Characterization of ORNL's High Thermal Conductivity Graphite Foam

Abstract

The recent development of light-weight foams has led to novel light-weight high-strength carbon based materials and structures. These materials exhibit very high specific strengths and low thermal conductivities. Likewise, the novel development of a very high thermal conductivity graphite foam will lead to novel ''out-of-the-box'' solutions for thermal management problems. With a thermal conductivity equivalent to aluminum 6061 and 1/5th the weight, this material is an enabling technology for thermal management problems ranging from heat sinks to radiators and satellite panels to aircraft heat exchangers. The ability to be machined into a heat sink resembling a metallic heat sink, have comparable thermal conductivities to metallic heat sinks, yet be 1/5th the weight is a significant advance to thermal management. However, the foam is not as rugged as the metallic heat sinks in its foamed and graphitized state. Therefore, the material must be rigidized to improve its durability under high demands applications, such as military vehicles. Therefore, this program focuses on several techniques previously conceived to rigidize the foam: carbon CVI, metalization (plating), and polymer coating. These techniques were all explored with success and should lead to improved heat sinks.