Electromechanical Properties of Ferroelectric (NaKLi)(NbTa)O <sub/>3</sub> –CaZrO <sub/>3</sub> Ceramics

摘要： Electromechanical Properties of Ferroelectric (NaKLi)(NbTa)O3–CaZrO3 Ceramics. The effect of CaZrO3 to electric and mechanical properties of (Na0.47K0.51Li0.02)(Nb0.8Ta0.2)O3 was investigated. With increment of CaZrO3, the crystal structure of (Na0.47K0.51Li0.02)(Nb0.8Ta0.2)O3 changed from the mixture of ferroelectric orthorhombic and rhombohedral phases to paraelectric pseudo-cubic phase. On the way of transition from ferroelectric to paraelectric phases, the composition range showing the mixture of ferroelectric/paraelectric phases with a structure of core/shell was revealed with an advent of relatively large strain behavior. The shell phase formed via solid-state diffusion of Nb, Ta, Na, K ions between (Na0.47K0.51Li0.02)(Nb0.8Ta0.2)O3 and CaZrO3 particles, followed by its subsequent solution process with mixing a Ta-rich perovskite with Ca and Zr ions. In contrast, the core phase formed via a solution-precipitation process, resulting in a Ta-depleted ferroelectric perovskite. Energy-dispersive X-ray analysis showed that core was a Nb-rich ferroelectric phase and the shell was a Ta-rich paraelectric phase with Ca and Zr ions at room temperature. This structure implies an interaction between straining behaviors in the core and shell phases under an electric field, leading large deformation in macro-scale.