Different packaging configurations in BaTiO3 – epoxy composite to model their dielectric constant

D. SANTIAGO; L. RAMAJO; D. RAMAJO; M.M. REBOREDO; M. S. CASTRO

Toledo, España

Congreso; Electroceramics 2006; 2006

The influence of packaging configuration on the dielectric properties of composite materials was investigated by a finite element method (FEM). This method allows to determine the dielectric constant of heterogeneous materials without imposing restrictions to the geometry and number of phases. In this work, the dielectric response of a two-phase three-dimensional material was evaluated solving the Laplace equation by FEM and employing a quasi-static approximation. The material was composed of a periodic distribution of spherical inclusions into a matrix and the amount of inclusions were varied in order to represent diluted and concentrate systems. Body centred (BC), body centred cubic (BCC) and face centred cubic (FCC) lattices were studied. A typical particle size was considered to represent the composite microstructure. The numerical calculations were performed and their results were confronted with experimental measurements of the effective complex permittivity of samples prepared by mixing both components and pouring them into suitable moulds (casting method). FEM results showed that BC, BCC and FCC structures cannot represent very well the dielectric performance of composites. Then, the particle size distribution was considered. In this case, results were in total agreement with the experimental data, because the incorporation of smaller particles into the octahedral and tetrahedral sites was considered.