Phase transitions in multiphase composites. Modellings of interface reactivity and of transport properties

In this review, we deal with active two-phase composites presenting a chang e in electrical properties. Two types of modellings are involved in such mu ltiphase materials : firstly, the modelling of the sintering process and th e interface reactivity which condition both electrical and mechanical prope rties of the resulting composites, secondly, the modelling of the electrica l responses and percolation depending on the interfaces and the composition . The chemical reactions at the interfaces of two-phase composites are firs tly described by a simplified Fick law approach. Finally, the transport pro perties in granular composites are discussed. Through several examples, we present the various simulation approaches which can be used to better under stand the final properties of such composites. Three types of approaches ar e presented : the microstructural approach, the effective medium approximat ion, the percolation theory.