Temperature dependence on structure, mechanical and electrical properties of bismuth lanthanum sodium titanate-modified lead zirconate titanate ceramics

The effects of sintering condition on phase evolution, physical, microstructure and dielectric properties of the PZT-3BLNT ceramics were investigated.The samples were prepared by a conventional mixed oxide method and sintered at the temperatures ranging from 1050-1200 °C under normal atmosphere for 2 h dwell time with a heating/cooling rate of 5 °C/min.X-ray diffraction indicated that the mixed rhombohedral-tetragonal phases were observed at lower sintering temperature of 1050 °C, while the tetragonal phase became dominant at higher sintering temperature (1200 °C).The optimum sintering temperature for preparation of high-density PZT-3BLNT ceramic was found to be 1200 °C.Linear shrinkage and average grain size tended to increase with increasing the sintering temperature.The effects of annealing conditions on mechanical and dielectric properties of the PZT-3BLNT ceramic sintered at 1200 °C were also studied in this work.It was found that the maximum room temperature dielectric constant ( r ) of 1313 and Vickers hardness (H V ) of 4.38 GPa were achieved for the sample annealed at 950 °C for 8 h dwell time and this value was ∼18-20% higher than that of the unannealed sample.This result was also well correlated with the maximum relative density observed for this annealing condition.