Shan Yingchun

Dy2O3 Doped (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 Ceramics

(Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 (BCTZ)+ xwt%Dy2O3(x = 0–0.20) ceramics were prepared by conventional solid-state process, and the effects of Dy2O3 on the microstructure and the electrical properties were investigated. X-ray diffraction pattern confirmed that the BCTZ ceramics exhibit tetragonal structure, and stable solid solutions between BCTZ and Dy2O3 were well established in the range investigated. SEM images show that the addition of Dy2O3 restrains abnormal grain growth and leads to the formation of homogeneous microstructures during sintering. Dy3+ occupies B-site at x = 0–0.15, and A-site at x = 0.20 respectively. A-site occupation of Dy3+ into BCZT ceramic facilitates the ferroelectric domains reorientation and thus improves the piezoelectric properties significantly from 315pC/N(x = 0) to 425pC/N(x = 0.20). The corresponding planar electromechanical coupling factor at x = 0.20 was 49.1%. The A-site occupation(x = 0.2) also exhibits superiority to the improvement of dielectric properties and ferroelectric properties for BCZT ceramics (ϵ33 = 3264 at 1 kHz, 2Pr = 28.4μC/cm2, 2Ec = 5.28 kV/cm).

Preparation of Bi3.15Dy0.85(Ti3-xFex)O12(x = 0-0.3) Ceramics and Their Electrical Properties

Bi3.15Dy0.85(Ti3-xFex)O12(x = 0−0.3) lead-free piezoelectric ceramics were prepared by a solid-state reaction method. The effects of the amount of Dy2O3 and Fe2O3 on the microstructure and electrical properties of the ceramics were investigated. X-ray diffraction shows that the introduction of Dy and Fe does not change the layered perovskite structure of Bi4Ti3O12. SEM images indicated that Bi3.15Dy0.85(Ti3-xFex)O12 ceramics with nearly pore-free microstructures and high densities were obtained. The dielectric constant decreases with the addition of Dy2O3, but remarkably increased with the amount of Fe2O3, and it decreases with frequency, showing a diffuse phase transition behavior.