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
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
• • 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
  • C23C4/06—Metallic material
  • C23C4/073—Metallic material containing MCrAl or MCrAlY alloys, where M is nickel, cobalt or iron, with or without non-metal elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
  • F05B2220/00—Application
  • F05B2220/30—Application in turbines
  • F05B2220/301—Application in turbines in steam turbines

Definitions

• the invention relates to an iron-based alloy according to claim 1, a protective layer according to claim 10, a layer system according to claim 11 and a method for producing the iron-based layer according to claim 16.
• MCrAlY Protective layers for metallic components intended to increase their corrosion resistance and / or oxidation resistance are known in the art in large numbers. Most of these protective layers are known under the collective name MCrAlY, where M stands for at least one of the elements from the group consisting of iron, cobalt and nickel and further components chromium, aluminum and yttrium.
• Thermal barrier coatings that are applied to turbine components are described, for example, in EP 1 541 810 A1.
• the effort to increase the inlet temperatures of the live steam in steam turbines is of great importance, because to achieve optimum thermal efficiency, the inlet temperature of the live steam is an important determinant.
• Due to the use of specially developed ferritic base materials for thermally highly stressed turbine components steam temperatures of approx. 620 ° C can currently be achieved.
• thermal barrier coatings on these base materials a fresh steam inlet temperature should be increased or the use of cost-effective materials should be made possible at the same steam temperature.
• a protective layer In order to achieve sufficient resistance to oxidation and corrosion of the ferritic base materials, it is necessary to resort to protective layers.
• a protective layer In addition to the sufficient chemical resistance of a protective layer, a protective layer must also be resistant to good mechanical properties Properties, not least in view of the mechanical interaction between the protective layer and the base material, have.
• the protective layer must be sufficiently ductile in order to be able to follow any deformations of the base material and not to break, since in this way points of attack for oxidation and corrosion would be created.
• the adhesive layer ensures good adhesion of the thermal barrier coating to the base material and, on the other hand, protection of the base material against oxidation and corrosion.
• top-coating Adhesive layers and / or top coatings made of Ni-Cr 80/20 and / or MCrAlY are especially good for the
• these abovementioned adhesive layers are suitable for base materials such as, for example, Ni-base alloys, with suitability above 700 ° C. appearing possible.
• a disadvantage of the use of these adhesive layers and / or top coatings is that their thermal expansion coefficient compared to the base materials or thermal barrier coatings is relatively high, which means that stresses and / or strains can lead to undesirable cracking.
• the object of the invention is therefore to provide a suitable material for the adhesive layer and / or top coatings.
• This object is achieved by an alloy according to claim 1, a protective layer according to claim 13 and a layer system according to claim 14.
• the object is also achieved by a method for producing a layer according to claim 16 and / or 19.
• the invention is based inter alia on the finding that the proportion of chromium content on the chemical and physical properties of the adhesive layer and / or the topcoat depends substantially on the chromium content, wherein the aluminum content plays an essential role.
• the solutions described in the claims accordingly disclose adhesive layer types and / or topcoats which, owing to their chemical composition, both satisfy the required properties with regard to oxidation and corrosion resistance and also have a suitable thermal expansion coefficient.
• the invention is characterized in that the thermal spraying a spray powder is used with a chromium content of 25 wt .-% to 35 wt .-% chromium, whereby a chromium content of 15 wt .-% - 30 wt. % is achieved in the iron-based layer after the manufacturing process. It has been determined by experiments that the chromium content of the spray powder falls by up to 10% by weight during the manufacturing process.
• an aluminum content of 1% by weight to 5% by weight of aluminum can be added to the sprayed powder.
• the lowest possible silicon content ⁇ 0.2% by weight is used.
• the elements Ce, Y and / or Hf can be used.
• the invention will be explained in more detail below.
• FIG. 1 shows a first exemplary embodiment of a component 1 designed according to the invention.
• the component 1 could, for example, be an inflow region of a turbine, in particular a steam turbine, and has a base material 4 and a thermal insulation layer 7 applied thereto.
• the thermal insulation layer 7 may be formed from a ceramic material.
• the thermal barrier coating 7 can be formed as a ceramic thermal barrier coating of zirconium oxide, the zirconium oxide being unstabilized, partially stabilized or fully stabilized by yttrium oxide and / or magnesium oxide.
• the ceramic thermal barrier coating may be titanium oxide, the thickness being between 0.1 mm and 2 mm.
• the ceramic thermal barrier coating 7 by thermal spraying such as atmospheric plasma spraying (APS) and by chemical or physical
• Coating methods such. As CVD or PVD can be used.
• FIG. 2 shows a further embodiment of the component 1 designed according to the invention.
• the difference between FIG. 1 and FIG. 2 is that at least one adhesive layer 10 comprising an iron-based alloy is formed between the base material 4 and the thermal barrier coating 7.
• the adhesive layer 10 serves firstly to protect against corrosion and / or oxidation of the base material and secondly to better bond the ceramic thermal barrier coating 7 to the base material 4. This is particularly the case when the ceramic thermal barrier coating and the base material consist of a metal.
• the iron-based adhesive layer in this case comprises 15 wt .-% to 30 wt .-% chromium.
• the iron-based alloy comprises 1.5 wt% to 2.5 wt% aluminum and less than 0.2 wt% silicon.
• the iron-based adhesive layer may comprise the element Y, the element hafnium and the element Ce with the following proportions by weight: 0.1% by weight to 0.7% by weight Y 0.1% by weight to 0.5% by weight Cerium 0.1 wt .-% to 0.5 wt .-% hafnium have.
• the adhesive layer 10 for protecting the base material 4 against oxidation and corrosion and erosion at a high temperature consists, for example, essentially of the following elements:
• Embodiment III 15% by weight to 30% by weight of chromium and 1.5% by weight to 3% by weight of aluminum and silicon with less than 0.2% by weight.
• the coefficients of thermal expansion of the base material 4 and of the adhesion layer 10 are thereby very well matched or even equal, so that there is no or only slight thermal stress between the base material 4 and the adhesion layer 10, which is a chipping and / or Cracking the adhesive layer 10 or could cause the thermal barrier coating. This is particularly important because in ferritic materials often no heat treatment for diffusion bonding is performed, but the thermal barrier coating 7 largely or only by adhesion to the base material adheres.
• the base material 4 may be a ferritic base alloy, a steel, in particular a 1% CrMoV steel or a 9% -13% chromium steel.
• ferritic substrates 4 of the component 1 consist of a 1% - 2% chromium steel for waves: such.
• the component 1 is manufactured by thermal spraying, using iron-based powder comprising 25% by weight to 35% by weight of chromium.
• iron-based powder comprising 25% by weight to 35% by weight of chromium.
• oxygen absorption during the injection process leads to a more or less pronounced formation of Cr oxides, which in turn results in a strong localized Cr depletion up to a fraction below 12%.
• the use of the iron-based powder according to the invention ensures that the iron-based alloy has a proportion of 15% by weight to 30% by weight of chromium after the production process.
• the manufacturing process is improved in that aluminum is added to the powder with 1 wt% to 5 wt% aluminum. After thermal spraying, an aluminum content of 1.5 wt.% To 3 wt.% Aluminum in the iron-based alloy remains.
• the process uses a powder comprising 28% to 30% by weight of chromium, aluminum being added to the powder with 2.5 wt .-% to 3.5 wt .-% aluminum.
• the powder in this case has less than 0.2 wt .-% silicon.
• the method of producing the iron-based layer using thermal spraying can be improved so that the iron-based powder consists of 25 wt% to 35 wt% of chromium.
• the powder may consist of 25 wt% to 35 wt% chromium and 1 wt% to 5 wt% aluminum.
• the iron-based powder may consist of 28% to 30%, 2.5% to 3.5%, by weight, aluminum and silicon less than 0.2% by weight.
• FIG. 3 shows a further exemplary embodiment of the component 1 designed according to the invention.
• An erosion protective layer 13 now forms the outer surface of the ceramic thermal barrier coating 7.
• the erosion protection layer 13 can also be referred to as a top coating. It consists in particular of a metal or a metal alloy and protects the component from erosion and / or wear, as is the case in particular in steam turbine power plants which have a scaling in the superheated steam region, where average flow velocities of about 50 m / sec and pressures of up to 350 bar occur.
• the erosion protection layer 13 may have substantially the same chemical elements as the adhesion layer 10.
• an adhesive layer 10 may still be present.

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

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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Citations (4)

• 2007
  • 2007-03-14 EP EP07005301A patent/EP1970461A1/de not_active Withdrawn
• 2008
  • 2008-03-13 EP EP08717765A patent/EP2132350A1/de not_active Withdrawn
  • 2008-03-13 JP JP2009553149A patent/JP2010522823A/ja active Pending
  • 2008-03-13 WO PCT/EP2008/053021 patent/WO2008110607A1/de not_active Ceased
  • 2008-03-13 CN CN200880008098A patent/CN101631888A/zh active Pending

Patent Citations (4)

Non-Patent Citations (3)

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