Influence of Nb2O5 doped amount on the property of BCTZ lead-free piezoelectric ceramics doped with Li2CO3

Abstract

Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCTZ) lead-free piezoelectric ceramics doped with Nb2O5 (0.1, 0.3, 0.5, 0.7, 0.9 wt%) and Li2CO3 (0.6 wt%) were prepared by conventional solid-state reaction method. Influence of Nb2O5 doping amount on the piezoelectric property, dielectric property, phase composition and microstructure of prepared BCTZ lead-free piezoelectric ceramics doped with Li2CO3 were investigated by X-ray diffraction and scanning electron microscopy and other analytical methods. The results showed that the sintered temperature decreased greatly when the BCTZ lead-free piezoelectric ceramics were co-doped with Nb2O5 and Li2CO3; a pure perovskite structure of BCTZ lead-free piezoelectric ceramics co-doped with Nb2O5 and Li2CO3 sintered at 1,020 °C could be also obtained. The grain size decreased when Nb2O5 doping amount increased. The piezoelectric constant (d33), the planar electromechanical coupling factor (kp), the relative dielectric constant (er) of BCTZ ceramics doped with Li2CO3 increased firstly and then decreased, the dielectric loss (tanδ) decreased firstly and then increased when Nb2O5 doping amount increased, indicating that Nb2O5 was “soft” additive. When Nb2O5 doping amount (z) was 0.7 wt% and Li2CO3 doping amount was 0.6 wt%, the BCTZ ceramics sintered at 1,020 °C possessed the best piezoelectric property and dielectric property, which d33 was 238 pC/N, kp was 29.33 %, er was 4,691, tanδ was 2.07 %.