Method of forming bond coat for barrier coating

Abstract

A method of forming a coated component is provided. The method may include: forming a bond coat on a surface of a substrate; thereafter, performing a first heat treatment on the bond coat on the surface of the substrate; thereafter, a barrier coating is formed on the bond coating; and performing a second heat treatment on the barrier coating layer on the bond coating layer to form a coated part. The bond coat may include MCrAlX, where M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof.

Description

Technical Field

[0001] The present invention generally relates to protective coatings on components and, more particularly, to a coating system including a bond coat positioned between a substrate and a barrier coating. Background Art

[0002] In commercial and military gas turbine engines, thermal barrier coatings ("TBCs") are increasingly used on components such as combustors, high-pressure turbine blades, vanes, and shrouds. The thermal insulation provided by TBCs enables such components to withstand higher operating temperatures, improve component durability, and improve engine reliability. TBCs are typically formed from ceramic materials and deposited on environmentally friendly bond coats to form so-called TBC systems. The bond coat material is typically selected to form a continuous and adherent oxide scale on its surface to promote adhesion of the ceramic coating to the bond coat. Summary of the Invention

[0003] A first aspect of the present invention relates to a method for forming a coated component, the method comprising: forming a bonding coating on a surface of a substrate, wherein the bonding coating comprises MCrAlX, where M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof; then performing a first heat treatment on the bonding coating on the surface of the substrate; thereafter, forming a barrier coating on the bonding coating; and performing a second heat treatment on the barrier coating on the bonding coating to form a coated component.

[0004] A second aspect of the present invention relates to a method for forming a combustion liner, the method comprising: forming a bond coating on a surface of a substrate having a thickness of 1800 μm or less, wherein the bond coating comprises MCrAlX, where M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof, and wherein the substrate comprises a nickel-based high-temperature alloy, a cobalt-based high-temperature alloy, or an iron-based high-temperature alloy; then performing a first heat treatment on the bond coating on the surface of the substrate; thereafter, forming a barrier coating on the bond coating; performing a second heat treatment on the barrier coating on the bond coating to form a coated component; thereafter, forming a plurality of internal channels extending through the barrier coating, through the bond coating, and through the substrate to form the combustion liner. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] A complete and enabling disclosure of the present invention (including the best mode thereof) to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0006] Figure 1 is a cross-sectional view of an exemplary coated component (e.g., a combustion liner) having a bond coat thereon;

[0007] Figure 2 yes Figure 1 a cross-sectional view of an exemplary coated component comprising a barrier coating on a bond coating;

[0008] Figure 3 yes Figure 2 a cross-sectional view of an exemplary coated component after forming a hole therethrough;

[0009] Figure 4 is a perspective cross-sectional view of a combustor assembly according to an exemplary embodiment of the present invention, the combustor assembly including a combustor liner having a coating system thereon; and

[0010] Figure 5 is a block diagram of an exemplary method of forming an exemplary coating system on a substrate to form a coated component, such as a combustion liner for a gas turbine engine.

[0011] Throughout the drawings and detailed description, unless otherwise described, the same drawing reference numerals will be understood to refer to the same or similar elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience. DETAILED DESCRIPTION

[0012] Reference will now be made in detail to the present embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter references to refer to features in the drawings. The same or similar reference numerals have been used in the drawings and the description to refer to the same or similar parts of the present invention.

[0013] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. In addition, all embodiments described herein should be considered exemplary unless otherwise specifically stated.

[0014] Throughout the specification and claims, range definitions are combinable and interchangeable, and such ranges are identified and include all subranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0015] In the present disclosure, when a layer is described as being "on" or "over" another layer or substrate, it should be understood that, unless explicitly stated to the contrary, the layers may be in direct contact with each other or have another layer or feature between them. Thus, these terms merely describe the relative position of the layers to each other and do not necessarily mean "on top of" because the relative position of above or below depends on the orientation of the device relative to the viewer.

[0016] As used herein, the term "coat" or "coating" refers to a material that is disposed on at least a portion of an underlying surface in a continuous or discontinuous manner. Furthermore, the term "coating" does not necessarily indicate a uniform thickness of the disposed material, and the disposed material may have a uniform or variable thickness. The term "coating" may refer to a single layer of coating material, or it may refer to multiple layers of coating material. The coating material may be the same or different in the multiple layers.

[0017] In this disclosure, chemical elements are discussed using their commonly used chemical abbreviations, such as those commonly found on the periodic table of elements. For example, hydrogen is represented by its commonly used chemical abbreviation, H; helium is represented by its commonly used chemical abbreviation, He; and so on.

[0018] The present invention relates to methods for forming coated components, such as coated components of gas turbine engines suitable for use during exposure to high temperatures (e.g., harsh thermal environments). More specifically, the present invention relates to a barrier coating system (e.g., a TBC) capable of exhibiting resistance to thermal cycling and contaminant penetration (e.g., of the type that may exist in the operating environment of a gas turbine engine). During the formation of the barrier coating system, residual stresses may form in the layers of the barrier coating system during the formation of such barrier coating system, particularly on relatively thin substrates (e.g., substrates having a thickness of less than 1800 μm). These stresses may cause cracking in the layers of the barrier coating system, which in turn may result in a loss of barrier function, reduced adhesion of the coating system to the substrate, or both.

[0019] Disclosed herein generally are methods suitable for forming barrier coating systems (e.g., TBC systems) having reduced residual stress in the layers of the barrier coating system, particularly in the bond coat layer thereof. The resulting barrier coating system formed by such methods can increase the tensile bond strength in the bond coat, thereby reducing crack formation therein and reducing crack formation in overlying barrier coating layers.

[0020] Figure 1 A cross-sectional view of an exemplary coated component 10 is shown having a bond coating 12 on a surface 14 of a substrate 16. In certain embodiments, the substrate 16 may be a superalloy-based substrate, for example, a substrate 16 comprising a nickel-based superalloy, a cobalt-based superalloy, or an iron-based superalloy. The substrate 16 may be relatively thin in its cross-sectional direction (i.e., generally perpendicular to the surface 14), which may be particularly susceptible to bending during thermal expansion cycles during use.

[0021] The bond coating 12 may be an aluminum-containing composition of the type typically used with TBC systems for gas turbine engine components. For example, the bond coating 12 may typically include MCrAlX, where M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof. In particular embodiments, the bond coating 12 may include a nickel-containing and aluminum-containing composition, such as MCrAlX, where M is Ni and optionally Co, and X is Hf, Y, Zr, or a combination thereof. In a particular embodiment, X is Y, such that the bond coating 12 comprises MCrAlY, where M is Ni and optionally Co (e.g., NiCrAlY).

[0022] Typically, the bond coat 12 can be formed using a precursor material comprising an MCrAlX composition, for example, using particles comprising the MCrAlX composition. Various processes can be used to deposit such particles, including thermal spray processes such as air plasma spraying (APS), vacuum plasma spraying (VPS), low pressure plasma spraying (LPPS), and high velocity oxygen fuel (HVOF) coating. Such thermal spraying techniques involve propelling particles of a molten or at least heat-softened MCrAlX composition onto the surface 14 of the substrate 16, wherein the particles are quenched and bonded to the surface 14 to produce the bond coat 12. Thus, the particles of the MCrAlX composition are deposited in the form of a molten "splat."

[0023] In one embodiment, the spraying conditions may include a target distance between the spray gun and the surface 14 of the substrate 16 of 5 cm to 15 cm (e.g., 8 cm to 13 cm). The surface temperature of the surface 14 of the substrate 16 may be relatively low (e.g., 20°C to 100°C), or may be heated as needed. In a particular embodiment, a plurality of particles are sprayed at a relatively high deposition rate. For example, a plurality of particles may be sprayed onto the surface 14 of the substrate 16 at a rate such that a bond coating having a thickness of 40 μm or more is formed per pass of the spray gun per second (e.g., a bond coating having a thickness of 50 μm or more is formed per pass of the spray gun per second). At these relatively high deposition rates, the residual stresses in the deposited bond coating 12 may be relatively high, which may result in subsequent cracking during use, particularly on relatively thin substrates that are susceptible to bending during thermal cycling.

[0024] During deposition, aluminum-containing bond coatings (e.g., the MCrAlX composition described above) can form aluminum oxide (alumina) therein through oxidation of the particles. For example, alumina can form on the boundaries of deposited particles of the MCrAlX composition. Bond coating 12 can be formed to a suitable thickness, such as 125 μm to 525 μm (e.g., 175 μm to 500 μm), such that bond coating 12 provides the desired functionality of protecting substrate 16 and anchoring the TBC thereto.

[0025] After being deposited on the surface 14 of the substrate 16, the bond coating 12 can then be subjected to a heat treatment (i.e., a first heat treatment) before any additional layers are applied thereto, wherein the surface 18 of the bond coating 12 is exposed during the first heat treatment. In a particular embodiment, the first heat treatment is performed under the following conditions: a first heat treatment temperature of 925°C to 1135°C, a first treatment duration of 1 hour to 20 hours, for example, a temperature of 1050°C to 1100°C, and a first treatment duration of 3 to 5 hours. The first heat treatment can be performed in an oxygen-deficient first atmosphere, for example, in a vacuum (e.g., having a first pressure of less than 95 kPa, for example, a first pressure of less than 10 kPa) or an atmosphere comprising an inert gas substantially free of oxygen (e.g., argon).

[0026] By this first heat treatment, before any additional layer (for example, any additional barrier coating, for example forming TBC) is deposited on the bond coating 12, the residual stress in the bond coating 12 is released, and the tensile bond strength of the bond coating 12 can be increased. That is, the tensile bond strength of the bond coating 12 can be increased from the deposited tensile bond strength (that is, the first tensile bond strength) before the first heat treatment to the second tensile bond strength after the first heat treatment, wherein the second tensile bond strength is greater than the first tensile bond strength. In one embodiment, the first tensile bond strength is at least twice the second tensile bond strength. As used herein, the tensile bond strength of the bond coating is measured in accordance with ASTM C 633.

[0027] After the first heat treatment, a barrier coating (eg, TBC) may be formed on the bond coating 12. Figure 2 , which shows a barrier coating 20 overlying the bond coating 12. In the illustrated embodiment, the barrier coating 20 has multiple layers, including an inner barrier coating 22, an interior barrier coating 24, and an outer barrier coating 26. The inner barrier coating 22 is deposited directly on the bond coating 12 to cover the bond coating 12, the inner barrier coating 24 is deposited directly on the inner barrier coating 22 to cover the inner barrier coating 22, and the outer barrier coating 26 is deposited directly on the inner barrier coating 24 and defines an outer surface 28 of the barrier coating 20, as well as a coating system 30 (including the bond coating 12 and the barrier coating 20). Therefore, when the coated component 10 is exposed to contaminants, the contaminants directly contact the outer surface of the barrier coating 20.

[0028] In one embodiment, the barrier coating 20 (and any barrier coating) may be formed from a yttria-stabilized zirconia (YSZ) material. For example, the multi-layer barrier coating 20 may include barrier coatings having different yttria contents. For example, the outer barrier coating 26 may have a higher yttria content than the inner barrier coating 22, resulting in an enhanced ability of the outer barrier coating 26 to react with contaminants contacting the outer surface 28 of the barrier coating 20. Contaminants of particular concern are materials containing calcium, magnesium, aluminum, silicon, or combinations thereof ("CMAS"). In this case, the yttria content of the outer barrier coating 26 is capable of reacting with molten CMAS deposits at temperatures greater than 1200°C to form a protective reaction product containing calcium yttria silicate, commonly referred to as an apatite phase. The reaction product forms a dense, adherent seal on the outer surface 28 of the barrier coating 20, which protects the underlying barrier coating 20 from further penetration by the CMAS.

[0029] In one embodiment, the outer barrier coating 26 contains 25 to 75 weight percent yttrium oxide, with the remainder being essentially zirconium oxide (allowing for unavoidable impurities), for example, 30 to 59 weight percent yttrium oxide, which is particularly sufficient to enable the reaction to form the desired calcium yttrium silicate reaction product while providing higher erosion resistance and spalling resistance than higher yttrium oxide contents. In contrast, the inner barrier coating 22 has a lower yttrium oxide content and can include a generally conventional yttrium oxide content (6 to 9 weight percent yttrium oxide), with the remainder being essentially zirconium oxide (allowing for unavoidable impurities).

[0030] The barrier coating 20 may have a controlled thickness and porosity throughout its thickness. In one embodiment, the porosity of the outer barrier coating 26 may differ from that of the inner barrier coating 22 in terms of its density (porosity) and thickness. Specifically, the inner barrier coating 22 may be deposited in a manner to achieve a relatively porous macrostructure, for example, with a porosity of 10 to 25 volume percent. In contrast, the outer barrier coating 26 may be deposited in a manner to achieve a less porous macrostructure than the inner barrier coating 22. The porosity of the outer barrier coating 26 may be 3 to 15 volume percent. To achieve the desired porosity level in each layer of the barrier coating 20, each layer of the barrier coating 20 may have a non-columnar structure resulting from deposition by a thermal spraying technique, such as air plasma spraying (APS), vacuum plasma spraying (VPS), low pressure plasma spraying (LPPS), and high velocity oxygen fuel (HVOF) coating. This type of thermal spraying involves propelling molten or at least heat-softened particles of a heat fusible material (e.g., metal, ceramic) onto a surface, where the particles are quenched and bonded to the surface to produce a coating. Thus, the various layers of the barrier coating 20 can be deposited in the form of molten "flat sputters," thereby producing a microstructure characterized by horizontal porosity due to the presence of the flat sputters (flat grains). The microstructure of the barrier coating layers can be modified to include dense vertical cracks. In one embodiment, the same thermal spray gun and process as described above can be used to deposit the bond coat 12 and the various layers of the barrier coating 20.

[0031] After depositing the barrier coating 20, the coated component 10 may be subjected to a second heat treatment to strengthen the deposited barrier coating 20 by reducing residual stresses in the barrier coating 20. Generally, the second heat treatment may be performed under the same, similar, or different conditions as the first heat treatment. In a particular embodiment, the second heat treatment is performed under the following conditions: a second heat treatment temperature of 925°C to 1135°C and a second treatment duration of 1 to 20 hours, for example, a temperature of 1050°C to 1100°C and a second treatment duration of 3 to 5 hours. The second heat treatment may be performed in an oxygen-deficient first atmosphere, for example, in a vacuum (e.g., having a second pressure of less than 95 kPa, for example, less than 10 kPa) or in an atmosphere containing an inert gas substantially free of oxygen (e.g., argon).

[0032] Through this second heat treatment, residual stress in the barrier coating 20 is released, and the tensile bond strength of the barrier coating 20 can be increased. That is, the tensile bond strength of the barrier coating 20 can be increased from the as-deposited tensile bond strength before the second heat treatment (i.e., the first tensile bond strength) to a second tensile bond strength after the second heat treatment, wherein the second tensile bond strength is greater than the first tensile bond strength. In one embodiment, the first tensile bond strength of the as-deposited barrier coating 20 is at least twice the second tensile bond strength of the heat-treated barrier coating 20.

[0033] In addition, in certain embodiments, the second heat treatment does not substantially affect the properties of the bonding coating 12 below, because the bonding coating 12 has already been heat treated during the first heat treatment. Therefore, the tensile bond strength of the bonding coating 12 may be relatively unchanged after the second heat treatment. In other words, the tensile bond strength of the bonding coating 12 after the second heat treatment (i.e., the third tensile bond strength of the bonding layer 12) may be within 15% of its second tensile bond strength (i.e., after the first heat treatment). In one embodiment, the third tensile bond strength is within 10% of the second tensile bond strength, for example, within 5% of the second tensile bond strength.

[0034] The relative thicknesses of the barrier coating 20 (including the various layers therein) can be controlled to achieve improvements in the spalling resistance of the barrier coating 20 .

[0035] After the second heat treatment, a plurality of internal channels 32 may be formed in the coated component 10, such as Figure 3 As shown, the plurality of internal passages 32 extend through the barrier coating 20, through the bond coating 12, and through the substrate 16. Thus, the plurality of internal passages 32 span the entire thickness of the coated component 10. When the coated component 10 is in the form of a combustion liner, the plurality of internal passages 32 may define cooling holes therein.

[0036] The internal passages may be formed by any suitable method, such as by laser drilling. It has been found that the aforementioned method (including a first heat treatment of the bond coating 12 and a second heat treatment of the barrier coating 20) allows the coated component 10 to be drilled with less chipping and cracking in the coating system 30 than using a method having only a single heat treatment. If desired, the coated component 10 can be brazed to the second component to form the final article.

[0037] As mentioned above, Figure 3 The coated component 10 may be a combustion liner for a gas turbine engine. Figure 4 , shows a cross section of a combustion liner 40 having a coating system 30 on a substrate 16, wherein the coating system 30 is formed as described above, having a bond coat and a barrier coat ( Figure 1-3). The combustion liner 40 may define a plurality of internal passages 32 therein, as described above with reference to Figure 3 The combustion liner 40 is shown as an outer combustion liner having the coating system 30 on the hot gas path side. In an alternative embodiment, the combustion liner 40 may be an inner combustion liner. The substrate 16 of the combustion liner 40 may be relatively thin, for example, having a thickness of 1800 μm or less, which is particularly susceptible to buckling and bending during the thermal cycles experienced during use.

[0038] See also Figure 5 , which is generally shown for forming a coating component (e.g., Figure 1-3 Coated parts shown in and Figure 4 ) is a method 50 for forming a combustion liner (such as the combustion liner shown in ). At 52, the method includes: forming a bond coating, such as the bond coating discussed above, on the surface of the substrate, wherein the bond coating comprises MCrAlX, where M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof. Thereafter, at 54, the bond coating (such as the bond coating described above) on the surface of the substrate is subjected to a first heat treatment. Thereafter, at 56, a barrier coating, such as the TBC described above, is formed on the bond coating. At 58, the barrier coating can then be subjected to a second heat treatment to form a coated component, such as the coated component described above. Optionally, at 60, after the second heat treatment, a plurality of internal channels can be formed in the coated component so as to extend through the barrier coating, through the bond coating, and through the substrate. Additionally, optionally, at 62, after the second heat treatment, the coated component is brazed to the second component.

[0039] Other aspects are provided by the following subjects:

[0040] A method for forming a coated component, the method comprising: forming a bonding coating on a surface of a substrate, wherein the bonding coating comprises MCrAlX, where M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof; then performing a first heat treatment on the bonding coating on the surface of the substrate; thereafter, forming a barrier coating on the bonding coating; and performing a second heat treatment on the barrier coating on the bonding coating to form the coated component.

[0041] A method according to any of the preceding clauses, wherein the substrate has a thickness of 1800 μm or less.

[0042] The method according to any of the preceding clauses, wherein the substrate comprises a nickel-based superalloy, a cobalt-based superalloy, or an iron-based superalloy.

[0043] The method of any of the preceding clauses, wherein the bond coat comprises MCrAlX, wherein M is Ni and optionally Co is present, and X is Hf, Y, Zr, or a combination thereof.

[0044] A method according to any of the preceding clauses, wherein X is yttrium, such that the bond coat comprises MCrAlY, where M is Ni and Co is optionally present.

[0045] A method according to any of the preceding clauses, wherein M is Ni, such that the bond coating comprises NiCrAlY.

[0046] The method of any of the preceding clauses, wherein forming the bond coat comprises spraying a plurality of particles comprising MCrAlX onto the surface of the substrate.

[0047] A method according to any of the preceding clauses, wherein the plurality of particles are sprayed onto the surface of the substrate at a rate such that a bond coat having a thickness of 40 μm or greater is formed per pass of the spray gun per second.

[0048] A method according to any of the preceding clauses, wherein the aluminium oxide is formed during air plasma spraying such that the bond coat comprises aluminium oxide and MCrAlX.

[0049] The method of any of the preceding clauses, wherein the bond coat is formed to a thickness of 125 μm to 525 μm.

[0050] The method according to any of the preceding clauses, wherein the first heat treatment is performed at a first heat treatment temperature of 925°C to 1135°C.

[0051] Method according to any of the preceding clauses, wherein the first heat treatment is performed for a first treatment duration of 1 hour to 20 hours.

[0052] Method according to any of the preceding clauses, wherein the first heat treatment is performed in a first atmosphere having a first pressure of less than 95 kPa.

[0053] Method according to any of the preceding clauses, wherein the first heat treatment is performed in a first atmosphere having a first pressure of less than 10 kPa.

[0054] A method according to any of the preceding clauses, wherein the bond coating has a first tensile bond strength before the first heat treatment and a second tensile bond strength after the first heat treatment, the second tensile bond strength being at least twice the first tensile bond strength.

[0055] The method according to any of the preceding clauses, wherein the second heat treatment is performed at a second heat treatment temperature of 925°C to 1135°C.

[0056] Method according to any of the preceding clauses, wherein the second heat treatment is performed for a second treatment duration of 1 hour to 20 hours.

[0057] Method according to any of the preceding clauses, wherein the second heat treatment is performed in a second atmosphere having a second pressure of less than 95 kPa.

[0058] The method of any of the preceding clauses, further comprising, after performing the second thermal treatment, forming a plurality of internal channels extending through the barrier coating, through the bond coating, and through the substrate.

[0059] A method according to any of the preceding clauses, further comprising brazing the coated component to the second component after performing the second heat treatment.

[0060] The method according to any of the preceding clauses, wherein the coated component is a combustion liner.

[0061] A coated component formed according to the method of any of the preceding clauses.

[0062] A method for forming a combustion liner, the method comprising: forming a bond coating on a surface of a substrate having a thickness of 1800 μm or less, wherein the bond coating comprises MCrAlX, where M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof, and the substrate comprises a nickel-based superalloy, a cobalt-based superalloy, or an iron-based superalloy; then performing a first heat treatment on the bond coating on the surface of the substrate; thereafter, forming a barrier coating on the bond coating; performing a second heat treatment on the barrier coating on the bond coating to form a coated component; thereafter, forming a plurality of internal channels extending through the barrier coating, through the bond coating, and through the substrate to form the combustion liner.

[0063] A combustion liner formed according to the method of any of the preceding clauses.

[0064] This written description uses examples to disclose the invention (including the best mode) and also to enable any person skilled in the art to practice the invention (including making and using any devices or systems and performing any combined methods). The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. If such other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that are insubstantially different from the literal language of the claims, such other examples are intended to be within the scope of the claims.

Claims

1. A method for forming a coated component, the method comprising: forming a bond coating on a surface of the substrate, wherein the bond coating comprises MCrAlX, wherein M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof; then performing a first heat treatment on the bonding coating on the surface of the substrate; Thereafter, forming a barrier coating on the bond coating; and, The barrier coating on the bond coating is subjected to a second heat treatment to form a coated part.

2. The method according to claim 1, wherein The thickness of the substrate is less than 1800 μm.

3. The method according to claim 1, wherein The substrate comprises a nickel-based high-temperature alloy, a cobalt-based high-temperature alloy, or an iron-based high-temperature alloy.

4. The method according to claim 1, wherein The bond coat comprises MCrAlX, wherein M is Ni and optionally Co is present, and X is Hf, Y, Zr, or a combination thereof.

5. The method according to claim 4, wherein X is yttrium, such that the bond coat comprises MCrAlY, where M is Ni and Co is optionally present.

6. The method according to claim 5, wherein: M is Ni, so that the bond coat comprises NiCrAlY.

7. The method according to claim 1, wherein Forming the bond coat includes spraying a plurality of particles comprising MCrAlX onto a surface of a substrate.

8. The method according to claim 7, wherein: The plurality of particles are sprayed onto the surface of the substrate at a rate such that a bond coat having a thickness of 40 μm or greater is formed per pass of the spray gun per second.

9. The method according to claim 7, wherein: Alumina is formed during the spraying process so that the bond coat contains alumina and MCrAlX.

10. A method of forming a combustion liner, the method comprising: forming a bond coating on a surface of a substrate having a thickness of 1800 μm or less, wherein the bond coating comprises MCrAlX, wherein M is Ni, Co, or a combination thereof, and X is Hf, Y, Zr, or a combination thereof, and wherein the substrate comprises a nickel-based superalloy, a cobalt-based superalloy, or an iron-based superalloy; then performing a first heat treatment on the bonding coating on the surface of the substrate; Thereafter, forming a barrier coating on the bond coating; performing a second heat treatment on the barrier coating on the bond coating to form a coated part; and Thereafter, a plurality of internal passages are formed extending through the barrier coating, through the bond coating, and through the substrate to form the combustion liner.

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