The permeability of an anisotropic block of compressed expanded graphite was measured by means of gas permeation and ion diffusion experiments. The critical pore diameter of the material was deduced from published Hg-injection experiments. Other length scales which were related to transport were deduced from published data, and calculated on the basis of several pore-structure models. It was found that only a model in which the pores were assumed to be cylinders was supported. This was confirmed by the formation factor which was derived from experimental values of the permeabilities, but only cylindrical pores whose lengths were equal to their diameters led to consistent results. The model was used to estimate the permeability and formation factor for the blocks of compressed expanded graphite. Very good agreement was found between the predictions and the experimental results.

Permeability and Formation Factor in Compressed Expanded Graphite. A.Celzard, J.F.Marêché: Journal of Physics - Condensed Matter, 2001, 13[20], 4387-403