EP1797218A1

EP1797218A1 - Layer system

Info

Publication number: EP1797218A1
Application number: EP05786847A
Authority: EP
Inventors: Georg Bostanjoglo; Nigel-Philip Cox; Rolf WILKENHÖNER
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2004-10-07
Filing date: 2005-09-05
Publication date: 2007-06-20
Also published as: EP1645660A1; WO2006040223A1

Abstract

Often, layer systems known in prior art, based on the type of coating, are only linked in a small manner to the substrate. This can lead to a removal of the layer in mechanically highly-charged components. The inventive layer system (1) comprises continuous anchoring means (10) or inner anchoring means (13) wherein one determined volume proportion (14) protrudes into the substrate (4) or into the intermediate layer and the material thereof is similar.

Description

layer system

The invention relates to a layer system according to the preamble of claim 1.

Components for high temperatures are usually provided with protective coatings today.

These may be metallic corrosion protection layers (MCrAlX layers) or ceramic thermal barrier layers as well as layer systems with metallic corrosion protection layers and ceramic thermal barrier coatings.

As a coating method for these coatings, plasma-assisted powder spraying processes are used because of their comparatively high cost-effectiveness.

The bonding of such layers to the substrate takes place by mechanical clamping and subsequent diffusion heat treatment. Occasionally, it can occur in highly loaded areas or unfavorable, i. Especially at mechanically high loaded points of the component to a detachment of the layer come in operation. The spalling of the layer during operation leads to damage to the base material, so that the component life is substantially reduced.

No. 5,869,798 discloses a method in which elevations are produced on a surface by means of a welding method, wherein the elevation consists of a different material than the underlying substrate.

EP 1 275 748 A2 discloses anchoring means disposed on, but not projecting into, a surface of the substrate or an intermediate layer.

DE 100 57 187 A1 discloses anchoring means which protrude into a substrate in order to improve the adhesion of a non-metallic material such as ceramic on the metallic substrate. EP 0 713 957 A1 discloses a method in which a depression in a layer is filled up with material.

Further prior art is known from DE 30 38 416 A1 as well as from the journal Journal of Materials Science 24 (1989), page 115-123 entitled "Enhanced metal-ceramic adhesion by sequential sputter deposition and pulsed laser melting of copper films on sapphire Substrates "by AJ Pedraza, MJ Godbole.

It is therefore an object of the invention to show a layer system which has a better connection of a protective layer to a substrate and / or of layers to one another.

The object is achieved by a layer system according to claim 1.

The layer system according to the invention has separately produced anchoring means which have a very strong connection to the substrate or to an intermediate layer arranged underneath it on the substrate and are bonded to the substrate or the other layer in a different way than the layer.

The stronger bonding of the anchoring means compared to the existing layer bonding (for example Ver¬ clamping by surface roughness), for example, by a fusion metallurgical bond, which is produced for example in a separate process. Thus, furthermore, the cost-effective and economical plasma spraying process can be used to apply the layer.

In the subclaims further advantageous measures are listed. The measures listed in the dependent claims can be advantageously combined with each other in an advantageous manner.

Show it

Figure 1 is a layer system according to the prior

Technique, Figure 2, 6, 7, 8, 9 according to the invention formed

3 shows a perspective top view of a layer system designed according to the invention, FIG. 4 shows method steps for producing a layer system, FIG. 5 shows method steps for producing a layer system, FIGS. 10 to 12 shows method steps for producing a layer system, FIG.

FIGS. 13, 14, 15 process steps for producing a layer system,

FIGS. 16, 17 process steps for producing a layer system,

FIG. 18 shows a gas turbine,

19 shows a combustion chamber and FIG. 20 shows a turbine blade.

FIG. 1 shows a layer system 1 'according to the prior art. The layer system 1 ^f has a substrate 4.

On the substrate surface 5 of the substrate 4, at least one layer, here for example an outer layer 9 with an outer surface 16, is present. This may be a metallic and / or ceramic outer layer 9. The bonding of the outer layer 9 to the substrate 4 or of layers with one another takes place according to the prior art solely by mechanical clamping (surface roughness) to the underlying surface and / or subsequent diffusion heat treatment.

FIG. 2 shows, starting from FIG. 1, a layer system 1 according to the invention.

The substrate 4 may be metallic or ceramic and be¬ in the case of gas turbine components, in particular of an iron-, nickel- or cobalt-based superalloy.

For turbine blades 120, 130 (FIGS. 18, 20), for example, an intermediate layer 7 (FIGS. 6, 7, 8), for example a metallic corrosion protection layer 7 of the MCrAlX type, is applied to the substrate 4, whereupon an additional outer layer is additionally provided 9, for example, a ceramic thermal insulation layer 9 (Fig. 6, 7, 8) is applied.

At least one inner anchoring means 13 and / or at least one continuous anchoring means 10 are present in the intermediate layer 7 (FIGS. 6, 7) and / or the outer layer 9 (FIGS. 2, 4, 5, 6, 8).

According to the invention, the continuous anchoring means 10 or inner anchoring means 13 with a certain proportion 14 of their total volume extend into the substrate 4 (FIGS. 2, 4, 5, 6, 7) or into the intermediate layer 7 (FIGS. 6, 8).

The proportion 14, ie an extent of the continuous anchoring means 10 or the inner anchoring means 13 in the substrate 4 (Fig. 2, 4, 5, 6, 7) or in the intermediate layer 7 (Fig. 6, 8) relative to the total volume the continuous anchoring means 10 or on the total volume of the inner anchoring means 13 the smaller volume fraction, so that the continuous anchoring means 10 or the inner anchoring means 13 with the larger volume fraction of the continuous anchoring means 10 or the inner anchoring means 13 in the farther out (surface 16) lying area, ie in the intermediate layer 7 (Fig. 6, 7) or the outer layer 9 (Figs. 2, 4, 5, 6, 8).

The volume fraction of fraction 14 is at most 30% by volume, i. the proportion of the volume of the anchoring means 10, 13 in the layer 7, 9 based on its total volume is at least 70vol% and is less than 100vol%.

Preferably, the volume fraction of the portion 14 is between 20 and 30vol%, between 10 and 20vol% or between 10 and 30vol%.

Preferably, the volume fraction of the fraction 14 can also be a maximum of 20 or at most 10vol%, but never 0vol%.

Instead of determining the fraction 14 by a volume specification, a length fraction can also be specified. If the anchoring means 10, 13 extend along a direction 11 starting from the substrate 4 or an intermediate layer 7 (direction 11, for example, perpendicular to a surface 5, 8, 16), then there is a length lio along the direction 11, which is the total length of the anchoring means 10 represents. A length Ii4, io represents the extent of the portion 14 of the continuous anchoring means 10 in the direction 11.

The same applies to the anchoring means 13, in which the length I1 _{3 represents} the total length of the anchoring means 13 and the length Ii4, i _3, the extension of the portion 14 in the direction 11 of the inner anchoring means thirteenth Likewise, there is a length l _s , which represents the layer thickness of the layer 7, 9.

As well as the volume fractions are obtained for the ratios lioio / lio or I1 ₀ 13 / I13 values different from zero to a maximum of 30%. Preferably, the values may be between 20% and 30%, between 10% and 20% or between 10% and 30%. Preferably also values of 20% or 10% are used.

The material class of the continuous anchoring means 10 or the inner anchoring means 13 corresponds to the material class of the intermediate layer 7 or the outer layer 9, in which it is arranged for the most part. A class of materials is understood to mean either metals or ceramics.

Thus, when the continuous anchoring means 10 or inner anchoring means 13 is mostly located in a metallic intermediate layer 7 (Figures 6, 7), the material of the continuous anchoring means 10 or inner anchoring means 13 is also metallic. In particular, the material of the continuous anchoring means 10 or the inner anchoring means 13 corresponds to the material of the intermediate layer 7, wherein slight changes may occur.

For example, the material of the intermediate layer 7 consists of an alloy of the MCrAlX type. The material of the continuous anchoring means 10 or the inner anchoring means 13 then for example also consists of an alloy of the type MCrAlX, wherein the chemical

In contrast to the material of the intermediate layer 7, for example, the composition is changed so that the continuous anchoring means 10 or the inner anchoring means 13 can be better produced in the intermediate layer 7 or have better mechanical properties. Likewise, the material of the intermediate layer 7 may be ceramic, in which case the continuous anchoring means 10 or the inner anchoring means 13 also consist of a ceramic, in particular the same ceramic.

When the continuous anchoring means 10 or the inner anchoring means 13 is for the most part disposed in the outer layer 9 (FIGS. 2, 4, 5, 8), in particular a ceramic layer, then the material of the continuous anchoring means 10 or the inner anchoring means 13 is also ceramic and corresponds in particular to the material of the outer layer 9.

Also, the material of the outer layer 9 and the continuous anchoring means 10 or the inner anchoring means 13 may be metallic (MCrAlX).

The continuous anchoring means 10 or the inner anchoring means 13 have, in particular, a different type of connection, in particular with an increased connection force (more precisely: force / per contact surface) to the substrate 4 or to the intermediate layer 7 compared to the type of connection Intermediate layer 7 to the substrate 4 and the outer layer 9 to the intermediate layer. 7

The continuous anchoring means 10 or the inner anchoring means 13 are, for example, melt-metallurgically bonded to the substrate 4 or the intermediate layer 7 by a suitably guided laser welding process. Likewise, it is conceivable that the intermediate layer 7 and / or outer layer 9 is applied at certain points by laser cladding (laser powder coating) and thus form continuous anchoring means 10 or inner anchoring means 13. The continuous anchoring means 10 or the inner anchoring means 13 can also be cast or produced in the casting of the substrate 4 with. The continuous anchoring means 10 or the inner anchoring means 13 represent adhesion bridges for the intermediate layer 7 or outer layer 9 surrounding the continuous anchoring means 10 or the inner anchoring means 13.

The continuous anchoring means 10 emanate from the substrate 4 or the intermediate layer 7 and extend in particular only to the inner surface 8 of the intermediate layer 7 or the outer surface 16 of the outer layer 9. The inner anchoring means 13 are formed by the intermediate layer 7 or the Covered outer layer 9, so that the inner anchoring means 13 do not extend to the inner surface 8 of the Zwischen¬ layer 7 or the outer surface 16 of the outer layer 9, that are within the intermediate layer 7 or the outer layer 9 ending arranged. They extend 13 to at least 10%, 20%, 30%, 40% or more of the thickness of the intermediate layer 7 or the outer layer 9 in the intermediate layer 7 or in the outer layer. 9

The continuous anchoring means 10 or the inner anchoring means 13 are for example only locally, so localized (Figure 3) on the substrate 4 or the intermediate layer 7 is present, namely, where the mechanical load is greatest. This is, for example, the area of the leading edge 409 (FIG. 20) of a turbine blade 120, 130. The remaining blade leaf 406 would then have no continuous anchoring means 10 or inner anchoring means 13.

Figure 3 shows a plan view of an inner surface 8 of an intermediate layer 7 or on an outer surface 16 of an outer layer 9. Dashed lines indicate the inner anchoring means

13, which do not extend to the inner surface 8 of the intermediate layer 7. The continuous anchoring means 10 or the inner anchoring means 13 may have on the substrate surface 5 different geometries such as circles, stitching (ie they are elongated and intersecting), waveforms, parallel paths and combinations thereof.

FIG. 6 shows a further layer system 1 designed according to the invention. The layer system 1 consists of a substrate 4 and, for example, two layers, an intermediate layer 7 and an outer layer 9.

The intermediate layer 7 is, for example, a metallic MCrAlX layer and the outer layer 9 is, for example, a ceramic thermal barrier coating 9 on the intermediate layer 7.

Continuous anchoring means 10 or inner anchoring means 13 are present both in the intermediate layer 7 and in the outer layer 9.

However, the intermediate layer 7 does not have to have continuous anchoring means 10 or inner anchoring means 13 in the sense of the present invention (FIG. 8). Likewise, the continuous anchoring means 10 or inner anchoring means 13 may be present only in the intermediate layer 7 (Figure 7).

In this case, some, but not necessarily all, continuous anchoring means 10 or inner anchoring means 13 in the intermediate layer 7 or the outer layer 9 must have a portion 14 which extends into the substrate 4 or the intermediate layer 7.

The continuous anchoring means 10 in the intermediate layer 7 and / or in the outer layer 9 may extend from the substrate surface 5 of the substrate 4 or the inner surface 8 of the intermediate layer 7 to the inner surface 8 of the intermediate layer 7 or the outer Surface 16 of the outer layer 9 extend, but not beyond. The inner anchoring means 13 are covered by the intermediate layer 7 or the outer layer 9, so that the inner anchoring means 13 do not extend to the inner surface 8 of the intermediate layers or the outer surface 16 of the outer layer 9.

The continuous anchoring means 10 or inner anchoring means 13 in the intermediate layer 7 improve the bonding of the intermediate layer 7 to the substrate 4.

The continuous anchoring means 10 or inner anchoring means 13 are present in particular in thermally and / or mechanically highly loaded areas.

For turbine blades, for example, this is the inflow edge 409, the trailing edge 422 (FIG. 20) or the transition between the airfoil 406 and the platform 403.

The layer system 1 is, for example, a component of a gas 100 (FIG. 18) (also aircraft turbine) or steam turbine. Ther- mically highly loaded components of the turbines have such a layer system, such as e.g. Turbine blades 120, 130, Hit¬ zeschildelemente 155 a combustion chamber 110 and other housing parts that are along the flow path of a hot Damp¬ fes or hot gas.

The layer system 1 can be applied to a newly manufactured component and to components that are refurbished after use (refurbishment). In this case, the components 1 are previously freed from degraded layers, cracks are repaired if necessary, and a renewed coating of the substrate 4 takes place.

FIG. 7 shows a further exemplary embodiment of a layer system 1 according to the invention. In this layer system 1, the continuous anchoring means 10 or inner anchoring means 13 are present only in the intermediate layer 7. On the intermediate layer 7, the outer layer 9 is present. A contact surface of the continuous anchoring means 10 on the inner surface 8 improves the adhesion of the outer layer 9 to a comparable contact surface with the intermediate layer 7. This is achieved, for example, in that the contact surfaces of the continuous anchoring means 10 form germinal points on the inner surface 8, for example epitaxially

Growing an outer layer 9 on the intermediate layer 7. Even without intermediate layer 7 (Fig. 4, 5, right), an improved layer system 1 is achieved in that the continuous anchoring means 10 or inner anchoring means 13 to an improved connection of the outer layer lead to the substrate 4.

In this case, some, but not necessarily all, continuous anchoring means 10 or inner anchoring means 13 extend into the substrate 4 with a portion 14.

FIG. 8 shows a further exemplary embodiment of a layer system 1 according to the invention with intermediate layer 7 and outer layer 9.

In this embodiment, the continuous anchoring means 10 or inner anchoring means 13 are present only in the outer layer 9.

In this case, some, but not necessarily all, continuous anchoring means 10 or inner anchoring means 13 extend into the intermediate layer 7.

FIG. 4 shows, by way of example, method steps of a method for producing a layer system 1. In a first step, an outer layer 9 is applied to the substrate 4 (not shown) in a known manner.

The outer layer 9 is treated, for example, with a laser 17 or an electron beam gun 17, which emits a corresponding laser or electron beam 19. By this type of treatment, the material of the outer layer 9 is locally converted to the substrate surface 5 of the substrate 4 or beyond with a proportion 14 into the substrate 4, for example, melted, so that there is a metallurgical fusion of material from the outer layer 9 in the substrate 4 results. With this method, continuous anchoring means 10 are produced, which extend from the substrate surface 5 up to the surface 16 of the outer layer 9.

The continuous anchoring means 10 are, for example, of a columnar design and can also be concave or convexly curved (FIG. 7).

The statements apply analogously to an intermediate layer 7, to which an outer layer 9 is applied.

FIG. 5 shows a further production method. In a first step, the at least one continuous anchoring means 10 or inner anchoring means 13 is first applied to the substrate 4, ie produced separately. This can be done in various ways, such as by a suitably guided laser welding process or Lasercladding.

The continuous anchoring means 10 or inner anchoring means 13 have in particular a very strong, in particular melt-metallurgical connection to the substrate 4. However, the continuous anchoring means 10 or inner anchoring means 13 may also have already been produced during the production of the substrate 4, for example by a casting process. In a subsequent process, the outer layer 9 is auf¬ brought, wherein the continuous anchoring means 10 or inner anchoring means 13 are enclosed by the material of the outer layer 9 and provide adhesion bridges for the outer layer 9.

FIG. 9a shows a further exemplary embodiment of a component 1 according to the invention (cross section through anchoring means 10, 13).

The continuous anchoring means 10 has a larger cross-sectional area at the outer surface 16 than at the lower substrate surface 5 (FIG. 9b, top view of FIG. 9a).

The shape of the continuous anchoring means 10 in cross section is here bell-shaped, for example. The cross-sectional contour may also have other shapes, such. B. a parabolic course, wherein the parabola can be open to the top 8, 16 (Fig. 9b) or down 9, 8.

The cross section of the continuous anchoring means 10 is formed here, for example, round. Dashed lines indicate the cross-sectional area of the continuous anchoring means 10 on the substrate surface 5 or in the substrate 4.

The continuous anchoring means 10 may also extend into the substrate 4 here (not shown). The statements apply analogously to an inner anchoring means 13

FIGS. 10 to 12 show a further method for producing the layer system 1.

The outer layer 9 and the continuous anchoring means 10 or inner anchoring means 13 are produced, for example, in layers, i. First, the outer layer 9 is produced in partial layers and then or simultaneously the anchoring means 10, 13th

In no case, at first, the anchoring means are at least mostly or completely produced (FIG. 5) and then the outer layer 9 or vice versa (FIG. 4).

Thus, starting from the substrate 4, which still has no outer layer 9, layered material for the outer layer 9 is applied and also in layers, the continuous anchoring means 10 or inner anchoring means 13 are generated.

Depending on whether continuous anchoring means 10 or inner anchoring means 13 are to be produced, at the points where a continuous anchoring means 10 or inner anchoring means 13 is to be formed, the spot is heated and fused, for example by means of a laser, i. the temperature is increased temporarily and locally.

If an inner anchoring means 13 is to be produced (FIG. 11) which is not intended to extend to the surface 16 of the outer layer 9, the outer layer 9 will no longer be locally melted at a certain height (FIG. 12).

The statements apply analogously to an intermediate layer 7, to which an outer layer 9 is applied. Figures 13 to 15 show another Herstellungsverfah¬ ren.

Here, an outer layer 9 (for example MCrAlX) is already present on the substrate 4. This is the case, in particular, when it is a component 1 to be repaired which was used, for example, and in particular has a local damage in the form of a depression 34.

This depression 34 is, for example, weakened or subjected to increased requirements in use and is treated in a first step, for example by means of a laser 17 (or electron beam gun) and its laser beams 19 (FIG. 13), so that continuous anchoring means 10 or inner anchoring means 13 are formed (FIG. Figure 14).

In a further method step, the recess 34 is filled with layer material 25, for example, from a material conveyor 22 (for example, by

Laser deposition welding), wherein either only layer material 25 is filled without the inner anchoring means 13 is further formed according to Figure 14, so that an inner anchoring means 13 is formed, which does not extend to the outer surface 16 or, for example, the laser 17 for laser deposition welding For example, also used to grow the continuous anchoring means 10 according to Figure 14 to the outer surface 16.

The continuous anchoring means 10 or inner anchoring means 13 may, but need not also extend with a portion 14 (indicated by dashed lines) in the substrate 4 or have a shape according to Figure 9, 5. The layer material 25 may be a material of the outer layer 9 or the substrate 4, but also have a different composition.

Likewise, no outer layer 9 can be present locally in the recess 34 and layer material 25, for example, of the outer layer 9 is applied, and continuous anchoring means 10 or inner anchoring means 13 are produced.

The explanations regarding FIGS. 13 to 15 apply analogously to the intermediate layer 7, to which an outer layer 9 is applied.

FIGS. 16, 17 show further exemplary embodiments of a method for producing a layer system 1.

To produce the outer layer 9, for example, a plasma torch 31 (FIG. 16) is used.

By means of a laser 17 and its laser beams 19, for example at the same time, for example by melting, a continuous anchoring means 10 or inner anchoring means 13 is produced in which the layer material 25 at least temporarily at the locations predetermined for the continuous anchoring means 10 or inner anchoring means 13 treated by means of the laser 17, that is, for example, is melted.

Similarly, two lasers 17, 17 '(FIG. 17) may be used, using a laser 17' for the deposition process, such as laser deposition welding using a material conveyor 22 (powder feeder) that supplies the laminate 25, and a laser 17, the as in FIG. 16, the continuous anchoring means 10 or inner anchoring means 13 are produced. In FIGS. 13, 14, 15 and 16, 17, the intermediate layer 7 and / or the outer layer 9 and the continuous anchoring means 10 or inner anchoring means 13 can be produced in layers.

Instead of the lasers 17, 17 'or plasma torches 31, electron beam guns can also be used. The use of lasers, plasma torches is not limited to the embodiments on anchoring means 10, 13 which extend with a proportion 14 into the substrate 4 or the intermediate layer 7 or to a specific cross-sectional shape as in FIG. 9.

FIG. 18 shows a gas turbine 100 in a longitudinal section.

The gas turbine 100 has inside a rotatably mounted about a Rotations¬ axis 102 rotor 103, which is also referred to as Turbi¬ nenläufer. Along the rotor 103, an intake housing 104, a compressor 105, a combustion chamber 110, for example a toroidal combustion chamber 110, in particular a ring combustion chamber 106, follow one another with a plurality of coaxially arranged burners

107, a turbine 108 and the exhaust housing 109. The annular combustion chamber 106 communicates with an annular annular hot gas channel 111, for example. There, for example, four turbine stages 112 connected in series form the turbine

108. Each turbine stage 112 is formed from two blade rings ge. As seen in the direction of flow of a working medium 113, in the hot gas channel 111 of a row of guide vanes 115, a series 125 formed of rotor blades 120 follows.

The guide vanes 130 are fastened to the stator 143, whereas the rotor blades 120 of a row 125 are secured by means of a Turbine disk 133 are mounted on the rotor 103. Coupled to the rotor 103 is a generator or a work machine (not shown).

During operation of the gas turbine 100, air 105 is sucked in by the compressor 105 through the intake housing 104 and sealed. The compressed air provided on the turbine-side end of the compressor 105 is fed to the burners 107 and mixed there with a fuel. The mixture is then burned in the combustion chamber 110 to form the working medium 113. From there, the working medium 113 flows along the hot gas channel 111 past the guide vanes 130 and the rotor blades 120. The working medium 113 unwinds on the rotor blades 120 in a pulse-transmitting manner, so that the rotor blades 120 drive the rotor 103 and this drives the working machine coupled to it ,

The components exposed to the hot working medium 113 are subject to thermal loads during the operation of the gas turbine 100. The guide vanes 130 and rotor blades 120 of the first turbine stage 112, viewed in the flow direction of the working medium 113, are subjected to the highest thermal load in addition to the heat shield bricks which line the annular combustion chamber 106. In order to withstand the temperatures prevailing there, they are cooled by means of a coolant. Likewise, the blades 120, 130 can have coatings against corrosion (MCrAlX, M = Fe, Co, Ni, X = Y, rare earths) and heat (thermal barrier coating, for example ZrC> 2, Y2O4-ZrO2).

The guide blade 130 has a guide blade root facing the inner housing 138 of the turbine 108 (not illustrated here) and a guide blade head opposite the guide blade root. The vane head faces the rotor 103 and fixed to a mounting ring 140 of the stator 143. FIG. 19 shows a combustion chamber 110 of a gas turbine 100. The combustion chamber 110 is designed, for example, as a so-called annular combustion chamber, in which a multiplicity of burners 107 arranged around the turbine shaft 103 in the circumferential direction open into a common combustion chamber space.

For this purpose, the combustion chamber 110 is configured in its entirety as a ring-shaped structure which is positioned around the turbine shaft 103.

To achieve a comparatively high efficiency, the combustion chamber 110 is designed for a comparatively high temperature of the working medium M of about 1000 ° C to 1600 ° C. In order to allow a comparatively long service life for these operating parameters, which are unfavorable for the materials, the combustion chamber wall 153 is provided on its side facing the working medium M with an inner lining formed of heat shield elements 155. Each heat shield element 155 is equipped on the working medium side with a particularly heat-resistant protective layer or made of high-temperature-resistant material. Due to the high temperatures inside the combustion chamber 110, a cooling system is additionally provided for the heat shield elements 155 or for their holding elements.

FIG. 20 shows a perspective view of a moving blade 120 or guide blade 130 of a turbomachine that extends along a longitudinal axis 121.

The turbomachine may be a gas turbine of an aircraft or a power plant for generating electricity, a steam turbine or a compressor.

The blade 120, 130 has, along the longitudinal axis 121, a fastening area 400, an adjacent blade platform 403 and an airfoil 406, one after another. As a guide blade 130, the blade 130 may have at its blade tip 415 another platform (not illustrated).

In the mounting region 400, a blade root 183 is formed, which serves for attachment of the blades 120, 130 to a shaft or a disc (not shown). The blade root 183 is designed, for example, as a hammer head. Other designs as fir tree or Schwäbwschwanzfuß are possible.

The blade 120, 130 has a leading edge 409 and a discharge edge 412 for a medium that flows past the blade plate 406.

In conventional blades 120, 130, in all areas 400, 403, 406 of the blade 120, 130, for example, massive metallic materials, in particular superalloys, are used. Such superalloys are known, for example, from EP 1 204 776 B1, EP 1 306 454, EP 1 319 729 A1, WO 99/67435 or WO

00/44949 known; these writings are part of the revelation. In this case, the blade 120, 130 can be produced by a casting process, also by directional solidification, by a forging process, by a milling process or combinations thereof.

Workpieces with a monocrystalline structure or structures are used as components for machines which are exposed to high mechanical, thermal and / or chemical stresses during operation.

The production of such monocrystalline workpieces follows er¬ example. by directed solidification from the melt. These are casting processes in which the liquid metallic alloy is transformed into a monocrystalline structure, i. to the single-crystal workpiece, or directionally solidified.

Here, dendritic crystals are aligned along the heat flow and form either a columnar crystalline Grain structure (columnar, ie grains that extend over the entire length of the workpiece and here, the general Sprach¬ use, referred to as directionally solidified) or a monocrystalline structure, ie the entire workpiece consists of a single crystal. In these processes, it is necessary to avoid the transition to globulitic (polycrystalline) solidification since, due to undirected growth, it is necessary to form transverse and longitudinal grain boundaries which negate the good properties of the directionally solidified or monocrystalline component.

If the term generally refers to directionally solidified structures, it means both single crystals that have no grain boundaries or at most small-angle grain boundaries, and stem crystal structures that have grain boundaries that are probably in the longitudinal direction but no transverse grain boundaries. These second-mentioned crystalline structures are also known as directionally solidified structures. Such methods are known from US Pat. No. 6,024,792 and EP 0 892 090 A1; These documents are part of the Offenba¬ tion.

Likewise, the blades 120, 130 may be coatings against corrosion or oxidation (MCrAlX; M is at least one element of the group iron (Fe), cobalt (Co), nickel (Ni), X is an active element and is yttrium (Y) and / or silicon and / or at least one element of the rare earths, or hafnium (Hf)). Such alloys are known from EP 0 486 489 B1, EP 0 786 017 Bl, EP 0 412 397 B1 or EP 1 306 454 A1, which are intended to be part of this disclosure.

On the MCrAlX may still be present a thermal barrier coating and consists for example of ZrÜ2, Y2Ü4-Zrθ2, ie it is not, partially or completely stabilized by yttrium oxide and / or calcium oxide and / or magnesium oxide. Suitable coating processes, such as electron beam evaporation (EB-PVD), produce stalk-shaped grains in the thermal barrier coating.

Refurbishment means that components 120, 130 may have to be freed from protective layers (eg by sandblasting) after use. This is followed by removal of the corrosion and / or oxidation layers or products. Optionally, even cracks in the component 120, 130 are repaired. This is followed by a re-coating of the component 120, 130 and a renewed use of the component 120, 130.

The blade 120, 130 may be hollow or solid. If the blade 120, 130 is to be cooled, it is hollow and may still have film cooling holes 418 (indicated by dashed lines).

Claims

claims

1. Layer system (1), at least consisting of a substrate (4) and an outer layer (9) on the substrate (4), in particular with at least one intermediate layer (7) between substrate (4) and outer layer (9) in which in the outer layer (9) and / or in the at least one intermediate layer (7)

Anchoring means are present with the majority of the total volume of anchoring means,

characterized,

in that in the outer layer (9) and / or in the intermediate layer (7) continuous anchoring means (10) and / or inner anchoring means (13) are present that the continuous anchoring means (10) or inner anchoring means (13) for the intermediate layer (7) into the substrate (4) or another intermediate layer (7) or that the continuous anchoring means (10) or inner anchoring means (13) for the outer layer (9) in the intermediate layer (7) or in the substrate (4) protrude and that the material of the continuous anchoring means (10) or the inner anchoring means (13) of the material class (metal, ceramic) of the intermediate layer (7) or the outer layer (9) corresponds, in the (7, 9) it with the predominant Part of a total volume is arranged, wherein the proportion in the layer (7, 9) is at least 70vol% and less than 100vol%.

Second layer system according to claim 1, characterized in that

the layer system (1) has an intermediate layer (7), in particular consisting of an alloy of the MCrAlX type.

3. Layer system according to claim 1 or 2, characterized in that

only in the intermediate layer (7) continuous anchoring means (10) or inner anchoring means (13) are present.

4. Layer system according to claim 1 or 2, characterized in that

in the intermediate layer (7) and in the outer layer (9) continuous anchoring means (10) or inner anchoring means (13) are present.

5. Layer system according to claim 1 or 2, characterized in that

only in the outer layer (9) through

Anchoring means (10) or inner anchoring means (13) are present.

6. layer system according to claim 1, characterized in that

the continuous anchoring means (10) or the inner anchoring means (13) have a different type of connection to the substrate (4) or to the intermediate layer (7) than the outer layer (9) to the intermediate layer (7) or to the substrate (4) or as the intermediate layer (7) to the substrate (4).

7. Layer system according to claim 1 or 6, characterized in that

the continuous anchoring means (10) or inner anchoring means (13) are fusion metallurgically bonded to the substrate (4) and / or the intermediate layer (7).

8. Layer system according to claim 1, 2, 3, 4 or 5, characterized in that

at least one, in particular a plurality of continuous anchoring means (10) or inner anchoring means (13) and the intermediate layer (7) are metallic.

9. Layer system according to one or more of the preceding claims, characterized in that

the continuous anchoring means (10) or inner anchoring means (13) are locally limited on the substrate (4) or the intermediate layer (7) are present.

10. SchichtSystem according to one or more of the preceding claims, characterized in that

the continuous anchoring means (10) or the inner anchoring means (13) are columnar-shaped.

11. Layer system according to claim 1, 9 or 10, characterized in that

the continuous anchoring means (10) extend only to an inner surface (8) of the intermediate layer (7) or only to the outer surface (16) of the outer layer (9).

12. Layer system according to claim 1, 9 or 10, characterized in that

the inner anchoring means (13) extend only within the intermediate layer (7) or the outer layer (9), in particular over at least 10% of the thickness of the intermediate layer (7) or the outer layer (9).

13. Layer system according to claim 1, characterized in that

the layer system (1) is a newly manufactured or reworked component of a gas (100) or steam turbine, in particular a turbine blade (120, 130), a heat shield element (155) or a housing part along the flow path of a hot gas.