Abstract
The temperature and composition dependence of thebarrier-controlled conductivity of two-phase composites is analysedreducing the problem to that of the site-bond percolation. It is shownthat the critical barrier height depends on the volume fraction φof the conducting phase, this giving rise to a specific φ-dependence of the activation energy of the conductivity near thepercolation threshold. Approximate relations suggested for the phaseboundary function of the site-bond problem make it possible toevaluate the distribution of inter-grain barrier characteristics fromthe measurements of the temperature and composition dependence of theconductivity near the percolation threshold.
