High-entropy ceramic thermal barrier coating

Abstract

The present invention is entitled "High-Entropy Ceramic Thermal Barrier Coating". The high-entropy ceramic (HEC) composition (40) comprises at least three different rare earth (RE) oxides and at least one of hafnium dioxide (HfO2) and zirconium dioxide (ZrO2). The at least three different rare earth oxides are in equal molar fractions. In one aspect, the high-entropy ceramic (HEC) composition (40) can be used in a thermal barrier coating (101).

Description

Technical Field

[0001] This disclosure relates generally to thermal barrier coatings. In particular, this disclosure relates to low thermal conductivity, high entropy ceramic (HEC) compositions in thermal barrier coatings. Background Technology

[0002] A gas turbine system is a mechanism used to convert the potential energy of fuel into heat energy and subsequently into mechanical energy for purposes such as propelling aircraft, generating electricity, and pumping fluids. One possible way to improve gas turbine efficiency is to use higher operating temperatures. However, the metallic materials used in gas turbines may be very close to the upper limit of their thermal stability at the gas turbine operating temperature. In the hottest part of a gas turbine, some metallic materials can be used at temperatures above their melting point. These materials can withstand these temperatures because they can be cooled by air. However, air cooling can reduce the overall efficiency of the gas turbine.

[0003] Thermal barrier coatings are applied to high-temperature operating components, such as, but not limited to, those in gas turbine systems. By utilizing thermal barrier coatings, the amount of cooling air required can be substantially reduced. Therefore, the use of thermal barrier coatings can increase gas turbine efficiency. Thermal barrier coatings can be applied to hot gas path components, such as, but not limited to, flame tubes, transition sections, turbine nozzles, and turbine blades / rotating blades.

[0004] Ceramic materials are commonly used in thermal barrier coatings. Yttrium-stabilized zirconia (YSZ) is a ceramic commonly used in thermal barrier coatings. The cubic crystal structure of zirconia or zirconium dioxide (ZrO2) is stabilized at room temperature by adding yttrium oxide or yttrium trioxide (Y2O3) to form YSZ. However, YSZ exhibits instability at higher temperatures and can decompose from its cubic crystal structure into a mixture of tetragonal and cubic zirconia, thus failing to provide ideal thermal barrier coating protection. Summary of the Invention

[0005] All aspects, examples, and features mentioned below can be combined in any technically possible way.

[0006] One aspect of this disclosure provides a high-entropy ceramic (HEC) composition comprising at least three different rare earth (RE) oxides; the at least three different rare earth oxides being in equal molar fractions; and at least one of hafnium dioxide (HfO2) and zirconium dioxide (ZrO2).

[0007] Another aspect of this disclosure includes any of the foregoing aspects, wherein at least three different rare earth (RE) oxides include at least one of the following: yttrium (Y), lanthanum (La), cerium (Ce), neodymium (Nd), gadolinium (Gd), samarium (Sm), erbium (Er), and ytterbium (Yb).

[0008] Another aspect of this disclosure includes any of the foregoing aspects, and wherein at least three different rare earth (RE) oxides include at least three of the following: Y2O3, La2O3, Gd2O3, Ce2O3, Nd2O3, Sm2O3, Yb2O3 and Er2O3.

[0009] Another aspect of this disclosure includes any of the foregoing aspects, wherein the molar fractions of at least three different rare earth oxides are each 0.167 moles, and the molar fraction of at least one of HfO2 and ZrO2 is 0.5 moles.

[0010] Another aspect of this disclosure includes any of the foregoing aspects, wherein the molar fractions of at least three different rare earth oxides are each 0.133 moles, and the molar fraction of at least one of HfO2 and ZrO2 is 0.6 moles.

[0011] Another aspect of this disclosure includes any of the foregoing aspects, wherein the molar fractions of at least three different rare earth oxides are each 0.1 moles, and the molar fraction of at least one of HfO2 and ZrO2 is 0.7 moles.

[0012] Another aspect of this disclosure includes any of the foregoing aspects, wherein the molar fractions of at least three different rare earth oxides are each 0.067 moles, and the molar fraction of at least one of HfO2 and ZrO2 is 0.8 moles.

[0013] One aspect of this disclosure provides a thermal barrier coating comprising at least two thermal barrier coating layers, wherein at least one of the at least two thermal barrier coating layers comprises a high entropy ceramic (HEC) composition comprising: at least three different rare earth (RE) oxides; the at least three different rare earth oxides being in equal molar fractions; and at least one of hafnium dioxide (HfO2) and zirconium dioxide (ZrO2).

[0014] Another aspect of this disclosure includes any of the foregoing aspects, and wherein at least three different rare earth (RE) oxides include at least one of the following: yttrium (Y), lanthanum (La), gadolinium (Gd), cerium (Ce), neodymium (Nd), samarium (Sm), erbium (Er) and ytterbium (Yb).

[0015] Another aspect of this disclosure includes any of the foregoing aspects, and wherein at least three different rare earth (RE) oxides include at least three of the following: Y2O3, La2O3, Gd2O3, Nd2O3, Ce2O3, Sm2O3, Yb2O3 and Er2O3.

[0016] Additional aspects of this disclosure include any of the foregoing aspects, wherein each of the at least three different rare earth oxides has an equal molar fraction of 0.167 mol, and at least one of HfO2 and ZrO2 has a molar fraction of 0.5 mol.

[0017] Another aspect of this disclosure includes any of the foregoing aspects, wherein the molar fraction of each of the at least three different rare earth oxides is 0.133 moles, and the molar fraction of at least one of HfO2 and ZrO2 is 0.6 moles.

[0018] Another aspect of this disclosure includes any of the foregoing aspects, wherein each of the at least three different rare earth oxides has an equal molar fraction of 0.1 mol, and at least one of HfO2 and ZrO2 has a molar fraction of 0.7 mol.

[0019] Another aspect of this disclosure includes any of the foregoing aspects, wherein the molar fraction of each of the at least three different rare earth oxides is 0.067 moles, and the molar fraction of at least one of HfO2 and ZrO2 is 0.8 moles.

[0020] Another aspect of this disclosure includes any of the foregoing aspects, and wherein the thermal barrier coating includes a substrate, an adhesive coating deposited on the substrate, a transition layer deposited on the adhesive coating, a first high-entropy ceramic (HEC) composition layer deposited on the transition layer, and a second high-entropy ceramic (HEC) composition layer deposited on the first high-entropy ceramic (HEC) composition layer.

[0021] Another aspect of this disclosure includes any of the foregoing aspects, wherein one of the first high-entropy ceramic (HEC) composition layer and the second high-entropy ceramic (HEC) composition layer is deposited by suspension plasma spraying (SPS) and forms a vertical crack entropy ceramic composition (HEC) composition layer.

[0022] Another aspect of this disclosure includes any of the foregoing aspects, and the thermal barrier coating further includes a polishing protective coating deposited onto the second high-entropy ceramic (HEC) composition layer.

[0023] One aspect of this disclosure provides a method for forming a layered article, the method comprising depositing at least two thermal barrier coatings on a substrate, wherein at least one of the at least two thermal barrier coatings comprises a high entropy ceramic (HEC) composition layer comprising: at least three different rare earth (RE) oxides; the at least three different rare earth oxides being in equal molar fractions; and at least one of hafnium dioxide (HfO2) and zirconium dioxide (ZrO2).

[0024] Another aspect of this disclosure includes any of the foregoing aspects, and wherein at least three different rare earth (RE) oxides include at least three of the following: Y2O3, La2O3, Gd2O3, Ce2O3, Nd2O3, Sm2O3, Yb2O3 and Er2O3.

[0025] Another aspect of this disclosure includes any of the foregoing aspects, and wherein the method further includes depositing an adhesive coating on a substrate, depositing a transition layer on the adhesive coating, depositing a first high-entropy ceramic (HEC) composition layer on the transition layer, and depositing a second high-entropy ceramic (HEC) composition layer on the first high-entropy ceramic (HEC) composition layer, wherein one of the first high-entropy ceramic (HEC) composition layer and the second high-entropy ceramic (HEC) composition layer is deposited by suspension plasma spraying (SPS) to form a vertical crack entropy ceramic composition (HEC) layer.

[0026] Two or more aspects described in this disclosure (including those described in this overview section) may be combined to form an implementation scheme not specifically described herein.

[0027] Details of one or more specific embodiments are set forth in the following figures and description. Other features, objects, and advantages will be apparent from the specification, figures, and claims.

[0028] The exemplary aspects of this disclosure are designed to address the problems described herein and / or other problems not discussed herein. Attached Figure Description

[0029] These and other features of the present disclosure will be more readily understood from the following detailed description of various aspects of the present disclosure in conjunction with the accompanying drawings depicting various embodiments thereof, wherein:

[0030] Figure 1 This is a table of high-entropy ceramic (HEC) compositions according to embodiments of this disclosure;

[0031] Figure 2 A schematic thermal barrier coating system having a high-entropy ceramic (HEC) composition layer on a substrate is shown according to an embodiment of the present disclosure;

[0032] Figure 3 Further schematic thermal barrier coating systems with high-entropy ceramic (HEC) composition layers on a substrate, according to other embodiments of the present disclosure, are shown.

[0033] Figure 4 Another schematic thermal barrier coating system with a high-entropy ceramic (HEC) composition layer on a substrate, according to another embodiment of the present disclosure, is shown; and

[0034] Figure 5 A flowchart is shown of a method for forming a thermal barrier coating comprising a high-entropy ceramic (HEC) composition layer according to an embodiment of the present disclosure.

[0035] It should be noted that the accompanying drawings of this disclosure are not necessarily drawn to scale. The drawings are intended to depict only typical aspects of this disclosure and should therefore not be considered as limiting the scope of this disclosure. In the drawings, similar numbers denote similar elements between figures. Detailed Implementation

[0036] First, in order to clearly describe the subject matter disclosed herein, it will be necessary to select certain terms when referring to and describing related thermal barrier coatings and compositions, particularly those used in turbomachinery. To the extent possible, common industry terms will be used and adopted in a manner consistent with their accepted meaning. Unless otherwise stated, such terms 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 understand that several different or overlapping terms may generally be used to refer to a particular component. An object that can be described herein as a single part may include multiple components and is referred to in another context as being composed of multiple components. Alternatively, an object that can be described herein as comprising multiple components may elsewhere be referred to as a single part.

[0037] In addition, several descriptive terms may be used periodically throughout this document, and it should prove helpful to define these terms at the beginning of this section. Unless otherwise stated, these terms and their definitions are as follows. As used herein, “downstream” and “upstream” are terms indicating the direction of fluid flow, such as through the working fluid of a turbine engine, or, for example, through the airflow of a combustor or through the coolant of one of the turbine's component systems. The term “downstream” corresponds to the direction of fluid flow, and the term “upstream” refers to the direction opposite to the flow (i.e., the direction from which the flow originates). Without further detail, the terms “front” and “rear” refer to directions, where “front” refers to the front end of the engine or compressor end, and “rear” refers to the rear section of the turbine.

[0038] It is often necessary to describe parts positioned at different radial locations relative to the central axis. The term "radial" refers to movement or position perpendicular to the axis. For example, if a first part is closer to the axis than a second part, this document will describe the first part as "radially inward" or "inner" of the second part. On the other hand, if the first part resides further away from the axis than the second part, this document may describe the first part as "radially outward" or "outer" of the second part. The term "axial" refers to movement or position parallel to the axis. Finally, the term "circumferential" refers to movement or position about the axis. It should be understood that such terms can be applied relative to the central axis of the turbine.

[0039] In addition, several descriptive terms may be used regularly in this document, as described below. The terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of a single component.

[0040] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that, when used in the specification, the terms “comprising” and / or “including” specify the presence of the 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 groups thereof. “Optional” or “optionally” means that an event or condition subsequently described may or may not occur, or a component or feature subsequently described may or may not be present, and the description includes instances where the event occurs or the component is present and instances where the event does not occur or the component is not present.

[0041] When an element or layer is referred to as “on another element or layer,” “attached to another element or layer,” “connected to another element or layer,” or “linked to another element or layer,” it may be directly on, attached to, connected to, or linked to another element or layer, or an intervening element or layer may be present. In contrast, when an element is referred to as “directly on another element or layer,” “directly attached to another element or layer,” “directly connected to another element or layer,” or “directly linked to another element or layer,” an intervening element or layer may not be present. Other terms used to describe the relationship between elements should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0042] As mentioned above, a gas turbine system converts potential energy into heat energy, and subsequently into mechanical energy for use. Improving the efficiency of a gas turbine is desirable, and this can be achieved by operating the gas turbine at higher temperatures. However, the metallic materials used in gas turbines, especially at the higher temperatures associated with hot gas path components, may be very close to the upper limit of their thermal stability under gas turbine operating conditions. In the hottest parts of a gas turbine, some metallic materials can even be used at temperatures above their melting point. Metallic materials can withstand these temperatures because they can be cooled, for example, by air, steam, or other cooling methods now known or subsequently developed. However, cooling can reduce the overall efficiency of the gas turbine.

[0043] Thermal barrier coatings can be applied to high-temperature operating components, such as, but not limited to, gas turbine systems. By utilizing thermal barrier coatings, the amount of cooling air required for the gas turbine can be reduced. Therefore, thermal barrier coatings can increase gas turbine efficiency. Thermal barrier coatings can be applied to hot gas path components, such as, but not limited to, flame tubes, transition sections, turbine nozzles, and turbine blades / rotating blades.

[0044] Generally, metallic materials (including those used in gas turbines) have a higher coefficient of thermal expansion than ceramic materials. Therefore, the ceramic material in a thermal barrier coating should have a coefficient of thermal expansion that matches that of the component substrate. This ensures that the ceramic coating material will not crack when the substrate expands upon heating. Zirconia (ZrO2) and hafnium dioxide (HfO2) both exhibit high coefficients of thermal expansion, hence their use in thermal barrier coatings.

[0045] Thermal barrier coatings can be deposited using several techniques. As illustrated in this disclosure, deposition techniques include, but are not limited to, thermal spraying (plasma spraying, flame spraying, and HVOF spraying), sputtering, and electron beam physical vapor deposition (EBPVD). Electron beam physical vapor deposition can produce columnar grain microstructures, which include small pillars separated by gaps extending into the coating. This structure may be referred to as dense vertical cracks or DVCs.

[0046] As mentioned above, yttrium-stabilized zirconium oxide (YSZ) has been used as a thermal barrier coating for gas turbine engines. While YSZ performs well in this function, improved materials need to be developed due to the need for increased operating temperatures to achieve higher energy conversion efficiency. To address this challenge, rare-earth zirconates forming fluorite-derived cubic pyrochlore structures can be used in thermal barrier coatings due to their low thermal conductivity, excellent chemical stability, and other suitable properties. The use of single-phase high-entropy multiphase components offers the potential for further reducing conductivity through greater phonon scattering resulting from higher dopant concentrations in the lattice and higher hardness and toughness properties that translate into improved corrosion resistance.

[0047] Pyrochlore is typically used to describe the ceramic structure of the composition A₂B₂O₇, where A may have 3... + or 2 + Price, and B can have 4 + Or 5 + The valence is 7, and the sum of the valences of A and B is 7. Typical pyrochlores with the potential to serve as thermal barrier coatings are those in which A is selected from rare earth elements or lanthanides and B is a mixture selected from the group consisting of zirconium, hafnium, and mixtures thereof. Many other pyrochlores exist that also have the potential to serve as thermal barrier materials.

[0048] Fluorite and pyrochlore are almost identical in terms of their cubic structure. Therefore, fluorite and pyrochlore can be considered as a single phase. Both fluorite and pyrochlore in the RE₂O₃-ZrO₂ system have cubic structures, but the difference lies in the fact that pyrochlore is ordered, thus exhibiting a bilattice parameter similar to fluorite.

[0049] Aspects embodied in this disclosure include the use of high-entropy oxide ceramic compositions (HECs) exhibiting low / ultra-low thermal conductivity. HECs, as embodied in this disclosure, also exhibit desired corrosion resistance properties in thermal barrier coatings. HECs provide a crystalline high-entropy single-phase product in thermal barrier coatings, with enhanced thermal conductivity reduction and improved toughness superior to conventional thermal barrier coating chemistry. Therefore, single-phase HECs in thermal barrier coatings offer advantages over current thermal barrier coatings.

[0050] According to this application, the term "entropy" refers to a measure of molecular anomalies, configurational anomalies, or systemic randomness, and according to this disclosure, it refers to a thermal barrier coating. Configurational anomalies or entropy combinations can be designed into mixed ceramic oxides. According to one aspect of the embodiments, entropy can be achieved by filling a single sublattice with a number of different cations or positively charged ions. As embodied in this disclosure, HEC promotes an entropy-stable form of crystalline material that can be incorporated into thermal barrier coatings. As embodied in this disclosure, HEC enables single-phase solid solutions of oxides in crystalline structures to achieve concentration levels that provide thermal protection.

[0051] Based on density adjustments, pyrochlore exhibits superior thermal insulation properties compared to more commonly used zirconia-based thermal barrier materials. Furthermore, many pyrochlore materials possess a phase relationship in which the pyrochlore structure is phase-stable up to its melting point. Most pyrochlores have melting points greater than approximately 3000℉ (approximately 1650℃), and typically greater than approximately 4000℉ (approximately 2200℃). Some materials with cubic and at least generally non-pyrochlore crystalline structures, such as gadolinium-zirconia oxide (Gd,Zr)O2, are also phase-stable up to at least approximately 3000℉ (1650℃). In the case of gadolinium-zirconia oxide, the converted pyrochlore gadolinium-zirconia structure tends to be a conventional cubic structure, which is also quite phase-stable. Additionally, all these materials are attached to alumina. These properties are applicable to thermal barrier coatings.

[0052] To improve the efficiency of gas turbines operating at high inlet temperatures, such as up to and above about 1300°C (2400°F), thermal barrier coatings provide low (“low K”) to ultra-low thermal conductivity (“ULK”). The low to ultra-low thermal conductivity of the thermal barrier coating enables greater temperature stability, thereby reducing the temperature on the substrate to which the thermal barrier coating is applied. Therefore, one aspect of the embodiments illustrates a thermal barrier coating having a high-entropy ceramic (hereinafter referred to as “HEC”) composition, which has both low K and ULK characteristics. As illustrated in this disclosure, HEC comprises a high-entropy alloy oxide ceramic composition. As illustrated in this disclosure, HEC includes improved corrosion resistance properties.

[0053] The HEC material produced according to the embodiments forms a microstructure of a deposited coating to obtain a highly durable ULK thermal barrier coating. As embodied in this disclosure, the thermal barrier coating with HEC is stable at higher gas turbine operating temperatures up to and above about 1300°C (2400°F).

[0054] Furthermore, the HEC material produced according to the implementation scheme enables the formation of crystalline high-entropy single-phase products. Crystalline high-entropy single-phase products offer further reductions in thermal conductivity and improved toughness compared to conventional thermal barrier coatings.

[0055] Anomalous or high-entropy combinations can be designed into hybrid ceramic oxides by filling individual sublattices with many different cations. The individual sublattice compositions of the combined design promote entropy-stable forms of the crystalline composition. As embodied in this disclosure, in these entropy-stable forms of the crystalline composition, cations are incorporated into the crystal structure as discussed herein.

[0056] One aspect of the implementation provides a single-phase solid solution of elemental composition in the form of rare earth oxides. The rare earth oxides form a crystalline structure at a relatively high concentration level. The high-entropy stable structure of the crystal provides a low thermal conductivity K, at least in part due to the multiple elements with different atomic radii formed within the crystal structure. This crystal structure with different atomic radii allows for increased phonon scattering, and thus increases the thermal conductivity K.

[0057] As illustrated in this disclosure, the molar-equal fractional components used for low thermal conductivity K include:

[0058] Low K(Y) x Zr x Gd x Zr)(Y x )O x x = the ratio can be approximately 0.1 to approximately 0.25.

[0059] ULK(Yb x Zr x Gd x Zr)(Y x The ratio of Ox can be approximately 0.1 to approximately 0.25.

[0060] As embodied in this disclosure, another aspect of the embodiments provides fractional systems with equal molar numbers for low thermal conductivity K, wherein the composition of the zirconium oxide system with equal molar number of atomic fraction doped / substituted atoms includes:

[0061] A: Low K: Where RE=Y,La,Gd,Ce,Nd,Sm,Yb,Ce,Er

[0062] For molecules with the same gram weight, the ratio x can be approximately 0.1 to approximately 0.3.

[0063] Example: (Y) 0.06 ,La 0.06 ,Gd 0.06 Zr 0.82 O 1.91 and (Y) 0.06 ,Gd 0.06 ,Yb 0.06 Zr 0.82 O 1.91

[0064] B:ULK: Where RE=Y,La,Gd,Nd,Ce,Sm,Yb,Ce,Er

[0065] For molecules with the same gram weight, the ratio of x can be approximately 0.1 to approximately 0.45.

[0066] Example: (Y)0.05 La 0.05 ,Gd 0.05 Ce 0.05 Zr 0.8 O 1.9 and (Y) 0.05 ,La 0.05, Gd 0.05, Yb 0.05 Zr 0.8 O 1.9

[0067] C:ULK: Where RE=RE=Y,La,Gd,Nd,Ce,Sm,Yb,Ce,Er

[0068] For molecules with the same gram weight, the ratio of x can be approximately 0.1 to approximately 0.45.

[0069] Example: (Y) 0.04 ,La 0.04 ,Gd 0.04 Ce 0.04 ,Sm 0.04 Zr 0.8 O 1.9 and (Y) 0.04 ,La 0.04 ,Gd 0.04 ,Yb 0.04 ,Sm 0.04 Zr 0.8 O 1.9

[0070] Hafnium oxide and zirconium oxide are similar in chemistry and monoclinic crystal structure. Hafnium oxide and zirconium oxide are completely soluble in each other to form solid solutions. Compounds of hafnium oxide and zirconium oxide formed from rare earth elements or lanthanides are tetragonal or cubic stable and also tend to be similar. However, stable hafnium oxide may become more structurally stable upon aging at higher operating temperatures.

[0071] Figure 1 This is a table of exemplary and non-limiting high-entropy ceramic (HEC) compositions as embodied in this disclosure. Figure 1 In the “Phase Composition” column, the molar percentage (%) of the phases obtained in the HEC thermal barrier coating composition is provided. Figure 1 Mole fractions of rare earth oxides and hafnium oxide and zirconium oxide are provided, wherein the values ​​of illustrative and non-limiting entries for Y2O3, La2O3, and Gd2O3 are in units of equal molar fractions. Figure 1The corresponding weight fractions of hafnium oxide and zirconium oxide are also provided, along with illustrative Y₂O₃, La₂O₃, and Gd₂O₃. Although Y₂O₃, La₂O₃, and Gd₂O₃ are listed in the table as illustrative rare earth oxides, aspects of the embodiments include other rare earth oxides, such as, but not limited to, Y₂O₃, La₂O₃, Gd₂O₃, Ce₂O₃, Sm₂O₃, Nd₂O₃, Yb₂O₃, Ce₂O₃, Sm₂O₃, and Er₂O₃.

[0072] As described above, zirconium oxide and hafnium oxide are interchangeable in the HEC composition. In one non-limiting aspect of the embodiment, the HEC composition comprises all zirconium oxide. In another non-limiting aspect, the HEC composition comprises all hafnium oxide, and in yet another non-limiting aspect, the HEC composition contains zirconium oxide and hafnium oxide in amounts equal to the sum of their amounts. Figure 1 The quantities are shown in the figure.

[0073] As illustrated in this disclosure, the composition may also contain certain oxide additives to inhibit sintering at high temperatures. One aspect of the embodiments provides oxide additives, such as, but not limited to, alumina (Al₂O₃), MgO, or CaO, to inhibit sintering at high temperatures. According to another aspect of the embodiments, in-situ formed complex oxides, such as, but not limited to, certain rare earth oxides, for example, but not limited to, Y₃Al₅O₃, are used. 12 Gd3Al5O 12 YAlO3, Nd2O3, and GdAlO3 can be added to the composition, as embodied in this disclosure, to suppress sintering at high temperatures.

[0074] One aspect of the implementation provides a thermal barrier coating system 100 with a high-entropy oxide ceramic (HEC) thermal barrier coating, and... Figures 2 to 4 As shown in the figure. According to aspects of this disclosure, the type and number of layers, their thickness, and their arrangement in the thermal barrier coating system 100 can be varied. Variations in type, number, thickness, and arrangement produce a thermal barrier coating 101 having an HEC composition that provides desired properties on a substrate 10, on which the thermal barrier coating system 100 is deposited.

[0075] refer to Figures 2 to 4 The thermal barrier coating system 100 includes a thermal barrier coating 101 deposited on a substrate 10. An adhesive coating 20 is deposited on the substrate 10. An exemplary adhesive coating is an MCrAlX adhesive coating, wherein: M represents a metallic substance such as Fe, Co, or Ni, and X represents at least one of Y, Ti, Yb, and Ta.

[0076] A transition layer 30 is deposited on the adhesive coating 20. The transition layer 30 provides a compatible surface for subsequent layers in the thermal barrier coating 101.

[0077] The binder coating 20 and the transition layer 30 can be deposited by any suitable deposition method. In some aspects as embodied in this disclosure, deposition methods for the binder coating 20 and the transition layer 30 may include air plasma spraying (APS), high-velocity oxygen fuel (HVOF), electron beam physical vapor deposition (EBPVD), and suspension plasma spraying (SPS), or other spraying deposition processes now known or subsequently developed.

[0078] Next, at least two layers comprising a high-entropy ceramic (HEC) composition are deposited on the transition layer 30. One layer is a high-entropy ceramic (HEC) composition layer 40 deposited by at least one of air plasma spraying (APS), high-velocity oxygen fuel (HVOF), electron beam physical vapor deposition (EBPVD), and suspension plasma spraying (SPS). Figure 2 Another layer is the high-entropy ceramic (HEC) composition layer 50 deposited on the high-entropy ceramic (HEC) composition layer 40 by suspension plasma spraying (SPS). Figure 2 As discussed in this paper, SPS provides the desired higher strength and toughness in thermal barrier coating 101 compared to other thermal barrier coating systems.

[0079] Figure 3 The thermal barrier coating system 100 configuration reverses the positioning of HEC composition layer 40 and HEC composition layer 50. Figure 3 In this embodiment, the HEC composition layer 50 is deposited on the transition layer 30 by suspension plasma spraying (SPS), which may be used for illustrative purposes and is not intended to limit the implementation in any way. The transition layer, comprising 8 YSZ, is applied by APS, and the HEC composition layer 40 is deposited on the HEC composition layer 50 by at least one of air plasma spraying (APS), high-velocity oxygen fuel (HVOF), electron beam physical vapor deposition (EBPVD), and suspension plasma spraying (SPS) or by another suitable deposition process now known or subsequently developed.

[0080] Figure 4 A thermal barrier coating system 100 is shown having a protective layer 75 disposed on the outermost HEC composition layer 40 and HEC composition layer 50. The protective layer 75 may include at least one property to protect the thermal barrier coating 101. As embodied in this disclosure, layer 75 may provide the thermal barrier coating 101 with higher toughness, abrasion or wear protection properties, environmental protection performance, increased aerodynamics, smoother (lower Ra), corrosion and abrasion resistance properties, and resistance to corrosive chemicals, as well as other thermal barrier coating properties now known or subsequently desired.

[0081] According to another aspect of the embodiments, a method is provided for preparing an HEC composition for use as a thermal barrier coating. As embodied in this disclosure, the method can be used to deposit an HEC layer as part of a thermal barrier coating on a substrate or component, which benefits from high-temperature protection.

[0082] refer to Figure 5 The steps for preparing the HEC composition may include:

[0083] Step 1: Under controlled conditions, HEC raw materials (raw materials) are used to produce single-phase crystalline microstructured materials or multiphase HEC crystalline microstructured materials. Powder synthesis can be used to prepare HEC powder raw materials. Step 1 induces the evaluation of the powder phase to determine the phase composition. Subsequent separation of the desired single phase from other phases in the HEC powder raw materials will yield blends of HEC powder raw materials.

[0084] Step 2: Apply Hollow Oven Spherical Process (HOSP) to the HEC powder raw material. HOSP enhances the low-k properties of the HEC powder raw material. HOSP passes the HEC powder raw material through a heat source such as a plasma torch. The HEC powder raw material is then collected in a chamber. As illustrated in this disclosure, the chamber may contain water. However, other aspects of the embodiments may include other media in the chamber. Further heat treatment of the HEC raw material may also be performed in the chamber. Heat treatment of the HEC raw material can produce the desired HEC crystalline phase. Heat treatment of the HEC raw material can improve the strength of the HEC material with the crystalline phase.

[0085] Step 3: Various deposition processes can be used to deposit HEC materials with crystalline phases in layers on a substrate or prepared surface. Exemplary but not limiting deposition processes include air plasma spraying (APS), electron beam physical vapor deposition (EBPVD), and suspension plasma spraying (SPS), as well as other spray deposition methods now known or subsequently developed. The HEC material with crystalline phases can be deposited on an MCrAlX binder coating, where: M represents a metallic substance such as Fe, Co, or Ni, and X represents at least one of Y, Ti, Yb, and Ta. Step 3 can be enhanced by generating a dense vertical crack layer (DVC) in the HEC layer with crystalline phases, where the DVC layer improves the strain tolerance of the deposited HEC material with crystalline phases.

[0086] As illustrated in this disclosure, another aspect of the method provides a suspension plasma spraying (SPS) process in step 3. SPS enables the deposition of a dense layer of HEC material with a crystalline phase using HEC powder raw materials. Compared to some conventional thermal barrier coatings, the SPS process results in thermal barrier coatings with higher strength and toughness.

[0087] The deposition of the binder coating 20 and transition layer 30 of the thermal barrier coating system 100 can be accomplished by any deposition method now known or subsequently developed. The binder coating 20 is initially deposited on the substrate 10. The transition layer 30 is then deposited on the binder coating 20. The HEC layer 40 is then applied, followed by the application of the HEC layer 50 via SPS. Figure 2 Of course, as mentioned above, the order in which HEC layer 40 and HEC layer 50 are applied can be reversed. Figure 3 Furthermore, a protective layer 75 may be applied to the last applied HEC layer of the thermal barrier coating 101 in the thermal barrier coating system 100.

[0088] As illustrated in this disclosure, the benefits of HEC thermal barrier coatings include enhanced thermal insulation with good corrosion resistance. As illustrated in this disclosure, HEC thermal barrier coatings allow for higher gas turbine efficiency, increased reliability through improved thermal insulation, and thus increased TBC life relative to YSZ. Other benefits of HEC thermal barrier coatings, as illustrated in this disclosure, include reduced required cooling flow rates in the gas turbine, improved (longer) maintenance and repair intervals, and higher gas turbine operating temperatures.

[0089] The foregoing figures illustrate some associated processes according to several embodiments of the present disclosure. In this regard, each figure or block within the flowcharts of the figures represents a process associated with an embodiment of the method. It should also be noted that in some alternative embodiments, the actions mentioned in the figures or blocks may not occur in the order shown in the figures, or, for example, may actually be performed substantially simultaneously or in reverse order, depending on the actions involved. Moreover, those skilled in the art will recognize that additional blocks may be added to describe the process.

[0090] As used throughout the specification and claims, approximate language can be used to modify any quantitative expression that allows for variation without causing a change in its underlying function. Therefore, values ​​modified by one or more terms (such as “about,” “approximately,” and “substantially”) are not limited to specified exact values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. Range limitations may be combined and / or interchanged herein and throughout the specification and claims; unless the context or language otherwise indicates, these ranges are identified and include all subranges contained therein. The term “about” applied to a specific value within a range applies to both ends of the range and may indicate + / - 10% of the value unless otherwise dependent on the precision of the instrument measuring that value.

[0091] All means or steps plus functional elements in the following claims are intended to include any structure, material, action, and equivalent for performing a function in conjunction with other claimed elements of a particular claim. This disclosure has been described for purposes of illustration and description, but it is not intended to be exhaustive or to limit the disclosure to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. Embodiments have been selected and described to best explain the principles and practical application of this disclosure and to enable others skilled in the art to understand various embodiments of this disclosure with various modifications suitable for the intended particular use.

Claims

1. A high-entropy ceramic (HEC) composition (40), said high-entropy ceramic (HEC) composition (40) comprising: At least three different rare earth (RE) oxides; the at least three different rare earth oxides are fractions with equal molar numbers; and At least one of hafnium dioxide (HfO2) and zirconium dioxide (ZrO2), At least three different rare earth (RE) oxides include at least three of the following: Y₂O₃, La₂O₃, Gd₂O₃, Ce₂O₃, Nd₂O₃, Sm₂O₃, Yb₂O₃, and Er₂O₃, and, The molar fractions of the at least three different rare earth oxides are each 0.1 moles, and the molar fraction of at least one of HfO2 and ZrO2 is 0.7 moles; and The high-entropy ceramic (HEC) composition (40) is a crystalline high-entropy single-phase composition.

2. The high entropy ceramic (HEC) composition (40) according to claim 1, wherein the molar fractions of the at least three different rare earth oxides are each 0.067 mol, and the molar fraction of at least one of HfO2 and ZrO2 is 0.8 mol.

3. A thermal barrier coating (101), said thermal barrier coating (101) comprising: At least two thermal barrier coatings, wherein at least one of the at least two thermal barrier coatings comprises a high entropy ceramic (HEC) composition (40), the high entropy ceramic (HEC) composition (40) comprising: At least three different rare earth (RE) oxides; the at least three different rare earth oxides are fractions with equal molar numbers; and At least one of hafnium dioxide (HfO2) and zirconium dioxide (ZrO2), At least three different rare earth (RE) oxides include at least three of the following: Y₂O₃, La₂O₃, Gd₂O₃, Ce₂O₃, Nd₂O₃, Sm₂O₃, Yb₂O₃, and Er₂O₃, and, The molar fractions of the at least three different rare earth oxides are each 0.1 moles, and the molar fraction of at least one of HfO2 and ZrO2 is 0.7 moles; and The high-entropy ceramic (HEC) composition (40) is a crystalline high-entropy single-phase composition.

4. The thermal barrier coating (101) according to claim 3, wherein each of the at least three different rare earth oxides has an equal molar fraction of 0.067 mol, and at least one of HfO2 and ZrO2 has a molar fraction of 0.8 mol.

5. The thermal barrier coating (101) according to claim 3, wherein the thermal barrier coating (101) comprises a substrate (10), an adhesive coating (20) deposited on the substrate (10), a transition layer (30) deposited on the adhesive coating (20), a first high-entropy ceramic (HEC) composition layer (75) deposited on the transition layer (30), and a second high-entropy ceramic (HEC) composition layer (75) deposited on the first high-entropy ceramic (HEC) composition layer (75).

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