KINETIC ASPECTS OF THE FORMATION OF LEAD ZIRCONIUM TITANATE

The kinetics of the second calcination step in the formation of PZT so lid solution (with perovskite ABO(3) lattice) has been investigated by using two different particle sizes of the B-site precursor (1.91 and 5.08 micrometers), the finer size being obtained by prolonged milling. In-situ analysis performed by high-temperature X-ray diffractometry i n a non-isothermal mode (20-800 degrees C) revealed a reduction of the calcination temperature by 100 degrees C with a decrease in particle size of the precursor. In order to clarify the mechanism of the solid- state reaction to PZT, isothermal heat treatment of the mixtures was p erformed in the temperature range 540-700 degrees C. The activation en ergies for the fine and the coarse powders were estimated as 150 and 2 10 kJ mol(1) respectively, and the reaction was found to follow the Ja nder model for diffusion-controlled solid-state reaction kinetics.