Ce and Y Co-Doping Effects for (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ Lead-Free Ceramics

CeO₂ and Y₂O₃ were co-doped to (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ ceramics and sintered by conventional solid-state reaction process to form x wt.% CeO₂-y wt.% Y₂O₃ doped (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ (Ce_xY_y-BCZT) ceramics. The effects of different contents of CeO₂-Y₂O₃ dopants to the (Ba_0.85Ca_0.15) (Zr_0.1Ti_0.9)O₃ composition were analyzed by studying the phase, surface microstructure, piezoelectric and ferroelectric properties of BCZT ceramics. In this study, we have shown that co-doping a small amount of CeO₂ and Y₂O₃ will not change the phase structure of (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ ceramics. However, the proper introduction of CeO₂ and Y₂O₃ can improve the piezoelectric constant and electromechanical coupling coefficient of BCZT ceramic samples. Moreover, these dopants can promote the grain growth process in (Ba_0.85Ca_0.15) (Zr_0.1Ti_0.9)O₃ ceramics. C_0.04Y_0.02 doped (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ ceramic has the best piezoelectric properties compared with other composition, the results are as follows: Relative density = 96.9%, K_p = 0.583, and d₃₃ = 678 pC/N, V = 8.9 V. It means that this Ce_0.04Y_0.02 doped (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ ceramic is a desired material in the application of lead-free ceramics.