Effects of CuO additive on structure and electrical properties of low-temperature sintered Ba0.98Ca0.02Zr0.02Ti0.98O3 lead-free ceramics

Lead-free Ba0.98Ca0.02Zr0.02Ti0.98O3–xmol% (x=0–2.0) CuO ceramics (BCZT–xCu) were fabricated by the traditional solid state reaction technique, and their structure and electrical properties were studied systematically. With the introduction of Cu, the orthorhombic–tetragonal (TO–T) phase transition shifted towards lower temperature, while Curie temperature (Tc) remained at relatively high value of about 120 °C. The sintering temperature was reduced by 150 °C than that for pure BCZT ceramics while showing equivalent properties. 0.8 mol% Cu modified ceramics showed excellent piezoelectric properties with d33=315pC/N and kp=44%. Besides these, a relatively high dielectric coefficient (εr=2280), a low dielectric loss (tanδ=1.14%), a high remnant polarization (Pr=11.6 μC/cm2) and low coercive field (Ec=0.37 kV/mm) were also obtained on Ba0.98Ca0.02Zr0.02Ti0.98O3–0.8 mol% Cu lead-free ceramics. Moreover, the influence of sintering temperature on the microstructure development and electrical properties of BCZT–0.8 mol% Cu ceramics has also been studied.