# US 2014/0197366 A1 · Boron nitride converted carbon fiber

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- Number: US 2014/0197366 A1
- Document ID: US20140197366A1
- Status: Published application
- Kind: A1
- Application number: 14/148,508
- Filed: 2014-01-06
- Published: 2014-07-17
- Earliest claimed: 2013-01-11
- Assignees: The Regents of the University of California
- Inventors: Michael Rousseas; William Mickelson; Alexander K. Zettl
- Web page: https://patentgrep.com/patent/US20140197366A1

## CPC

- H01B 1/04: mainly consisting of carbon-silicon compounds, carbon or silicon
- D01F 8/18: from other substances
- D01F 11/124: {Boron, borides, boron nitrides}
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS

## Abstract

This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

## Claims

### Claim 1

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

### Claim 2 (depends on 1)

The method of claim 1, wherein the boron oxide and the carbon fiber are heated to about 1000° C. to 2000° C.

### Claim 3 (depends on 1)

The method of claim 1, wherein the boron oxide and the carbon fiber are heated to about 1500° C. to 2000° C.

### Claim 4 (depends on 1)

The method of claim 1, wherein the carbon fiber is heated to a higher temperature than the boron oxide.

### Claim 5 (depends on 1)

The method of claim 1, wherein operations (b), (c), and (d) occur over a time period of about 30 minutes to 120 minutes.

### Claim 6 (depends on 1)

The method of claim 1, wherein substantially all of the carbon fiber is converted to boron nitride.

### Claim 7 (depends on 1)

The method of claim 1, wherein the nitrogen-containing gas includes nitrogen.

### Claim 8 (depends on 1)

The method of claim 1, wherein the nitrogen-containing gas includes nitrogen, and wherein a ratio of a partial pressure of boron oxide to a partial pressure of nitrogen is about 1 to 2 during operation (d).

### Claim 9 (depends on 1)

The method of claim 1, wherein a pressure is about 1 bar during operation (d).

### Claim 10 (depends on 1)

The method of claim 1, wherein the carbon fiber is in a form selected from a group consisting of individual carbon fibers and a woven cloth including carbon fiber.

### Claim 11 (depends on 1)

The method of claim 1, wherein the carbon fiber has a substantially circular cross-section, and wherein the portion of the carbon fiber converted to boron nitride includes the portion of the carbon fiber proximate a perimeter of the substantially circular cross-section.

### Claim 12 (depends on 1)

The method of claim 1, wherein the boron oxide and the carbon fiber are separated from one another during operations (b), (c), and (d).

### Claim 13

A structure comprising:
a carbon fiber core; and
a boron nitride layer surrounding the carbon fiber core, the boron nitride layer having substantially the same morphology as the carbon fiber core.

### Claim 14 (depends on 13)

The structure of claim 13, wherein the boron nitride layer is not coated onto the carbon fiber core.

### Claim 15 (depends on 13)

The structure of claim 13, wherein the carbon fiber core has a diameter of about 5 microns to 20 microns.

### Claim 16 (depends on 13)

The structure of claim 13, wherein the boron nitride layer has a thickness of about 10 nanometers to 1.5 microns.

### Claim 17 (depends on 13)

The structure of claim 13, wherein the boron nitride layer has a substantially uniform thickness.

### Claim 18 (depends on 13)

The structure of claim 13, wherein the structure has a color selected from a group consisting of red, green, blue, and variations thereof.

### Claim 19 (depends on 13)

The structure of claim 13, wherein the structure has a color other than black.

### Claim 20

A structure including a carbon fiber core and a boron nitride layer surrounding the carbon fiber core, the boron nitride layer having substantially the same morphology as the carbon fiber core, prepared by a process comprising:
(a) providing boron oxide and carbon fiber;
(b) heating the boron oxide to melt the boron oxide and heating the carbon fiber;
(c) mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide; and
(d) converting at least a portion of the carbon fiber to boron nitride.