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EP-3784813-B1 - COATING COMPRISING MCRAL-X COATING LAYER

EP3784813B1EP 3784813 B1EP3784813 B1EP 3784813B1EP-3784813-B1

Inventors

  • RAMM, JUERGEN
  • WIDRIG, BENO
  • JARRY, Oliver
  • HUNOLD, Oliver

Dates

Publication Date
20260506
Application Date
20190424

Claims (11)

  1. A coated substrate comprising a substrate (1) comprising a metal substrate surface (11) coated with a coating system (7) consisting of or comprising a functional coating film (5), said functional coating film (5) consisting of or comprising at least one MCrAl-X coating layer, wherein • the at least one MCrAl-X coating layer is deposited directly on the metal substrate (11), or • the at least one MCrAl-X coating layer is deposited on an intermediate coating layer (3) that is formed of at least one substrate matching layer (31), wherein the at least one substrate matching layer (31) is deposited directly on the metal substrate surface (11), wherein the layer deposited directly on the metal substrate surface (11), it means respectively the MCrAl-X coating layer if it is deposited directly on the metal substrate surface (11) or the substrate matching layer (31) if it is deposited on the metal substrate surface (11) exhibits: • epitaxial growth in part or totally, or • heteroepitaxial growth in part or totally, I. wherein the concentration of the main component in the substrate (1) differs from the concentration of the main component in the substrate matching layer (31) or in the MCrAl-X coating layer deposited directly on the substrate surface in not more than 30% in composition (wt.%), II. or wherein both the substrate matching layer (31) and the metal surface (11) of the substrate (1) have a similar crystalline structure defined as similar of the maximal mismatch in the lattice parameter is of 5% , or in the case that the MCrAl-X layer is deposited directly on the substrate surface then it is applicable that both the MCrAl-X-layer and the metal surface (11) of the substrate (1) have a similar crystalline structure defined as similar if the maximal mismatch in the lattice parameter is of 5%, characterized in that the MCrAl-X coating layer comprises at least two sublayers, a first sublayer and a second sublayer, wherein the first sublayer is deposited nearest to the metal substrate surface (11) and the second sublayer is deposited onto the first sublayer, wherein the both the first sublayer and the second sublayer comprises the same elements but the second sublayer has a higher Al content than the first sublayer, and the MCrAl-X layer comprises at least two sublayers, a first sublayer and a second sublayer, wherein the second layer comprises oxygen and is therefore a MCrAl-X-O layer.
  2. The coated substrate according to claim 1, characterized in that the material of the metal substrate surface (11) is a super alloy or a nickel aluminide.
  3. The coated substrate according to claim 2, characterized in that the material of the metal substrate surface (11) is a super alloy of the type nickel based super alloy or cobalt based super alloy or a nickel/cobalt based super alloy.
  4. The coated substrate according to any one of the previous claims 1 to 3, characterized in that the concentration of Al in the second sublayer in relation to the first sublayer taking into account only the concentration of the metallic components M, Cr and Al in atomic percentage is twice as much.
  5. The coated substrate according to any one of the previous claims 1 to 4, characterized in that the oxygen in the second sublayer increases gradually.
  6. The coated substrate according to any one of the previous claims 1 to 5, characterized in that the aluminum in the second sublayer increases gradually.
  7. The coated substrate according to any one of the previous claims 1 to 6, characterized in that in the MCrAl-X layer, and if present then also in the MCrAl-X-O material: - M is Ni or Co or Ni-Co, and - X is Y or Er or Zr.
  8. The coated substrate according to any one of the previous claims 1 to 7, characterized in that at least one layer of MCrAl-X-O material is present in the functional coating film (5), wherein this layer comprises an oxygen content corresponding to a value between 50 at.% and 60 at.% +/-3at.% - the range including the border values 50 at.% and 60 at.% - considering all elements present in this layer for the determination of the element composition in atomic percentage.
  9. The coated substrate according to any one of the previous claims 1 to 8, characterized in that at least one layer of MCrAl-X material is present in the functional coating film (5), wherein this layer exhibits fcc crystalline structure.
  10. The coated substrate according to any one of the previous claims 1 to 9, characterized in that the layer that is deposited directly on the metal substrate surface (11) has a similar crystalline structure compared to the crystalline structure of the material of the metal substrate (1), respectively of the metal substrate surface (11), wherein the maximal mismatch in the lattice parameter is of 5%, preferably maximal 1%.
  11. A method for producing a coated substrate comprising at least one metal substrate surface (11) coated with a coating system (7) comprising a functional coating film (5) and an intermediate coating film (3) that is formed of at least one substrate matching layer (31) or an MCrAl-X layer and is deposited between the at least one metal surface (11) and the functional coating film (5), wherein the functional coating film (5) comprises at least one layer of the type MCrAl-X and/or at least one layer of the type MCrAl-X-O, wherein both the substrate matching layer (31) and the metal surface (11) of the substrate (1) have a similar crystalline structure defined as similar of the maximal mismatch in the lattice parameter is of 5% or in the case that the MCrAl-X layer is deposited directly on the substrate surface then it is applicable that both the MCrAl-X-layer and the metal surface (11) of the substrate (1) have a similar crystalline structure defined as similar if the maximal mismatch in the lattice parameter is of 5%, characterized in that the at least one layer of the type MCrAl-X and/or the at least one layer of the type MCrAl-X-O is deposited by using a physical vapor deposition (PVD) technique, wherein the used PVD technique is arc evaporation or magnetron sputtering, if sputtering preferably HiPIMS, wherein a target composed of M, Cr, Al and X is used as coating source material and in case of deposition of at least one layer of the type MCrAl-X-O, oxygen flow gas is used as reactive gas.

Description

The present invention relates to a new coating system comprising at least one MCrAl-X coating layer synthesized by using physical vapor deposition techniques, the coating being applicable for protecting metal substrates, in particular for protecting turbine components. Technical Background WO 2018/193035 A1 describes a superalloy workpiece comprising: - a superalloy substrate - an interface layer (IF-1) of essentially the same superalloy composition directly on a surface of the superalloy substrate, followed by - a transition layer (TL) of essentially the same superalloy and supperalloy oxides or a different metal composition and different metal oxides whereby oxygen content of the transition layer is increasing from IF-1 towards - a barrier layer (IF-2) of super alloy oxides or of different metal oxides. EP 3 029 113 A1 describes a coated substrate comprising a substrate material, which is coated at least in part with an oxidation-resistant coating, wherein the coating consists of or comprises a wear-resistant abrasive coating layer, which consists of coated abrasive particles embedded in an oxidation-resistant matrix material, wherein at least some of the abrasive particles consist of α-Al2O3 and the abrasive particles are coated with a first particle coating layer disposed on the abrasive particles and an optional second particle coating layer disposed on the first particle coating layer, wherein the matrix material consists of or comprises the compound MCrAlY, wherein M is at least one element selected from the group consisting of Ni, Co and Fe. A method for manufacturing such a coated substrate is also described. EP 1 295 969 A1 relates to a method of growing a MCrAlY-coating and an article coated with the MCrAlY-coating. A gas turbine component consists of a superalloy base material with a single crystal structure and a protective MCrAlY-coating. The MCrAlY-coating the MCrAlY has a gamma / beta -phase and single crystal structure, which is epitaxial with the base material. US 2011/0268987 A1 relates to a MCrAlX layer having differing chromium and aluminum content. A two-ply MCrAlX layer is provided. The two-ply MCrAlX layer includes nickel and cobalt, but also Cr, Al and Y, differ significantly, in order to improve both oxidation resistance and thermal-mechanical strength. A layer system including a substrate and the two-ply MCrAlX layer is also described. The MCrAlX layer includes an inner layer and an outer layer. Summary of the Invention The invention is defined by appended claims. Advantages and Description of the Invention The main purpose of the present invention is to enable the synthesis of coatings which form excellent interfaces to "metal substrates" and which can be exposed to temperatures which are approaching the melting temperatures of the substrate material without delamination. The term "metal substrate" used in the present description and in the context of the present invention refers to substrates made of a material exhibiting metallic properties, e.g. a nickel-based alloy or a nickel aluminide. For example, a coating according to the present invention can be provided on surfaces of turbine blade tips for improving performance of these turbine blade tips. In this manner, the surface of the blade tip, which comes in contact with abradable material (rubbing) during operation is protected against mechanical wear and corrosion by the coating provided before operation according to the present invention. Furthermore, a coating according to the present invention can provide a significantly improvement of metal substrates. In particular turbine blades made of a material consisting of or comprising a nickel-based alloy or a nickel aluminide exhibit a significantly increased oxidation resistance after being coated according to the present invention. The deposition of the coating of the present invention is performed by Physical Vapour Deposition (PVD) methods, like cathodic arc evaporation, sputtering or high power pulsed sputtering (commonly known as High Power Impulse Magnetron Sputtering (HiPIMS) or High Power Pulsed Magnetron Sputtering (HPPMS)), preferably by cathodic arc evaporation. The present invention provides a new, innovative and very useful coating 7 comprising a functional coating film 5, wherein the functional coating film 5 is formed of at least one MCrAl-X coating layer 5 synthesized by using physical vapor deposition techniques, as it is schematically shown in Fig. 1a, Fig 1b and Fig. 1c. Optionally, the coating 7 can comprise one top coating film 10 deposited atop the functional coating film 5 as it is shown in Fig. 1b. Alternatively, the inventive coating system 7 comprises a functional coating film 5 and an intermediate coating film 3, wherein the intermediate coating film 3 is deposited on a surface 11 of a metal substrate 1, so that the intermediate coating film 3 is deposited between the surface 11 and the functional coating film 5, wherein the functional coating film 5