No abstract

A new method for making piezoelectric ceramics with high stability and high coupling is described. Two ceramics in the PZT system with compositions on opposite sides of the morphotropic phase boundary are prepared first. By means of mixed sintering. a mixture or composite ceramic is obtained. If the compositions of the two components and their weight ratio are carefully adjusted and the sintering temperatures are appropriate, the composite ceramic will possess very high temperature stability and a high coupling coefficient.

Complex dielectric constant ϵ=ϵ'-iϵ" of a semiconducting BaTiO3 ceramics has been measured at room temperature over the frequency range of 10kHz-500MHz. This dielectric response can be approximately described by the Debye type relaxation equations, whereas the conductivity dominates the imaginary part at lower frequencies. From the dielectric measurement, the resistivity and the dielectric constant have been evaluated for the grains and grain boundaries separately.