Structure and electrical properties in CuO-modified BCZT lead-free piezoelectric ceramics

Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 - x wt% CuO (BCZT- x Cu) lead-free piezoelectric ceramics were designed and synthesized using a traditional solid-state reaction method to improve both the relaxor behavior and the electrical properties of BCZT lead-free piezoelectric ceramics. The Cu 2+ diffuses into the BCZT lattice and forms ABO 3 perovskite solid solution. Additionally, X-ray diffraction patterns and Raman spectra reveal that the introduction of CuO causes phase transition from the O-T phase coexistence to the O phase in BCZT- x Cu. SEM displays that BCZT- x Cu has a well microstructure at CuO doping amount between 0.5 wt% and 1 wt%. With the increasing CuO content, the orthorhombic-tetragonal ( T O-T ) phase transition shifted towards higher temperature, while Curie temperature ( T c ) shifted towards lower temperature. Moreover, the dielectric diffusivity γ increases from 1.63 to 1.92 as x increases. Results indicate that optimal electrical properties, namely d 33 = 315 pC/N, k p = 34%, ε r = 3213, tan δ = 2.71%, P r = 7.45 µC/cm 2 and E c = 2.75 kV/cm are achieved in the 1 wt% CuO added ceramic sintered at 1250°C for 2 h.