Method for producing an improved binding surface in a metal layer for a ceramic layer system
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- SIEMENS ENERGY GLOBAL GMBH & CO KG
- Filing Date
- 2024-08-28
- Publication Date
- 2026-06-10
AI Technical Summary
The significant difference in thermal expansion coefficients between metal and ceramic layers in high-temperature or varying temperature applications leads to flaking issues in ceramic protective layer systems, especially in gas turbines.
A layer system comprising a nickel or cobalt-based metallic substrate coated with a structured metallic adhesion layer, applied using techniques like plasma spray or laser metal deposition, followed by a zirconia-based ceramic layer. The metallic adhesion layer is structured through laser ablation to create micro-scale depressions, enhancing mechanical bonding with the ceramic layer.
The structured metallic adhesion layer increases the contact surface area and mechanical reliability, thereby improving the adherence and durability of the ceramic layer, reducing flaking and enhancing the overall performance in high-temperature conditions.
Smart Images
Figure EP2024073981_10042025_PF_FP_ABST
Abstract
Description
[0001] Method for producing an improved bonding surface in a metal layer for a ceramic layer system
[0002] The invention relates to an improved surface of a metallic layer for a ceramic layer system.
[0003] Layer systems comprise a substrate that is to be protected by a layer against external influences such as heat, corrosion, and erosion. Particularly with ceramic protective layers such as EP 1 971 705 B1, there is the problem of the significantly different expansion coefficients of metal and ceramic when the layer system is used at high temperatures and / or fluctuating temperatures.
[0004] Therefore, a metallic layer is often used as an adhesion promoter layer between the substrate and the outermost protective layer, see EP 4 208 830 Al.
[0005] In the case of gas turbines, the turbine blades are coated with a ceramic protective layer in the hot gas area. The substrate is metallic and preferably comprises a nickel- or cobalt-based superalloy.
[0006] A metallic adhesion promoter layer is then present on the substrate, which is also nickel or cobalt-based and contains other elements such as at least chromium, aluminum, yttrium, etc.
[0007] Only then is the ceramic protective layer applied. Even if the expansion behavior between the substrate and the layers or between the layers is adapted, chipping can still occur.
[0008] It is therefore an object of the invention to solve the above-mentioned problem.
[0009] The object is achieved by a layer system according to claim 4 and a method according to claim 1. The subclaims list further advantageous measures which can be combined with one another as desired in order to achieve further advantages.
[0010] The figure shows schematically the manufacturing process and the ceramic layer system according to the invention.
[0011] The figure and the description represent only exemplary embodiments of the invention.
[0012] In the figure, a substrate 4, in particular made of a nickel or cobalt-based material, is provided for the process.
[0013] The metallic substrate 4 is then coated with a metallic adhesion promoter layer 7, in particular a NiCoCrAlY layer. NiCoCrAlY may contain further elements and includes, among others, NiCoCrAlYTaSiFe, NiCoCrAlYRe, NiCoCrAlYTa, NiCoCrAlYTaSi, and NiCoCrAlYFeSi.
[0014] The metallic adhesion promoter layer 7 is applied, inter alia, by known plasma spraying processes such as APS, VPS or by means of LMD (Laser Metal Deposition), HVOF, galvanic processes or diffusion processes, etc., and adheres to the substrate 4.
[0015] In a further step according to the figure, the surface 8 of the metallic adhesion promoter layer 7 is structured preferably by means of an ablation process, here preferably a laser ablation with a laser beam 13 of a laser 10.
[0016] These can preferably be point-shaped or trench-shaped depressions 15. Or, as a result of the material removal, they can be truncated cones, preferably in the form of micro-Morse cones, in particular with self-locking adhesion, which preferably have a height of 100 μm. The depressions 15 are then present between the truncated cones. The structured surface 8' can encompass the entire surface of the metallic adhesion promoter layer 7 or can be or become formed only partially.
[0017] The structuring is done in a defined manner and not by simple roughening, such as by sandblasting.
[0018] Likewise, there is no simple remelting of the surface 8 .
[0019] This results in an enlarged contact surface 18 ' and 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 ' is achieved .
[0020] The ceramic layer 16 is preferably based on zirconium oxide (ZrO2).
[0021] The ceramic layer 16 can be formed as a single layer or a double layer.
[0022] This processing can be carried out during the production of new parts or also in the case of repairs, in which the substrate 4 according to the figure represents a decoated substrate after use.
Claims
Patent claims 1. 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 with a ceramic layer (16) takes place.
2. Method according to claim 1, wherein the metallic adhesion promoter layer (7) is applied by a plasma process, in particular APS, VPS, or an HVOF process or an LMD process.
3. Method according to one or both of claims 1 or 2, wherein the ceramic layer (16) is applied by an APS method.
4. Ceramic layer system, comprising: a metallic substrate (4) a metallic adhesion promoter layer (7'), the surface (8') of which is coated by the coating process structured by a material-removing process, and a ceramic layer (16) on the structured surface (18').
5. Method according to one or more of claims 1, 2 or 3 or ceramic layer system according to claim 4, wherein the metallic adhesion promoter layer (7, 7') comprises an alloy based on NiCoCrAlY, in particular NiCoCrAlYTaSiFe, NiCoCrAlYRe, NiCoCrAlYTa, NiCoCrAlYTaSi or NiCoCrAlYFeSi.
6. 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, wherein the ceramic layer (16) comprises a zirconium oxide-based layer.
7. 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 micro-Morse cones, form the structured surface (8', 18').