The application of effective-medium theory for the nondestructive characterization of ceramic composites

In this paper is presented the application of effective-medium theory (EMT) on ferrite ceramic composites with various volume fractions of spinel phase in an M-hexaferrite matrix in order to determine the phase composition. The permeabilities, which were calculated with effective-medium theory from measured permeabilities of single-phase samples, were matched with measured effective permeability of composite samples. From analysis of composites sintered at two different temperatures it is also shown that by presented method one can detect the formation of new phases. In this way obtained volume fractions of spinel phase were compared with values from the X-ray powder diffraction (XRD) analysis and the nominal composition mass. It is shown that EMT quantitative phase determination of magnetic composites is comparable to XRD quantitative phase analysis and represents a simple and fast complementary alternative.