Effects of Zr/Ti Ratio on Phase Formation and Dielectric Properties of 0.8Pb(Zr_xTi_{1 − x})O₃–0.2Pb(Co_1/3Nb_2/3)O₃ Ceramics

Abstract

The 0.8Pb(Zr _x Ti _{1 − x} )O ₃ -0.2Pb(Co _1/3 Nb _2/3 )O ₃ , [0.8PZT-0.2PCN] ceramics are expected to display excellent dielectric properties in compositions close to the morphotropic phase boundary (MPB). The influence of Zr/Ti ratio on phase formation and dielectric properties of the 0.8Pb(Zr _x Ti_{1 − x} )O ₃ -0.2Pb(Co _1/3 Nb _2/3 )O ₃ ceramics have been investigated in order to identify the morphotropic phase boundary (MPB) composition in this system. With XRD analysis, the crystal structure of dense specimens appeared to change gradually from tetragonal to rhombohedral with increasing Zr content. The dielectric properties measurements showed a maximum dielectric constant at x = 0.50 ± 0.01, while the transition temperature decreased with increasing Zr content in the system. Moreover, all ceramics showed diffused phase transition behaviors with a minimum diffusivity at x = 0.50 ± 0.01. These results clearly showed the significance of Zr/Ti ratio in controlling the electrical properties of the PZT–PCN ceramic system.

Keywords:

• PZT–PCN
• MPB
• Zr/Ti ratio
• Dielectric properties
• Phase formation

Acknowledgments

The authors wish to express profound gratitude to Materials Science Groups, Oregon State University for ceramics preparation and measurement. This work was supported by the Commission on Higher Education (CHE), the Thailand Research Fund (TRF), the Faculty of Science, Chiang Mai University, and Naresuan University Phayao.