On the Electrical Conductivity of Particulate Composites

Abstract

Two new equations are developed for effective electrical conductivity of concentrated particulate composites using a differential scheme along with the solution of an infinitely dilute dispersion of particles in a continuous matrix. The proposed equations are evaluated using 16 sets of experimental data on the electrical conductivity of two-phase particulate systems. The following model developed in the paper describes the experimental data very well: (σ/σm)1/3 (σd — σm)/ (σd — σ) = (1 — φ/φm )—αφm ) where σ, σm and σd are electrical conductivities of composite, matrix, and dispersed phase (filler) respectively, φ is volume fraction of filler, φm is the maximum packing volume fraction of filler, and α is a constant of the order of unity. In the special case of α = 1 and φm = 1, this model reduces to the well-known Bruggeman equation for the electrical conductivity of two-phase particulate systems. The predictions of the proposed model are significantly different from the predictions of the existing general effective media (GEM) model.