Crystalline boron nitride aerogels

Patent metadata

Field	Value
Publication number	US-9840414-B2
Application number	US-201715408297-A
Country	US
Kind code	B2
Filing date	Jan 17, 2017
Priority date	Jul 1, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

This disclosure provides methods and materials related to boron nitride aerogels. For example, one aspect relates to a method for making an aerogel comprising boron nitride, comprising: (a) providing boron oxide and an aerogel comprising carbon; (b) heating the boron oxide to melt the boron oxide and heating the aerogel; (c) mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide; and (d) converting at least a portion of the carbon to boron nitride to obtain the aerogel comprising boron nitride. Another aspect relates to a method for making an aerogel comprising boron nitride, comprising heating boron oxide and an aerogel comprising carbon under flow of a nitrogen-containing gas, wherein boron oxide vapor and the nitrogen-containing gas convert at least a portion of the carbon to boron nitride to obtain the aerogel comprising boron nitride.

First claim

What is claimed is:

1. A method for making an aerogel comprising boron nitride, comprising:
(a) providing boron oxide and an aerogel comprising carbon;
(b) heating the boron oxide to melt the boron oxide and heating the aerogel;
(c) mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide; and
(d) converting at least a portion of the carbon to boron nitride to obtain the aerogel comprising boron nitride.

2. The method of claim 1 , wherein the aerogel comprising carbon comprises sp 2 carbon.

3. The method of claim 1 , wherein the aerogel comprising carbon is a graphene aerogel.

4. The method of claim 1 , wherein the boron oxide is heated to a temperature of at least about 1500° C.

5. The method of claim 1 , wherein the boron oxide is heated to a temperature of about 1600° C. to about 1800° C.

6. The method of claim 1 , wherein flow rate of the nitrogen-containing gas is about 1000 sccm to about 2000 sccm.

7. The method of claim 1 , wherein the nitrogen-containing gas is N 2 .

8. The method of claim 1 , wherein the aerogel comprising carbon is substantially free of contact with liquid boron oxide.

9. The method of claim 1 , wherein at least about 95 atomic percent of the carbon is converted to boron nitride.

10. The method of claim 1 , wherein the aerogel comprising boron nitride obtained has an ordered crystalline structure comprising atomic layers of hexagonal boron nitride laying on top of one another, and wherein atoms contained in a first layer are superimposed on atoms contained in a second layer.

11. A method for making an aerogel comprising boron nitride, comprising heating boron oxide and an aerogel comprising carbon under flow of a nitrogen-containing gas, wherein boron oxide vapor and the nitrogen-containing gas convert at least a portion of the carbon to boron nitride to obtain the aerogel comprising boron nitride.

12. The method of claim 11 , wherein the aerogel comprising carbon comprises sp 2 carbon.

13. The method of claim 11 , wherein the aerogel comprising carbon is a graphene aerogel.

14. The method of claim 11 , wherein the boron oxide is heated to a temperature of at least about 1500° C.

15. The method of claim 11 , wherein the boron oxide is heated to a temperature of about 1600° C. to about 1800° C.

16. The method of claim 11 , wherein flow rate of the nitrogen-containing gas is about 1000 sccm to about 2000 sccm.

17. The method of claim 11 , wherein the nitrogen-containing gas is N 2 .

18. The method of claim 11 , wherein the aerogel comprising carbon is substantially free of contact with liquid boron oxide.

19. The method of claim 11 , wherein at least about 95 atomic percent of the carbon is converted to boron nitride.

20. The method of claim 11 , wherein the aerogel comprising boron nitride obtained has an ordered crystalline structure comprising atomic layers of hexagonal boron nitride laying on top of one another, and wherein atoms contained in a first layer are superimposed on atoms contained in a second layer.

Assignees

• L Livermore Nat Security Llc
• Univ California

Inventors

• Zettl Alexander K
• Rousseas Michael
• Goldstein Anna P
• Mickelson William
• Worsley Marcus A
• Woo Leta

Classifications

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• C04B2235/656

  characterised by specific heating conditions during heat treatment · CPC title

• C01B21/064

  with boron · CPC title

• C01B21/0645 Primary

  Preparation by carboreductive nitridation · CPC title

• C04B2235/80

  Phases present in the sintered or melt-cast ceramic products other than the main phase · CPC title