Multilayer interface coating with thermally-grown oxide for improved durability

Patent metadata

Field	Value
Publication number	US-12565454-B2
Application number	US-202217866024-A
Country	US
Kind code	B2
Filing date	Jul 15, 2022
Priority date	Jul 15, 2022
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

A coated fiber structure for use in a ceramic matrix composite comprises a fiber and a coating system applied to and circumscribing the fiber. The coating system comprises a first boron nitride layer, a silicon carbide layer extending coaxially with and in direct contact with the first boron nitride layer, a first thermally-grown oxide layer formed on the silicon carbide layer, and a second boron nitride layer extending coaxially with and in direct contact with the first thermally-grown oxide layer.

First claim

The invention claimed is:

1 . A coated fiber structure for use in a ceramic matrix composite, the coated fiber structure comprising:
a fiber comprising silicon carbide; and a coating system applied to and circumscribing the fiber, the coating system comprising:
a first thermally-grown oxide layer formed on the fiber, wherein the first thermally-grown oxide layer comprises silica;
a first boron nitride layer extending coaxially with and in direct contact with the first thermally-grown oxide layer, wherein the first boron nitride layer comprises an anisotropic region adjacent to the first thermally grown oxide layer;
a silicon carbide layer extending coaxially with and in direct contact with the first boron nitride layer;
a second thermally-grown oxide layer formed on the silicon carbide layer, wherein the second thermally-grown oxide layer comprises silica; and
a second boron nitride layer extending coaxially with and in direct contact with the second thermally-grown oxide layer, wherein the second boron nitride layer comprises an anisotropic region adjacent to the second thermally grown oxide layer.

2 . The coated fiber structure of claim 1 , wherein the second boron nitride layer further comprises an isotropic region on a side of the anisotropic region opposite the second thermally-grown oxide layer.

3 . The coated fiber structure of claim 1 , wherein:
the first boron nitride layer has a thickness ranging from 50 nm to 200 nm; the silicon carbide layer has a thickness ranging from 50 nm to 500 nm; the second thermally-grown oxide layer has a thickness ranging from 50 nm to 200 nm; and the second boron nitride layer has a thickness ranging from 50 nm to 200.

4 . The coated fiber structure of claim 3 , wherein the silicon carbide layer has a thickness ranging from 250 nm to 500 nm.

5 . The coated fiber structure of claim 3 , wherein the second first boron nitride layer further comprises an isotropic region on a side of the anisotropic region opposite the first thermally-grown oxide layer.

6 . The coated fiber structure of claim 3 , wherein the first thermally-grown oxide layer has a thickness ranging from 50 nm to 100 nm.

7 . The coated fiber structure of claim 3 and further comprising: a silicon-doped boron nitride layer extending coaxially with and in direct contact with the second boron nitride layer, the silicon-doped boron nitride layer having a thickness ranging from 50 nm to 200 nm.

8 . A ceramic matrix composite comprising:
a plurality of the coated fiber structures of claim 1 ; and a silicon carbide matrix formed upon the second boron nitride layer of the plurality of the coated fiber structures.

9 . A method of forming a ceramic matrix composite, the method comprising:
forming a fibrous preform by:
arranging a plurality of ceramic fibers;
forming a first thermally-grown oxide layer on the plurality of ceramic fibers;
depositing a first boron nitride layer on the first thermally-grown oxide layer, wherein the first boron nitride layer extends coaxially and is in direct contact with the first thermally-grown oxide layer;
depositing a silicon carbide layer on the first boron nitride layer;
forming a second thermally-grown oxide layer on the silicon carbide layer, wherein the second thermally-grown oxide layer comprises silica; and
depositing a second boron nitride layer on the second thermally-grown oxide layer, wherein the second boron nitride layer extends coaxially and is in direct contact with the second thermally-grown oxide layer; and
depositing a silicon carbide matrix on the fibrous preform.

10 . The method of claim 9 , wherein the second boron nitride layer comprises:
an anisotropic region adjacent the second thermally-grown oxide layer; and an isotropic region on a side of the anisotropic region opposite the second thermally-grown oxide layer.

11 . The method of claim 9 , wherein the first boron nitride layer comprises:
an anisotropic region adjacent the first thermally-grown oxide layer; and an isotropic region on a side of the anisotropic region opposite the first thermally-grown oxide layer.

12 . The method of claim 11 , wherein forming the first thermally-grown oxide layer and the second thermally-grown oxide layer comprises heating the preform to a temperature ranging from 800° C. to 1200° C. for a period ranging from one hour to 24 hours.

13 . The method of claim 9 , wherein the step of depositing each of the first boron nitride layer, the silicon carbide layer, and the second boron nitride layer comprises chemical vapor infiltration.

14 . The method of claim 9 and further comprising: prior to depositing the silicon carbide matrix, depositing a silicon-doped boron nitride layer on the second boron nitride layer.

15 . The method of claim 14 , wherein the step of depositing the silicon-doped boron nitride layer comprises chemical vapor infiltration.

16 . The method of claim 9 , wherein the step of depositing the silicon carbide matrix comprises at least one of chemical vapor infiltration, slurry infiltration, melt infiltration, and polymer infiltration and pyrolysis.

Assignees

• Raytheon Tech Corp
• Rtx Corp

Inventors

• Callaway Evan B

Classifications

• C04B35/62849 Primary

  Silica or silicates · CPC title

• C04B35/62897

  Coatings characterised by their thickness · CPC title

• C04B35/62894

  with more than one coating layer · CPC title

• C04B35/62886

  by wet chemical techniques · CPC title

• C04B35/62884

  by gas phase techniques · CPC title