formers, such as aluminum, for example up to 20% and chromium, for example up to 40%, are added.
• stable oxide formers such as aluminum, for example up to 20% and chromium, for example up to 40%.
• the coordination of the composition is becoming ever more extensive and complicated the coating on the superalloy to be coated, based on cobalt or nickel, in order to overcome adhesion problems or to minimize diffusion processes or to build up protective stable oxides on the surface.
• the object of the invention is to provide a component made of a base material based on nickel or cobalt with a protective layer, which has a higher thermal fatigue, oxidation and corrosion resistance at temperatures above 800 ° C than components with previously known coatings and the disadvantages of these Overcomes coatings and specify a method for producing such a component.
• the invention solves the problems and disadvantages as they exist in the prior art by using the material of the base material for a coating of the same type, so that diffusion processes do not occur and adhesion problems do not occur on the oxide-free surface of the base material.
• a chipping of protective layer particles is hereby overcome.
• a uniform, stable and protective oxide layer is advantageously formed on the grain surface when such components are used in the oxidizing hot gas stream of, for example, turbines. Since the grain boundaries of this coating have fewer grain boundary deposits than the base material, the grain boundary corrosion is advantageously reduced.
• the layer thickness is advantageously not limited to less than 100 ⁇ m.
• the base and coating material is preferably composed of the following elements:
• This superalloy is commercially available under the name IN 100, so that both the base material and the coating material are available at low cost.
• the grain volume of the coating is at least three powers of ten smaller than the grain volume of the base material.
• the grain boundaries of the preferred base material IN 100 have titanium and vanadium-containing grain boundary deposits, which form unstable or low-melting oxides.
• the coating therefore preferably has fewer precipitations at the grain boundaries than the base material, which advantageously improves the resistance to oxidation and corrosion.
• a particularly preferred embodiment of the protective layer consists in the protective layer being a plasma spray layer which, owing to the high rate of solidification, advantageously crystallizes extremely fine-grained and has a low excretion rate.
• This method has the advantage that it is suitable for mass production.
• the surface preparation is carried out by plasma etching with an argon plasma.
• This preparation has the advantage of being free from contamination and is compatible with a low-pressure plasma spraying process, so that both the surface preparation and the coating of the base material can be carried out on a component with an assembly process. This advantageously improves the quality, since it is not necessary to move it to another plant and there are no residence times in a normal atmosphere.
• the surface preparation is carried out by means of chemical removal, so that a high throughput is advantageously achieved.
• Abrasive beam processing is preferably used as surface abrasion, since this method advantageously allows large-area components such as rotor disks to be prepared for a subsequent coating.
• the coating by means of plasma spraying with a plasma spraying material in the same chemical composition as the base material can be carried out in the case of high quality requirements in the low pressure plasma spraying process and in the case of large parts and / or high demands on economy by means of plasma spraying under protective gas.
• Optimal growth of the coating on the base material is achieved by epitaxial recrystallization at a solution annealing temperature between 1150 ° C and 1250 ° C.
• the bottom layer of the fine-grained coating recrystallizes in the same crystal orientation as the large-volume crystallites of the base material at the coating boundary, so that an intensive interlocking between the fine-grain coating and the coarse-grained base material is advantageously created, which significantly increases the adhesion compared to conventional foreign coatings .
• the coated component can then be cooled to 1000 ° C to 800 ° C at 30 ° C / min to 80 ° C / min and subjected to a multi-stage aging heat treatment.
• a two-stage aging process has preferably been used to form a suitable ⁇ / ⁇ ′-structure at 1080 ° C. to 1120 ° C. for 2 hours to 6 hours, followed by 900 ° C. to 980 ° C. for Proven for 10 hours to 20 hours with intermediate cooling to 750 to 800 ° C.
• a heat treatment With such a heat treatment, the properties of the base material which have been changed by the solution annealing are regenerated, and the strength values of the layer are advantageously increased.
• a mechanical post-treatment of the surface of the protective layer improves the hardness by preferably shot peening and serves to smooth the surface.
• the surface can also be smoothed by pressure flow machining or vibratory finishing.
• a diffusion coating as aftertreatment of the surface can preferably be carried out on the fine-grained coating.
• This has the advantage that deep diffusions like them along the grain boundary precipitations of the base material, in which fine-grained coating with fewer grain boundary precipitations does not occur.
• the diffusion zone in the fine-grained coating is thus advantageously more uniform and homogeneous with z.
• the aluminum doping z. B. increases the oxidation resistance up to temperatures of 1250 ° C.
• a coarse crystalline turbine blade made of IN 100 as the base material which is composed of the following elements: there is a low-pressure plasma layer of the same chemical composition, which has a grain volume 3 ⁇ 10 3 times finer than the base material having.
• the coated component In the thermal fatigue test (test temperature 1050 ° C), the coated component withstands three times the number of thermal load changes than the uncoated base material.
• a coarsely crystalline turbine blade made of In 100 as the base material which is composed of the following elements: the surface of the base material is removed by an average of 0.5 to 10 ⁇ m by means of argon plasma etching at a pressure of 2 kPa to 4 kPa.
• the base material is coated with plasma spray material with the same chemical composition as the base material at a pressure of 4 kPa and a temperature of the base material of 900 ° C. for 120 seconds.
• epitaxial recrystallization is carried out in a high vacuum furnace.
• the component is kept at a solution annealing temperature of 1200 ° C for 4 hours and cooled to 800 ° C at a cooling rate of 60 ° C / min.
• a two-stage heat treatment is carried out in a high vacuum at 1100 ° C for 4 hours and at 950 ° C for 16 hours with intermediate cooling at 60 ° C / min to 800 ° C.
• the surface of the component is smoothed and solidified by blasting with zirconium oxide balls with a diameter of 0.5 mm to 1 mm.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• General Engineering & Computer Science (AREA)
• Coating By Spraying Or Casting (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Other Surface Treatments For Metallic Materials (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=6375923

Family Applications (1)

Country Status (4)

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Family Cites Families (7)

• 1989
  • 1989-03-09 DE DE3907625A patent/DE3907625C1/de not_active Expired - Lifetime
• 1990
  • 1990-03-01 EP EP90103963A patent/EP0386618B1/de not_active Expired - Lifetime
  • 1990-03-08 CA CA002011753A patent/CA2011753A1/en not_active Abandoned
  • 1990-03-08 JP JP2059815A patent/JPH02277760A/ja active Pending

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