Strength Enhancement and Application Development of Carbon Foam for Thermal Management Systems

Carbon foam is recognized as having the great potential to replacement for metal fins in thermal management systems such as heat exchangers, space radiators, and thermal protection systems. An initial barrier to implementation was the inherent weakness and friability of the carbon foams. Ceramic Composites Inc. has demonstrated the ability to increase the compressive strength by 2 times through the treatment of the carbon foam ligaments with a uniform silicon carbide coating, serving to enhance strength and reduce friability, with minimal influence upon the thermal properties. The process is amenable to automation using commercially available equipment. An overview of the technical approach will be presented, along with the envelope of enhanced material properties achieved under the program. Carbon foams of various pedigrees have been studied since the late 1960s when the first reticulated foams were produced. These foams were thermally insulating and remained so for many years with research in the 1970s focused primarily upon producing carbon foams from alternative precursors. In the early 1990s, researchers at the Wright Patterson Air Force Base Materials Lab pioneered mesophase pitch derived graphitic foams, specifically for replacing expensive 3-D woven fiber performs in polymer composites and as replacements for honeycomb materials. This was one of the first high thermal conductivity carbon foams and the technology was licensed by MER Corporation of Tucson, AZ.