Three-dimensional woven ceramic matrix composites

Abstract

A gas turbine engine component, comprises a densified three-dimensional woven ceramic matrix composite comprising the shape of the gas turbine engine component, the densified three-dimensional woven ceramic matrix composite further comprises a three-dimensional woven structure comprising a densified ceramic matrix disposed on, within and throughout a three-dimensional weave comprising at least one inorganic fiber comprising at least one multilayer coating material structure disposed thereupon, wherein the at least one multilayer coating material structure comprises at least one first interface coating material layer comprising a boron nitride; at least one coating material layer comprising a silicon nitride; at least one second interface coating material layer comprising the boron nitride; and at least one third interface coating material layer comprising a Si3N4-BN multilayer coating having one or more alternating layers comprising at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.

Description

RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01THREE-DIMENSIONAL WOVEN CERAMIC MATRIX COMPOSITESCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Provisional Patent Application No. 63 / 678,284 filed on August 1, 2024, which is hereby incorporated by reference for all purposes as if fully set forth herein.FIELD OF THE INVENTION

[0001] The subject matter disclosed herein relates to ceramic matrix composites (CMCs) and, in particular, to three-dimensional woven ceramic matrix composites.BACKGROUND OF THE INVENTION

[0002] Three-dimensional woven fabrics are fabrics that may be formed to near net shapes with considerable thickness. There is no need for layering to create a part, because a single fabric provides the full three-dimensional reinforcement. The three-dimensional woven fabric is a variant of the two-dimensional weaving process, and three-dimensional woven fabric is an extension of the very old technique of creating double and triple woven cloth. Fibers placed in the thickness direction are called z-fiber, warp weaver, or binder fiber for three-dimensional woven fabrics. More than one layer of fabric may be woven at the same time, and z-fiber may interlace warp and weft fibers of different layers during the process. At the end of the weaving process, an integrated three-dimensional woven structure, which may have a considerable thickness, can be produced. Three-dimensional woven structures may create composite materials with fiber volume fractions to 50%.

[0003] For instance, angle-interlock three-dimensional woven structures are one type of three- dimensional woven structures that are common. In the interlock structures, fibers may be woven from one layer of fibers to another and then back to the original layer to lock adjacent layers to each other. In complex interlock structures, fibers may be woven at specified points into severalRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 layers in order to join multiple layers. These structures have a great advantage over laminated materials because of their excellent resistance to layer delamination.

[0004] By using jacquard woven techniques such as bifurcation, three-dimensional woven preforms can be created into nearly endless shapes. The microstructure of a three-dimensional woven composite may be determined by the fiber architecture to the woven preform and weaving process, and the process of consolidation. When compared to a two-dimensional composite, the impact resistance, compression after impact, and delamination control is significantly improved with a three-dimensional composite without significantly reducing the mechanical properties along the plane.

[0005] However, various defects may be inadvertently created during the three-dimensional weaving process that may possibly degrade the in-plane, through-thickness, and impact properties of the resultant three-dimensional composite.SUMMARY OF THE INVENTION

[0006] According to an embodiment of the present disclosure, there is provided a three- dimensional woven ceramic matrix composite, comprising a densified three-dimensional woven structure comprising a densified ceramic matrix disposed on, within and throughout a three- dimensional weave comprising at least one inorganic fiber comprising at least one multilayer coating material structure disposed thereupon, wherein the at least one multilayer coating material structure comprises at least one first interface coating material layer comprising a boron nitride; at least one coating material layer comprising a silicon nitride; at least one second interface coating material layer comprising the boron nitride; and at least one third interface coating material layer comprising a SisN^BN multilayer coating having one or more alternating layers comprising at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0007] According to another embodiment of the present disclosure, there is provided a method for manufacturing a three-dimensional woven ceramic matrix composite, comprising the steps of providing at least one inorganic fiber; fabricating a three-dimensional woven structure using the at least one inorganic fiber; forming a multilayered coating material structure on each inorganic fiber of the three-dimensional woven structure, according to the following steps; disposing at least one first interface coating material layer on an exterior surface of each of the fibers to form at least one interface coated fiber, disposing at least one coating material layer on the at least one first interface coating material layer, disposing at least one second interface coating material layer on the at least one coating material layer, disposing at least one third interface coating material layer onto the at least one second interface coating material layer to form the multilayered coating material structure on each fiber; disposing at least one ceramic matrix coating material on the multilayered coating material structure of each fiber to form a three-dimensional woven ceramic matrix composite preform; and densifying the at least one ceramic matrix coating material to form a densified three-dimensional woven ceramic matrix composite comprising a densified ceramic matrix, wherein the at least one first interface coating and the at least one second interface coating comprise boron nitride, wherein the at least one coating material layer comprises a silicon nitride, and wherein the at least one third interface coating material layer comprises a Si3N4-BN multilayer coating having one or more alternating layers comprising at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.

[0008] According to yet another embodiment of the present disclosure, there is provided a gas turbine engine component, comprising a densified three-dimensional woven ceramic matrix composite comprising the shape of the gas turbine engine component, the densified three- dimensional woven ceramic matrix composite further comprising a three-dimensional woven structure comprising a densified ceramic matrix disposed on, within and throughout a three- dimensional weave comprising at least one inorganic fiber comprising at least one multilayer coating material structure disposed thereupon, wherein the at least one multilayer coatingRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 material structure comprises at least one first interface coating material layer comprising a boron nitride; at least one coating material layer comprising a silicon nitride; at least one second interface coating material layer comprising the boron nitride; and at least one third interface coating material layer comprising a SisN^BN multilayer coating having one or more alternating layers comprising at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.

[0009] According to yet another embodiment of the present disclosure, there is provided a gas turbine engine, comprising at least one gas turbine engine component comprising a densified three-dimensional woven ceramic matrix composite, the densified three-dimensional woven ceramic matrix composite further comprising a three-dimensional woven structure comprising a densified ceramic matrix disposed on, within and throughout a three-dimensional weave comprising at least one inorganic fiber comprising at least one multilayer coating material structure disposed thereupon, wherein the at least one multilayer coating material structure comprises at least one first interface coating material layer comprising a boron nitride; at least one coating material layer comprising a silicon nitride; at least one second interface coating material layer comprising the boron nitride; and at least one third interface coating material layer comprising a SisN^BN multilayer coating having one or more alternating layers comprising at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.

[0010] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven ceramic matrix composite further comprising at least one layer of silicon nitride disposed adjacent the boron nitride layer and between the boron nitride layer and the SisN^BN multilayer coating.

[0011] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven ceramic matrix composite furtherRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 comprising at least one additional layer of boron nitride disposed adjacent the silicon nitride layer and between the silicon nitride layer and the SisN^BN multilayer coating.

[0012] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the first thickness is approximately 2 nanometers to approximately 30 nanometers.

[0013] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the second thickness is approximately 2 nanometers to approximately 30 nanometers.

[0014] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the SisIX -BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.

[0015] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the SisIX -BN multilayer coating is uniform throughout the coated substrate, and a ratio of a thickness of the boron nitride layer of the SisIX -BN multilayer coating to a thickness of the silicon nitride layer of the SiaN^BN multilayer coating comprises approximately 1 to approximately 4.

[0016] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven ceramic matrix composite further comprising at least one layer of silicon carbide disposed adjacent the SisIXk-BN multilayer coating and opposite the at least one layer of boron nitride.

[0017] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one inorganic fiber comprises silicon carbide.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0018] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises at least one of the following: turbostratic boron nitride, amorphous boron nitride, and hexagonal boron nitride.

[0019] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises a low temperature amorphous or turbostratic boron nitride, a high temperature hexagonal boron nitride, or both a low temperature amorphous or turbostratic boron nitride and a high temperature hexagonal boron nitride.

[0020] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven ceramic matrix composite further comprising at least one additional coating material layer comprising a silicon-doped boron nitride.

[0021] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one third interface coating material layer comprises a thickness of approximately 50 nm to approximately 300 nm.

[0022] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises either a high temperature hexagonal boron nitride layer or a multilayer sequence comprising at least one layer of a low temperature amorphous or turbostratic boron nitride and at least one layer of carbon, wherein the multilayer sequence further comprises at least one inner layer comprising a formula: Cxi-(BN- C)X-(BN)X2 where x is 2, 3, 4 or 5; and, xi and X2 are each independently 0 or 1.

[0023] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of low temperature amorphous or turbostratic boron nitride comprises a thickness of approximately 20 nm to approximately 200 nm.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0024] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a thickness of greater than 0 to less than approximately 10 nm.

[0025] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a continuous form, a discontinuous form or a mixture of a continuous form and a discontinuous form.

[0026] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a pyrolytic carbon.

[0027] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the densified ceramic matrix comprises a silicon carbide.

[0028] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven structure comprises at least one of the following: angle interlock layer-to-layer, angle interlock through-the-thickness, orthogonal weave, and combinations comprising at least one of the foregoing.

[0029] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one first interface coating material layer comprises a thickness of approximately 10 nm to approximately 500 nm.

[0030] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one coating material layer comprises a thickness of approximately 10 nm to approximately 50 nm.

[0031] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven ceramic matrix composite further comprising at least one thermal barrier coating layer on the densified three-dimensional woven structure.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0032] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven ceramic matrix composite further comprising at least one environmental barrier coating layer on the densified three-dimensional woven structure.

[0033] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, densifying comprises any one of the following densification techniques: chemical vapor infiltration, melt-infiltration, polymer infiltration and pyrolysis, and combinations comprising at least one of the foregoing.

[0034] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, disposing comprises any one of the following techniques: chemical vapor infiltration, chemical vapor deposition, atomic layer deposition, and combinations comprising any one of the foregoing.

[0035] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the method further comprising the step of disposing at least one thermal barrier coating layer on the densified three-dimensional woven ceramic matrix.

[0036] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the method further comprising the step of disposing at least one thermal barrier coating layer and at least one environmental barrier coating layer, in sequence or in opposite sequence, on the densified three-dimensional woven ceramic matrix.

[0037] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises either a high temperature hexagonal boron nitride layer or a multilayer sequence comprising at least one layer of a low temperature amorphous or turbostratic boron nitride and at least one layer of carbon, wherein the multilayer sequence further comprises at least one inner layer comprising a formula: Cxi-(BN- C)X-(BN)X2 where x is 2, 3, 4 or 5; and, xi and X2 are each independently 0 or 1.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0038] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of low temperature amorphous or turbostratic boron nitride comprises a thickness of approximately 20 nm to approximately 200 nm.

[0039] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a thickness of greater than 0 to less than approximately 10 nm.

[0040] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a pyrolytic carbon.

[0041] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a continuous form, a discontinuous form or a mixture of a continuous form and a discontinuous form.

[0042] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one first interface coating material layer is disposed at a thickness of approximately 10 nm to approximately 500 nm.

[0043] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one coating material layer is disposed at a thickness of approximately 10 nm to approximately 50 nm.

[0044] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the method further comprisingthe step of disposing at least one third interface coating material layer comprising a silicon-doped boron nitride.

[0045] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one third interface coating material layer is disposed at a thickness of approximately 50 nm to approximately 300 nm.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0046] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the method further comprising at least one layer of silicon nitride disposed adjacent the boron nitride layer and between the boron nitride layer and the Si3N4-BN multilayer coating.

[0047] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the method further comprising at least one additional layer of boron nitride disposed adjacent the silicon nitride layer and between the silicon nitride layer and the SialX -BN multilayer coating.

[0048] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the first thickness is approximately 2 nanometers to approximately 30 nanometers.

[0049] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the second thickness is approximately 2 nanometers to approximately 30 nanometers.

[0050] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the SijN^BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.

[0051] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the SisIX -BN multilayer coating is uniform throughout the coated substrate, and a ratio of a thickness of the boron nitride layer of the SisIX -BN multilayer coating to a thickness of the silicon nitride layer of the SiaN^BN multilayer coating comprises approximately 1 to approximately 4..

[0052] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the method further comprising at least one layer of siliconRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 carbide disposed adjacent the SiaN^BN multilayer coating and opposite the at least one layer of boron nitride.

[0053] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine component further comprises at least one layer of silicon nitride disposed adjacent the boron nitride layer and between the boron nitride layer and the Si3N4-BN multilayer coating.

[0054] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine component further comprises at least one additional layer of boron nitride disposed adjacent the silicon nitride layer and between the silicon nitride layer and the S13N4-BN multilayer coating.

[0055] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the first thickness is approximately 2 nanometers to approximately 30 nanometers.

[0056] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the second thickness is approximately 2 nanometers to approximately 30 nanometers.

[0057] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the SisN^BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.

[0058] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the SisIX -BN multilayer coating is uniform throughout the coated substrate, and a ratio of a thickness of the boron nitride layer of the SisIX -BN multilayer coating to a thickness of the silicon nitride layer of the SisN^BN multilayer coating comprises approximately 1 to approximately 4.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0059] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine component further comprises at least one layer of silicon carbide disposed adjacent the SisN^BN multilayer coating and opposite the at least one layer of boron nitride.

[0060] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one inorganic fiber comprises silicon carbide.

[0061] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises at least one of the following: turbostratic boron nitride, amorphous boron nitride, and hexagonal boron nitride.

[0062] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises a low temperature amorphous or turbostratic boron nitride, a high temperature hexagonal boron nitride, or both a low temperature amorphous or turbostratic boron nitride and a high temperature hexagonal boron nitride.

[0063] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine component further comprises at least one additional coating material layer comprising a silicon-doped boron nitride.

[0064] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one additional coating material layer comprises a thickness of approximately 50 nm to approximately 300 nm.

[0065] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises either a high temperature hexagonal boron nitride layer or a multilayer sequence comprising at least one layer of a low temperature amorphous or turbostratic boron nitride and at least one layer of carbon, whereinRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 the multilayer sequence further comprises at least one inner layer comprising a formula: Cxi-(BN- C)X-(BN)X2 where x is 2, 3, 4 or 5; and, Xi and X2 are each independently 0 or 1.

[0066] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of low temperature amorphous or turbostratic boron nitride comprises a thickness of approximately 20 nm to approximately 200 nm.

[0067] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a thickness of greater than 0 to less than approximately 10 nm.

[0068] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a continuous form, a discontinuous form or a mixture of a continuous form and a discontinuous form.

[0069] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a pyrolytic carbon.

[0070] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the densified ceramic matrix comprises a silicon carbide.

[0071] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven structure comprises at least one of the following: angle interlock layer-to-layer, angle interlock through-the-thickness, orthogonal weave, and combinations comprising at least one of the foregoing.

[0072] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one first interface coating material layer comprises a thickness of approximately 10 nm to approximately 500 nm.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0073] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one coating material layer comprises a thickness of approximately 10 nm to approximately 50 nm.

[0074] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine component further comprises at least one thermal barrier coating layer on the densified three-dimensional woven ceramic matrix composite.

[0075] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine component further comprises at least one environmental barrier coating layer on the densified three-dimensional woven ceramic matrix composite.

[0076] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine component further comprises at least one thermal barrier coating layer and at least one environmental barrier coating layer, in sequence or in opposite sequence, on the densified three-dimensional woven ceramic matrix composite.

[0077] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine further comprises at least one layer of silicon nitride disposed adjacent the boron nitride layer and between the boron nitride layer and the SisIX -BN multilayer coating.

[0078] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, further comprising at least one additional layer of boron nitride disposed adjacent the silicon nitride layer and between the silicon nitride layer and the SisIX -BN multilayer coating.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0079] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the first thickness is approximately 2 nanometers to approximately 30 nanometers.

[0080] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the second thickness is approximately 2 nanometers to approximately 30 nanometers.

[0081] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the SisN^BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.

[0082] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the SisN^BN multilayer coating is uniform throughout the coated substrate, and a ratio of a thickness of the boron nitride layer of the SisIX -BN multilayer coating to a thickness of the silicon nitride layer of the SiaN^BN multilayer coating comprises approximately 1 to approximately 4.

[0083] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine further comprising at least one layer of silicon carbide disposed adjacent the SisIX -BN multilayer coating and opposite the at least one layer of boron nitride.

[0084] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, wherein the at least one inorganic fiber comprises silicon carbide.

[0085] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises at least one of the following: turbostratic boron nitride, amorphous boron nitride, and hexagonal boron nitride.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0086] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises a low temperature amorphous or turbostratic boron nitride, a high temperature hexagonal boron nitride, or both a low temperature amorphous or turbostratic boron nitride and a high temperature boron nitride.

[0087] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the densified ceramic matrix comprises a silicon carbide.

[0088] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the three-dimensional woven structure comprises at least one of the following: angle interlock layer-to-layer, angle interlock through-the-thickness, orthogonal weave, and combinations comprising at least one of the foregoing.

[0089] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one first interface coating material layer comprises a thickness of approximately 10 nm to approximately 500 nm.

[0090] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one coating material layer comprises a thickness of approximately 10 nm to approximately 50 nm.

[0091] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine further comprising at least one thermal barrier coating layer on the densified three-dimensional woven ceramic matrix composite.

[0092] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine further comprising at least one environmental barrier coating layer on the densified three-dimensional woven ceramic matrix composite.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0093] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine further comprising at least one thermal barrier coating layer and at least one environmental barrier coating layer, in sequence or in opposite sequence, on the densified three-dimensional woven ceramic matrix composite.

[0094] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the gas turbine engine further comprising at least one additional coating material layer further comprises a silicon-doped boron nitride.

[0095] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one additional coating material layer comprises a thickness of approximately 50 nm to approximately 300 nm.

[0096] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the boron nitride comprises either a high temperature hexagonal boron nitride or a multilayer sequence comprising at least one layer of a low temperature amorphous or turbostratic boron nitride and at least one layer of carbon, wherein the multilayer sequence further comprises at least one inner layer comprising a formula: Cxi-(BN- C)X-(BN)X2 where x is 2, 3, 4 or 5; and, xi and X2 are each independently 0 or 1.

[0097] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of low temperature amorphous or turbostratic boron nitride comprises a thickness of approximately 20 nm to approximately 200 nm.

[0098] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a thickness of greater than 0 to less than approximately 10 nm.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0099] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a continuous form, a discontinuous form or a mixture of a continuous form and a discontinuous form.

[0100] In further embodiments of the present disclosure, including further embodiments of the above exemplary embodiments, the at least one layer of carbon comprises a pyrolytic carbon.BRIEF DESCRIPTION OF FIGURES

[0101] The features of the disclosure believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The disclosure itself, however, both as to organization and method of operation, can best be understood by reference to the description of the preferred embodiment(s) which follows, taken in conjunction with the accompanying drawings in which:

[0102] FIG. 1 is an exemplary three-dimensional woven ceramic matrix composite.

[0103] FIG. 2 is an illustration of a cross-sectional view of an inorganic fiber having an exemplary multilayer coating structure disposed on an exterior surface of the fiber.

[0104] FIG. 3 is a flowchart illustrating an exemplary method for fabricating three- dimensional woven ceramic matrix composites.DETAILED DESCRIPTION OF THE INVENTION

[0105] The embodiments of the present disclosure can comprise, consist of, and consist essentially of the features and / or steps described herein, as well as any of the additional or optional ingredients, components, steps, or limitations described herein or would otherwise be appreciated by one of skill in the art. It is to be understood that all concentrations disclosedRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 herein are by weight percent (wt. %.) based on a total weight of the composition unless otherwise indicated.

[0106] As used herein, a "coated preform" or "coated substrate" refers to an interface coated ceramic fiber preform or an interface coated ceramic fiber substrate. As also used herein, a "partially densified CMC" or "partially densified ceramic matrix composite" refers to a coated substrate or preform that includes a structural support material layer that facilitates rigidization of the preform to become self-supporting, also known as a rigidized coated substrate or rigidized coated preform. As also used further herein, a "ceramic matrix composite" or "CMC" refers to a matrix infiltrated into the coated substrate or coated preform or alternatively, a matrix infiltrated into the rigidized partially densified CMC.

[0107] Referring to FIG. 1, exemplary three-dimensional woven ceramic matrix composites disclosed herein may include a three-dimensional woven structure fabricated by a three-dimensional weaving loom. Representative three-dimensional woven structures for use in three-dimensional woven ceramic matrix composites may include, but are not limited to, angle interlock layer-to-layer, angle interlock through-the-thickness, and three-dimensional orthogonal; individually, and combinations thereof. For example, the exemplary three- dimensional woven structure illustrated in FIG. 1 is utilized in fabricating ceramic composites, metal matrix composites, and organic matrix composites.

[0108] In at least one embodiment, three-dimensional woven structure 100 may include at least three sets of fibers, e.g., +bias and / or -bias fibers (also referred to as ±bias fibers or +warp fibers) 110 relative to the spanwise thickness of the structure 100; and, filling fibers 120, also known as fill stuffers or fillers; alone or in combinations thereof. ±Bias fibers 110 may be oriented through and across the span of the thickness of the weave. Each ±bias fiber 110 may be oriented until coming to the exterior top or exterior bottom surfaces, respectively, of the weave. In at least one embodiment, each ±bias fiber 110 may be moved towards exterior top or exterior bottom surfaces, respectively, until the respective ±bias fiber 110 reaches an edge of the weave.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01In at least one other embodiment, each ±bias fiber 110 may be moved towards exterior top or exterior bottom surfaces, respectively, until approaching a filling fiber 120. ±Bias fibers 110 may be locked by several filling fibers 120 according to the number of layers. Rather than merely fabricate a single fibertow orfiber bundle, the three-dimensional woven structure may comprise a plurality of fiber tows or fiber bundles woven together into a desired near net shape. With respect to near net shapes, through-the-thickness weaves may possess three-dimensional woven architectures exhibiting various shapes and dimensions.

[0109] When considering fiber properties, any inorganic fibers suitable for use in ceramic matrix composites may be utilized. For example, suitable inorganic fibers may include, but are not limited to, silicon carbide (SiC) fibers. Suitable SiC fibers for use herein may include, but are not limited to, Sylramic fibers commercially available from COI Ceramics, San Diego, California; Hi-Nicalon™ Type S and Hi-Nicalon™ fibers commercially available from Nippon Carbon Co., Ltd., Tokyo, Japan; Tyranno Fibers® commercially available from UBE Corporation, Tokyo, Japan; Nicalon™ fibers also commercially available from COI Ceramics, San Diego, California; and, Nextel™ 720 fibers commercially available from 3M®, St. Paul, Minnesota; individually, and combinations thereof. The SiC fibers may be coated with at least one coating layer or forming a multilayer coating structure thereon before or after the weaving process. While fabricating additional coating layers requires additional processing steps, the exemplary resultant multilayer coating structure disclosed herein may lead to significantly improved performance in terms of durability of the resultant composite. Although the exemplary multilayer coating structure as follows may be described using a particular exemplary combination of material(s) and layer(s), other material(s) as disclosed herein may be utilized and other arrangement(s) of the layer(s) disclosed herein may be utilized so as to achieve numerous variations of the exemplary multilayer coating structure.

[0110] Referring now to FIG. 2, an exemplary inorganic fiber comprising an exemplary multilayer coating structure 200 may include a SiC fiber 210 comprising at least one exemplary interface coating material(s) layer(s) 220, 240 disposed on an exterior surface of fiber 210, andRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 at least one exemplary additional coating material(s) layer(s) 230, 250a, b disposed on the exterior surface of the interface coating material(s) layer(s) 220, 240. The exemplary interface coating material(s) may be any materials suitable for controlling the debonding and chemical compatibility of oxidation products with SiC fibers. Suitable interface coating material(s) may include, but are not limited to, boron nitride (BN), carbon (C), Si-doped boron nitride (SiBN), silicon nitride (SisN4), SiC, boron carbide (B4C), individually, and combinations thereof. In at least one embodiment, the exemplary interface coating material(s) layer(s) may exhibit and possess an exemplary thickness of between tens of nanometers to low hundreds of nanometers. In at least one other embodiment, the exemplary interface coating material(s) layer(s) may exhibit and possess an exemplary thickness(es) of, for example, approximately 10 nm to approximately 500 nm; approximately 30 nm to approximately 400 nm; approximately 50 nm to approximately 200 nm; approximately 70 nm to approximately 150 nm; approximately 80 nm to approximately 120 nm; including any range that can be constructed using the specific thickness values disclosed herein. In at least one embodiment, the exemplary interface coating material(s) may be disposed on the exterior surface of the SiC fibers using any technique capable of depositing, adhering and coating the material on the exterior surface. Suitable deposition techniques may include, but are not limited to, chemical vapor infiltration (CVI), chemical vapor deposition (CVD), atomic layer deposition (ALD), individually, and combinations thereof.

[0111] For instance, at least one exemplary BN layer(s) 220, 240 may be disposed on an exterior surface of the SiC fibers. The exemplary BN layer may be a temperature gradient BN layer. That is, the part of the layer first provided on the SiC fiber(s) may be a high temperature layer followed by a series of layers whose temperatures decrease until a low temperature BN layer is finally formed. Those series of layers, in turn, form a microstructure gradient through the entire BN layer. To achieve the microstructure gradient for the resultant exemplary BN layer(s), the deposition processing temperature may be continuously and gradually adjusted or even abruptly adjusted while depositing each exemplary BN material layer(s). That is, as each BN layer is deposited, the deposition temperature may be adjusted, e.g., continuously or abruptly,RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 throughout the process. And, as the deposition temperature is adjusted, the composition of each deposited BN material layer may change. For instance, a BN material layer deposited at a low temperature may exhibit and possess an amorphous or turbostractic structure, while a BN material layer deposited at a high temperature may exhibit and possess a more crystalline structure. The exemplary low temperature BN material layer may be deposited at temperatures of less than approximately 1100°C. In contrast, the exemplary high temperature BN material layers may be deposited at temperatures greater than approximately 1100°C and less than approximately 1400°C. In at least one exemplary embodiment, the exemplary BN layer may include amorphous or turbostratic boron nitride.

[0112] In at least one other embodiment, the exemplary BN layer(s) 220, 240 may be provided as low temperature BN material layers, as discussed above, and also may further include carbon, e.g., pyrolytic carbon. The carbon, e.g., pyrolytic carbon, may be in a continuous or discontinuous form, or a mixture of continuous and discontinuous forms. In such an exemplary embodiment, at least one BN layer 220, 240 may include exemplary layers of carbon (C) in addition to the low temperature BN. Those exemplary layers of BN and C may further include an inner layer sequence exhibiting and possessing an exemplary composition represented by the formula: CXI-(BN-C)X-(BN)X2 where x is 2, 3, 4 or 5; and, Xi and X2 are each independently 0 or 1. When xi is 0 X2 is 1, the inner layer sequence may be (BN-C)X-(BN), such that the deposited carbon layer may be within and between the BN layers. For instance, the exemplary multiple layers may include thin layers of carbon, e.g., approximately 10 nm or less, greater than 0 to less than approximately 10 nm, approximately 0.5 to approximately 4 nm, approximately 1 nm to approximately 4 nm, approximately 1 nm to approximately 2 nm, approximately 1 nm to approximately 3 nm, approximately 3 nm to approximately 4 nm, approximately 2 nm to approximately 3 nm, or approximately 2 nm to approximately 4 nm, and slightly thicker layers of BN, e.g., from tens of nm to low hundred nm, e.g., approximately 20 nm to approximately 200 nm, approximately 30 nm to approximately 180 nm, approximately 40 nm to approximately 150 nm, approximately 50 nm to approximately 120 nm, approximately 60 nm to approximately 120RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 nm, approximately 80 nm to approximately 100 nm, e.g., approximately 90 nm, including any ranges that can be formed from these numbers. These thin C and thicker BN layers may be disposed in a repeating manner to form a repeating structure. The resultant repeating BN and C structure exhibits and possesses a combined thickness of between approximately 40 nm to approximately 200 nm. In the scheme of the exemplary multilayer coating material structure disclosed herein, the resultant exemplary multiple layers of BN and C may limit or may even entirely prevent tunnel oxidation from occurring. In at least one embodiment, the exemplary BN and C multilayer coating may be disposed on the on an exterior surface of the SiC fibers using any technique capable of depositing, adhering and coating the BN and C on the SiC fiber surface. Suitable deposition techniques may include, but are not limited to, chemical vapor infiltration (CVI), chemical vapor deposition (CVD), atomic layer deposition (ALD), individually, and combinations thereof.

[0113] In an at least one embodiment, at least one exemplary coating material(s) layer(s) 230, 250a, b may be disposed on the interface coating material(s) layer(s) 220, 240. For example, at least one amorphous and smooth SiN layer 230 can be provided in the exemplary multilayer structure that is directly in contact with the exemplary low temperature BN layer 210. SiN has a similar oxidation rate as SiC, but is especially beneficial in this multilayer system as it lacks the rough crystalline nature of a SiC layer. Thicker layers of SiN may be more protective. However, if a SiN layer is too thick, e.g., roughly greater than 50 nm, the thick SiN layer may strongly fuse neighboring SiC fibers. In turn, the strongly fused neighboring SiC fibers may lead to the composite becoming embrittled. In at least one embodiment, an exemplary SiN layer 230 may exhibit and possess a thickness of, for example, from the high tens of nanometers to the low hundreds of nanometers. In at least one other embodiment, the exemplary SiN layer 230 may exhibit and possess a thickness of, for example, approximately 10 nm to approximately 50 nm; approximately 15 nm to approximately 45 nm; approximately 20 nm to approximately 40 nm; approximately 25 nm to approximately 35 nm; approximately 20 nm to approximately 30 nm; including any range that can be constructed using the specific thickness values disclosed herein.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01In at least one embodiment, the exemplary additional coating material(s), e.g., SiN, may be disposed on the interface coating material(s) layer(s) using any technique capable of depositing, adhering and coating the additional coating material(s) on the interface coating material(s). Suitable deposition techniques may include, but are not limited to, chemical vapor infiltration (CVI), chemical vapor deposition (CVD), atomic layer deposition (ALD), individually and combinations thereof.

[0114] In at least one embodiment, at least one exemplary additional coating material(s) layer(s) may include an exemplary SisN^BN multilayer coating 250a (see FIG. 2). The exemplary SisN4-BN multilayer coating 250a may be formed using a multilayer structure containing individual layers of BN and Si3N4. As discussed below, the exemplary Si3N4-BN multilayer coating may contain alternating layers of boron nitride and silicon nitride deposited at different temperatures and other processing parameters to ensure that the ratio of boron nitride and silicon nitride deposited may be uniform throughout the deposition process. The resultant exemplary SisN4-BN multilayer coating 250a may serve as a functional IFC with improved durability performance. For instance, when the thin layers of boron nitride and silicon nitride of the exemplary Si3N4-BN multilayer coating disclosed herein oxidize, the aforementioned thin layers form a borosilicate glass with a composition like that of a SiBN composition with an equivalent Si content.

[0115] The Si3N4-BN multilayer coating 250a may comprise a pattern of alternating layers having at least one silicon nitride layer and at least one boron nitride layer. The thickness of the silicon nitride layer may be approximately 2 nanometers to approximately 30 nanometers, while the thickness of the boron nitride layer may be approximately 2 nanometers to approximately 30 nanometers. In at least one embodiment, the thickness of a BN layer of the Si3N4-BN multilayer coating 250a deposited within the coated preform may be as proximate to the thickness of a BN layer of the Si3N4-BN multilayer coating 250a deposited on the exterior of the coated preform. The resultant exemplary SisN4-BN multilayer coating 250a may exhibit and possess a total thickness of approximately 50 nanometers to approximately 300 nanometers. The overallRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 composition of the SiaN^BN multilayer coating 250a may be nearly uniform throughout the at least partially densified CMC. If the SiglX -BN multilayer coating 250a differs spatially throughout the entire partially densified CMC, then the SisIX -BN multilayer coating 250a may not function as intended in all locations throughout the entire partially densified CMC. Such incongruity can be detrimental to both the durability and performance of the resultant CMC-based gas turbine engine component.

[0116] In at least one alternative embodiment, at least one exemplary additional coating material(s) layer(s) may include at least one exemplary silicon-doped boron nitride ("SiBN") coating layer 250b. At least one exemplary SiBN coating layer 250b may seal matrix cracks occurring therein. At least one exemplary SiBN coating layer 250b may also prevent further oxidation in the BN layer 240, the SiN layer 230, and the BN layer 220. In at least one embodiment, the exemplary SiBN coating layer may exhibit and possess a thickness of, for example, from the high tens of nm to low hundreds of nm. In at least one other embodiment, the exemplary SiBN coating layer may exhibit and possess a thickness of, for example, approximately 50 nm to approximately 300 nm; approximately 80 nm to approximately 200 nm; approximately 90 nm to approximately 180 nm; approximately 100 nm to approximately 150 nm; approximately 120 nm to approximately 140 nm; including any range that can be constructed using the specific thickness values disclosed herein.

[0117] Following the completion of the fiber coating layers, a ceramic matrix material may be disposed on, within and throughout the preform. The ceramic matrix material disposition may be achieved through a variety of means including but not limited to chemical vapor infiltration (CVI), polymer infiltration and pyrolysis (PIP), and melt infiltration (Ml). These densification techniques may be used alone or in conjunction with each other, and one or more times, to convert the preform into the densified matrix of the densified CMC.

[0118] Next, in at least one embodiment, at least one protective layer (not shown), e.g., a thermal barrier coating (TBC) and / or environmental barrier coating (EBC), may be disposed onRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 the densified ceramic matrix composite. In at least one instance, the TBC and / or EBC helps protect the densified ceramic matrix composite from experiencing high thermal stress and from degrading under the high temperatures. In at least one embodiment, the TBC and / or EBC may be disposed onto the exemplary densified ceramic matrix composite using any technique capable of depositing, adhering and coating the TBC and / or EBC onto the composite. For example, suitable deposition techniques may include, but are not limited to, CVI, CVD, ALD, PVD, EBPVD, individually, and combinations thereof.

[0119] In at least one embodiment, the TBC (not shown) may include a bond coat and at least one ceramic layer. The bond coat may be a diffusion or overlay bond coat comprising, for example, an aluminide or MCrAlY, where M can be iron, cobalt, nickel, individually, or combination thereof. In at least one instance, a surface of the bond coat may be roughened, such as by grit blasting or peening, to improve adhesion of the ceramic layer to be deposited thereupon. The ceramic layer may have a single layer or multiple layers of material and may include layers of differing chemical composition. For example, the ceramic layer may include an inner yttrium stabilized zirconia (YSZ) layer deposited on bond coat and an outer gadolinium- stabilized zirconium (GDZ) layer deposited on the YSZ layer.

[0120] In at least one embodiment, the EBC (not shown) may comprise at least one low conductivity coating layer(s). The EBC, for example, may have a thermal conductivity capable of reducing the formation of thermal stresses in the exemplary multilayer coating material structure. In at least one embodiment, the EBC may comprise a first layer that may include silicon or silica, and at least one or more secondary layers that may include any of the following: a rare earth silicate layer, a yttrium monosilicate, a mullite layer; a mullite and alkaline earth aluminosilicate layer; a barium strontium aluminosilicate layer, a ytterbium based layer, other similar materials, individually, and combinations thereof.

[0121] In at least one embodiment, each of the layers, other than the BN layer(s), may be smooth and / or amorphous. Amorphous and smooth layer(s) may lead to achieving consistent,RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 accurate thicknesses of the various layers within the layer system. In the instant case, the term "smooth" means deviations in the layer thicknesses are limited to ± 10 nm, or ± 10 % deviation from the average layer thickness of the entire multilayer coating disclosed herein. The exemplary layer system containing the above disclosed layers in an exemplary arrangement as disclosed herein may improve the durability of the interface coating material layer(s) and, in turn, may extend a CMC material-containing gas turbine engine component's life cycle.

[0122] In at least one embodiment, the exemplary three-dimensional woven CMC preform disclosed herein comprises a fiber volume content of approximately 25 percent by volume to approximately 37 percent by volume based on a total fiber volume content of the three-dimensional woven CMC preform. More particularly, the fiber volume fraction in all three directions may not be the same. For instance, the fiber volume content of the three-dimensional weave further comprises an x-plane fiber volume fraction of approximately 20 percent by volume to approximately 24 percent by volume based on the fiber volume content of the three- dimensional weave; a y-plane fiber volume fraction of approximately 8 percent by volume to approximately 12 percent by volume based on the fiber volume content of the three-dimensional weave; and, a z-plane fiber volume fraction of approximately 1.8 percent by volume to approximately 3 percent by volume based on the fiber volume content of the three-dimensional weave. Total fiber volume may be maximized to achieve at least sufficient multi-directional reinforcement of the preform. By doing so, the fiber content in the x-, y- and z- directions may be sufficient to meet the multi-directional structural requirements of the preform. The z- direction fiber volume fraction may be maximized in order to ensure high effective through- thickness properties of the preform.

[0123] In at least one embodiment, the resultant densified CMC exhibits and possesses a density of greater than approximately 2.6 grams per cubic centimeter and, more particularly, approximately 2.95 grams per cubic centimeter to approximately 3.00 grams per cubic centimeter. In at least one embodiment, the resultant densified CMC also exhibits and possesses a porosity of approximately 5 percent to approximately 15 percent by volume based on the totalRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 density of the densified CMC. The density and porosity of the preform share an inverse relationship. That is, as the density of the densified CMC increases, the porosity of the densified CMC decreases. Both characteristics may be attributed to the volume fraction of the respective fibers in the x-, y-, z- directions and x-y, y-z and x-z planes. In at least one embodiment, the volume fraction of fibers in the y-direction may be twice the volume fraction of fibers in the x- direction. When the x and y values are different, as mentioned, the three-dimensional weave may be considered unbalanced. In at least one embodiment, the fibers disposed in the x- and y- directions may be relatively straight and stiff. In contrast, the fibers disposed in the z-direction may be relatively pliable. Those x- and y-direction fibers are maintained as straight as possible in-plane to achieve the highest in-plane matrix cracking strength and rupture strength. Fiber fracture caused by bending and abrasion may be avoided by maintaining a warp weaver bend radius greater than a fiber fracture radius.

[0124] Referring now to FIG. 3, an exemplary method for fabricating at least a densified CMC is illustrated by a flowchart 300. At an exemplary step 310, at least one SiC fiber may be provided. Next, using those SiC fibers, at an exemplary step 320, a ceramic preform, e.g., a three- dimensional weave as discussed above, may be fabricated. The three-dimensional weave may be fabricated using a three-dimensional weaving loom. Suitable three-dimensional weaving looms may include, but are not limited to, a jacquard weaving loom, combinations comprising a jacquard weaving loom, and the like. Next, at an exemplary step 330, at least one exemplary interface coating material layer, e.g., boron nitride, may be disposed on an exterior surface of each one of the SiC fibers of the ceramic preform to begin fabricating a coated preform. Next, at an exemplary 340, at least one exemplary additional coating material layer, e.g., silicon nitride, may be disposed on an exterior surface of each boron nitride layer. Next, at an exemplary step 350, at least one exemplary additional interface coating material layer, e.g., boron nitride, may be disposed on an exterior surface of each silicon nitride layer.

[0125] Next, at an exemplary step 360a, a SisN^BN multilayer coating 250a may be deposited on either the boron nitride layer 210 (See also FIG. 2) or the optional additional boronRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 nitride layer 230 (See FIG. 3). When depositing the SisN^BN multilayer coating 250a, the layer of silicon nitride may be deposited at a first deposition temperature until achieving a first thickness. The first deposition temperature may be a temperature optimally suited for silicon nitride alone rather than an SiBN composition. For example, the temperature for silicon nitride deposition may be approximately 850°C to approximately l,000°C. Once deposited, the deposition temperature may be lowered until reaching a second deposition temperature suitable for depositing amorphous boron nitride. Once reached, the layer of boron nitride may be deposited at the second deposition temperature until achieving a second thickness. The second deposition temperature may be approximately 650°C to approximately 850°C. When preparing to deposit the next silicon nitride layer of the SisN^BN multilayer coating 250a, the deposition temperature again may be raised until reaching the first deposition temperature. Once reached, the next silicon nitride layer of the pattern of alternating layers of SisN^BN multilayer coating 250a may be deposited. Once deposited, the deposition temperature again may be lowered until reaching the second deposition temperature. Once reached, the next boron nitride layer of the pattern of alternating layers of SisN^BN multilayer coating 250a may be deposited. These exemplary steps may be repeated until the resultant pattern of alternating layers of boron nitride and silicon nitride constitute the SisN^BN multilayer coating 250a at a desired overall thickness.

[0126] When depositing each alternating layer via a CVI process, a natural gradient in thickness forms from the exterior to the interior locations throughout the coated preform due to depletion of precursor gases diffusing therethrough. An exemplary ratio of interior to exterior thicknesses of BN orSi3N4 layers may be driven by preform geometry and process conditions such as the deposition temperature. For example, a ratio of the thickness of the BN layer of the SisN4- BN multilayer coating deposited within the coated preform to the thickness of a BN layer of the Si3N4-BN multilayer coating deposited on the exterior of the coated preform may be approximately 0.1 to approximately 1, and preferably as close to approximately 1 as possible. For example, in a given coated preform geometry, a BN deposition temperature of approximately 700°C and a SisN4 deposition temperature of approximately 950°C in combination may yield aRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 ratio of external to internal thickness of approximately 0.4. In this case, the resultant SisN^BN multilayer coating 250a composition would be uniform throughout, that is, throughout the interior and on the exterior too, of the coated preform, as well as the eventual, resultant CMC article. If the BN deposition were increased to 800°C, the ratio for BN internal to external thickness may decrease to a lower value, e.g., approximately 0.2, that is, the external BN to SisN4 thickness ratio within the SisN^BN multilayer coating 250a may be greater than interior BN to SisN4 thickness ratio within the SisN4-BN multilayer coating 250a. In this instance, the resultant external Si3N4-BN multilayer coating composition may become boron-rich and the internal SisN4- BN multilayer coating composition may become boron lean. This resultant mismatch in the composition of the Si3N4-BN multilayer coating throughout the coated preform may detrimentally impact the durability performance. Consequently, the ratio of BN to SisN4 thickness at a given location of the coated preform also may determine the durability performance of the SisN4-BN multilayer coating 250a. The composition targets for SisN4-BN multilayer coating 250a correspond to an exemplary ratio of the BN individual layer thickness of the Si3N4-BN multilayer coating 250a to the Si3N4 individual layer thickness of the SisN4-BN multilayer coating 250a that may be approximately 1 to approximately 4. The exemplary ratio can also indicate silicon may be present in an amount of approximately 10 atomic percent to approximately 15 atomic percent. If the ratio is less than 1, then the resultant Si-rich Si3N4-BN multilayer coating 250a may be slow to oxidize and plug the matrix crack. If the ratio is greater than 4, then the resultant SisN4-BN multilayer coating 250a may oxidize to form a boria-rich borosilicate glass which may readily volatilize at operational temperatures in the presence of small amounts of water vapor. More silicon in the glass may be needed to stabilize and seal the crack. The aforementioned ratio range of 1 to 4 may ensure the SisN4-BN multilayer coating 250a may oxidize quickly due to the boron content and may be sufficiently stable in operational conditions due to the silicon content.

[0127] In at least one other embodiment, at an exemplary step 360b, at least one exemplary additional coating material layer, e.g., silicon-doped boron nitride, may be disposedRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 on an exterior surface of each exemplary additional boron nitride layer to form the exemplary multilayer coating structure disclosed herein. In at least one embodiment, the silicon-doped boron nitride coating layer may be disposed using any technique capable of depositing, adhering and coating the outermost coating material(s). Suitable deposition techniques may include, but are not limited to, CVI, CVD, ALD, individually, and combinations thereof.

[0128] In yet at least one other embodiment, neither the SisN^BN multilayer coating 250a nor the silicon-doped boron nitride coating layer 250b may be disposed on the exterior surface of each exemplary additional boron nitride layer. In this instance, the exemplary process disclosed herein proceeds from step 350 to step 370 (see FIG. 3) according to the dashed arrow labeled 360c.

[0129] Once all the layers of the exemplary multilayer coating system have been disposed onto the SiC fibers, at an exemplary step 370, at least one ceramic matrix material can be deposited on, within and throughout the coated fibers, which leads to the formation of the ceramic matrix of the eventual CMC. Suitable techniques for matrix formation may include, but are not limited to, infiltration techniques, combinations comprising infiltration techniques, and the like. Once the ceramic matrix coating material is disposed on, within and throughout the fibers of the three-dimensional woven structure, the ceramic preform, or resultant woven structure, becomes a coated preform as mentioned above.

[0130] In at least one embodiment, at any one of exemplary steps 380a, 380b and 380c of FIG. 3, the coated preform may undergo at least partial densification to form a partially densified CMC. Partial densification techniques may be any technique that partially densifies the ceramic matrix composite material and, in turn, fabricates a structural support material layer that facilitates rigidization of the coated preform to become self-supporting, also known as a partially densified CMC. The resultant structural support material can fill any interstitial voids, spaces and / or spatial areas between the SiC fibers comprising the exemplary multilayer coating structure disclosed herein, and also reduce the porosity of the partially densified CMC. In anRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 exemplary step 380a of FIG. 3, the coated preform may be at least partially densified using a chemical vapor infiltration (CVI) technique. In at least one embodiment, any suitable CVI technique may at least partially densify the coated preform at a temperature range of approximately 700 degrees Celsius to approximately 1,200 degrees Celsius and at a pressure range of less than approximately 1 torr and up to approximately 50 torr.

[0131] In another exemplary step 380b of FIG. 3, the partially densified CMC may be fully densified using a melt-infiltration (Ml) technique. For example, the partially densified CMC may be infiltrated with at least one molten metal, at least one molten metalloid, at least one molten metal alloy, molten metalloid alloy, individually, and combinations thereof. For example, at least one molten metalloid may be silicon. Any melt-infiltration technique may be used to infiltrate the partially densified CMC. Suitable melt-infiltration techniques may be performed at a temperature range of approximately 1,200 degrees Celsius to approximately 1,600 degrees Celsius or, in the alternative or in consideration of, a maximum temperature supported by the inorganic fiber, e.g., SiC fiber, of the partially densified CMC.

[0132] In yet another exemplary step 380c of FIG. 3, the partially densified CMC may be fully densified using a polymer infiltration and pyrolysis (PIP) technique. Suitable PIP techniques involve infiltrating the preform with a polysilane undera vacuum and applying heat until reaching a curing temperature. Suitable polysilanes for use herein may include, but are not limited to, polycarbosilane, combinations comprising polycarbosilane, and the like. Next, the infiltrated preform may gradually undergo pyrolysis until the polysilane slowly decomposes into a ceramic material, e.g., silicon carbide and silicon nitride. The infiltration and pyrolysis steps may be repeated until the resultant ceramic matrix composite may exhibit and possess the desired characteristics, e.g., porosity. When utilizing any one of the aforementioned techniques at exemplary steps 380a-380c of FIG. 3, the densification materials entering the partially densified CMC may react with at least the interface coating material(s), additional coating material(s), and ceramic matrix coating material(s), individually, and combinations thereof, such that the resultant reactants are present within the resultant densified three-dimensional woven CMC.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01

[0133] Next, at an exemplary step 390, at least one exemplary TBC and / or EBC layer(s) may be disposed on an exterior surface of the exemplary densified three-dimensional woven CMC to serve as at least one protective layer(s) (See FIG. 3).

[0134] While the present disclosure has been particularly described, in conjunction with specific preferred embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present disclosure.

Claims

RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01CLAIMSWhat is claimed is:

1. A three-dimensional woven ceramic matrix composite, comprising: a densified three-dimensional woven structure comprising a densified ceramic matrix disposed on, within and throughout a three-dimensional weave comprising at least one inorganic fiber comprising at least one multilayer coating material structure disposed thereupon, wherein the at least one multilayer coating material structure comprises: at least one first interface coating material layer comprising a boron nitride; at least one coating material layer comprising a silicon nitride; at least one second interface coating material layer comprising the boron nitride; and at least one third interface coating material layer comprising a S13N4-BN multilayer coating having one or more alternating layers comprising: at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.

2. The three-dimensional woven ceramic matrix composite of claim 1, further comprising at least one layer of silicon nitride disposed adjacent the boron nitride layer and between the boron nitride layer and the SisN^BN multilayer coating.

3. The three-dimensional woven ceramic matrix composite of claim 1, further comprising at least one additional layer of boron nitride disposed adjacent the silicon nitride layer and between the silicon nitride layer and the SisN^BN multilayer coating.

4. The three-dimensional woven ceramic matrix composite of claim 1, wherein the first thickness is approximately 2 nanometers to approximately 30 nanometers.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V015. The three-dimensional woven ceramic matrix composite of claim 1, wherein the second thickness is approximately 2 nanometers to approximately 30 nanometers.

6. The three-dimensional woven ceramic matrix composite of claim 1, wherein the SisN^BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.

7. The three-dimensional woven ceramic matrix composite of claim 1, wherein the SisN^BN multilayer coating is uniform throughout the coated substrate, and a ratio of a thickness of the boron nitride layer of the SisN^BN multilayer coating to a thickness of the silicon nitride layer of the SisN^BN multilayer coating comprises approximately 1 to approximately 4.

8. The three-dimensional woven ceramic matrix composite of claim 1, further comprising at least one layer of silicon carbide disposed adjacent the SisN^BN multilayer coating and opposite the at least one layer of boron nitride.

9. The three-dimensional woven ceramic matrix composite of claim 1, wherein the at least one inorganic fiber comprises silicon carbide.

10. The three-dimensional woven ceramic matrix composite of claim 1, wherein the boron nitride comprises at least one of the following: turbostratic boron nitride, amorphous boron nitride, and hexagonal boron nitride.

11. The three-dimensional woven ceramic matrix composite of claim 1, wherein the boron nitride comprises a low temperature amorphous or turbostratic boron nitride, a high temperature hexagonal boron nitride, or both a low temperature amorphous or turbostratic boron nitride and a high temperature hexagonal boron nitride.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0112. The three-dimensional woven ceramic matrix composite of claim 1, further comprising at least one additional coating material layer comprising a silicon-doped boron nitride.

13. The three-dimensional woven ceramic matrix composite of claim 12, wherein the at least one third interface coating material layer comprises a thickness of approximately 50 nm to approximately 300 nm.

14. The three-dimensional woven ceramic matrix composite of claim 1, wherein the boron nitride comprises either a high temperature hexagonal boron nitride layer or a multilayer sequence comprising at least one layer of a low temperature amorphous or turbostratic boron nitride and at least one layer of carbon, wherein the multilayer sequence further comprises at least one inner layer comprising a formula: CXI-(BN-C)X-(BN)X2 where x is 2, 3, 4 or 5; and, xi and X2 are each independently 0 or 1.

15. The three-dimensional woven ceramic matrix composite of claim 14, wherein the at least one layer of low temperature amorphous or turbostratic boron nitride comprises a thickness of approximately 20 nm to approximately 200 nm.

16. The three-dimensional woven ceramic matrix composite of claim 14, wherein the at least one layer of carbon comprises a thickness of greater than 0 to less than approximately 10 nm.

17. The three-dimensional woven ceramic matrix composite of claim 14, wherein the at least one layer of carbon comprises a continuous form, a discontinuous form or a mixture of a continuous form and a discontinuous form.

18. The three-dimensional woven ceramic matrix composite of claim 14, wherein the at least one layer of carbon comprises a pyrolytic carbon.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0119. The three-dimensional woven ceramic matrix composite of claim 1, wherein the densified ceramic matrix comprises a silicon carbide.

20. The three-dimensional woven ceramic matrix composite of claim 1, wherein the three- dimensional woven structure comprises at least one of the following: angle interlock layer-to- layer, angle interlock through-the-thickness, orthogonal weave, and combinations comprising at least one of the foregoing.

21. The three-dimensional woven ceramic matrix composite of claim 1, wherein the at least one first interface coating material layer comprises a thickness of approximately 10 nm to approximately 500 nm.

22. The three-dimensional woven ceramic matrix composite of claim 1, wherein the at least one coating material layer comprises a thickness of approximately 10 nm to approximately 50 nm.

23. The three-dimensional woven ceramic matrix composite of claim 1, further comprising at least one thermal barrier coating layer on the densified three-dimensional woven structure.

24. The three-dimensional woven ceramic matrix composite of claim 1, further comprising at least one environmental barrier coating layer on the densified three-dimensional woven structure.

25. The three-dimensional woven ceramic matrix composite of claim 1, further comprising at least one thermal barrier coating layer and at least one environmental barrier coating layer, in sequence or in opposite sequence, on the densified three-dimensional woven structure.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0126. A method for manufacturing a three-dimensional woven ceramic matrix composite, comprising the steps of: providing at least one inorganic fiber; fabricating a three-dimensional woven structure using the at least one inorganic fiber; forming a multilayered coating material structure on each inorganic fiber of the three- dimensional woven structure, according to the following steps; disposing at least one first interface coating material layer on an exterior surface of each of the fibers to form at least one interface coated fiber, disposing at least one coating material layer on the at least one first interface coating material layer, disposing at least one second interface coating material layer on the at least one coating material layer, disposing at least one third interface coating material layer onto the at least one second interface coating material layer to form the multilayered coating material structure on each fiber; disposing at least one ceramic matrix coating material on the multilayered coating material structure of each fiber to form a three-dimensional woven ceramic matrix composite preform; and densifying the at least one ceramic matrix coating material to form a densified three- dimensional woven ceramic matrix composite comprising a densified ceramic matrix, wherein the at least one first interface coating and the at least one second interface coating comprise boron nitride, wherein the at least one coating material layer comprises a silicon nitride, and wherein the at least one third interface coating material layer comprises a SisIX -BN multilayer coating having one or more alternating layers comprising: at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0127. The method of claim 26, wherein densifying comprises any one of the following densification techniques: chemical vapor infiltration, melt-infiltration, polymer infiltration and pyrolysis, and combinations comprising at least one of the foregoing.

28. The method of claim 26, wherein disposing comprises any one of the following techniques: chemical vapor infiltration, chemical vapor deposition, atomic layer deposition, and combinations comprising any one of the foregoing.

29. The method of claim 26, further comprising disposing at least one thermal barrier coating layer on the densified three-dimensional woven ceramic matrix.

30. The method of claim 26, further comprising disposing at least one environmental barrier coating layer on the densified three-dimensional woven ceramic matrix.

31. The method of claim 26, further comprising disposing at least one thermal barrier coating layer and at least one environmental barrier coating layer, in sequence or in opposite sequence, on the densified three-dimensional woven ceramic matrix.

32. The method of claim 26, wherein the boron nitride comprises either a high temperature hexagonal boron nitride layer or a multilayer sequence comprising at least one layer of a low temperature amorphous or turbostratic boron nitride and at least one layer of carbon, wherein the multilayer sequence further comprises at least one inner layer comprising a formula: Cxi-(BN- C)X-(BN)X2 where x is 2, 3, 4 or 5; and, xi and X2 are each independently 0 or 1.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0133. The method of claim 32, wherein the at least one layer of low temperature amorphous or turbostratic boron nitride comprises a thickness of approximately 20 nm to approximately 200 nm.

34. The method of claim 32, wherein the at least one layer of carbon comprises a thickness of greater than 0 to less than approximately 10 nm.

35. The method of claim 32, wherein the at least one layer of carbon comprises a pyrolytic carbon.

36. The method of claim 32, wherein the at least one layer of carbon comprises a continuous form, a discontinuous form or a mixture of a continuous form and a discontinuous form.

37. The method of claim 26, wherein the at least one first interface coating material layer is disposed at a thickness of approximately 10 nm to approximately 500 nm.

38. The method of claim 26, wherein the at least one coating material layer is disposed at a thickness of approximately 10 nm to approximately 50 nm.

39. The method of claim 26, further comprising disposing at least one third interface coating material layer comprising a silicon-doped boron nitride.

40. The method of claim 39, wherein the at least one third interface coating material layer is disposed at a thickness of approximately 50 nm to approximately 300 nm.

41. The method of claim 26, further comprising at least one layer of silicon nitride disposed adjacent the boron nitride layer and between the boron nitride layer and the SisN^BN multilayer coating.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0142. The method of claim 26, further comprising at least one additional layer of boron nitride disposed adjacent the silicon nitride layer and between the silicon nitride layer and the SisIX -BN multilayer coating.

43. The method of claim 26, wherein the first thickness is approximately 2 nanometers to approximately 30 nanometers.

44. The method of claim 26, wherein the second thickness is approximately 2 nanometers to approximately 30 nanometers.

45. The method of claim 26, wherein the SisIX -BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.

46. The method of claim 26, wherein the SisN^BN multilayer coating is uniform throughout the coated substrate, and a ratio of a thickness of the boron nitride layer of the SisIX -BN multilayer coating to a thickness of the silicon nitride layer of the SisIX -BN multilayer coating comprises approximately 1 to approximately 4.

47. The method of claim 26, further comprising at least one layer of silicon carbide disposed adjacent the SisNzj-BN multilayer coating and opposite the at least one layer of boron nitride.

48. A gas turbine engine component, comprising: a densified three-dimensional woven ceramic matrix composite comprising the shape of the gas turbine engine component, the densified three-dimensional woven ceramic matrix composite further comprising: a three-dimensional woven structure comprising a densified ceramic matrix disposed on, within and throughout a three-dimensional weave comprising at least oneRTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 inorganic fiber comprising at least one multilayer coating material structure disposed thereupon, wherein the at least one multilayer coating material structure comprises: at least one first interface coating material layer comprising a boron nitride; at least one coating material layer comprising a silicon nitride; at least one second interface coating material layer comprising the boron nitride; and at least one third interface coating material layer comprising a SisIX -BN multilayer coating having one or more alternating layers comprising: at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness.

49. The gas turbine engine component of claim 48, further comprising at least one layer of silicon nitride disposed adjacent the boron nitride layer and between the boron nitride layer and the SisN4-BN multilayer coating.

50. The gas turbine engine component of claim 48, further comprising at least one additional layer of boron nitride disposed adjacent the silicon nitride layer and between the silicon nitride layer and the SisIXU-BN multilayer coating.

51. The gas turbine engine component of claim 48, wherein the first thickness is approximately 2 nanometers to approximately 30 nanometers.

52. The gas turbine engine component of claim 48, wherein the second thickness is approximately 2 nanometers to approximately 30 nanometers.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0153. The gas turbine engine component of claim 48, wherein the SisN^BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.

54. The gas turbine engine component of claim 48, wherein the Si3N4-BN multilayer coating is uniform throughout the coated substrate, and a ratio of a thickness of the boron nitride layer of the SisN4-BN multilayer coating to a thickness of the silicon nitride layer of the SisN4-BN multilayer coating comprises approximately 1 to approximately 4.

55. The gas turbine engine component of claim 48, further comprising at least one layer of silicon carbide disposed adjacent the SisN4-BN multilayer coating and opposite the at least one layer of boron nitride.

56. The gas turbine engine component of claim 48, wherein the at least one inorganic fiber comprises silicon carbide.

57. The gas turbine engine component of claim 48, wherein the boron nitride comprises at least one of the following: turbostratic boron nitride, amorphous boron nitride, and hexagonal boron nitride.

58. The gas turbine engine component of claim 48, wherein the boron nitride comprises a low temperature amorphous or turbostratic boron nitride, a high temperature hexagonal boron nitride, or both a low temperature amorphous or turbostratic boron nitride and a high temperature hexagonal boron nitride.

59. The gas turbine engine component of claim 48, further comprising at least one additional coating material layer comprising a silicon-doped boron nitride.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0160. The gas turbine engine component of claim 59, wherein the at least one additional coating material layer comprises a thickness of approximately 50 nm to approximately 300 nm.

61. The gas turbine engine component of claim 48, wherein the boron nitride comprises either a high temperature hexagonal boron nitride layer or a multilayer sequence comprising at least one layer of a low temperature amorphous or turbostratic boron nitride and at least one layer of carbon, wherein the multilayer sequence further comprises at least one inner layer comprising a formula: CXI-(BN-C)X-(BN)X2 where x is 2, 3, 4 or 5; and, Xi and X2 are each independently 0 or 1.

62. The gas turbine engine component of claim 61, wherein the at least one layer of low temperature amorphous or turbostratic boron nitride comprises a thickness of approximately 20 nm to approximately 200 nm.

63. The gas turbine engine component of claim 61, wherein the at least one layer of carbon comprises a thickness of greater than 0 to less than approximately 10 nm.

64. The gas turbine engine component of claim 61, wherein the at least one layer of carbon comprises a continuous form, a discontinuous form or a mixture of a continuous form and a discontinuous form.

65. The gas turbine engine component of claim 61, wherein the at least one layer of carbon comprises a pyrolytic carbon.

66. The gas turbine engine component of claim 48, wherein the densified ceramic matrix comprises a silicon carbide.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0167. The gas turbine engine component of claim 48, wherein the three-dimensional woven structure comprises at least one of the following: angle interlock layer-to-layer, angle interlock through-the-thickness, orthogonal weave, and combinations comprising at least one of the foregoing.

68. The gas turbine engine component of claim 48, wherein the at least one first interface coating material layer comprises a thickness of approximately 10 nm to approximately 500 nm.

69. The gas turbine engine component of claim 48, wherein the at least one coating material layer comprises a thickness of approximately 10 nm to approximately 50 nm.

70. The gas turbine engine component of claim 48, further comprising at least one thermal barrier coating layer on the densified three-dimensional woven ceramic matrix composite.

71. The gas turbine engine component of claim 48, further comprising at least one environmental barrier coating layer on the densified three-dimensional woven ceramic matrix composite.

72. The gas turbine engine component of claim 48, further comprising at least one thermal barrier coating layer and at least one environmental barrier coating layer, in sequence or in opposite sequence, on the densified three-dimensional woven ceramic matrix composite.

73. A gas turbine engine, comprising: at least one gas turbine engine component comprising a densified three-dimensional woven ceramic matrix composite, the densified three-dimensional woven ceramic matrix composite further comprising:RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V01 a three-dimensional woven structure comprising a densified ceramic matrix disposed on, within and throughout a three-dimensional weave comprising at least one inorganic fiber comprising at least one multilayer coating material structure disposed thereupon, wherein the at least one multilayer coating material structure comprises: at least one first interface coating material layer comprising a boron nitride; at least one coating material layer comprising a silicon nitride; at least one second interface coating material layer comprising the boron nitride; and at least one third interface coating material layer comprising a SisN^BN multilayer coating having one or more alternating layers comprising: at least one layer of silicon nitride at a first thickness; and at least one layer of boron nitride at a second thickness74. The gas turbine engine of claim 73, further comprising at least one layer of silicon nitride disposed adjacent the boron nitride layer and between the boron nitride layer and the SisN^BN multilayer coating.

75. The gas turbine engine of claim 73, further comprising at least one additional layer of boron nitride disposed adjacent the silicon nitride layer and between the silicon nitride layer and the Si3N4-BN multilayer coating.

76. The gas turbine engine of claim 73, wherein the first thickness is approximately 2 nanometers to approximately 30 nanometers.

77. The gas turbine engine of claim 73, wherein the second thickness is approximately 2 nanometers to approximately 30 nanometers.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0178. The gas turbine engine of claim 73, wherein the SisN^BN multilayer coating comprises a total thickness of approximately 50 nanometers to approximately 300 nanometers.

79. The gas turbine engine of claim 73, wherein the SisN^BN multilayer coating is uniform throughout the coated substrate, and a ratio of a thickness of the boron nitride layer of the Si3N4- BN multilayer coating to a thickness of the silicon nitride layer of the SisN^BN multilayer coating comprises approximately 1 to approximately 4.

80. The gas turbine engine of claim 73, further comprising at least one layer of silicon carbide disposed adjacent the SisN^BN multilayer coating and opposite the at least one layer of boron nitride.

81. The gas turbine engine of claim 73, wherein the at least one inorganic fiber comprises silicon carbide.

82. The gas turbine engine of claim 73, wherein the boron nitride comprises at least one of the following: turbostratic boron nitride, amorphous boron nitride, and hexagonal boron nitride.

83. The gas turbine engine of claim 73, wherein the boron nitride comprises a low temperature amorphous or turbostratic boron nitride, a high temperature hexagonal boron nitride, or both a low temperature amorphous or turbostratic boron nitride and a high temperature boron nitride.

84. The gas turbine engine of claim 73, wherein the densified ceramic matrix comprises a silicon carbide.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0185. The gas turbine engine of claim 73, wherein the three-dimensional woven structure comprises at least one of the following: angle interlock layer-to-layer, angle interlock through- the-thickness, orthogonal weave, and combinations comprising at least one of the foregoing.

86. The gas turbine engine of claim 73, wherein the at least one first interface coating material layer comprises a thickness of approximately 10 nm to approximately 500 nm.

87. The gas turbine engine of claim 73, wherein the at least one coating material layer comprises a thickness of approximately 10 nm to approximately 50 nm.

88. The gas turbine engine of claim 73, further comprising at least one thermal barrier coating layer on the densified three-dimensional woven ceramic matrix composite.

89. The gas turbine engine of claim 73, further comprising at least one environmental barrier coating layer on the densified three-dimensional woven ceramic matrix composite.

90. The gas turbine engine of claim 73, further comprising at least one thermal barrier coating layer and at least one environmental barrier coating layer, in sequence or in opposite sequence, on the densified three-dimensional woven ceramic matrix composite.

91. The gas turbine engine of claim 73, further comprising at least one additional coating material layer further comprises a silicon-doped boron nitride.

92. The gas turbine engine of claim 91, wherein the at least one additional coating material layer comprises a thickness of approximately 50 nm to approximately 300 nm.RTX Ref. No. 181840US01MWZB Ref. No. RTXPW-0052-V0193. The gas turbine engine of claim 73, wherein the boron nitride comprises either a high temperature hexagonal boron nitride or a multilayer sequence comprising at least one layer of a low temperature amorphous or turbostratic boron nitride and at least one layer of carbon, wherein the multilayer sequence further comprises at least one inner layer comprising a formula: Cxi-(BN-C)x-(BN)x2 where x is 2, 3, 4 or 5; and, xi and X2 are each independently 0 or 1.

94. The gas turbine engine of claim 93, wherein the at least one layer of low temperature amorphous or turbostratic boron nitride comprises a thickness of approximately 20 nm to approximately 200 nm.

95. The gas turbine engine of claim 93, wherein the at least one layer of carbon comprises a thickness of greater than 0 to less than approximately 10 nm.

96. The gas turbine engine of claim 93, wherein the at least one layer of carbon comprises a continuous form, a discontinuous form or a mixture of a continuous form and a discontinuous form.

97. The gas turbine engine of claim 93, wherein the at least one layer of carbon comprises a pyrolytic carbon.

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