The Influence of Zr/Ti Content on the Morphotropic Phase Boundary and on the Properties of PZT–SFN Piezoelectric Ceramics

AbstractThe polycrystalline samples of (1-x)Pb (Zry Ti1-y)O3-xSm(Fe3+0.5, Nb5+0.5)O3 [PZT–SFN] (where x = 0.02 and 0.41 ≤ y ≤ 0.57) were prepared by a high-temperature solid-state reaction technique. All samples were sintered at a temperature of 1150 oC for 2h. The crystallographic phase and microstructure of the ceramics were examined by using X-ray diffraction (XRD) and atomic force microscopy (AFM). The experimental result shows that the samples consist of a mixture of tetragonal and rhombohedral phases (morphotropic phase boundary MPB) in the range of 0.53 ≤ y ≤ 0.55, grains grow up homogeneously and the minimum value of Curie temperature was obtained with y = 0.53 and 0.55. Main piezoelectric parameters are optimized at around y = 0.53-0.55 with a high piezoelectric coefficient (d31 = 106- 117 pC/N), a planar electromechanical coefficient (kp = 61.7- 61.8%), a high dielectric constant (ɛr = 798- 974) and a low dissipation factor (tan δ = 1.405% - 1.356%) measured at 1kHz room temperature, which indicates that the PZT–SFN ceramics are promising for practical applications