ELASTIC-MODULUS AND MECHANICAL LOSS ASSOCIATED WITH PHASE-TRANSITIONSAND DOMAIN-WALLS MOTIONS IN PZT BASED CERAMICS

Elastic modulus (shear modulus G or Young's modulus E) and internal fr iction Q(-1) were measured as a function of temperature on undoped Pb( Zr50Ti50)O-3, Pb(Zr52Ti48)O-3, Pb(Zr54Ti46)O-3 ceramics from -180 degr ees C to 500 degrees C. Experiments were performed at low and medium f requencies (0.1 Hz - 4 kHz). The E(T) curves show two anomalies which are due to following phase transitions: tetragonal to cubic (T-C) and rhombohedral to tetragonal (TR-T). The To temperatures are in good agr eement with phase diagram from literature. The TR-T temperatures allow to complete the phase diagram of the morphotropic phase boundary of P ZT in the low temperature range. Moreover, Q(-1)(T) curves recorded at low frequencies show two relaxation peaks; their activation energy an d relaxation time are determined using the Arrhenius plots. These two relaxation peaks could be attributed to the interaction of domain wall s with point defects.