Elastic Modulus and Mechanical Loss Associated with Phase Transitions and Domain Walls Motions in PZT Based Ceramics

Elastic modulus (shear modulus G or Young's modulus E) and internal friction Q-1 were measured as a function of temperature on undoped Pb(Zr50Ti50)O3, Pb(Zr52Ti48)O3, Pb(Zr54Ti46)O3 ceramics from -180°C to 500°C. Experiments were performed at low and medium frequencies (0.1 Hz - 4 kHz). The E(T) curves show two anomalies which are due to following phase transitions : tetragonal to cubic (Tc) and rhombohedral to tetragonal (TR-T). The Tc temperatures are in good agreement with phase diagram from litterature. The TR-T temperatures allow to complete the phase diagram of the morphotropic phase boundary of PZT in the low temperature range. Moreover, Q-1(T) curves recorded at low frequencies show two relaxation peaks ; their activation energy and relaxation time are determined using the Arrhenius plots. These two relaxation peaks could be attributed to the interaction of domain walls with point defects.