Experimental investigation and modeling of effective thermal conductivity and its temperature dependence in a carbon-based foam

The effects of test temperature and a graphitization heat treatment on thermal and thermo-mechanical properties of a carbon-based foam material called CFOAM® are investigated experimentally. Thermal diffusivity is determined using a laser flash method, heat capacity via the use of differential scanning calorimetry, while (linear) thermal expansion is measured using a dilatometric technique. Experimental results are next used to compute the effective thermal conductivity and the coefficient of thermal expansion as a function of test temperature. The computed thermal conductivity results are then compared with their counterparts obtained using our recent model. The agreement between the experiment-based and the model-based results is found to be fairly good only in the case when the graphitization temperature is high relative to the maximum test temperature and, hence, CFOAM® does not undergo a significant additional graphitization during testing. A potential use of CFOAM® as an insulation material in thermal protection systems for the space vehicles is discussed.