Functional barrier coating and related methods thereof

Abstract

A new class of multi-component rare earth multi-silicate materials has been created for use in harsh environments such as gas turbine engines. Moreover, by combining two-or-more rare earth disilicates the properties (for example, thermal expansion, thermal conductivity, etc.) can be tailored to fit specific applications, such as having a matching thermal expansion with that of silicon-based composites and a low thermal conductivity close to that of 1 W/m K. Applications can be extended for use with other material classes such as MCrAlY, MAX-phase, and refractory metal alloys, utilizing a thermal expansion of up to about 1510.sup.6/ C. By mixing of specific sets of rare earth disilicates it is possible to obtain a high entropy or entropy stabilized mixture, and utilize features such as sluggish diffusion, and more.

Claims

1. A barrier coating for application to a substrate material, said barrier coating comprising: a) a bond coat and a functional barrier, or b) a functional barrier; and wherein the functional barrier comprises: a multi-component rare earth multi-silicate comprising a composition represented by the following formula: (Y.sub.0.2Lu.sub.0.2Ho.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2, (Y.sub.0.2La.sub.0.2Sm.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2, or (Y.sub.0.2La.sub.0.2Lu.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2; and wherein the multi-component rare earth multi-silicate is characterized by at least one thermophysical or thermochemical property.

2. The barrier coating of claim 1, wherein the substrate material and/or bond coat comprises a silicon based material comprising: silicon, SiAlON, Si.sub.3N.sub.4, or SiC.

3. The barrier coating of claim 1, wherein the substrate material and/or bond coat comprises a MAX-phase material.

4. The barrier coating of claim 1, wherein the substrate material comprises a MCrAlY, where M is Ni or Co, or a high-entropy alloy material.

5. The barrier coating of claim 1, wherein the substrate material and/or bond coat comprises a refractory metal such as Nb, Ta, Mo, W, Re, or a high-entropy refractory alloy material.

6. The barrier coating of claim 1, wherein the substrate material comprises a nickel and/or cobalt-based superalloy.

7. The barrier coating of claim 1, wherein the barrier coating further comprises an intermediate coat.

8. The barrier coating of claim 7, wherein the intermediate coat comprises ZrO.sub.2, HfO.sub.2, or combinations thereof.

9. The barrier coating of claim 5, wherein the top layer comprises ZrO.sub.2, HfO.sub.2, a rare earth monosilicate, or combinations thereof.

10. The barrier coating of claim 1, wherein the multi-component rare earth multi-silicate is a single-phase compound above and below temperature of use.

11. The barrier coating of claim 1, wherein the multi-component rare earth multi-silicate transforms from a single-phase compound to a multi-phase compound when the temperature goes below temperature of use.

12. The barrier coating of claim 1, wherein the functional barrier is further characterized by a coefficient of thermal expansion that matches a coefficient of thermal expansion of the bond coat.

13. The barrier coating of claim 1, wherein the functional barrier is characterized by a coefficient of thermal expansion is from about 3.510.sup.6 C..sup.1 to about 1510.sup.6 C..sup.1.

14. The barrier coating of claim 1, wherein the barrier coating is a thermal barrier coating (TBC).

15. The barrier coating of claim 1, wherein the barrier coating is an environmental barrier coating (EBC).

16. The barrier coating of claim 1, wherein the barrier coating is an impact protective barrier layer or thermal shock protective layer.

17. The barrier coating of claim 1, wherein the at least one thermophysical or thermochemical property comprises: thermal conductivity, coefficient of thermal expansion, refractive index, density, chemical diffusivity, elastic modulus, or optical absorption.

18. The barrier coating of claim 1, wherein the at least one thermophysical or thermochemical property can be adjusted as specified by changing the combination of elements in the multi-component rare earth multi-silicate.

19. The barrier coating of claim 18, wherein the at least one thermophysical or thermochemical property to be adjusted is coefficient of thermal expansion.

20. The barrier coating of claim 18, wherein the at least one thermophysical or thermochemical property to be adjusted is thermal conductivity.

21. The barrier coating of claim 1, wherein the functional barrier is further characterized by a thermal conductivity of less than 5 W/(m*K) at 200 C.

22. The barrier coating of claim 1, wherein the functional barrier is further characterized by melting point of about 1600 C. or greater.

23. The barrier coating of claim 1, wherein the barrier coating is configured to be applied to a silicon-carbide based ceramic compound.

24. The barrier coating of claim 21, wherein the barrier coating is configured to be applied to a component of gas turbine engine.

25. The barrier coating of claim 1, wherein the barrier coating further comprises a top layer.

26. The barrier coating of claim 7, wherein the barrier coating further comprises a top layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The foregoing and other objects, features and advantages of the present invention, as well as the invention itself, will be more fully understood from the following description of preferred embodiments, when read together with the accompanying drawings.

(2) The accompanying drawings, which are incorporated into and form a part of the instant specification, illustrate several aspects and embodiments of the present invention and, together with the description herein, serve to explain the principles of the invention. The drawings are provided only for the purpose of illustrating select embodiments of the invention and are not to be construed as limiting the invention.

(3) FIG. 1 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating.

(4) FIG. 2 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating.

(5) FIG. 3 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating.

(6) FIG. 4 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating.

(7) FIG. 5 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating.

(8) FIGS. 6(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 1, examining the effect of mixing small radius rare-earth cation disilicates on thermal conductivity reduction while retaining a coefficient of thermal expansion (CTE) of about 410.sup.6 C..sup.1, using five (5) rare-earth disilicates (RE-DS) in an equi-molar ratio.

(9) FIGS. 7(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 2, examining the effect of mixing multi-phase rare earth disilicates (RE-DS) on coefficient of thermal expansion (CTE) and thermal conductivity, using five (5) rare-earth disilicates (RE-DS) in an equi-molar ratio.

(10) FIG. 8(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 3, further examining the effect of mixing various multi-phase rare earth disilicates (RE-DS) on coefficient of thermal expansion (CTE) and thermal conductivity, using five (5) rare-earth disilicates (RE-DS) in an equi-molar ratio.

(11) FIG. 9(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 4, examining the addition of a large radius rare-earth cation to the MCDS-1 mixture, using six (6) rare-earth disilicates (RE-DS) in an equi-molar ratio.

(12) FIG. 10(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 5, examining the addition of a medium radius rare-earth cation to the MCDS-1 mixture, using six (6) rare-earth disilicates (RE-DS) in an equi-molar ratio.

DETAILED DESCRIPTION OF ASPECTS OF EXEMPLARY EMBODIMENTS

(13) FIG. 1 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating 1 comprised of a substrate material 10 and functional barrier 30. In an embodiment, the substrate material 10 may be, but not limited thereto, any one or more of the following: silicon-based ceramic composite, silicon-based ceramic compound, MAX-phase, MCrAlY, refractory metal alloy (e.g., high-entropy), and nickel and/or cobalt-based superalloy.

(14) FIG. 2 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating 1 comprised of a substrate material 10, bond coat 20, and functional barrier 30. In an embodiment, the substrate material 10 may be, but not limited thereto, any one or more of the following: silicon-based ceramic composite, silicon-based ceramic compound, MAX-phase, refractory metal alloy (e.g., high-entropy), and nickel and/or cobalt-based superalloy. In an embodiment, the bond coat 20 may be, but not limited thereto, any one or more of the following: silicon, silicon-based ceramic compound, MAX-phase, MCrAlY, and refractory metal alloy (e.g., high-entropy).

(15) FIG. 3 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating 1 similar to FIG. 2 and further comprises and intermediate coating or layer 50.

(16) FIG. 4 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating 1 comprised of a substrate material 10, bond coat 20, functional barrier 30, and top coat or layer 40. In an embodiment, the substrate material 10 may be, but not limited thereto, any one or more of the following: silicon-based ceramic composite, silicon-based ceramic compound, MAX-phase, refractory metal alloy (e.g., high-entropy), and nickel and/or cobalt-based superalloy. In an embodiment, the bond coat 20 may be, but not limited thereto, any one or more of the following: silicon, silicon-based ceramic compound, MAX-phase, MCrAlY, and refractory metal alloy (e.g., high-entropy).

(17) FIG. 5 schematically illustrates a partial cross-sectional view of an embodiment of a barrier coating 1 similar to FIG. 4 and further comprises and intermediate coating or layer 50.

(18) Aspects of various embodiment of the barrier coating 1 which is disclosed herein may include a variety of layers and components. As used herein, references to the term bonded are to be understood to include direct and indirect bonding through another layer, such as a bondcoat 20 or an intermediate layer. In an embodiment, for example, the functional barrier 30 may be further characterized by a coefficient of thermal expansion that matches a coefficient of thermal expansion of the bond coat 20. In an embodiment, for example, the functional barrier 30 may be further characterized by a coefficient of thermal expansion that matches a coefficient of thermal expansion of the silicon-based composite. As used herein, references to the term matched or matches, in reference to a coefficient of thermal expansion, are to be understood to refer to a first layer, such as functional barrier 30, having a coefficient of thermal expansion within about +/15% of a coefficient of thermal expansion of a second layer, such as bond coat 20.

(19) Aspects of various embodiment of the barrier coating 1 which is disclosed herein may include a variety of deposition techniques of applying the various layers to other layers or components. For example, some deposition techniques for fabricating the barrier coating 1 and associated layers and components include, but not limited thereto, the following: electron beam physical vapor deposition (EB-PVD), electron beam directed vapor deposition (EB-DVD), electron beam co-axial plasma deposition (EB-CPD), electron beam spotless arc deposition (EB-SAD), atmospheric plasma spray (APS), high-velocity oxygen fuel spraying (HVOF), vacuum plasma spray (VPS), low-pressure plasma spray (LPPS), suspension plasma spray (SPS), physical vapor deposition (PVD), or plasma spray physical vapor deposition (PS-PVD). The deposition techniques disclosed in any of the cited references 1-33 that are hereby incorporated by reference herein in their entirety and may be employed within the context of the various embodiments provided herein.

(20) Multi-Component Rare Earth Multi-Silicate Material

(21) An aspect of an embodiment provides a multi-component rare earth multi-silicate. A non-limiting example of the multi-component rare earth multi-silicate is an entropy stabilized rare earth multi-silicate. A multi-component rare earth multi-silicate may comprise a composition represented by the following formula:
(X.sub.a1.sup.1X.sub.a2.sup.2 . . . X.sub.an.sup.n).sub.uO.sub.z-mSiO.sub.2; wherein: a.sub.1, a.sub.2, through a.sub.n can be equal to any number between 0 and 1, wherein the sum of a.sub.1+a.sub.2+ . . . +a.sub.n is equal to 1; n is at least 2; u is 1 or 2; z is 2 or 3; m is greater than 1; and X.sup.1, X.sup.2, through X.sup.n are selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Zr, and Ti; and wherein the multi-component rare earth multi-silicate is characterized by at least one thermophysical or thermochemical property.

(22) A non-limiting example of the multi-component rare earth multi-silicate may comprise a formula: (Y.sub.0.2La.sub.0.2Sm.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2, (Y.sub.0.2Lu.sub.0.2Ho.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2, Or (Y.sub.0.2La.sub.0.2Lu.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2.

(23) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property may comprise, but not limited thereto: thermal conductivity, coefficient of thermal expansion, refractive index, density, chemical diffusivity, elastic modulus, or optical absorption.

(24) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property can be adjusted as specified (or tuned) by changing the combination of elements in the multi-component rare earth multi-silicate.

(25) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property to be adjusted may be, but not limited thereto, thermal conductivity.

(26) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property to be adjusted may be, but not limited thereto, coefficient of thermal expansion.

(27) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property to be adjusted may be, but not limited thereto, refractive index.

(28) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property to be adjusted may be, but not limited thereto, optical absorption.

(29) For an embodiment of the multi-component rare earth multi-silicate the multi-component rare earth multi-silicate may be, but not limited thereto, characterized by a coefficient of thermal expansion from about 3.510.sup.6 C..sup.1 to about 1510.sup.6 C..sup.1.

(30) The present inventor notes that regarding aspects of various embodiments that the thermal expansion to design may be dependent on the exact combination of substrate material used and may be closely dependent on the exact application it is intended for.

(31) There may not be a single value to design for, and thus embodiments shall not be constrained to specific substrate/coating materials to a specific thermal expansion range. In an embodiment, a range of thermal expansion coefficients for the substrate material 10 (such as shown, for example but not limited thereto in FIGS. 1-5) to be implemented so as to tailor the material that may include, but not limited thereto, silicon carbide substrate material 10 from about 4.010.sup.6 C..sup.1 to about 5.510.sup.6 C..sup.1. In an embodiment, a range of thermal expansion coefficients for the substrate material 10 to be implemented so as to tailor the material that may include, but not limited thereto, nickel and/or cobalt based superalloy substrate material from about 9.010.sup.6 to about 15.010.sup.6 C..sup.1. In an embodiment, a range of thermal expansion coefficients for the substrate material 10 to be implemented so as to tailor the material that may include, but not limited thereto, MCrAlY substrate material from about 9.010.sup.6 C..sup.1 to about 15.010.sup.6 C..sup.1. In an embodiment, a range of thermal expansion coefficients for the substrate material 10 to be implemented so as to tailor the material that may include, but not limited thereto, MAX Phase (e.g. Ti2AlC or the like) substrate material from about 8.010.sup.6 C..sup.1 to about 11.010.sup.6 C..sup.1. In an embodiment, a range of thermal expansion coefficients for the substrate material 10 to be implemented so as to tailor the material that may include, but not limited thereto, refractory alloys substrate material from about 4.010.sup.6 C..sup.1 to about 10.010.sup.6 C..sup.1.

(32) For an embodiment of the multi-component rare earth multi-silicate the multi-component rare earth multi-silicate may be, but not limited thereto, characterized by a thermal conductivity of less than 5 W/(m*K) at or above 200 C.

(33) For an embodiment of the multi-component rare earth multi-silicate the multi-component rare earth multi-silicate may be, but not limited thereto, characterized by a melting point of about 1600 C. or greater.

(34) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property is adjusted for application of the multi-component rare earth multi-silicate in a barrier coating 1. For an embodiment of the multi-component rare earth multi-silicate the barrier coating 1 may be, but not limited thereto, a thermal barrier coating (TBC). For an embodiment of the multi-component rare earth multi-silicate the barrier coating 1 may be, but not limited thereto, an environmental barrier coating (EBC).

(35) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property may be adjusted for application of the multi-component rare earth multi-silicate that is, but not limited thereto, a component in a hypersonic leading edge.

(36) For an embodiment of the multi-component rare earth multi-silicate of claim the at least one thermophysical or thermochemical property may be adjusted for application of the multi-component rare earth multi-silicate that, but not limited thereto, a component in a fuel cell.

(37) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property may be adjusted for application of the multi-component rare earth multi-silicate that may be, but not limited thereto, a component in an impact protective barrier layer.

(38) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property may be adjusted for application of the multi-component rare earth multi-silicate that may be, but not limited thereto, a component in a shock protective layer.

(39) For an embodiment of the multi-component rare earth multi-silicate the at least one thermophysical or thermochemical property may be adjusted for application of the multi-component rare earth multi-silicate that may be, but not limited thereto, a component in an optical layer.

(40) For an embodiment of the multi-component rare earth multi-silicate the multi-component rare-earth multi-silicate transforms from a single-phase compound to a multi-phase compound when the temperature goes below temperature of use. For example, if a material is used in the range of 1000-1300 C., or solely at 1300 C., then if the temperature is lowered to, for example, room temperature, it drops below temperature of use. Other applications and environments for temperature of use are considered part of the various embodiments of the present invention, and may be employed within the context of the various embodiments of the present invention disclosed herein.

(41) For an embodiment of the multi-component rare earth multi-silicate the multi-component rare-earth multi-silicate is a single-phase compound that may be above and below temperature of use.

(42) For an embodiment of the multi-component rare earth multi-silicate the multi-component rare earth multi-silicate is for application in a barrier coating, wherein the barrier coating comprises at least one of, but not limited thereto, the following: a thermal barrier coating (TBC); an environmental barrier coating (EBC); an impact protective barrier layer; or thermal shock protective layer.

(43) General Barrier Coating with Multi-Component Rare Earth Multi-Silicate

(44) Referring to FIGS. 1-5, for example, an aspect of an embodiment provides a barrier coating 1 for application to a substrate material 10. For an embodiment of the barrier coating 1 the barrier coating 1 may comprise: a) a bond coat 20 and a functional barrier 30 or b) a functional barrier 30. For an embodiment, the functional barrier 30 may comprise a multi-component rare earth multi-silicate. A non-limiting example of the multi-component rare earth multi-silicate is an entropy stabilized, or high entropy, rare earth multi-silicate. The multi-component rare earth multi-silicate may comprise a composition represented by the following formula:
(X.sub.a1.sup.1X.sub.a2.sup.2 . . . X.sub.an.sup.n).sub.uO.sub.z-mSiO.sub.2; wherein: a.sub.1, a.sub.2, through a.sub.n can be equal to any number between 0 and 1, wherein the sum of a.sub.1+a.sub.2+ . . . +a.sub.n is equal to 1; n is at least 2; u is 1 or 2; z is 2 or 3; m is greater than 1; and X.sup.1, X.sup.2, through X.sup.n are selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Zr, and Ti; and wherein the multi-component rare earth multi-silicate is characterized by at least one thermophysical or thermochemical property.

(45) For an embodiment of the barrier coating 1 the substrate material 10 and/or bond coat 20 comprises a silicon based material comprising, but not limited thereto, the following: silicon, SiAlON, Si.sub.3N.sub.4, or SiC.

(46) For an embodiment of the barrier coating 1 the substrate material 10 and/or bond coat 20 may comprise, but not limited thereto, a MAX-phase material.

(47) For an embodiment of the barrier coating 1 the substrate material 10 comprises a MCrAlY, where M is Ni or Co, or a high-entropy alloy material.

(48) For an embodiment of the barrier coating 1 the substrate material 10 and/or bond coat 20 may comprise a refractory metal such as, but not limited thereto, Nb, Ta, Mo, W, Re, or a high-entropy refractory alloy material.

(49) For an embodiment of the barrier coating 1 the substrate material 10 may comprise, but not limited thereto, a nickel and/or cobalt-based superalloy.

(50) For an embodiment of the barrier coating 1 the barrier coating 1 may further comprise, but not limited thereto, an intermediate coat or layer 50.

(51) For an embodiment of the barrier coating 1 the intermediate coat or layer 50 may comprise ZrO.sub.2, HfO.sub.2, or combinations thereof.

(52) For an embodiment of the barrier coating 1 the barrier coating 1 may further comprise, but not limited thereto, a top layer or coat 40.

(53) For an embodiment of the barrier coating 1 the top layer 40 may comprise, but not limited thereto, the following ZrO.sub.2, HfO.sub.2, a rare earth monosilicate, or combinations thereof.

(54) For an embodiment of the barrier coating 1 the functional barrier 30 may comprise, but not limited thereto, a multi-component multi-silicate rare earth comprising a formula:
(Y.sub.0.2Lu.sub.0.2Ho.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2.

(55) For an embodiment of the barrier coating 1 the multi-component rare earth multi-silicate may be a single-phase compound above and below temperature of use.

(56) For an embodiment of the barrier coating 1 the multi-component rare earth multi-silicate transforms from a single-phase compound to a multi-phase compound when the temperature goes below temperature of use.

(57) For an embodiment of the barrier coating 1 the functional barrier 30 may be further characterized by a coefficient of thermal expansion that matches a coefficient of thermal expansion of the bond coat 20.

(58) For an embodiment of the barrier coating 1 the functional barrier 30 may be characterized by a coefficient of thermal expansion is from about 3.510.sup.6 C..sup.1 to about 1510.sup.6 C..sup.1.

(59) For an embodiment of the barrier coating 1 the barrier coating 1 may be, but not limited thereto, a thermal barrier coating (TBC).

(60) For an embodiment of the barrier coating 1 the barrier coating 1 may be, but not limited thereto, an environmental barrier coating (EBC).

(61) For an embodiment of the barrier coating 1 the barrier coating 1 may be, but not limited thereto, an impact protective barrier layer or thermal shock protective layer.

(62) For an embodiment of the barrier coating 1 the at least one thermophysical or thermochemical property may comprise, but not limited thereto, the following: thermal conductivity, coefficient of thermal expansion, refractive index, density, chemical diffusivity, elastic modulus, or optical absorption.

(63) For an embodiment of the barrier coating 1 the at least one thermophysical or thermochemical property can be adjusted as specified (or tuned) by changing the combination of elements in the multi-component rare earth multi-silicate.

(64) For an embodiment of the barrier coating 1 the at least one thermophysical or thermochemical property to be adjusted is coefficient of thermal expansion.

(65) For an embodiment of the barrier coating 1 the at least one thermophysical or thermochemical property to be adjusted is thermal conductivity.

(66) For an embodiment of the barrier coating 1 the functional barrier 30 may be further characterized by a thermal conductivity of less than 5 W/(m*K) at 200 C.

(67) For an embodiment of the barrier coating 1 the functional barrier 30 may be further characterized by melting point of about 1600 C. or greater.

(68) For an embodiment of the barrier coating 1 the barrier coating 1 may be configured to be applied to a silicon-carbide based ceramic compound.

(69) For an embodiment of the barrier coating 1 the barrier coating 1 may be configured to be applied to, but not limited thereto, a component of gas turbine engine.

(70) Method of Applying as a Barrier Coating

(71) Referring to FIGS. 1-5, for example, an aspect of an embodiment provides a method for applying a barrier coating 1 to a substrate material 10. An embodiment of the method may comprise: a) applying a bond coat 20 and a functional barrier 30 or b) applying a functional barrier 30. For an embodiment, the functional barrier 30 may comprise: a multi-component rare earth multi-silicate. A non-limiting example of the multi-component rare earth multi-silicate is an entropy stabilized, or high entropy, rare earth multi-silicate. The multi-component rare earth multi-silicate may comprise a composition represented by the following formula:
(X.sub.a1.sup.1X.sub.a2.sup.2 . . . X.sub.an.sup.n).sub.uO.sub.z-mSiO.sub.2; wherein: a.sub.1, a.sub.2, through a.sub.n can be equal to any number between 0 and 1, wherein the sum of a.sub.1+a.sub.2+ . . . +a.sub.n is equal to 1; n is at least 2; u is 1 or 2; z is 2 or 3; m is greater than 1; and X.sup.1, X.sup.2, through X.sup.n are selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Zr, and Ti; and wherein the multi-component rare earth multi-silicate is characterized by at least one thermophysical or thermochemical property.

(72) For an embodiment of the method the bond coat 20 is applied first, followed by the functional barrier 30.

(73) An embodiment of the method may further comprise, but not limited thereto, applying an intermediate coat 50.

(74) For an embodiment of the method the bond coat 20 may be applied first, followed by the intermediate coat 50, followed by the functional barrier 30.

(75) An embodiment of the method may further comprise, but not limited thereto, applying a top layer or coat 40.

(76) For an embodiment of the method the top layer or coat 40 may be the final layer applied.

(77) For an embodiment of the method the substrate material 10 and/or bond coat 20 may comprises a silicon-based material such as, but not limited thereto, silicon, SiAlON, Si.sub.3N.sub.4, or SiC.

(78) For an embodiment of the method the substrate material 10 and/or bond coat 20 may comprise a MAX-phase material.

(79) For an embodiment of the method the substrate material 10 and/or bond coat 20 may comprise a MCrAlY, where M is, but not limited thereto, Ni or Co, or a high-entropy alloy material.

(80) For an embodiment of the method the substrate material 10 and/or bond coat 20 may comprise a refractory metal such as, but not limited thereto, Nb, Ta, Mo, W, Re, or a high-entropy refractory alloy material.

(81) For an embodiment of the method the intermediate coat or layer 50 may comprise, but not limited thereto, ZrO.sub.2, HfO.sub.2, or combinations thereof.

(82) For an embodiment of the method the top coat or layer 40 may comprise, but not limited thereto, ZrO.sub.2, HfO.sub.2, a rare earth monosilicate, or combinations thereof.

(83) For an embodiment of the method the functional barrier 30 may comprise a multi-component rare earth multi-silicate comprising a formula, such as but not limited thereto, the following: (Y.sub.0.2La.sub.0.2Sm.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2, (Y.sub.0.2Lu.sub.0.2Ho.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2, or (Y.sub.0.2La.sub.0.2Lu.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2.

(84) For an embodiment of the method the barrier coating 1 may be applied to a silicon-carbide based ceramic material.

(85) For an embodiment of the method the barrier coating 1 may be applied to, but not limited thereto, a component of a gas turbine engine (or other types of components in other areas, environments, operations, systems, or applications; including any disclosed in any of the cited references 1-33 that are hereby incorporated by reference herein in their entirety and may be employed within the context of the various embodiments provided herein).

(86) For an embodiment of the method the multi-component rare earth multi-silicate may be a single-phase compound above and below temperature of use.

(87) For an embodiment of the method the multi-component rare earth multi-silicate transforms from a single-phase compound to a multi-phase compound when the temperature goes below temperature of use.

(88) For an embodiment of the method the functional barrier 30 may be further characterized by a coefficient of thermal expansion that matches a coefficient of thermal expansion of the silicon-based composite.

(89) For an embodiment of the method the functional barrier 30 may be further characterized by a coefficient of thermal expansion that is from about 3.510.sup.6 C..sup.1 to about 1510.sup.6 C..sup.1.

(90) For an embodiment of the method the barrier coating 1 may be a thermal barrier coating (TBC).

(91) For an embodiment of the method the barrier coating 1 may be, but not limited thereto, an impact protective barrier layer or thermal shock protective layer.

(92) For an embodiment of the method the barrier coating 1 may be, but not limited thereto, an environmental barrier coating (EBC).

(93) For an embodiment of the method the at least one thermophysical or thermochemical property may comprise, but not limited thereto, the following: thermal conductivity, coefficient of thermal expansion, refractive index, density, chemical diffusivity, elastic modulus, or optical absorption.

(94) For an embodiment of the method at least one thermophysical or thermochemical property to be adjusted as specified (or tuned) may be, but not limited thereto, the coefficient of thermal expansion.

(95) For an embodiment of the method at least one thermophysical or thermochemical property to be adjusted may be, but not limited thereto, thermal conductivity.

(96) For an embodiment of the method the functional barrier 30 may be further characterized by a thermal conductivity of less than 5 W/(m*K) at or above 200 C.

(97) For an embodiment of the method the functional barrier 30 may be further characterized by melting point of about 1600 C. or greater.

(98) For an embodiment of the method the barrier coating 1 may be applied by, but not limited thereto, the following: electron beam physical vapor deposition (EB-PVD), electron beam directed vapor deposition (EB-DVD), electron beam co-axial plasma deposition (EB-CPD), electron beam spotless arc deposition (EB-SAD), atmospheric plasma spray (APS), high-velocity oxygen fuel spraying (HVOF), vacuum plasma spray (VPS), low-pressure plasma spray (LPPS), suspension plasma spray (SPS), physical vapor deposition (PVD), or plasma spray physical vapor deposition (PS-PVD) (as well as a combination of one or more such application techniques).

(99) Silicon-based Ceramic Compound Barrier Coating

(100) Referring to FIGS. 1-5, for example, an aspect of an embodiment provides a silicon based ceramic compound comprising a barrier coating 1. In an embodiment, the barrier coating 1 may comprise: a) a bond coat 20 and a functional barrier 30 or b) a functional barrier 30. For an embodiment, the functional barrier 30 may comprise: a multi-component rare earth multi-silicate. A non-limiting example of the multi-component rare earth multi-silicate is an entropy stabilized, or high entropy, rare earth multi-silicate. The multi-component rare earth multi-silicate may comprise a composition represented by the following formula:
(X.sub.a1.sup.1X.sub.a2.sup.2 . . . X.sub.an.sup.n).sub.uO.sub.z-mSiO.sub.2; wherein: a.sub.1, a.sub.2, through a.sub.n can be equal to any number between 0 and 1, wherein the sum of a.sub.1+a.sub.2+ . . . +a.sub.n is equal to 1; n is at least 2; u is 1 or 2; z is 2 or 3; m is greater than 1; and X.sup.1, X.sup.2, through X.sup.n are selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Zr, and Ti; and wherein the multi-component rare earth multi-silicate is characterized by at least one thermophysical or thermochemical property.

(101) For an embodiment of the silicon based ceramic compound the bond coat 20 may comprise a silicon-based material comprising, but not limited thereto, the following: silicon, SiAlON, Si.sub.3N.sub.4, or SiC.

(102) For an embodiment of the silicon based ceramic compound the bond coat 20 may comprise a MAX-phase material.

(103) For an embodiment of the silicon based ceramic compound the bond coat 20 may comprise a MCrAlY, where M is, but not limited thereto, Ni or Co, or a high-entropy alloy material.

(104) For an embodiment of the silicon based ceramic compound the bond coat 20 may comprise a refractory metal such as, but not limited thereto, Nb, Ta, Mo, W, Re, or a high-entropy refractory alloy material.

(105) For an embodiment of the silicon based ceramic compound the barrier coating 1 may further comprise, but not limited thereto, an intermediate coat or layer 50.

(106) For an embodiment of the silicon based ceramic compound the intermediate coat or layer 50 may comprise, but not limited thereto, ZrO.sub.2, HfO.sub.2, or combinations thereof.

(107) For an embodiment of the silicon based ceramic compound the barrier coating 1 may further comprise, but not limited thereto, a top layer or coat 40.

(108) For an embodiment of the silicon based ceramic compound the top layer or coat 40 may comprise, but not limited thereto, ZrO.sub.2, HfO.sub.2, a rare earth monosilicate, or combinations thereof.

(109) For an embodiment of the silicon based ceramic compound the functional barrier 30 may comprise a multi-component rare earth multi-silicate comprising a formula including, but not limited thereto, the following: (Y.sub.0.2La.sub.0.2Sm.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2, (Y.sub.0.2Lu.sub.0.2Ho.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2, or (Y.sub.0.2La.sub.0.2Lu.sub.0.2Er.sub.0.2Yb.sub.0.2).sub.2O.sub.3-2SiO.sub.2.

(110) For an embodiment of the silicon based ceramic compound the silicon based ceramic compound may be, but not limited thereto, a component of a gas turbine engine (or other types of components in other areas, environments, operations, systems, or applications; including any disclosed in any of the cited references 1-33 that are hereby incorporated by reference herein in their entirety and may be employed within the context of the various embodiments provided herein).

(111) For an embodiment of the silicon based ceramic compound the multi-component rare earth multi-silicate may be a single-phase compound above and below temperature of use.

(112) For an embodiment of the silicon based ceramic compound the multi-component rare earth multi-silicate transforms from a single-phase compound to a multi-phase compound when the temperature goes below temperature of use.

(113) For an embodiment of the silicon based ceramic compound the functional barrier 30 may be further characterized by a coefficient of thermal expansion that matches a coefficient of thermal expansion of the silicon based composite.

(114) For an embodiment of the silicon based ceramic compound the functional barrier 30 may be further characterized by a coefficient of thermal expansion is from about 3.510.sup.6 C..sup.1 to about 1510.sup.6 C..sup.1.

(115) For an embodiment of the silicon based ceramic compound the barrier coating 1 may be, but not limited thereto, a thermal barrier coating (TBC).

(116) For an embodiment of the silicon based ceramic compound the barrier coating 1 may be, but not limited thereto, an environmental barrier coating (EBC).

(117) For an embodiment of the silicon based ceramic compound the barrier coating 1 may be, but not limited thereto, an impact protective barrier layer or thermal shock protective layer.

(118) For an embodiment of the silicon based ceramic compound the at least one thermophysical or thermochemical property may comprise, but not limited thereto, thermal conductivity, coefficient of thermal expansion, refractive index, density, chemical diffusivity, elastic modulus, or optical absorption.

(119) For an embodiment of the silicon based ceramic compound the at least one thermophysical or thermochemical property to be adjusted as specified (or tuned) may be coefficient of thermal expansion.

(120) For an embodiment of the silicon based ceramic compound the at least one thermophysical or thermochemical property to be adjusted as specified (or tuned) may be thermal conductivity.

(121) For an embodiment of the silicon based ceramic compound the functional barrier 30 may be further characterized by a thermal conductivity of less than 5 W/(m*K) at or above 200 C.

(122) For an embodiment of the silicon based ceramic compound the functional barrier 30 may be further characterized by melting point of about 1600 C. or greater.

(123) For an embodiment of the silicon based ceramic compound the barrier coating 1 may be deposited by, but not limited thereto, the following: electron beam physical vapor deposition (EB-PVD), electron beam directed vapor deposition (EB-DVD), electron beam co-axial plasma deposition (EB-CPD), electron beam spotless arc deposition (EB-SAD), atmospheric plasma spray (APS), high-velocity oxygen fuel spraying (HVOF), vacuum plasma spray (VPS), low-pressure plasma spray (LPPS), physical vapor deposition (PVD); suspension plasma spray (SPS), or plasma spray physical vapor deposition (PS-PVD) (as well as a combination of one or more such deposition techniques).

EXAMPLES

(124) Practice of an aspect of an embodiment (or embodiments) of the invention will be still more fully understood from the following examples and experimental results, which are presented herein for illustration only and should not be construed as limiting the invention in any way.

Example and Experimental Results No. 1

(125) FIG. 6(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 1, examining the effect of mixing small radius rare-earth cation disilicates on thermal conductivity reduction while retaining a coefficient of thermal expansion (CTE) of about 410.sup.6 C..sup.1, using five (5) rare-earth disilicates (RE-DS) in an equi-molar ratio. Accordingly, it is demonstrated that the properties (for example, thermal conductivity, etc.) can be tailored to fit specific applications. In a non-limiting approach, the experiment included: cold-pressed oxides at 40 MPa, anneal at 1500 C. for 72 hours; 91.6% density; thermal conductivity measured using hot disc method=2.20.54 W/m K; and CTE measured by dilatometry=4.3510.sup.6/ C.

Example and Experimental Results No. 2

(126) FIG. 7(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 2, examining the effect of mixing multi-phase rare earth disilicates (RE-DS) on coefficient of thermal expansion (CTE) and thermal conductivity, using five (5) rare-earth disilicates (RE-DS) in an equi-molar ratio. Accordingly, it is demonstrated that the properties (for example, thermal expansion, thermal conductivity, etc.) can be tailored to fit specific applications. In a non-limiting approach, the experiment included: cold-pressed oxides at 40 MPa, annealed at 1500 C. for 72 hours; 86.4% density; thermal conductivity=1.130.15 W/m K; and CTE=7.0510.sup.6/ C.

Example and Experimental Results No. 3

(127) FIG. 8(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 3, further examining the effect of mixing various multi-phase rare earth disilicates (RE-DS) on coefficient of thermal expansion (CTE) and thermal conductivity, using five (5) rare-earth disilicates (RE-DS) in an equi-molar ratio. Accordingly, it is demonstrated that the properties (for example, thermal expansion, thermal conductivity, etc.) can be tailored to fit specific applications. In a non-limiting approach, the experiment included: cold-pressed oxides at 40 MPa, annealed at 1500 C. for 72 hours; 92.7% density; thermal conductivity=1.570.44 W/m K; and CTE=6.5810.sup.6 C..sup.1.

Example and Experimental Results No. 4

(128) FIG. 9(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 4, examining the addition of a large radius rare-earth cation to the MCDS-1 mixture, using six (6) rare-earth disilicates (RE-DS) in an equi-molar ratio. Accordingly, it is demonstrated that the properties (for example, thermal expansion, thermal conductivity, etc.) can be tailored to fit specific applications. In a non-limiting approach, the experiment included: cold-pressed oxides at 40 MPa, annealed at 1500 C. for 72 hours; 97.3% density; thermal conductivity=1.80 W/m K; and CTE=6.5410.sup.6 C..sup.1.

Example and Experimental Results No. 5

(129) FIG. 10(A)-(D) are screenshots of the experimental results for a multi-component disilicate (MCDS), sample no. 5, examining the addition of a medium radius rare-earth cation to the MCDS-1 mixture, using six (6) rare-earth disilicates (RE-DS) in an equi-molar ratio. Accordingly, it is demonstrated that the properties (for example, thermal expansion, thermal conductivity, etc.) can be tailored to fit specific applications. In a non-limiting approach, the experiment included: cold-pressed oxides at 40 MPa, annealed at 1500 C. for 72 hours; 52.3% density; thermal conductivity=1.78 W/m K; and CTE=5.6410.sup.6 C..sup.1.

REFERENCES

(130) The devices, systems, articles, components, apparatuses, compositions, materials, machine readable medium, computer program products, and methods of various embodiments of the invention disclosed herein may utilize aspects (e.g., devices, systems, articles, components, apparatuses, compositions, materials, machine readable medium, computer program products, and methods) disclosed in the following references, applications, publications and patents and which are hereby incorporated by reference herein in their entirety, and which are not admitted to be prior art with respect to the present invention by inclusion in this section: 1. U.S. Patent Application Publication No. US 2017/0236692 A1, Wadley, et al., Coaxial Hollow Cathode Plasma Assisted Directed Vapor Deposition and Related Method Thereof, Aug. 17, 2017. 2. U.S. Pat. No. 9,640,369 B2, Wadley, et al., Coaxial Hollow Cathode Plasma Assisted Directed Vapor Deposition and Related Method Thereof, May 2, 2017. 3. 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(131) Unless clearly specified to the contrary, there is no requirement for any particular described or illustrated activity or element, any particular sequence or such activities, any particular size, speed, material, duration, contour, dimension or frequency, or any particularly interrelationship of such elements. Moreover, any activity can be repeated, any activity can be performed by multiple entities, and/or any element can be duplicated. Further, any activity or element can be excluded, the sequence of activities can vary, and/or the interrelationship of elements can vary. It should be appreciated that aspects of the present invention may have a variety of sizes, contours, shapes, compositions and materials as desired or required.

(132) In summary, while the present invention has been described with respect to specific embodiments, many modifications, variations, alterations, substitutions, and equivalents will be apparent to those skilled in the art. The present invention is not to be limited in scope by the specific embodiment described herein. Indeed, various modifications of the present invention, in addition to those described herein, will be apparent to those of skill in the art from the foregoing description and accompanying drawings. Accordingly, the invention is to be considered as limited only by the spirit and scope of the following claims, including all modifications and equivalents.

(133) Still other embodiments will become readily apparent to those skilled in this art from reading the above-recited detailed description and drawings of certain exemplary embodiments. It should be understood that numerous variations, modifications, and additional embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of this application. For example, regardless of the content of any portion (e.g., title, field, background, summary, abstract, drawing figure, etc.) of this application, unless clearly specified to the contrary, there is no requirement for the inclusion in any claim herein or of any application claiming priority hereto of any particular described or illustrated activity or element, any particular sequence of such activities, or any particular interrelationship of such elements. Moreover, any activity can be repeated, any activity can be performed by multiple entities, and/or any element can be duplicated. Further, any activity or element can be excluded, the sequence of activities can vary, and/or the interrelationship of elements can vary. Unless clearly specified to the contrary, there is no requirement for any particular described or illustrated activity or element, any particular sequence or such activities, any particular size, speed, material, dimension or frequency, or any particularly interrelationship of such elements. Accordingly, the descriptions and drawings are to be regarded as illustrative in nature, and not as restrictive. Moreover, when any number or range is described herein, unless clearly stated otherwise, that number or range is approximate. When any range is described herein, unless clearly stated otherwise, that range includes all values therein and all sub ranges therein. Any information in any material (e.g., a United States/foreign patent, United States/foreign patent application, book, article, etc.) that has been incorporated by reference herein, is only incorporated by reference to the extent that no conflict exists between such information and the other statements and drawings set forth herein. In the event of such conflict, including a conflict that would render invalid any claim herein or seeking priority hereto, then any such conflicting information in such incorporated by reference material is specifically not incorporated by reference herein.