Low-temperature sintering of Li2O-doped BaTiO3 lead-free piezoelectric ceramics

Low-temperature sintering of BaTiO3 ceramics using Li2O as sintering aids was investigated with a special influences of Li2O content (0–4 mol%) and sintering temperature (1000–1100°C) on crystalline structure and electrical properties. The sinterability of BaTiO3 ceramics significantly improved by adding Li2O, whose densification sintering temperature reduced from 1300°C to 1000°C. XRD pattern indicated that BaTiO3-xLi2O samples were single phase with a tetragonal symmetry as x = 0–0.3 mol%, while the samples became an orthorhombic symmetry as x = 0.5–4 mol%. The densification sintering temperature in which samples showed relative density higher than 90 % decreased with increasing Li2O content. A maximum d33 value (200 pC/N) was obtained for the BaTiO3-0.5 mol%Li2O sample sintered at 1050°C, which is attributed to a vicinity of the phase transition and the high density. Adding Li2O not only reduced the sintering temperature but also obtained the acceptable piezoelectric properties, which will make BaTiO3 become a kind of promising and practical lead-free piezoelectric ceramics.