Effects of multiple sintering additives on crystal structure, morphology and tunable mechanisms of BCZT ceramics

(Ba_0.91Ca_0.09)(Zr_0.2Ti_0.8)O₃ ceramics adding different sintering additives (Li₂CO₃, CuO and Bi₂O₃) were prepared to investigate the effects of multiple sintering additives on the dielectric and tunable performances. The ability of multiple sintering additives to promote grain growth and densification of BCZT ceramics is stronger than that of single sintering additives. Influenced by grain size, the tunable mechanisms of BCZT ceramics mightily depends on the sintering additives. The tunability of BCZT ceramics adding with Li₂CO₃ and CuO is mainly determined by the contribution of lattice polarization, while that of BCZT ceramics adding with CuO is jointly determined by lattice polarization and polar nano-regions polarization. The good tunable properties with large tunability (39.4%) and low loss tangent (0.0033) were achieved at 6.38 kV/cm when both CuO and Li₂CO₃ were added into BCZT ceramics. The results suggest that multiple sintering additives can effectively improve the tunable properties of ceramics.