Modelisation of electrical intergrain contacts at high frequencies

A number of physical and physicochemical properties of granular materials can be traced to the nature of the interfaces and contact between the grains. In this paper we deal more specifically with the electrical resistance of the inter-granular contacts. More generally we will consider the frequency-dependent contact a.c. impedance. We propose a modelling of the mesoscopic electrical contacts which can lead to a better understanding of some macroscopic properties of these materials, in particular the interaction with electromagnetic field. This modelling makes use of the percolation model and the representation of contacts by equivalent electrical circuits.