CN109982838B

CN109982838B - Gallium and/or indium containing compositions and methods of forming the same

Info

Publication number: CN109982838B
Application number: CN201780071063.8A
Authority: CN
Inventors: G·H·柯比; J·万
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2016-09-16
Filing date: 2017-09-01
Publication date: 2021-09-21
Anticipated expiration: 2037-09-01
Also published as: EP3496942A1; JP6870075B2; WO2018052739A1; CA3130995C; JP2019529314A; CA3130995A1; EP3496942A4; CA3036964C; CN109982838A; CA3036964A1

Abstract

A composition is provided that includes a silicon-containing material (e.g., a silicon metal and/or silicide) and from about 0.001% to about 85% of a Ga-containing compound, an In-containing compound, or a mixture thereof. The silicon-based layer may be an adhesion coating directly on the surface of the substrate. Alternatively or additionally, the silicon-based layer may be an outer layer defining a substrate surface having an environmental barrier coating thereon. Coated components, and a method of coating a ceramic component are also provided. A gas turbine engine including such a ceramic assembly is also provided.

Description

Gallium and/or indium containing compositions and methods of forming the same

PRIORITY INFORMATION

The present application claims 2016, U.S. patent application No. 15/267,335 filed 9, 16; U.S. patent application No. 15/267,370 filed on 9, 16, 2016; and U.S. patent application No. 15/267,400 filed on 2016, 9, 16.

Technical Field

The present invention generally relates to the inclusion of gallium (Ga) and/or indium (In) compounds In silicon-based coatings (silicone-based coatings). In particular, silicon-based coatings (e.g., silicon bond coats) containing Ga and/or In are generally provided for environmental barrier coatings of ceramic components.

Background

In order to increase the efficiency of gas turbine engines, higher gas turbine engine operating temperatures are continually sought. However, as operating temperatures increase, the high temperature durability of engine components must correspondingly increase. Significant advances in high temperature performance have been achieved by forming iron, nickel and cobalt based superalloys. Nevertheless, since many hot gas path components are composed of superalloys, Thermal Barrier Coatings (TBC) can be used to insulate the component and can maintain a significant temperature differential between the bearing alloy and the coating surface, thus limiting thermal exposure of the structural component.

While superalloys have found widespread use in components used in gas turbine engine monoliths, particularly in high temperature sections, alternative lightweight substrate materials, such as Ceramic Matrix Composite (CMC) materials, have been proposed. The CMC and monolithic ceramic components may be coated with an Environmental Barrier Coating (EBC) to protect them from the harsh environment of high temperature engine parts. EBC can provide a dense, gas-tight seal against corrosive gases in a hot combustion environment.

Silicon carbide and silicon nitride ceramics oxidize in dry, high temperature environments. This oxidation produces a passivated silicon oxide scale (oxide scale) on the surface of the material. In a humid, high temperature environment containing water vapor, such as a turbine engine, oxidation and recession (recision) occurs due to the formation of a passivating silicon oxide scale and the subsequent conversion of the silicon oxide to gaseous silicon hydroxide. To prevent dishing in a humid, high temperature environment, an Environmental Barrier Coating (EBC) is deposited on the silicon carbide and silicon nitride materials.

Currently, EBC materials are made from rare earth silicate compounds. These materials stop (seal out) water vapor, preventing water vapor from reaching the silicon oxide scale on the silicon carbide or silicon nitride surface, thereby preventing dishing. However, such materials do not prevent oxygen permeation, which leads to oxidation of the underlying substrate. Oxidation of the substrate produces a passivated silicon oxide skin with the release of carbon oxide or nitrogen oxide gases. Carbon oxides (i.e. CO, CO)₂) Or nitrogen oxides (i.e. NO, NO)₂Etc.) gas cannot escape through the dense EBC and thus bubbles. The use of a silicon bond coat has heretofore been a solution to this blistering problem. The silicon bond coating provides blunting upon oxidation (under EBC)A layer of oxidized silicon) does not release gaseous by-products.

However, the presence of a silicon bond coat limits the upper operating temperature of the EBC because the melting point of silicon metal is relatively low. In use, a Thermally Grown Oxide (TGO) layer of silicon oxide is formed on top of a silicon metal bond coat layer of a multi-layer EBC system. The silicon scale remains amorphous at temperatures below 1200 c, and sometimes even below 1315 c, although this property also depends on the time the bond coating is exposed to this temperature. At higher temperatures, or when a small amount of vapor penetrates the EBC to reach the bond coat, the silicon oxide skin crystallizes (e.g., into cristobalite), which undergoes a phase change with a large volume change upon cooling. The volume change causes the EBC coating to flake off.

Therefore, it is desirable to improve the properties of silicon bond coats in EBCs to achieve higher operational temperature limits of EBCs.

Disclosure of Invention

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

Generally, a composition is provided that includes a silicon-containing material (e.g., a silicon metal and/or silicide) and about 0.001% to about 85% of a Ga-containing compound, an In-containing compound, or a mixture thereof. For example, the silicon-based layer may be an adhesive coating directly on the substrate surface. Alternatively or additionally, the silicon-based layer may be an outer layer defining a substrate surface having an environmental barrier coating thereon.

Also generally provided are coated components, which in one embodiment include a ceramic component comprising CMC layers and defining a surface and a bond coat directly on the surface of the ceramic component, the bond coat comprising such a composition.

A method of coating a ceramic component is also generally provided. In one embodiment, a bond coat is applied directly to a surface of a ceramic component, the bond coat comprising silicon metal and at least one of a Ga-containing compound, an In-containing compound, or a mixture thereof.

Gas turbine engines comprising such ceramic assemblies are also generally provided.

These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Drawings

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

FIG. 1 is a cross-sectional side view of an exemplary ceramic component including a silicon base layer;

FIG. 2 is a cross-sectional side view of the exemplary ceramic component of FIG. 1 including a thermally grown oxide layer on a silicon base layer;

FIG. 3 is a cross-sectional side view of another exemplary ceramic component including a silicon base layer;

FIG. 4 is a cross-sectional side view of the exemplary ceramic component of FIG. 3 including a thermally grown oxide layer on a silicon base layer; and

FIG. 5 is a schematic cross-sectional view of an exemplary gas turbine engine, according to various embodiments of the present subject matter.

Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.

Detailed Description

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

As used herein, the terms "first," "second," and "third" are used interchangeably to distinguish one component from another component, and are not intended to denote the position or importance of the respective component.

Chemical elements are discussed in this disclosure using their common chemical abbreviations, such as those commonly found in the periodic table of elements. For example, hydrogen is represented by its common chemical abbreviation H; helium is represented by its common chemical abbreviation He; and so on. As used herein, "Ln" refers to a rare earth element or a mixture of rare earth elements. More specifically, "Ln" refers to rare earth elements: scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or a mixture thereof.

In the present disclosure, when a layer is described as being "on" or "over" another layer or substrate, it is to be understood that the layers may be in direct contact with each other or have another layer or feature between the layers unless expressly stated to the contrary. Thus, these terms merely describe the relative position of the layers to one another and do not necessarily mean "above.

Silicon-based coatings comprising Ga-containing compounds, In-containing compounds, or mixtures thereof, for use with environmental barrier coatings for ceramic components, and methods of forming the same, are generally provided. In particular embodiments, silicon-based bond coats for Environmental Barrier Coatings (EBC) are generally provided for high temperature ceramic components, as well as methods of forming and using the same. In particular, the silicon-based bond coat includes a Ga and/or In containing composition for preventing thermally grown oxide ("TGO") crystallization on the silicon-based bond coat In EBC, which In turn prevents spallation of the coating caused by such crystallization of TGO. That is, the introduction of Ga and/or In into the silicon-based bond coat keeps the TGO (i.e., SiO) In the amorphous phase. Thus, the operating temperature of the silicon-based bond coat (and thus the TGO and EBC coatings) can be increased. In addition, the inclusion of Ga and/or In can suppress and prevent crystallization of TGO without greatly accelerating the growth rate of TGO. In addition, the reaction and/or solubility In silicon oxide of Ga-containing compounds and/or In-containing compounds or mixtures thereof is limited, which limits the rate of scale growth.

Fig. 1-4 illustrate exemplary embodiments of a ceramic component 100 formed from a substrate 102 and a silicon base layer 104a (fig. 1), 104b (fig. 3), respectively. Each of the silicon-based

layers

104a, 104b includes a silicon-containing material and about 0.001% to about 85% of a Ga-containing compound, an In-containing compound, or a mixture thereof, for example about 1% to about 60% by weight of a Ga-containing compound, an In-containing compound, or a mixture thereof (e.g., about 1% to about 50% by weight, such as about 1% to about 25% by weight). Generally, the Ga-containing compound, the In-containing compound, or the mixture thereof is not reactive with the composition (e.g., silicon metal) of the silicon-based layer 104 a.

In one embodiment, the silicon-based layers 104a may include Ga-containing compounds, In-containing compounds, or mixtures thereof, and silicon-containing materials (e.g., silicon metal, silicide, etc.) In a continuous phase interleaved with one another. For example, the silicon-containing material and the Ga-containing compound, the In-containing compound, or the mixture thereof are interleaved continuous phases containing from about 0.001% to about 85% by volume of the Ga-containing compound, the In-containing compound, or the mixture thereof, for example, from about 1% to about 60% by volume (e.g., from about 40% to about 60% by volume of the Ga-containing compound, the In-containing compound, or the mixture thereof). For example, the silicon-based layer 104a may include about 15% to about 85% by volume of a Ga-containing compound, an In-containing compound, or a mixture thereof, with the balance being a silicon-containing compound.

In another embodiment, the Ga-containing compound, the In-containing compound, or a mixture thereof forms a plurality of discrete phases, such as discrete particulate phases, dispersed within the silicon-containing material (e.g., within the continuous phase of the silicon-containing material). In such embodiments, the silicon-based layer 104a may comprise from about 0.001% to about 40% by volume of a Ga-containing compound, an In-containing compound, or a mixture thereof, such as from about 1% to about 25% by volume (e.g., from about 1% to about 10% by volume of a Ga-containing compound, an In-containing compound, or a mixture thereof).

In one particular embodiment, the substrate 102 is formed from a CMC material (e.g., a silicon-based non-oxide ceramic matrix composite). As used herein, "CMC" refers to siliceous or oxide-oxide, matrix, and reinforcement materials. As used herein, "monolithic ceramic" refers to a material without fiber reinforcement (e.g., having only a matrix material). Herein, CMC and monolithic ceramic are collectively referred to as "ceramic".

Some examples of CMCs useful herein include, but are not limited to, materials having a matrix and reinforcing fibers, including non-silicon oxide-based materials such as silicon carbide, silicon nitride, silicon oxycarbide, silicon oxynitride, and mixtures thereof. Examples include, but are not limited to, CMCs having a silicon carbide matrix and silicon carbide fibers; a CMC having a silicon nitride matrix and silicon carbide fibers; and CMC with a silicon carbide/silicon nitride matrix mixture and silicon carbide fibers. In addition, the CMC may have a matrix and reinforcing fibers composed of oxide ceramics. In particular, the oxide-oxide CMC may be composed of a matrix and reinforcing fibers comprising an oxide-based material, such as alumina (Al)₂O₃) Silicon dioxide (SiO)₂) Aluminosilicates, and mixtures thereof. The aluminosilicate may include a crystalline material, such as mullite (3 Al)₂O₃ 2SiO₂) And glassy aluminosilicates.

In the embodiment of fig. 1, substrate 102 defines a surface 103, and a coating 106 is formed on surface 103. Coating 106 includes a silicon-based layer 104a and an environmental barrier coating 108. In a particular embodiment, the silicon-based layer 104a is a bond coat in which the silicon-containing material is a silicon metal, a silicide (e.g., a rare earth silicide, a molybdenum silicide, a rhenium silicide, or mixtures thereof), or mixtures thereof. In one embodiment, a composition comprising silicon metal and a Ga-containing compound, an In-containing compound, or a mixture thereof is generally provided (e.g., In the relative amounts described above (e.g., about 0.01 to about 85% by volume). In an alternative embodiment, a composition is generally provided that comprises a silicide (e.g., a rare earth silicide, a molybdenum silicide, a rhenium silicide, or mixtures thereof) and a Ga-containing compound, an In-containing compound, or mixtures thereof (e.g., In the above-described relative amounts (e.g., about 0.01 to about 85% by volume).

In use, a thermally grown oxide ("TGO") layer is formed on a surface of the bond coat. For example, a silicon oxide layer (sometimes referred to as a "silicon scale" or "silica scale") is formed on a bond coat of silicon metal and/or silicide. Referring to fig. 2, a thermally grown oxide layer 105 (e.g., silicon oxide) may be present directly on a silicon-based layer 104a (e.g., an adhesion coating comprising a silicon-containing material (silicon metal and/or silicide)) as it is formed during exposure of the component 100 to oxygen (e.g., during fabrication and/or use). The thermally grown oxide layer 105 remains substantially amorphous at its operating temperature due to the presence of the Ga-containing compound, the In-containing compound, or a mixture thereof In the silicon-based layer 104a, where "operating temperature" refers to the temperature at which the thermally grown oxide layer 105 is grown. For example, for a silicon metal bond coat, the TGO layer may remain amorphous at operating temperatures below about 1415 ℃ (e.g., about 1200 ℃ to about 1410 ℃), which is slightly below the melting point of the silicon based bond coat (the melting point of the Si metal is about 1414 ℃). In another example, for a silicide bond coat, the TGO layer may remain amorphous at an operating temperature below about 1485 ℃ (e.g., about 1200 ℃ to about 1415 ℃), which is slightly below the maximum use temperature of CMC. Without wishing to be bound by any particular theory, it is believed that gallium and/or indium in the silicon base layer 104a migrate into the thermally grown oxide layer 105 and inhibit crystallization of the thermally grown oxide layer (e.g., silicon oxide) that would otherwise crystallize at these temperatures. Without wishing to be bound by any particular theory, it is presently believed that Ga and/or In inhibit crystallization of the amorphous silicon-containing material by impurities (e.g., Na and/or K).

In the embodiment shown in fig. 1 and 2, silicon-based layer 104a is directly on surface 103 without any layers in between. However, in other embodiments, there may be more than one layer between the silicon-based layer 104a and the surface 103.

Fig. 3 shows another embodiment of a ceramic component 100, the ceramic component 100 having a substrate 102, wherein the substrate 102 has an outer layer 104b, the outer layer 104b defining a surface 103 of the substrate 102. That is, the outer layer 104b is integral with the substrate 102. In this embodiment, the outer layer 104b is a silicon-based layer, and the coating 106 is on the surface 105. The coating 106 may include an environmental barrier coating 108 and/or other layers (e.g., a bond coat, etc.). In one embodiment, the outer layer 104b may be a monolithic ceramic layer comprising silicon. For example, the outer layer 104b may comprise silicon carbide. In one embodiment, the substrate 102 may include an outer layer 104b (e.g., comprising silicon carbide as a monolithic ceramic layer) on a plurality of CMC layers forming the remainder of the substrate.

Fig. 4 illustrates a thermally grown oxide layer 105 (e.g., silicon oxide) directly on a silicon-based layer 104b (e.g., a bond coat comprising a silicon-containing material (silicon metal)), which is formed during exposure of the component 100 to oxygen (e.g., during fabrication and/or use). Due to the presence of the Ga-containing compound and/or the In-containing compound In the silicon-based layer 104b, the thermally grown oxide layer 105 remains substantially amorphous at the operating temperature of the thermally grown oxide layer 105. Without wishing to be bound by any particular theory, it is believed that gallium and/or indium in the silicon base layer 104b migrate into the thermally grown oxide layer 105 and inhibit crystallization of the thermally grown oxide layer (e.g., silicon oxide) that would otherwise crystallize at these temperatures.

As described above, regardless of the specific position of the silicon-based layer 104 In the ceramic component 100, a Ga-containing compound, an In-containing compound, or a mixture thereof is included In the silicon-based

layers

104a, 104 b. In a particular embodiment, the Ga-containing compound, the In-containing compound, or the mixture thereof is In the form of an oxide or a nitride.

For example, the Ga-containing compound may be gallium nitride (GaN), gallium oxide (Ga)₂O₃) Or mixtures thereof. In embodiments where the Ga-containing compound comprises gallium oxide, the gallium oxide may be doped in another oxide. For example, the Ga-containing compound may be doped with up to about 10 mol% Ga₂O₃Zirconium oxide (ZrO)₂) Hafnium oxide (HfO)₂) Or a combination thereof.

In one embodiment, the Ga-containing compound may be a gallium-metal-oxide. For example, in one embodiment, the Ga-containing compound may have the formula:

Ga_2-xM_xO₃

wherein x is 0 to less than 2 when M is In, 0 to about 1.4 when M is Al, 0 to about 1.4 when M is B, 0 to about 1.4 when M is Fe, or mixtures thereof. In one embodiment, x is greater than 0 to less than 2 when M is In, greater than 0 to about 1.4 when M is Al, greater than 0 to about 1.4 when M is B, and greater than 0 to about 1.4 when M is Fe, or mixtures thereof, such that at least one other metal (In, Al, B, and/or Fe) is present In the gallium-metal-oxide.

In one embodiment, the Ga-containing compound may be a rare earth-gallium-oxide. For example, in one embodiment, the Ga-containing compound may have the formula:

Ln_4-xD_xGa_2-yIn_yO₉

wherein Ln is La, Ce, Pr, Nd, Pm, Sm or a mixture thereof; d is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or mixtures thereof, D is different from Ln (i.e., D is a different element or combination of elements from Ln); and y is 0 to about 1 (e.g., 0 ≦ y ≦ 1, such as 0 ≦ y ≦ 0.5). In one embodiment, y is greater than 0 to about 1 (e.g., 0< y ≦ 1, such as 0< y ≦ 0.5). If D is La, Ce, Pr, Nd, Pm, Sm, or a mixture thereof (i.e., having an atomic radius of Sm or greater), then x is from 0 to less than 4 (e.g., 0< x <4, such as 0< x ≦ about 2). However, if D is Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or mixtures thereof (i.e., having an atomic radius less than Sm), then x is from 0 to about 2 (e.g., 0< x <2, such as 0< x ≦ about 1).

In another embodiment, the Ga-containing compound may have the formula:

Ln₃Ga_5-xM_xO₁₂

wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a mixture thereof; and x is 0 to less than 5 (e.g., 0 ≦ x <5, such as 0< x ≦ 2.5) for M is In, 0 to less than 5 (e.g., 0 ≦ x <5, such as 0< x ≦ 2.5) for M is Al, 0 to less than 5 (e.g., 0 ≦ x <5, such as 0< x ≦ 2.5) for X is Fe, 0 to about 2.5 (e.g., 0 ≦ x ≦ 2.5) for X is B, or a combination thereof. In one embodiment, M is B, wherein x is greater than 0 to about 2.5 (e.g., 0< x ≦ 2.5), such as about 0.1 to about 2 (e.g., 0.1 ≦ x ≦ 2). In one embodiment, x is greater than 0 (e.g., 0.1 to about 2) such that at least one M (e.g., In, Al, Fe, and/or B) is present In the Ga-containing compound.

In another embodiment, the In-containing compound may be indium nitride (InN), indium oxide (In)₂O₃) Or mixtures thereof. In embodiments where the In-containing compound comprises indium oxide, the indium oxide may be doped In another oxide. For example, the In-containing compound may be doped with up to about 10 mol% In₂O₃Zirconium oxide (ZrO)₂) Hafnium oxide (HfO)₂) Or a combination thereof.

In one embodiment, the In-containing compound may be an indium-metal-oxide. For example, In one embodiment, the In-containing compound may have the formula:

In_2-xM_xO₃

wherein x is 0 to less than 2 when M is Ga, x is 0 to about 1.4 when M is Al, x is 0 to about 1.4 when M is B, and x is 0 to about 1.4 when M is Fe, or mixtures thereof. In one embodiment, x is greater than 0 to less than 2 when M is Ga, x is greater than 0 to about 1.4 when M is Al, x is greater than 0 to about 1.4 when M is B, and x is greater than 0 to about 1.4 when M is Fe, or mixtures thereof, such that at least one other metal (Ga, Al, B, and/or Fe) is present in the indium-metal-oxide.

In one embodiment, the In-containing compound may have the formula:

Ln₃In_5-xM_xO₁₂

wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a mixture thereof; and x is 0 to less than 5 (e.g., 0 ≦ x <5, such as 0< x ≦ 2.5) for M is Ga, 0 to less than 5 (e.g., 0 ≦ x <5, such as 0< x ≦ 2.5) for M is Al, 0 to less than 5 (e.g., 0 ≦ x <5, such as 0< x ≦ 2.5) for X is Fe, 0 to about 2.5 (e.g., 0 ≦ x ≦ 2.5) for X is B, or a combination thereof. In one embodiment, M is B, wherein x is greater than 0 to about 2.5 (e.g., 0< x ≦ 2.5), such as about 0.1 to about 2 (e.g., 0.1 ≦ x ≦ 2). In one embodiment, x is greater than 0 (e.g., 0.1 to about 2) such that at least one M (e.g., Ga, Al, Fe, and/or B) is present In the In-containing compound.

In one embodiment, the Ga-containing compound, the In-containing compound, or the mixture thereof may have a formula of:

Ln_2-x-yGa_xIn_ySi₂O₇

wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a mixture thereof; x is 0 to about 1; y is 0 to about 1; and the sum of x and y is greater than 0 (i.e., (x + y) > 0). In one embodiment, the sum of x and y is from greater than 0 to about 1 (i.e., 0< (x + y) ≦ about 1), such as from greater than 0 to about 0.5 (i.e., 0< (x + y) ≦ about 0.5).

Ln_2-x-yGa_xIn_ySi₂O₅

The environmental barrier coating 108 of fig. 1-4 can include any combination of one or more layers formed from materials selected from typical EBC or TBC layer chemistries including, but not limited to, rare earth silicates (monosilicates and disilicates), mullite, Barium Strontium Aluminosilicate (BSAS), hafnium oxide, zirconium oxide, stabilized hafnium oxide, stabilized zirconium oxide, rare earth hafnates, rare earth zirconates, rare earth gallates, and the like.

The ceramic assembly 100 of fig. 1-4 is particularly suitable for use as components found in high temperature environments, such as those found in gas turbine engines, e.g., combustor components, turbine blades (turbine blades), shrouds, nozzles, heat shields, and vanes (vanes). In particular, the turbine component may be a CMC component located within a hot gas flow path of the gas turbine such that the coating forms an environmental barrier coating on the component to protect the component within the gas turbine when exposed to the hot gas flow path.

FIG. 5 is a schematic cross-sectional view of a gas turbine engine according to an exemplary embodiment of the present disclosure. More specifically, for the embodiment of FIG. 5, the gas turbine engine is a high-bypass turbofan jet engine 10(a high-bypass turbojet engine), referred to herein as "turbofan engine 10". As shown in fig. 5, the turbofan engine 10 defines an axial direction a (extending parallel to a longitudinal centerline 12 provided for reference) and a radial direction R. Generally, turbofan 10 includes a fan section 14 and a core turbine engine 16 disposed downstream of fan section 14. Although described below with reference to turbofan engine 10, the present disclosure is applicable to turbomachines in general, including turbojet, turboprop and turboshaft gas turbine engines, including industrial and marine gas turbine engines and auxiliary power units.

The exemplary core turbine engine 16 depicted generally includes a substantially tubular casing 18 defining an annular inlet 20. The housing 18 encloses, in continuous flow relationship, a compressor section including a booster or Low Pressure (LP) compressor 22 and a High Pressure (HP) compressor 24; a combustion section 26; a turbine section including a High Pressure (HP) turbine 28 and a Low Pressure (LP) turbine 30; and an injection exhaust nozzle portion 32. A High Pressure (HP) shaft or spool 34 drivingly connects the HP turbine 28 to the HP compressor 24. A Low Pressure (LP) shaft or spool 36 drivingly connects the LP turbine 30 to the LP compressor 22.

For the embodiment shown, fan section 14 includes a variable pitch fan 38, with variable pitch fan 38 having a plurality of fan blades 40 connected to a disk 42 in a spaced apart manner. As shown, fan blades 40 extend generally outward from disk 42 in radial direction R. Each fan blade 40 is rotatable about pitch axis P relative to disk 42 by means of fan blade 40 being operatively connected to a suitable actuating member 44, which actuating members 44 are configured to collectively vary the pitch of fan blades 40 in unison. Together, fan blades 40, disk 42, and actuating member 44 may be rotated about longitudinal axis 12 by LP shaft 36 on optional power gearbox 46. Power gearbox 46 includes a plurality of gears for reducing the rotational speed of LP shaft 36 to a more efficient fan rotational speed.

Still referring to the exemplary embodiment of FIG. 5, disk 42 is covered by a rotatable forward nacelle 48, the forward nacelle 48 having an aerodynamic profile to facilitate airflow through the plurality of fan blades 40. Additionally, exemplary fan section 14 includes an annular fan casing or outer nacelle 50, casing or outer nacelle 50 circumferentially surrounding at least a portion of fan 38 and/or core turbine engine 16. It should be appreciated that nacelle 50 may be configured to be supported relative to core turbine engine 16 by a plurality of circumferentially spaced apart outlet guide vanes 52. Further, a downstream portion 54 of nacelle 50 may extend on an exterior of core turbine engine 16 to define a bypass airflow passage 56 therebetween.

During operation of the turbofan engine 10, a volume of air 58 enters the turbofan 10 through the nacelle 50 and/or an associated inlet 60 of the fan section 14. As the volume of air 58 passes through fan blades 40, a first portion of air 58 is channeled or directed into bypass airflow channel 56 as indicated by arrow 62, and a second portion of air 58 is channeled or directed into LP compressor 22 as indicated by arrow 64. The ratio between the first portion of air 62 and the second portion of air 64 is commonly referred to as a bypass ratio (a bypass ratio). The pressure of the second portion of air 64 is then increased as it passes through the High Pressure (HP) compressor 24 and into the combustion section 26, where the second portion of air 64 is mixed with fuel and combusted to provide combustion gases 66.

The combustion gases 66 are channeled through HP turbine 28 wherein a portion of thermal and/or kinetic energy from combustion gases 66 is extracted through sequential stages (HP turbine stages) of HP turbine stator vanes 68, which HP turbine stator vanes 68 are coupled to casing 18 and HP turbine rotor blades 70, which HP turbine rotor blades 70 are coupled to HP shaft or spool (spool)34 to rotate HP shaft or spool 34 to support operation of HP compressor 24. The combustion gases 66 are then channeled through the LP turbine 30 wherein a second portion of the thermal and kinetic energy of the combustion gases 66 is extracted through sequential stages of LP turbine stator blades 72, the LP turbine stator blades 72 coupled to the outer casing 18 and LP turbine rotor blades 74, the LP turbine rotor blades 74 coupled to the LP shaft or spool 36 to rotate the LP shaft or spool 36 to support operation of the LP compressor 22 and/or rotation of the fan 38.

Subsequently, the combustion gases 66 are directed through the jet exhaust nozzle portion 32 of the core turbine engine 16 to provide propulsive thrust. At the same time, the pressure of the first portion of air 62 is substantially increased as the first portion of air 62 is directed through the bypass airflow passage 56 before the first portion of air 62 is exhausted from the fan nozzle exhaust portion 76 of the turbofan 10, also providing propulsive thrust. HP turbine 28, LP turbine 30, and jet exhaust nozzle portion 32 at least partially define a hot gas path 78 for channeling combustion gases 66 through core turbine engine 16.

Methods for coating ceramic components are also generally provided. In one embodiment, the method includes applying a bond coat directly on a surface of the ceramic component, wherein the bond coat comprises a silicon-containing material (e.g., silicon metal and/or silicide), and at least one of a Ga-containing compound, an In-containing compound, or a mixture thereof.

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 devices or systems and performing the methods contained therein. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other embodiments are to be considered within the scope of the claims if they contain structural elements that do not differ from the literal language of the claims, or if they contain equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A ceramic component, comprising:

a substrate defining a surface, wherein the substrate is formed from a Ceramic Matrix Composite (CMC) material; and

a silicon-based layer directly forming a bond coat on the surface of the substrate, wherein the silicon-based layer comprises a silicon-containing material and 0.001 wt% to 85 wt% of a Ga-containing compound, an In-containing compound, or a mixture thereof,

at least one of the Ga-containing compound, the In-containing compound, or the mixture thereof forms a continuous grain boundary within the silicon-containing material.

2. The ceramic component of claim 1, wherein at least one of a Ga-containing compound, an In-containing compound, or a mixture thereof reacts or dissolves into silicon scale formed on the bond coat to inhibit the formation of crystals of the silicon scale.

3. The ceramic component of claim 1, wherein the silicon-containing material is silicon metal.

4. The ceramic component of claim 3, wherein a thermally grown oxide is on the bond coat, and wherein the thermally grown oxide layer remains amorphous at an operating temperature below 1415 ℃.

5. The ceramic assembly of claim 1, wherein the silicon-containing material comprises a silicide.

6. The ceramic component of claim 5, wherein a thermally grown oxide is on the bond coat, and wherein the thermally grown oxide layer remains amorphous at an operating temperature below 1485 ℃.

7. The ceramic assembly of claim 5, wherein the silicide comprises molybdenum silicide, rhenium silicide, or a mixture thereof.

8. The ceramic assembly of claim 1, wherein the ceramic assembly further comprises:

an environmental barrier coating on the silicon base layer.

9. The ceramic component of claim 1, wherein at least one of the Ga-containing compound, the In-containing compound, or the mixture thereof is non-reactive with the silicon-containing material.

10. The ceramic component according to any one of the preceding claims, wherein the silicon-based layer comprises a silicon-containing material and 0.001 to 85 wt% of a Ga-containing compound.

11. The ceramic component of claim 10, wherein the Ga-containing compound is selected from:

GaN；

Ga₂O₃；

Ga_2-xM_xO₃wherein, when M is In, x is 0 to 2; when M is Al, x is 0 to 1.4; when M is B, x is 0 to 1.4; when M is Fe, x is 0 to 1.4; or mixtures thereof;

doped with up to 10 mol% Ga₂O₃ZrO of₂、HfO₂Or a combination thereof;

Ln_2-x-yGa_xIn_ySi₂O₇wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or mixtures thereof; x is greater than 0 to 1; y is 0 to 1;

Ln_2-x-yGa_xIn_ySi₂O₅wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or mixtures thereof; x is greater than 0 to 1; y is 0 to 1;

Ln_4-xD_xGa_2-yIn_yO₉wherein Ln is La, Ce, Pr, Nd, Pm, Sm or mixtures thereof; d is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or mixtures thereof, wherein D is different from Ln, x is 0 to less than 4 if D is La, Ce, Pr, Nd, Pm, Sm or mixtures thereof, and 0 to 2 if D is Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or mixtures thereof; and y is 0 to 1;

Ln₃Ga_5-xM_xO₁₂wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or mixtures thereof; when M is In, x is not less than 0<5, when M is Al, x is more than or equal to 0<5, when M is Fe, x is more than or equal to 0<5, when M is B, x is more than or equal to 0 and less than or equal to 2.5, or the combination of the x and the x; and

mixtures thereof.

12. The ceramic component of any of claims 1-9, wherein the silicon-based layer comprises a silicon-containing material and 0.001 wt% to 85 wt% of an In-containing compound.

13. The ceramic component of claim 12, wherein the In-containing compound is selected from the group consisting of:

InN；

In₂O₃；

In_2-xM_xO₃wherein x is 0 to 2 when M is Ga, x is 0 to 1.4 when M is Al, x is 0 to 1.4 when M is B, and x is 0 to 1.4 when M is Fe, or a mixture thereof;

doped with 0.1 mol% to 10 mol% In₂O₃ZrO of₂、HfO₂Or a combination thereof;

Ln_2-x-yGa_xIn_ySi₂O₇wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or mixtures thereof; x is 0 to 1; y is greater than 0 to 1;

Ln_2-x-yGa_xIn_ySi₂O₅wherein Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or mixtures thereof; x is 0 to 1; y is greater than 0 to 1;

Ln_4-xD_xIn_2-yGa_yO₉wherein Ln is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, or mixtures thereof; d is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a mixture thereof; x is 0 to 2; y is 0 to 1; and

mixtures thereof.