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

Lead zirconate titanate-platinum dual phase composites, which have been sho wn to exhibit a very interesting electric field dependence of the dielectri c constant, were prepared. The sintering properties and microstructure were analyzed. No chemical reaction between PZT and Pt was found in the composi te. 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 te rms of the metal concentration. The dielectric constant of the composites i ncreases with increasing metal concentration and approaches a maximum near the percolation threshold while the electrical conductivity and the dielect ric losses remain small. It is indicative that the composites show a conspi cuous effect of the tortuous, near-percolative metal phase. (C) 2001 Elsevi er Science Ltd. All rights reserved.