A novel technique for fabricating high thermal conductivity pitch-based carbon foams has been developed and patented at Oak Ridge National Laboratory under the direction of the U.S. Department of Energy (DOE) Office of Transportation Technologies. This technique produces a graphitic foam with thermal conductivity equivalent to aluminum alloys at 1/5th their weight, see Figure to right. It also exhibits an open porous structure with more than 100 times greater surface area than typical heat exchangers (>20 m2/g). The cell walls are made of highly oriented graphite planes, similar to high performance carbon fibers, which have been estimated to exhibit a thermal conductivity greater than 1700 W/m·K (copper is 400 W/m·K).
Recently, many aerospace applications have identified improved thermal management as a leading research objective. Many heat sinks and heat exchangers are bulky and require large surface areas to dump waste heat to the environment. The use of graphite foams as an alternative to current materials is very attractive from the standpoint of reducing weight, volume, while improving heat transfer efficiencies.
In addition, the foam absorbs sound very well, better than the pyrell foam in anechoic chambers, and is the only material in nature that absorbs sound and conducts heat. The new material is a lightweight, very high thermal conductivity graphite foam and is drastically different from graphite foams developed by others. In the 10 short years since its invention, it has already demonstrated the ability to dramatically improve the transfer of unwanted heat. While optimization of the graphite foam and its incorporation into complex systems is still under development, it clearly has the potential to improve many commercial systems.
Applications Being Explored Currently:
- Power electronics cooling
- demonstrated 10x cooling potential compared to traditional heat sinks
- Personal cooling
- Firefighterers, soldiers, HAZMAT, etc.
- Transpiration/evaporative cooling
- electronics and leading edges
- heavy vehicles, racing vehicles, aircraft, fuel celled vehicles
- Nuclear reactor core
- Space Radiator (Lockheed Martin)
- Flight qualified and deployed
- Composite materials
- Brake and clutch cooling
- High temperature friction applications
- Batteries and Battery Cooling
- Poco Graphite, Inc.
Lee Wiechmann: (940) 393-4324
- Koppers Inc.
Tom Golubic: (412) 826-3955