APPLICATIONS OF TECHNOLOGY:
- Carbon fibers used in high temperature environments or harsh chemical (e.g. oxidative) environments, e.g., aerospace or nuclear industries
- Non-black color carbon fiber
- Increased oxidation resistance, from 600°C for raw carbon fibers to almost 1000°C for boron nitride converted fibers
- Potential for reduced cost
- No toxic compounds required
- Applicable to all forms of carbon fiber
- Enables colored carbon fibers for commercial products
A research team led by Alex Zettl has developed a new material, boron nitride converted carbon fibers, and an inexpensive technology for the conversion. The Berkeley Lab fibers demonstrate an increase in oxidation resistance – from 600°C for raw carbon fibers to almost 1000°C for the boron nitride converted fibers. Oxidation resistance is essential for incorporating carbon fibers into composites such as ceramic and metal matrices. Incorporating boron into the fiber preserves material strength as well.
This approach differs from boron nitride coated fibers in that the existing skin of the carbon fiber is directly converted to boron nitride, as opposed to adding an epitaxial layer of boron nitride to carbon fibers. The Berkeley Lab technology results in a coating intimately coupled to the underlying fiber and, in the case of polyacrylonitrile (PAN) fibers, preserves the original morphology and surface texture of the starting material – all without the expensive or toxic precursors.
The Berkeley Lab technology may be applied to any form of carbon fiber on the market making it easy to incorporate into existing industrial processes. The technology enables coloring of carbon fibers, for which there is currently no known process.
DEVELOPMENT STAGE: Proven principle. In tests, carbon fiber skin (about 300 nm deep) was successfully converted into boron nitride.
STATUS: Issued U. S. Patent # 9,305,677. Available for licensing or collaborative research.
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
REFERENCE NUMBER: IB-2013-032