Improved surface of a metallic layer for a ceramic coating system

Abstract

The invention relates to a method for producing a layer system (1) with improved adhesion, in which a metallic substrate (4) is provided, wherein the metallic substrate (4) is coated with a metallic adhesion promoter layer (7), wherein the metallic adhesion promoter layer (7) has a surface (8), wherein the surface (8) is then structured, in particular by a laser beam (13) of a laser (10), and then the coating with a ceramic layer (16) is carried out.

Description

The invention relates to an improved surface of a metallic layer for a ceramic layer system.Layer systems have a substrate which is to be protected by a layer against external influences such as heat, corrosion, erosion. In particular in the case of ceramic protective layers such as, for example, EP 1 971 705 B1, there is the problem of the significantly different coefficients of expansion of metal and ceramic when the layer system is used at high temperatures and / or changing temperatures. Therefore, a metallic layer is often used as adhesion promoter layer between substrate and outermost protective layer, see EP 4 208 830 A1. In the case of gas turbines, the turbine blades are provided with a ceramic protective layer in the hot gas region. The substrate is metallic and preferably comprises a nickel- or cobalt-based superalloy. On the substrate there is then a metallic adhesion promoter layer which is likewise nickel or cobalt-based and has further elements such as at least chromium, aluminum, yttrium,... Only then is the ceramic protective layer applied. Even if the expansion behavior between substrate is matched to the layers or between the layers, chipping can again and again occur.It is therefore an object of the invention to solve the above problem.The object is achieved by a layer system according to claim 4 and a method according to claim 1.The dependent claims list further advantageous measures which can be combined with one another as desired in order to achieve further advantages.The figure schematically shows the production method and the ceramic layer system according to the invention.The figure and the description represent only exemplary embodiments of the invention.In the figure, a substrate 4, in particular made of a nickel- or cobalt-based material, is provided for the method. The metallic substrate 4 is then coated with a metallic adhesion promoter layer 7, in particular a NiCoCrAlY. NiCoCrAlY may include other elements and includes, among others, NiCoCrAlYTaSiFe NiCoCrAlYRe, NiCoCrAlYTa, NiCoCrAlYTaSi NiCoCrAlYFeSi.The metallic adhesion promoter layer 7 is applied, inter alia, by known methods of plasma spraying, such as APS, VPS or else by means of LMD (laser metal deposition), HVOF, electroplating methods or diffusion methods etc., and adheres to the substrate 4.In a further step according to the figure, a laser 10 is preferably structured the surface 8 of the metallic adhesion promoter layer 7 by means of an ablative method, here preferably laser ablation with a laser beam 13. These can preferably be punctiform or trench-shaped depressions 15. Or, by means of the material removal, truncated cones, preferably in the form of micromorse cones, in particular with self-locking adhesion, will be present, which preferably have a height of 100 μm. The depressions 15 are then present between the truncated cones.The structured surface 8' can comprise the entire surface of the metallic adhesion promoter layer 7 or can be formed only partially.The structuring is effected in a defined manner and not by simple roughening, for example by sandblasting. Likewise, no simple re-melting of the surface 8 takes place.This achieves an increased contact surfaces 18' and an increased adhesion, so that during the subsequent coating with a ceramic layer 16 an improved mechanical adhesion of the ceramic layer 16 to the metallic layer 7' takes place.The ceramic layer 16 is preferably based on zirconium oxide (ZrO 2). The ceramic layer 16 can be formed as a single layer or a double layer.This processing can be carried out during the production of new parts or also in the case of repair, in which the substrate 4 according to the figure represents a de-coated substrate after use.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 1 971 705 B1

[0002] EP 4 208 830 A1

[0002]

Claims

Method for producing a layer system (1) with improved adhesion, in which a metallic substrate (4) is provided, wherein the metallic substrate (4) is or is coated with a metallic adhesion promoter layer (7), wherein the metallic adhesion promoter layer (7) has a surface (8), wherein the surface (8) is then structured by material removal, in particular by a laser beam (13) of a laser (10), and then the coating is carried out with a ceramic layer (16).Method according to Claim 1, in which the metallic adhesion promoter layer (7) is applied by a plasma method, in particular APS, VPS, or an HVOF method or an LMD method.Method according to one or both of Claims 1 or 2, in which the ceramic layer (16) is applied by an APS method.A ceramic layer system, comprising: a metallic substrate (4) a metallic adhesion promoter layer (7'), the surface (8') of which is structured by a material-removing method according to the coating method, and a ceramic layer (16) on the structured surface (18').Method according to one or more of Claims 1, 2 or 3 or ceramic layer system according to Claim 4, in which the metallic adhesion promoter layer (7, 7') comprises an alloy based on NiCoCrAlY, in particular NiCoCrAlYTaSiFe NiCoCrAlYRe, NiCoCrAlYTa, NiCoCrAlYTaSi or NiCoCrAlYFeSi.Method according to one or more of Claims 1, 2 or 3 or 5 or ceramic layer system according to one or both of Claims 4 or 5, in which the ceramic layer (16) has a zirconium oxide-based layer.Method according to one or more of claims 1, 2 or 3 or 5, 6 or ceramic layer system according to one or more of claims 4, 5 or 6, in which truncated cones, preferably in the form of micromorse cones, form the structured surface (8', 18').

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