Modelling study on the electrical behaviour of YSZ-based composites

Electrical properties of yttria-stabilised zirconia/alumina (YSZ/Al2O3) composites were tentatively foreseen by simulating their complex impedance spectra. A digital image-based model was developed to describe the electrical conduction process in polycrystalline mono- or multi-phase materials. The microstructure of each polycrystalline sample was reconstructed using the Voronoi tessellation technique (in fact, ad hoc modifications with respect to the original algorithm were introduced) and it was then converted into a threedimensional electrical network according to a set of well-defined rules. The network was solved via an iterative procedure for different frequency values and successively the Nyquist plot generated The complex impedance spectra of different composites were simulated considering the alumina content (5,10 and 15 %wt) as a parameter; both the bulk and grain boundary electrical conductivity were calculated and the Anhenius plots obtained. Experimental and simulated results were compared and discussed.