Grain size effect on piezoelectric and ferroelectric properties of BaTiO3 ceramics

A series of dense barium titanate (BaTiO3, BTO) ceramics with different grain sizes (GS) were prepared by two-step sintering method. The effect of GS on piezoelectric coefficient (d33) and planar electromechanical coupling factor (kp) displayed a trend similar to that on relative permittivity (ɛ′). The values of d33, kp, and ɛ′ increased significantly with decreasing GS, reaching maximum values (ɛ′ = 6079, d33 = 519 pC/N and kp = 39.5%) at approximately 1 μm, and then decreased rapidly with further decreasing GS. The results revealed that high-performance BTO ceramics could be effectively prepared by controlling GS. Polarization–electric field hysteresis loops and temperature dependence of ɛ′ were also investigated.