Chiang Mai Journal of Science

 In this study, effects of uniaxial stress on the dielectric properties of poled ceramics in PMN-PZT system are investigated. The ceramics with a formula (x)Pb(Mg_1/3Nb_2/3)O₃-(1-x)Pb(Zr_0.52Ti_0.48)O₃ or (x)PMN-(1-x)PzT when x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0 are prepared by a conventional mixed-oxide method. Phase formation behavior and microstructural features of these ceramics are studied by an X-rays diffraction (XRD) and a scanning electron microscopy (SEM) methods, respectively. In addition, other physical properties, e.g, firing shrinkage and density, are measured. The dielectric properties under the uniaxial stress of the poled PMN-PZT ceramics are observed at stress levels up to 5 MPa using a uniaxial compressometer. It is found that with increasing applied stress the dielectric constant of the PZT-rich compositions increases slightly, while that of the PMN-rich compositions decreases. On the other hand, the dielectric loss tangent for most of the compositions first rises and then drops with increasing applied stress.