Influence of barium content on the properties and structure of low temperature sintered BCZT lead-free piezoelectric ceramics

The influence of barium content on dielectric and piezoelectric properties of low temperature sintered (Ba_xCa_1-x)(Zr_0.1Ti_0.9)O₃ doped with 0.2wt.%Li₂CO₃ (BCZT-0.2Li) lead-free piezoelectric ceramics was studied by scanning electron microscope(SEM) and X-ray diffraction(XRD) and other analytical methods and conventional solid state method. TiO₂ was chemically pure raw materials, other raw materials were analytical pure raw materials. The results showed that with the increasing of the content of barium, the grain size of BCZT-0.2Li ceramics decreased gradually, the diffraction peaks of perovskite structure was obvious, there was miscellaneous peak.With the increasing of the content of barium, the planar electromechanical coupling coefficient(k_p)and the piezoelectric strain constant(d₃₃)and the thickness electromechanical coupling coefficient(k_t)and the dielectric constant(ε_r) of low temperature sintered BCZT-0.2Li ceramics all increased first and then decreased, dielectric loss(tanδ)of low temperature sintered BCZT ceramics decreased first and then increased. When the content of barium was 0.85 mol, the properties of low temperature sintered BCZT-0.2Li ceramics was optimum, which k_p was 0.42, d₃₃ was 87 pC/N, kt was 0.046, tanδ was 0.013, ε_r was 2020, the sintered temperature was 1050°C.