Low-temperature sintering of barium calcium zirconium titanate lead-free piezoelectric ceramics

Abstract

The need for lead-free piezoceramics has caused a renewal of interest in BaTiO3-based systems. Recently, it was found that ceramics in the (Ba,Ca)(Zr,Ti)O3 system have properties comparable to those of Pb(Zr,Ti)O3. However, these ceramics require rather high sintering temperatures of 1450-1550?C. In this work, the effect of TiO2 and CuO addition on the sintering behavior, microstructure, dielectric and piezoelectric properties of (Ba0.85Ca0.15)(Zr 0.1Ti0.9)O3 (BCTZ) ceramics will be discussed. BCTZ ceramics were prepared by the mixed oxide route and 1 mol % of TiO 2 or CuO was added. Undoped and doped ceramics were sintered at 1350°C for 1-5 h. CuO was found to be a very effective sintering aid, with samples sintered for 1 h at 1350°C having a bulk density of 95% theoretical density; however the piezoelectric properties were greatly reduced, probably due to the small grain size.