Sintering and electrical properties of PZT/Pt dual-phase composites

Lead zirconate titanate–platinum dual phase composites, which have been shown to exhibit a very interesting electric field dependence of the dielectric constant, were prepared. The sintering properties and microstructure were analyzed. No chemical reaction between PZT and Pt was found in the composite. Neither did Pt atoms dissolve into the PZT lattice. The behavior of the effective electrical resistivity and the effective dielectric permittivity of the composites were investigated experimentally and theoretically in terms of the metal concentration. The dielectric constant of the composites increases with increasing metal concentration and approaches a maximum near the percolation threshold while the electrical conductivity and the dielectric losses remain small. It is indicative that the composites show a conspicuous effect of the tortuous, near-percolative metal phase.