Method of forming a boron nitride (BN) nanotube interface coating on ceramic fibers

Patent metadata

Field	Value
Publication number	US-11434175-B2
Application number	US-202016890203-A
Country	US
Kind code	B2
Filing date	Jun 2, 2020
Priority date	Jun 4, 2019
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

An electrophoretic deposition method of forming a boron nitride (BN) nanotube interface coating on ceramic fibers has been developed. The method comprises immersing first and second electrodes in a suspension including surface-modified BN nanotubes, where the first electrode includes ceramic fibers positioned on a surface thereof. The surface-modified BN nanotubes comprise BN nanotubes with an electrically charged polymer adsorbed on surfaces thereof. A voltage is applied to the first and second electrodes, and the surface-modified BN nanotubes move toward the first electrode and deposit on the ceramic fibers. After the deposition of the surface-modified BN nanotubes, the ceramic fibers are removed from the suspension and heat treated. Accordingly, a BN nanotube interface coating is formed on the ceramic fibers.

First claim

What is claimed is:

1. A method of forming a boron nitride nanotube interface coating on ceramic fibers, the method comprising:
immersing first and second electrodes in a suspension including surface-modified boron nitride (BN) nanotubes, the first electrode including ceramic fibers positioned on a surface thereof, the surface-modified BN nanotubes comprising BN nanotubes with an electrically charged polymer adsorbed on surfaces thereof, and a concentration of the surface-modified BN nanotubes in the suspension being from about 20 vol. % to about 60 vol. %;
applying a voltage to the first and second electrodes, the surface-modified BN nanotubes moving toward the first electrode and depositing on the ceramic fibers;
after the deposition of the surface-modified BN nanotubes, removing the ceramic fibers from the suspension; and
heat treating the ceramic fibers, thereby forming a BN nanotube interface coating on the ceramic fibers.

2. The method of claim 1 , wherein the electrically charged polymer comprises a positively charged polymer, and wherein the first electrode comprises a cathode.

3. The method of claim 2 , wherein the positively charged polymer comprises chitosan.

4. The method of claim 1 , wherein the ceramic fibers are arranged as a fiber tow, a fabric, or a fiber preform on the first electrode.

5. The method of claim 1 , wherein the ceramic fibers comprise silicon carbide fibers.

6. The method of claim 1 , wherein the suspension comprises a pH in a range from 2 to 5.

7. The method of claim 1 , wherein the suspension is an aqueous suspension.

8. The method of claim 1 , wherein the voltage is in a range from about 5 V to about 50 V.

9. The method of claim 1 , wherein the voltage is applied for a time duration in a range from about 1 min to about 60 min.

10. The method of claim 1 , wherein the BN nanotube interface coating has a thickness in range from about 0.05 micron to about 5 microns.

11. The method of claim 1 , wherein the heat treatment is carried out in a controlled environment comprising a vacuum or an inert gas atmosphere.

12. The method of claim 1 , wherein the heat treatment is carried out at a temperature in a range from about 900° C. to about 1600° C.

13. The method of claim 1 , wherein the heat treatment is carried out for a time duration in a range from about 30 min to about 4 h.

14. The method of claim 1 , wherein, during the heat treatment, the electrically charged polymer is pyrolyzed and thereby removed from the surfaces of the BN nanotubes.

15. A ceramic matrix composite (CMC) component comprising the ceramic fibers with the BN nanotube interface coating made by the method of claim 1 .

16. A method of making a ceramic matrix composite (CMC), the method comprising:
forming a fiber preform comprising a framework of ceramic fibers;
forming a boron nitride (BN) nanotube interface coating on the ceramic fibers, the forming comprising:
immersing first and second electrodes in a suspension including surface-modified boron nitride (BN) nanotubes, the first electrode including ceramic fibers positioned on a surface thereof, the surface-modified BN nanotubes comprising BN nanotubes with an electrically charged polymer adsorbed on surfaces thereof, and a concentration of the surface-modified BN nanotubes in the suspension being from about 20 vol. % to about 60 vol. %;
applying a voltage to the first and second electrodes, the surface-modified BN nanotubes moving toward the first electrode and depositing on the ceramic fibers;
after the deposition of the surface-modified BN nanotubes, removing the ceramic fibers from the suspension; and
heat treating the ceramic fibers, thereby forming the BN nanotube interface coating on the ceramic fibers;

forming a rigidized fiber preform from the fiber preform;
infiltrating the rigidized fiber preform with a slurry comprising ceramic particles, thereby forming an impregnated fiber preform;
infiltrating the impregnated fiber preform with a molten material,
wherein, upon cooling, a CMC comprising BN nanotube-coated ceramic fibers in a ceramic matrix is formed.

17. The method of claim 16 , wherein the BN nanotube interface coating is formed on the ceramic fibers prior to forming the fiber preform.

18. The method of claim 16 , wherein the BN nanotube interface coating is formed on the ceramic fibers after forming the fiber preform.

Assignees

• Rolls Royce Corp
• Rolls Royce High Temperature Composites Inc

Inventors

• Shi Jun
• Shim Sungbo

Classifications

• C04B2235/3821

  Boron carbides · CPC title

• C25D13/22

  Servicing or operating {apparatus or multistep processes} · CPC title

• C04B35/62868 Primary

  Boron nitride · CPC title

• C25D13/12

  characterised by the article coated · CPC title

• C04B35/573

  obtained by reaction sintering {or recrystallisation} · CPC title