Influence of Co Ion Doped Amount on Property of BCTZ Piezoelectric Ceramics Sintered at Low Temperature.

Ba0.85Ca0.15Ti0.9Zr0.1O3(abbreviated as BCTZ) lead-free piezoelectric ceramics co-doped with Li2CO3(0.6 wt.%) and different Co ion content (x = 0, 0.25, 0.4, 0.6, 0.8 wt.%) were prepared by conventional solid state reaction method. Influence of Co ion doped amount on the phase structure, microstructure, piezoelectric properties and dielectric properties of prepared BCTZ piezoelectric ceramics doped with Li2CO3were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and other analytical methods. The results show that Co2+and Co3+instead of Zr4+did not change the crystal structure and all the BCTZ piezoelectric ceramics possessed single phase perovskite structure with orthorhombic symmetry when Co ion doped amount was less than 0.6 wt.%. When Co ion doped amount was 0.8 wt.%, impurity phase appeared in the ceramics. The piezoelectric constant(d33), planar electromechanical coupling coefficient (kp), the dielectric constant (ϵr) and the relative density of BCTZ ceramics increased first and then decreased, the dielectric loss (tanδ) of BCTZ ceramics decreased first and then increased at the same time, the optimize sintered temperature (ts) decreased while Co ion doped amount increased. The influence of Co ion doped amount on the properties of BCTZ ceramics doped with Li2CO3were caused by lattice distortion and “hard effect” piezoelectric additive. The BCTZ ceramics had the optimum properties, which d33was 316 pC/N, tanδ was 0.021, kpwas 0.43, ϵrwas 3209, the sintered temperature was 1010°C, the relative density was 99%, while Co ion doped amount was 0.60 wt.% and Li2CO3doped amount was 0.6 wt.%. [ABSTRACT FROM AUTHOR]