Maxwell-Fricke equation

In the material, two phases S and / are identified, which are the continuing phase (the bulk material) and the dispersed phase (the pores), respectively. D, Df denote their corresponding diffusion coefficients. Vf is the volume fraction of dispersed phase over the whole volume. A generalised Maxwell s equation developed by Fricke is expressed as follows ... 

Recently, Pollack derived, by adapting a simple procedure, a Maxwell-Wagner type of equation for a highly elongated ellipsoid of revolution (18). Although his procedure is considerably different from those of Fricke and Sillars, the final form is essentially the same. He derived the following equations for the relaxation time ... 

The Fricke Model for Two-Phase Dispersions. Expressions similar to those of Maxwell have been derived for ellipsoidal particles of random orientation (Fricke [1932]) and for aligned ellipsoidal particles (Fricke [1953]). The expressions contain form factors which depend on the axial ratio of the ellipsoids and their orientation with respect to the electric field. The case of random orientation is the most interesting, as it describes a realistic ceramic microstructure and results in the following equation ... 

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