COATING COMPOSITIONS, COATED TURBINE COMPONENTS, AND METHODS OF APPLYING COATINGS - Patent application

Abstract

The composition includes aluminum (Al) and a blend of carbide and nickel-chromium (Ni-20Cr). A method of applying the coating composition is provided, the method including blending the carbide and nickel-chromium (Ni-20Cr) with aluminum (Al) to form a composition, wherein the carbide and nickel-chromium (Ni-20Cr) are in the range of 90% to about 99.5% by weight of the composition and the aluminum (Al) is in the range of about 0.5% to less than about 10% by weight; and spraying the blend onto a turbine component.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to coated articles and methods of applying coatings. More specifically, the present disclosure relates to anti-degradation coated articles and methods of applying anti-degradation coatings to articles. [Background technology]

[0002] Turbomachinery components, including compressors such as, but not limited to, axial compressors, centrifugal compressors, and rotary compressors, are often at risk of reduced operational efficiency due to corrosion of turbine blades used in the compressor system. Furthermore, turbomachinery includes turbines formed with stages of turbine blades, including rotor blades and stator blades. Over time, corrosion or fouling of the blades can reduce the turbine's efficiency. Blades can help collect deposits, such as iron oxide particulates and other oxide debris, from gases and fluids in later stages of the turbine. Deterioration of blade surfaces by operating fluids and gases and / or reaction of particulate deposits can be rapid. Furthermore, compressor downtime can lead to the potential for moisture condensation in a corrosive environment, further enhancing blade surface deterioration.

[0003] Because deposits may not be water-soluble, surface damage cannot be easily removed by water washing. In an attempt to improve the performance of turbomachinery components, including compressors in large industrial gas turbines, such as those used by public utilities to generate electricity, online water washing, atomization, and evaporative cooler systems have been employed. These systems typically involve introducing water droplets into the compressor inlet, resulting in the compressor's first-stage blades being subjected to water droplets at high speeds. Compressor blades made of iron-based alloys, including 400-series stainless steel, are susceptible to water droplet erosion at their leading edges, including the root where the blade airfoil attaches to the blade platform. Blades are also susceptible to corrosion pitting along their leading edge surfaces due to the accumulation of contaminant particles, which causes galvanic corrosion. Corrosion is exacerbated when turbines operate in or near corrosive environments, such as near chemical or petroleum plants or near seawater. Compressor blade degradation is also exacerbated when exhaust gas recirculation (EGR) is employed to increase exhaust CO2 concentrations, as flue gases with higher CO2 concentrations are more easily decarbonized. EGR results in acidic conditions in the compressor, which can lead to corrosion and an increased risk of pitting.

[0004] Deterioration of turbomachinery components can be reduced by protecting blade surfaces using several coating techniques for coating turbomachinery components. For example, blade surfaces are known to be protected by pure coatings on the blades. U.S. Patent Application Publication No. 2007 / 0261965 describes compositions and methods for providing coated objects with high temperature resistance. Coated objects can be produced by electrodepositing one or more metal or metal alloy layers on a substrate and heat treating the coated substrate so that the layers and the substrate partially and / or completely interdiffuse.

[0005] Due to the potentially corrosive and erosive working environment of turbine components, it is believed that the application of a hard, oxidation-resistant coating may be desirable. Additionally, compressor downtime conditions can result in the potential for moisture condensation in the corrosive environment, further enhancing blade surface degradation. Known solutions to this problem are described in U.S. Patent Application Publication Nos. 2009 / 0297720 and 2011 / 0165433.

[0006] Additionally, the hot gas path components of gas turbines and aircraft engines, particularly the turbine blades, vanes, nozzles, seals, and stationary shrouds, operate at high temperatures, often above 2,000°F (degrees Fahrenheit).

[0007] Turbine or turbomachine components that are frequently exposed to gas, air, or steam flows are provided with protective coatings to reduce wear, erosion, corrosion, and / or degradation during operation. For example, corrosion- or wear-resistant coatings may be applied to the turbine or turbomachine components to reduce or eliminate erosion and wear of gas and steam turbine or turbomachine components, particularly late-stage gas turbine compressor blades and vanes. However, the corrosion- or wear-resistant coatings may not provide protection against corrosion of the turbine or turbomachine components. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent Application Publication No. 2009 / 0297720

[0009] [Patent Document 2] U.S. Patent Application Publication No. 2011 / 0165433 Summary of the Invention

[0010] All aspects, examples, and features described below can be combined in any technically possible manner.

[0011] One aspect of the present disclosure provides a composition comprising aluminum (Al); and a blend of carbide and nickel-chromium (Ni-20Cr).

[0012] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the carbide includes carbon and chromium (Cr—C).

[0013] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the carbide includes at least one of tungsten carbide (WC), molybdenum carbide (Mo—C), titanium carbide (Ti—C), chromium carbide (Cr—C), silicon carbide (Si—C), aluminum carbide (Al4Cr3), and combinations thereof.

[0014] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the blend of carbide and nickel-chromium (Ni-20Cr) can include 75 wt. % chromium carbide (Cr—C) and 25 wt. % nickel-chromium (Ni-20Cr).

[0015] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the total weight of the blend of carbide and nickel-chromium (Ni-20Cr) is in the range of 90% to about 99.5% by weight of the composition.

[0016] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein aluminum (Al) is in the range of about 0.5% to less than 10% by weight of the composition.

[0017] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein aluminum (Al) is in the range of about 5% to about 11% by weight of the composition.

[0018] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein aluminum (Al) is in the range of about 6% to about 11% by weight of the composition.

[0019] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein aluminum (Al) is in the range of about 7% to about 11% by weight of the composition.

[0020] Another embodiment of the present disclosure includes any of the preceding embodiments, and wherein the aluminum (Al) is in the range of about 8% to about 11% by weight of the composition.

[0021] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein aluminum (Al) is in the range of about 8.5% to about 9.5% by weight of the composition.

[0022] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the aluminum (Al) is about 9% by weight of the composition.

[0023] One aspect of the present disclosure provides a coated turbomachinery component; a coated turbomachinery component comprising a turbomachinery component; and a coating comprising a blend of carbide and nickel-chromium (Ni-20Cr), and aluminum (Al).

[0024] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the carbide includes carbon and chromium (Cr—C).

[0025] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the carbide includes at least one of tungsten carbide (WC), molybdenum carbide (Mo—C), titanium carbide (Ti—C), chromium carbide (Cr—C), silicon carbide (Si—C), and combinations thereof.

[0026] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the blend of carbide and nickel-chromium (Ni-20Cr) can include 75 wt. % chromium carbide (Cr—C) and 25 wt. % nickel-chromium (Ni-20Cr).

[0027] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the total weight of the blend of carbide and nickel-chromium (Ni-20Cr) is in the range of 90% to about 99.5% by weight of the composition.

[0028] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein aluminum (Al) is in the range of about 0.5% to less than 10% by weight of the composition.

[0029] Another embodiment of the present disclosure includes any of the preceding embodiments, wherein the aluminum (Al) is about 9% by weight of the composition.

[0030] One aspect of the present disclosure provides a method of applying a coating to a turbine component, the method including blending carbide and nickel-chromium (Ni-20Cr) with aluminum (Al) to form a blend including carbide and nickel-chromium (Ni-20Cr) in a range of 90% to about 99.5% by weight of the blend, with the remainder being aluminum (Al); and spraying the blend onto the turbine component.

[0031] Another aspect of the present disclosure includes any of the aforementioned aspects, wherein the spraying includes spraying by at least one of physical vapor deposition (PVD), high velocity oxygen fuel (HVOF), high velocity air fuel (HVAF), atmospheric plasma spray (APS), low pressure plasma spray (VPS), and cold spray.

[0032] Two or more aspects described in this disclosure, including those described in this Summary section, may be combined to form an embodiment not specifically described herein.

[0033] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description and drawings, and from the claims.

[0034] These and other features of the present disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure, taken in conjunction with the accompanying drawings which illustrate various embodiments of the present disclosure. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a perspective view of a coated article according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective view of another coated article according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0036] It should be noted that the drawings of the present disclosure are not necessarily to scale. The drawings are intended to depict only typical aspects of the disclosure and therefore should not be considered limiting of the scope of the disclosure. In the drawings, like reference numerals represent like elements throughout.

[0037] As an initial matter, in order to clearly explain the subject matter of this disclosure, it becomes necessary to select specific terminology when describing and referring to relevant compositions for machine components within turbomachinery. Wherever possible, common industry terminology is used and utilized consistent with its accepted meaning. Unless otherwise noted, such terminology should be given a broad interpretation consistent with the context of this application and the scope of the appended claims. Those skilled in the art will recognize that in many cases, a particular component may be referred to using several different or overlapping terms. What may be described herein as being a single part may include, and be referred to in other contexts as consisting of multiple components. Alternatively, what may be described herein as comprising multiple components may be referred to elsewhere as a single part.

[0038] Additionally, as noted below, certain descriptive terms may be used conventionally herein: the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another, but are not intended to denote the location or importance of the individual components.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural unless expressly stated otherwise. It will be further understood that the terms "comprise" and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. "Optional" or "optionally" means that a subsequently-stated event or circumstance may or may not occur, or that a subsequently-stated component or element may or may not be present, and the description is meant to include instances in which the event occurs or component is present as well as instances in which it does not occur or is not present.

[0040] When an element or layer is referred to as "on," "engaged," "connected," or "coupled" to another element or layer, it can be directly on, engaged, connected, or coupled to the other element or layer, or intervening elements or layers may be present. Conversely, when an element is referred to as "directly on," "directly engaged," "directly connected," or "directly coupled" to another element or layer, there may not be intervening elements or layers. Other terms used to describe relationships between elements should be interpreted similarly (e.g., "between" versus "directly between," "adjacent to" versus "directly adjacent to," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0041] Aspects of the embodiments include coated articles and methods of applying coatings. Embodiments of the present disclosure reduce corrosion of components, increase galvanic compatibility, maintain or substantially maintain the wear resistance of coatings, increase efficiency, extend the time between inspections, extend operational life, reduce maintenance costs, provide a single-step corrosion-erosion protective coating process, enable wet compression in gas turbines, and combinations thereof, compared to methods and articles that do not use one or more of the features disclosed herein.

[0042] Additionally, the present disclosure relates to coating compositions for the prevention of degradation of coated articles. Furthermore, the present disclosure relates to methods and systems for applying anti-degradation coatings. The systems and methods can protect metal objects to reduce efficiency losses due to erosion and corrosion. More particularly, the present disclosure relates to anti-degradation coating systems and methods for protecting turbomachinery components to reduce efficiency losses due to erosion and corrosion. Furthermore, the present disclosure relates to anti-degradation coating systems and methods for protecting the coated surfaces of components from oxidative roughening and maintaining initial levels of fatigue properties throughout operation.

[0043] Blades and vanes, such as stainless steel blades and vanes used in compressors of land-based gas turbine engines (e.g., for power generation), have demonstrated susceptibility to erosion and corrosion pitting of their airfoil surfaces. Erosion and corrosion pitting are believed to be related to various electrochemical dissolution processes resulting from water droplets and the impact of chemicals present in the droplets, air intake, and combinations thereof. Electrochemically induced corrosion and erosion occurring on airfoil surfaces can lead to cracks due to the cyclic thermal and operating stresses experienced by turbomachinery components. Water droplet exposure can also result from the use of online water washing, atomization and evaporative cooling, or various combinations of these processes to increase compressor efficiency.

[0044] Additionally, water droplet exposure can result from the environment in which the gas turbine operates, which can be a highly corrosive environment, such as, but not limited to, an environment near a chemical or petrochemical plant where various chemical species can be found in the gas turbine inlet air, or an ocean coastline or other saltwater environment where various sea salts can be present in the gas turbine inlet air, or a combination of the above, or an environment in other applications where the gas turbine inlet contains corrosive chemical species.

[0045] Embodiments of the present disclosure relate to coatings for reducing the degradation of compressor blades during operation. The reduced degradation is achieved by using erosion and corrosion resistant systems blended with aluminum (Al). For example, as embodied by the present disclosure, aluminum (Al) with hard phase components in a blend of carbides and nickel chromium (Ni-20Cr) can protect turbomachinery surfaces from oxidation and maintain initial fatigue properties over the operating life of the component.

[0046] 1 and 2 illustrate a turbomachinery component coated with a composition as embodied by the present disclosure. The coated article 1 can include, but is not limited to, a turbine component, a hot gas path component, a rotating component, or a combination thereof. For example, in one embodiment, the coated article 1 can be a compressor blade. In another embodiment, the coated article 1 can include a late or final stage turbine blade. Other coated articles 1 can include a compressor vane, a centrifugal pump impeller, a pipeline, or a combination thereof.

[0047] 1 and 2, the coated article 1 includes an airfoil 10 having a leading edge 14, a trailing edge 16, a tip edge 22, and a blade root 26. A span 28 of the airfoil 10 extends from the leading edge 22 to the blade root 26. A platform 27 is disposed between the blade root 26 and the airfoil 10. The surface of the airfoil 10 within the span 28 constitutes an airfoil surface 32 of the blade 1 and is exposed to the flowpath of intake air entering the gas turbine system. FIGS. 1 and 2 show the airfoil surface 32 of the airfoil 10 including a convex surface 30 and a concave surface 34, respectively, extending between the leading edge 14 and the trailing edge 16.

[0048] The coating composition embodied by the present disclosure can be applied to the airfoil 10 and platform 27 as a coating 40. The coating 40 can be applied by a suitable spray process and system, as described herein. As embodied by the present disclosure, the coating composition includes a blend of carbide and nickel-chromium (Ni-20Cr), and aluminum (Al). In certain aspects of the embodiment, the carbide includes chromium carbide (Cr-C).

[0049] As implemented by the present disclosure, the carbide may include a blend of carbon and chromium (Cr—C), however, other carbides are within the scope of embodiments, including tungsten carbide (WC), molybdenum carbide (Mo—C), titanium carbide (Ti—C), chromium carbide (Cr—C), silicon carbide (Si—C), and combinations thereof.

[0050] As embodied by one embodiment of the present disclosure, a blend of carbide and nickel-chromium (Ni-20Cr) can include 75 wt. % chromium carbide (Cr-C) and 25 wt. % nickel-chromium (Ni-20Cr). The chromium carbide (Cr-C) can be blended with nickel-chromium (Ni-20Cr) powder. The total weight of the blend of carbide and nickel-chromium (Ni-20Cr) can be in the range of 90 wt. % to about 99.5 wt. % of the composition, with the remainder being aluminum (Al). Thus, according to the present disclosure, aluminum (Al) can be provided in the composition in the range of about 0.5 wt. % to less than 10 wt. %.

[0051] In certain embodiments of the present disclosure, aluminum (Al) can be provided in the range of about 5% to about 11%, about 6% to about 11%, about 7% to about 11%, about 8% to about 11%, about 8% to about 10%, or about 8.5% to about 9.5%. Furthermore, aluminum (Al) can be provided at about 9%. Furthermore, in certain aspects of the present disclosure, the Ni-20Cr content in the blend can be in the range of about 25% to about 20%.

[0052] As a non-limiting example of a coating composition as embodied by the present disclosure, 1000 grams of coating composition would include 91% or 910 grams by weight of a blend of 75% chromium carbide (Cr—C) and 25% nickel-chromium (Ni-20Cr), and 9% or 90 grams by weight of aluminum (Al). Thus, 75% of a 910-gram blend of carbide and nickel-chromium (Ni-20Cr) would include 682 grams of chromium carbide (Cr—C) (or, 910 x 0.75 = 68.2% by weight), 228 grams of nickel-chromium (Ni-20Cr) (or, 910 x 0.25 = 22.8% by weight), and 90 grams (9% by weight) of aluminum (Al).

[0053] The coatings can be applied to turbomachinery components by spray processes and systems, which as embodied by the present disclosure may include, but are not limited to, physical vapor deposition (PVD), high velocity oxygen fuel (HVOF), high velocity air fuel (HVAF), atmospheric plasma spray (APS), low pressure plasma spray (VPS), and cold spray using a galvanic anode element.

[0054] The coating, as embodied by the present disclosure, can improve the galvanic compatibility and fatigue properties of the coated article without affecting the spray process and the aerodynamics of the system. Galvanic corrosion is the process by which materials in contact with an oxide corrode. These properties include control of coverage, surface finish, and thickness.

[0055] As embodied by the present disclosure, the coating composition can also improve erosion performance and pitting resistance. Furthermore, the blend of carbides with nickel-chromium (Ni-20Cr) and aluminum (Al) in the coating can also provide protection from high-temperature oxidation. Furthermore, the coating can be surface treated after application to improve fatigue resistance. For example, surface treatments can include, but are not limited to, shot peening and / or mild grit blasting to improve fatigue resistance.

[0056] The chromium carbide particles in the composition can typically be 1-2 microns or finer. These chromium carbide particles can be agglomerated, sintered, and then ground with nickel-chromium (Ni-20Cr) feedstock to create powder blends of carbide and nickel-chromium (Ni-20Cr) in various size fractions between 10 and 105 microns.

[0057] These powders can then be applied by an appropriate spraying process and system. According to certain embodiments of the present disclosure, the size fraction can be in the range of about 10 to about 38 microns for HVAF, about 15 to about 45 microns for HVOF, about 5 to about 38 microns for cold spray, and about 45 to about 105 microns for APS.

[0058] As used herein throughout this specification and claims, approximation language can be applied to modify any quantitative expression that can reasonably vary without resulting in a change in the basic function involved. Thus, values ​​modified by terms such as "approximately," "about," and "substantially" are not limited to the exact value specified. In at least some instances, approximation language can correspond to the precision of the instrument used to measure the value. Here, and throughout this specification and claims, range limitations are combinable and / or interchangeable, and unless the context or language dictates otherwise, such ranges are identified and include all subranges encompassed therein. As used herein, "about" and "approximately" indicate + / - 10% of, or a range from, the stated value.

[0059] The corresponding structure, material, acts, and equivalents of all means-plus-function or step-plus-function elements in the following claims are intended to encompass any structure, material, or acts for performing that function in combination with other specifically claimed claim elements. The description of the present disclosure has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The present embodiments were chosen and described in order to best explain the principles and practical application of the disclosure and to enable others skilled in the art to understand the disclosure in various embodiments with various modifications as suited to the particular uses envisioned. [Explanation of symbols]

[0060] 1 Coated articles 1 blade 10 Airfoil 14 leading edge 16 Trailing edge 22 Tip edge 26 Blade base 27 Platform 28 spans 30 Convex 32 Airfoil surface 34 Concave 40 Coating

Claims

1. Blends of carbides with nickel-chromium (Ni-20Cr), and Aluminum (Al) A composition comprising:

2. The composition of claim 1 , wherein the carbide comprises chromium carbide (Cr—C).

3. The carbide may be tungsten carbide (W—C), molybdenum carbide (Mo—C), titanium carbide (Ti—C), chromium carbide (Cr—C), silicon carbide (Si—C), aluminum carbide (Al ４ Cr ３ ), and combinations thereof.

4. 2. The composition of claim 1, wherein the blend of the carbide and the nickel-chromium (Ni-20Cr) comprises 75% by weight chromium carbide (Cr—C) and 25% by weight nickel-chromium (Ni-20Cr).

5. 10. The composition of claim 1, wherein the total weight of the blend of the carbide and the nickel-chromium (Ni-20Cr) ranges from 90% to about 99.5% by weight of the composition.

6. 10. The composition of claim 1, wherein the aluminum (Al) ranges from about 0.5% to less than about 10% by weight of the composition.

7. 10. The composition of claim 1, wherein the aluminum (Al) is in the range of about 5% to about 11% by weight of the composition.

8. 10. The composition of claim 1, wherein the aluminum (Al) is in the range of about 6% to about 11% by weight of the composition.

9. 10. The composition of claim 1, wherein the aluminum (Al) is in the range of about 7% to about 11% by weight of the composition.

10. 10. The composition of claim 1, wherein the aluminum (Al) is in the range of about 8% to about 11% by weight of the composition.

11. 10. The composition of claim 1, wherein the aluminum (Al) is in the range of about 8.5% to about 9.5% by weight of the composition.

12. 10. The composition of claim 1, wherein the aluminum (Al) is about 9% by weight of the composition.

13. Turbomachinery components, and Blends of carbides with nickel-chromium (Ni-20Cr); and Contains aluminum (Al) coating 1. A coated turbomachinery component, comprising:

14. The coated turbomachinery component of claim 13 , wherein the carbide comprises chromium carbide (Cr—C).

15. The carbide may be tungsten carbide (W—C), molybdenum carbide (Mo—C), titanium carbide (Ti—C), chromium carbide (Cr—C), silicon carbide (Si—C), aluminum carbide (Al ４ Cr ３ 14. The coated turbomachinery component of claim 13, comprising at least one of:

16. 14. The coated turbomachinery component of claim 13, wherein the blend of carbide and nickel-chromium (Ni-20Cr) comprises 75 wt. % chromium carbide (Cr-C) and 25 wt. % nickel-chromium (Ni-20Cr).

17. The coated turbomachinery component of claim 13, wherein a total weight of the blend of the carbide and the nickel-chromium (Ni-20Cr) is in the range of 90% to about 99.5% by weight of the composition.

18. The coated turbomachinery component of claim 13, wherein the aluminum (Al) is in the range of about 0.5% to less than 10% by weight of the composition.

19. The coated turbomachinery component of claim 13 , wherein the aluminum (Al) is about 9% by weight of the composition.

20. 1. A method of applying a coating to a turbomachinery component, comprising: blending carbide and nickel-chromium (Ni-20Cr) with aluminum (Al) to form a composition, wherein said carbide and said nickel-chromium (Ni-20Cr) range from 90% to about 99.5% by weight of said composition, and said aluminum (Al) ranges from about 0.5% to less than about 10% by weight of said composition; and spraying the composition onto the turbomachinery component; A method comprising:

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