Low temperature sintering and dielectric properties of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3−xCu2+ ceramics obtained by the sol-gel technique

Abstract Lead-free Cu 2+ -modified (Ba 0.85 Ca 0.15 )(Ti 0.9 Zr 0.1 )O 3 (BCZT− x Cu 2+ ) piezoelectric ceramics was synthesized by sol-gel method. The effects of Cu 2+ additions on sintering characteristics, the phase structure, microstructure, electrical properties and complex impedance characteristic were investigated systematically. The XRD patterns exhibited a pure perovskite structure without impurity phase in all samples. SEM micrographs, temperature dependence of dielectric constant and polarization-electric field ( P-E ) hysteresis loops indicated that a small amount of Cu 2+ addition affected the properties obviously. The results revealed that the addition of Cu 2+ significantly improved the sinterability of BCZT ceramics which resulted in a reduction of sintering temperature from 1440 °C to 1230 °C. The TG-DSC was analyzed to verify the reaction process of BCZT−Cu 2+ materials. (Ba 0.85 Ca 0.15 )(Ti 0.9 Zr 0.1 )O 3 ceramics with x=0.020 Cu 2+ exhibited good electrical properties: e m =12,112, T c =360 K, e r =2614, tan δ =0.026, K p =0.47 and d 33 =382 pC/N. The results indicated that Cu 2+ -modified BCZT ceramics could be a promising candidate for commercial purposes.