CMAS RESISTANT, HIGH STRAIN TOLERANT AND LOW THERMAL CONDUCTIVITY THERMAL BARRIER COATINGS AND THERMAL SPRAY COATING METHOD

Abstract

An erosion and CMAS resistant coating arranged on a TBC coated substrate and including at least one porous vertically cracked (PVC) coating layer providing lower thermal conductivity and being disposed over a layer of MCrAlY wherein M represents Ni, Co or their combinations. At least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer is deposited over the at least one PVC coating layer.

Claims

1. An erosion and CMAS resistant coating comprising: at least one porous vertically cracked (PVC) coating layer providing low thermal conductivity disposed over a thermal barrier coating (TBC) that includes a layer of MCrAlY, wherein M represents Ni, Co or their combinations; and at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer deposited over the at least one PVC coating layer.

2. The coating of claim 1, wherein the at least one DVC layer is a top layer.

3.-4. (canceled)

5. The coating of claim 1, wherein the at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer comprises Re stabilized ZrO2 or HfO2 mixed with rare earth oxide.

6. The coating of claim 1, wherein the at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer comprises Re stabilized ZrO2 or HfO2 mixed with rare earth silicate.

7. The coating of claim 1, wherein the at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer comprises Re stabilized ZrO2 or HfO2 mixed with rare earth aluminate.

8. The coating of claim 1, wherein the at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer comprises Re stabilized ZrO2 or HfO2 mixed with rare earth aluminate or silicate.

9. The coating of claim 1, wherein the at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer comprises Re stabilized ZrO2 or HfO2 mixed with alkaline oxide.

10. The coating of claim 1, wherein the at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer comprises Re stabilized ZrO2 or HfO2 mixed with gadolinium zirconate.

11. The coating of claim 1, wherein the at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer comprises a mixture of a mixture of two or more of: Re stabilized ZrO2 or HfO2 mixed with rare earth oxide; Re stabilized ZrO2 or HfO2 mixed with rare earth silicate; Re stabilized ZrO2 or HfO2 mixed with rare earth aluminate; Re stabilized ZrO2 or HfO2 mixed with rare earth aluminate or silicate; Re stabilized ZrO2 or HfO2 mixed with alkaline oxide; and Re stabilized ZrO2 or HfO2 mixed with gadolinium zirconate.

12. The coating of claim 1, wherein the at least one dense vertically cracked (DVC) erosion and CMAS resistant coating layer comprises full thickness vertical cracks.

13. The coating of claim 1, wherein the at least one porous vertically cracked (PVC) coating layer comprises full thickness vertical cracks.

14. An erosion and CMAS resistant coating according to claim 1 arranged on a substrate.

15. The coating of claim 14, further comprising at least one bond coating layer disposed between the TBC and the substrate.

16.-25. (canceled)

26. The coating of claim 14, wherein the substrate is a superalloy substrate.

27. A method of plasma spraying an erosion and CMAS resistant coating on an TBC coated substrate, comprising: depositing at least one porous vertically cracked (PVC) thermal barrier coating layer providing lower thermal conductivity onto the TBC coated substrate; and depositing a dense vertically cracked (DVC) erosion and CMAS resistant coating material over the at least one PVC thermal barrier coating layer.

28. The method of claim 27, wherein the TBC coated substrate comprises at least one bond coating layer arranged between an TBC layer and the substrate.

29. The method of claim 27, wherein the plasma spraying comprises one of: atmospheric plasma spraying (APS); plasma spray-physical vapor deposition (PS-PVD); or suspension plasma spray (SPS).

30.-31. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The accompanying drawings are included to provide further understanding of the invention and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the figures:

[0064] FIG. 1 schematically shows a multi-layer coating in accordance with the invention; and

[0065] FIG. 2 shows a scanning electron microscope (SEM) cross-section of an applied multi-layer coating in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0066] The following detailed description illustrates by way of example, not by way of limitation, the principles of the disclosure. This description will clearly enable one skilled in the art to make and use the disclosure, and describes several embodiments, adaptations, variations, alternatives and uses of the disclosure, including what is presently believed to be the best mode of carrying out the disclosure. It should be understood that the drawings are diagrammatic and schematic representations of exemplary embodiments of the disclosure and are not limiting of the present disclosure nor are they necessarily drawn to scale.

[0067] The novel features which are characteristic of the disclosure, both as to structure and method of operation thereof, together with further aims and advantages thereof, will be understood from the following description, considered in connection with the accompanying drawings, in which an embodiment of the disclosure is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only, and they are not intended as a definition of the limits of the disclosure.

[0068] In the following description, the various embodiments of the present disclosure will be described with respect to the enclosed drawings. As required, detailed embodiments of the present disclosure are discussed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the embodiments of the disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure.

[0069] The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present disclosure only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present disclosure. In this regard, no attempt is made to show structural details of the present disclosure in more detail than is necessary for the fundamental understanding of the present disclosure, such that the description, taken with the drawings, making apparent to those skilled in the art how the forms of the present disclosure may be embodied in practice.

[0070] As used herein, the singular forms “a,” “an,” and “the” include the plural reference unless the context clearly dictates otherwise. For example, reference to “a powder material” would also mean that mixtures of one or more powder materials can be present unless specifically excluded. As used herein, the indefinite article “a” indicates one as well as more than one and does not necessarily limit its referent noun to the singular.

[0071] Except where otherwise indicated, all numbers expressing quantities used in the specification and claims are to be understood as being modified in all examples by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by embodiments of the present disclosure. At the very least, and not to be considered as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of significant digits and ordinary rounding conventions.

[0072] Additionally, the recitation of numerical ranges within this specification is considered to be a disclosure of all numerical values and ranges within that range (unless otherwise explicitly indicated). For example, if a range is from about 1 to about 50, it is deemed to include, for example, 1, 7, 34, 46.1, 23.7, or any other value or range within the range.

[0073] As used herein, the terms “about” and “approximately” indicate that the amount or value in question may be the specific value designated or some other value in its neighborhood. Generally, the terms “about” and “approximately” denoting a certain value is intended to denote a range within ±5% of the value. As one example, the phrase “about 100” denotes a range of 100±5, i.e. the range from 95 to 105. Generally, when the terms “about” and “approximately” are used, it can be expected that similar results or effects according to the disclosure can be obtained within a range of ±5% of the indicated value.

[0074] As used herein, the term “and/or” indicates that either all or only one of the elements of said group may be present. For example, “A and/or B” shall mean “only A, or only B, or both A and B”. In the case of “only A”, the term also covers the possibility that B is absent, i.e. “only A, but not B”.

[0075] The term “at least partially” is intended to denote that the following property is fulfilled to a certain extent or completely.

[0076] The terms “substantially” and “essentially” are used to denote that the following feature, property or parameter is either completely (entirely) realized or satisfied or to a major degree that does not adversely affect the intended result.

[0077] The term “comprising” as used herein is intended to be non-exclusive and open-ended. Thus, for example a composition comprising a compound A may include other compounds besides A. However, the term “comprising” also covers the more restrictive meanings of “consisting essentially of” and “consisting of”, so that for example “a composition comprising a compound A” may also (essentially) consist of the compound A.

[0078] The various embodiments disclosed herein can be used separately and in various combinations unless specifically stated to the contrary.

[0079] The invention is described with reference to FIG. 1 which schematically shows a multi-layer coating. As is evident in FIG. 1, the multi-layer coating utilizes a top coating layer that is a strain tolerant DVC coating top layer. This layer is disposed over an underlying PVC coating system which is used to decrease the thermal conductivity of the layers. The DVC/PVC layers can be composed of tough rare earth element (Re) stabilized ZrO.sub.2 or HfO.sub.2 mixed with a CMAS resistant chemistry composition. The one or more DVC layers provide erosion resistant and the one or more PVC layers provide the CTE mitigation between the one or more high CTE top layer and the one or more low CTE bottom layers of TBC. The DVC and PVC layer(s) are arranged over a bond coating B and substrate S.

[0080] The DVC layer(s) can be composed of tough Re stabilized ZrO.sub.2 or HfO.sub.2 mixed with CMAS resistant chemistry to improve the erosion and CMAS resistance of the TBC/CMC system. In addition, the PVC strain tolerant transition layer(s) provides CTE mitigation between the high CTE top layer(s) (DVC layer) and the low CTE bottom layer(s) TBC. Next, PVC microstructure further reduces thermal conductivity of the TBC system.

[0081] Non-limiting embodiments of the DVC top layer(s) and/or the PVC layer(s), with the DVC being erosion and CMAS resistant and with the PVC being a thermal barrier and CTE mitigation layer, include the following (with exemplary rare earth oxides including Yttrium oxide, Lanthanum oxide, Cerium oxide, Praseodymium oxide, Neodymium oxide, Samarium oxide, Europium oxide, Gadolinium oxide, terbium oxide, Dysprosium oxide, holmium oxide, erbium oxide, ytterbium oxide, Lutetium oxide, Scandium oxide, Thulium oxide): [0082] Re stabilized ZrO.sub.2 or HfO.sub.2 [0083] Re stabilized ZrO.sub.2 or HfO.sub.2 mixture with Rare earth oxides; or [0084] Re stabilized ZrO.sub.2 or HfO.sub.2 mixture with Rare earth Silicate; or [0085] Re stabilized ZrO.sub.2 or HfO.sub.2 mixture with Rare earth Aluminate; or [0086] Re stabilized ZrO.sub.2 or HfO.sub.2 mixture with Rare earth Aluminate Silicate; or [0087] Re stabilized ZrO.sub.2 or HfO.sub.2 mixture with alkaline oxides; or [0088] Re stabilized ZrO.sub.2 or HfO.sub.2 mixture with Gadolinium Zirconate; or [0089] Any combinations of the above.

[0090] The DVC top layer(s) or coating can have a CTE of ˜9×10.sup.−6/degrees C. to 13×10.sup.−6/degrees C., as well as a thickness of between 2 mils and 40 mils. This layer or coating can be applied by atmospheric plasma spraying (APS), plasma spray-physical vapor deposition (PS-PVD) or suspension plasma spray (SPS).

[0091] The PVC intermediate layer(s) or coating can have a CTE of ˜9×10.sup.−6/degrees C. to 13×10.sup.−6/degrees C., as well as a thickness of between 1 mil and 40 mils. This layer or coating can be applied by atmospheric plasma spraying (APS), plasma spray-physical vapor deposition (PS-PVD) or suspension plasma spray (SPS).

[0092] The bond coating layer(s) or coating B can be MCrAlY (M=Ni, CO) as well as have a thickness of between 2 mils and 13 mils. This layer or coating can be applied by atmospheric plasma spraying (APS), high velocity oxy-fuel (HVOF), high velocity air-fuel (HVAF), plasma spray-physical vapor deposition (PS-PVD) or suspension thermal spray.

[0093] In embodiments, the porosity of the DVC layer(s) can be 0% to 5% and the cracks can extend either partially through the thickness of the layer(s), i.e., less than 50% of the thickness, or about 50% of the thickness, and can even extend through an entire thickness of the layer(s). In embodiments, the cracks can be substantially vertical cracks and can range between 20 and 200 cracks per inch or linear inch. In non-limiting embodiments, the DVC layer(s) can also be of a type known in the art and described in one or more of the herein incorporated documents.

[0094] In embodiments, the porosity of the PVC layer(s) can be 5% to 25% and the cracks can extend either partially through the thickness of the layer(s), i.e., less than 50% of the thickness, or about 50% of the thickness, and can even extend through an entire thickness of the layer(s). In embodiments, the cracks can be substantially vertical cracks and can range between 20 and 200 cracks per inch or linear inch. In non-limiting embodiments, the PVC layer(s) can also be of a type known in the art and described in one or more of the herein incorporated documents.

Non-Limiting Examples

[0095] The follow tables include a description of the coating system shown in FIGS. 1 and 2 as well as the parameters used to form the same with a Sinplex Plasma Torch.

TABLE-US-00001 Chemistry Thickness Plasma Layer composition range torch Process Super- Ni based 3 mm n/a n/a alloy alloy S (sub- strate) bond NiCrAlY ~200 um SinplexPro ™ Ar/H2 coat B plasma gas (bond coat) PVC 7YSZ ~400 um SinplexPro ™ Ar/H2 plasma gas DVC Gd2Zr2O7 ~200 um SinplexPro ™ Ar/H2 plasma gas Bond coat PVC DVC layer layer layer Material Amdry 386-4 See Examples below Composition NiCrAlYHfSi 8YSZ Gd2Zr2O7 Gun current Amps 450 540 500 Voltage Volts 80.5 106 91 Gun power kW 37 57 46 Argon flow Nlpm 50 90 70 Hydrogen flow Nlpm 2 7.5 5 Powder feed g/min × 1 50 90 40 rate

[0096] The follow tables include a description of another coating system according to the invention as well as the parameters used to form the same with a Sinplex Plasma Torch.

TABLE-US-00002 Chemistry Thickness Plasma Layer composition range torch Process Superalloy Ni or Co 3 mm n/a n/a S based alloy (substrate) bond coat CoNiCrAlY ~200 um SinplexPro ™ Ar/H2 B plasma gas (bond coat) PVC 7YSZ ~400 um SinplexPro ™ Ar/H2 plasma gas DVC Gd2Zr2O7 ~200 um SinplexPro ™ Ar/H2 plasma gas

TABLE-US-00003 Bond coat PVC DVC layer layer layer Material Amdry 955C See Examples below Composition CoNiCrAIYi 8YSZ Gd2Zr2O7 Gun current Amps 500 540 500 Voltage Volts 91 106 91 Gun power kW 45.4 57 46 Argon flow Nlpm 50 90 70 Hydrogen flow Nlpm 4 7.5 5 Powder feed g/min × 1 45 90 40 rate

[0097] Further, at least because the invention is disclosed herein in a manner that enables one to make and use it, by virtue of the disclosure of particular exemplary embodiments, such as for simplicity or efficiency, for example, the invention can be practiced in the absence of any additional element or additional structure that is not specifically disclosed herein.

[0098] It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.