The structural and electrical properties of Pb[ZrxTi0.95-x(Mo1/3In2/3)0.05]O3 piezoelectric ceramics system with the composition near the morphotropic phase boundary were investigated as a function of the Zr/Ti ratio. Studies were performed on the samples prepared by the conventional method of thermal synthesis of mixed oxides. The materials structure was investigated by X-ray diffractometry to demonstrate the co-existence of the tetragonal and rhombohedral phases. In the present system, the MPB, in which the tetragonal and rhombohedral phases coexist, is in a composition range of 0.47 ≤ x ≤ 0.50. The lattice constants of the a and c axes for the samples were calculated from the XRD patterns. Microstructure of the sintered ceramics was observed by scanning electron microscopy (SEM) of free surfaces specimens. The relative permittivity, dielectric dissipation, piezoelectric coefficient and electromechanical coupling factor reach at maximum value x = 0.49 (εr = 7300.345 (at the Curie temperature), tanδ = 0.002050, d31 = 94.965 PC/N and kp = 0.513 and a Curie temperature of 430°C). These properties are very promising for applications in ultrasonic motors.
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