SHIPPER JR (US)
KULKARNI ANAND A (US)
WO2017142572A1 | 2017-08-24 | |||
WO2017196298A1 | 2017-11-16 |
US20150197456A1 | 2015-07-16 | |||
EP2431495A1 | 2012-03-21 |
CLAIMS What is claimed is: 1. A turbine blade comprising: a root; a platform coupled to the root; an airfoil coupled to the platform, the root, the platform, and the airfoil formed as one continuous piece from a Ceramic Matrix Composite (CMC) material; an interlayer formed directly onto and bonded to at least a portion of the airfoil; and a thermal barrier coating (TBC) bonded to at least the interlayer. 2. The turbine blade of claim 1, wherein CMC material is an alumina based CMC. 3. The turbine blade of claim 1, wherein the interlayer is formed from a ceramic material. 4. The turbine blade of claim 3, wherein the interlayer is one of alumina and yttria- stabilized zirconia. 5. The turbine blade of claim 1 , wherein the interlayer is applied using an additive manufacturing process. 6. The turbine blade of claim 1, wherein the TBC includes a yttria-stabilized zirconia. 7. The turbine blade of claim 6, wherein the TBC is applied using a thermal spraying process. 8. The turbine blade of claim 1 , wherein the root is adapted to connect to a rotor and the turbine blade is a rotating blade. 9. A turbine blade comprising: a root; a platform coupled to the root; an airfoil coupled to the platform, at least a portion of at least one of the root, the platform, and the airfoil formed from a Ceramic Matrix Composite (CMC) material; an interlayer formed from a ceramic material and directly bonded to at least a portion of the CMC material using a selective laser melting process; and a thermal barrier coating (TBC) thermally sprayed and bonded to the interlayer, the TBC being zirconia based. 10. The turbine blade of claim 9, wherein the root, the platform, and the airfoil are formed as a single continuous component from the Ceramic Matrix Composite (CMC) material. 11. The turbine blade of claim 9, wherein the entire airfoil is formed from a Ceramic Matrix Composite (CMC) material. 12. The turbine blade of claim 9, wherein the CMC material is an alumina based CMC. 13. The turbine blade of claim 9, wherein the interlayer is one of alumina and yttria- stabilized zirconia. 14. The turbine blade of claim 9, wherein the TBC includes a yttria-stabilized zirconia. 15. The turbine blade of claim 9, wherein the root is adapted to connect to a rotor and the turbine blade is a rotating blade. 16. A method of forming a turbine blade comprising: forming at least a portion of the turbine blade using a Ceramic Matrix Composite (CMC) material; applying an interlayer of material to at least a portion of the turbine blade manufactured from the CMC material using a high temperature additive manufacturing process; and bonding a thermal barrier coating (TBC) to the interlayer. 17. The method of claim 16, wherein the high temperature additive manufacturing process is a selective laser melting process. 18. The method of claim 16, wherein the interlayer material includes a ceramic material. 19. The turbine blade of claim 18, wherein the interlayer is one of alumina and yttria- stabilized zirconia. 20. The turbine blade of claim 16, wherein the TBC includes a yttria-stabilized zirconia. 21. The turbine blade of claim 20, wherein the TBC is applied using a thermal spraying process. 22. The method of claim 16, wherein the turbine blade includes a vane portion and wherein the vane portion is made from the CMC material. |
TECHNICAL FIELD
[0001] The present disclosure is directed, in general, to the manufacture of high-temperature gas turbine components including a ceramic matrix composite (CMC), and more specifically, the application of a thermal barrier coating (TBC) to that CMC.
BACKGROUND
[0002] Gas turbine components, and in particular blades often operate in higher temperature regimes. In order to accommodate these temperatures, as well as potentially higher
temperatures, new materials and processes are necessary.
SUMMARY
[0003] A turbine blade includes a root, a platform coupled to the root, and an airfoil coupled to the platform. The root, the platform, and the airfoil are formed as one continuous piece from a Ceramic Matrix Composite (CMC) material. An interlayer is formed directly onto and bonded to at least a portion of the airfoil, and a thermal barrier coating (TBC) is bonded to at least the interlayer.
[0004] In another construction, a turbine blade includes a root, a platform coupled to the root, and an airfoil coupled to the platform. At least a portion of at least one of the root, the platform, and the airfoil is formed from a Ceramic Matrix Composite (CMC) material. An interlayer is formed from a ceramic material and directly bonded to at least a portion of the CMC material using a selective laser melting process, and a thermal barrier coating (TBC) is thermally sprayed and bonded to the interlayer, the TBC being zirconia based.
[0005] In another construction, a method of forming a turbine blade includes forming at least a portion of the turbine blade using a Ceramic Matrix Composite (CMC) material, applying an interlayer of material to at least a portion of the turbine blade manufactured from the CMC material using a high temperature additive manufacturing process, and bonding a thermal barrier coating (TBC) to the interlayer.
[0006] The foregoing has outlined rather broadly the technical features of the present disclosure so that those skilled in the art may better understand the detailed description that follows.
Additional features and advantages of the disclosure will be described hereinafter that form the subject of the claims. Those skilled in the art will appreciate that they may readily use the conception and the specific embodiments disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Those skilled in the art will also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure in its broadest form.
[0007] Also, before undertaking the Detailed Description below, it should be understood that various definitions for certain words and phrases are provided throughout this specification and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases. While some terms may include a wide variety of embodiments, the appended claims may expressly limit these terms to specific embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Fig. 1 is a perspective view of a turbine blade.
[0009] Fig. 2 is an enlarged cross section of a portion of the surface of the turbine blade of Fig. 1
[0010] Fig. 3 is a partially broken away perspective view of a gas turbine.
[0011] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
DETAILED DESCRIPTION
[0012] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout.
The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.
[0013] Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms“including,” “having,” and“comprising,” as well as derivatives thereof, mean inclusion without limitation. The singular forms“a”,“an” and“the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term“and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term“or” is inclusive, meaning and/or, unless the context clearly indicates otherwise. The phrases“associated with” and“associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like.
[0014] Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.
[0015] In addition, the term "adjacent to" may mean: that an element is relatively near to but not in contact with a further element; or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase“based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.
[0016] Fig. 3 illustrates a gas turbine 110, or combustion turbine of the type commonly used in power generation. The gas turbine 100 includes an intake section 115, a compressor section 120, a combustion section 125, a turbine section 130, and an exhaust section 135. The compressor section 120 and the turbine section 130 include a series of alternating stationary blades 140 (sometimes referred to as guide vanes) and rotating blades 145 that operate to compress incoming air in the compressor section 120, and to expand combustion gases in the turbine section 30. A rotor 50 extends the length of the turbine 110 and defines a rotational axis 155 of the gas turbine 110 about which the rotor 150 rotates.
[0017] A hot gas path 155 extends from the combustion section 125 through the turbine section 130 and into the exhaust section 135 and includes any components or feature that contacts hot combustion gases (or other gases or high temperature steam in a steam turbine) during operation. Thus, the rotating blades 145 and stationary blades 140 are part of the hot gas path.
[0018] The invention described herein is applicable to virtually any component in the gas turbine 110 but is particularly well-suited to components in the hot gas path 155 such as, but not limited to the rotating blades 145, the stationary bladesl40, ring segments, ceramic heat shields, etc.
The invention will be described in detail with regard to its application to a blade 10 (rotating or stationary) but should not be limited to this application alone.
[0019] Fig. 1 illustrates a basic version of the turbine blade 10 that is of the type used in gas turbines or steam turbines for power generation. The blade 10 of Fig. 1 is greatly simplified but includes a root 15, a platform 20, and a vane portion 25. In most constructions, the root 15, the platform 20, and the vane portion 25 are formed as one continuous piece from one material. However, other constructions may form different parts of the blade 10 separately using similar or different materials. As one of ordinary skill will understand, a gas turbine blade 10 often includes features such as apertures in the leading edge, near the tip of the vane portion 25, or in other locations that require cooling flow to facilitate cooling. These details have been omitted from Fig. 1 for clarity.
[0020] The blade root 15 is formed to attach to a rotor or disk if it is a rotating blade or to a blade ring or casing for stationary blades. Each application of the blade 10 has different operating conditions and therefore may include differently shaped or sized roots 15. Before proceeding, it is important to note that as used herein the term“blade” is intended to cover both rotating and stationary blades unless otherwise specifically noted. The terms“guide vane” or“vane” are sometimes used to refer to stationary blades but any description of features applied to guide vanes or vanes are equally applicable to rotating blades.
[0021] The vane portion 25 is an airfoil-shaped portion that interacts with the fluid flowing through the turbine to expand the fluid and produce rotation of the rotor. The platform 20 is an interface between the root 15 and the vane portion 25 and is also generally exposed to the fluid that passes through the turbine. As noted above, the vane portion 25 also includes additional features that are omitted for clarity.
[0022] In one construction of the blade 10 of Fig. 1 , at least the vane portion 25 is formed from a ceramic matrix composite (CMC) material 30. CMC materials 30 are composed of several layers or plies that consist of a ceramic matrix material and ceramic fibers. In one construction, alumina (A1203) is used as both the matrix material and the fiber material with other materials being possible. Other possible CMC materials (matrix and/or fibers) include, but are not limited to SiC, oxides (Ox), and/or mullite.
[0023] Fig. 2 is an enlarged view of the surface of the vane portion 25 in an area formed from the CMC material 30. As illustrated in Fig. 2, the surface of the vane 25 includes the CMC material 30 as a base, an interlayer 35 bonded to the CMC material 30, and a thermal barrier coating (TBC) 40 bonded to the interlayer 35. [0024] Due to the high-operating temperature of the turbine blade 10, it is desirable to apply the TBC 40 to the CMC material 30. However, it is difficult to achieve a suitable bond between the TBC 40 and the CMC material 30. The attachment is susceptible to spallation due to the relatively smooth surface of the CMC material 30. However, the typical solution of grit blasting the surface to increase the roughness and enhance the bond between the TBC 40 and the CMC material 30 is not suitable as the grit blasting process tends to damage the fibers of the CMC material 30. The interlayer 35 is formed between the CMC 30 and the TBC 40 to enhance the bond strength of the TBC 40.
[0025] In most constructions, the interlayer 35 is a ceramic material with alumina (A1203) or yttria stabilized zirconia (e.g., 8YSZ) being well-suited. To apply the interlayer 35, a high temperature additive manufacturing process is utilized. One process well-suited to the application of the interlayer 35 is selective laser melting (SLM). Using this process, the material being applied is powdered and a laser is used to selectively melt the powder and bond the material to the CMC base material 30 at a first interface line 45. Other suitable processes could use an electron beam, a plasma, or other high temperature processes to bond the interlayer 35 to the CMC 30.
[0026] The TBC 40 is then applied to the interlayer 35 to provide additional thermal and environmental protection for the CMC material 30. In the illustrated construction, the preferred TBC material 40 includes a pyrochlore-based ceramic or zirconia-based TBC 40 with yttria stabilized zirconia (e.g., 8YSZ) being well-suited in this application. Typical application of the TBC 40 utilizes an atmospheric plasma spray process (APS) that produces a second interface line 50. The bonding between the interlayer 35 and the sprayed TBC 40 is predominantly achieved by the mechanical interlocking of the TBC material 40 and the interlayer 35 and is enhanced by the rough surface finish left by the process used to apply the interlayer 35.
[0027] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form. [0028] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims.
Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.