Properties of lead zirconate titanate ceramics determined using microwave and hot-press hybrid sintering process

Piezoelectric materials play an important role in smart, material and structural systems, and high-performance piezoelectric actuators with larger force and displacement output are in demand. It was shown in our previous work that the hybrid sintering process using a 28 GHz microwave technique and hot pressing offers advantages over conventional technologies reference. It was also confirmed that the maximum achieved value of piezoelectric constant d(31) of the specimens of the hybrid-sintering process is approximately 360 x 10(-12) m/V which is about 38% larger than 260 x 10(-12) m/V, the d(31) of the conventionally sintered specimens. In this study, the material properties, including electromechanical coupling factor. Young's modulus, frequency constant, Curie temperature and dielectric constant, of the specimens fabricated with the microwave sintering process were further investigated for different sintering temperatures. The Curie point T-c decreases, but the dielectric constant epsilon (r) at T-c increases with the grain size of specimens for all sintering methods. The influence of grain size on T-c and epsilon (r) can be attributed to the residual stress induced by the lattice mismatch between the cubic phase and the tetragonal-rhombohedral mixed phase.