Determination of the lead titanate zirconate phase diagram by the measurements of the internal friction and Young's modulus

The paper presents investigations of the phase transitions for undoped PZT ceramics obtained by the conventional ceramic sintering from amorphous nanopowders prepared by the sol-gel method, with various compositions and Zr/Ti ratios. The phase transitions are also studied by electric conductivity (sigma) measurements as a function of the temperature. The values of sigma, till the point of phase transition (T-C), are low and are in the range of 10(-7)-10(-3)Omega(-1).m(-1). In the paraelectric phase (above TC) the values of sigma as a function of the Zr/Ti ratio are in the range of 5x10(-3)-3x10(-1)Omega(-1).m(-1). Phase transitions, identified by Young's modulus anomalies and internal friction peaks are in accordance with those found by electric conductivity studies and correspond to the transition point between cubic paraelectric phase and tetragonal or rhombohedral ferroelectric phase. The values of Young's modulus at room temperature are in the range of 80-140 GPa, and their rapid growth in the phase transition point is observed.