Effect of Nb2O5 Addition on the Physical and Electrical Properties of Lead-Free (Na0.5Bi0.5)TiO3-Ba(Sn0.08Ti0.92)O3 Ceramics

摘要

In this paper,(Na0.5Bi0.5)TiO3-based solid solutions were studied to improve piezoelectric properties as those found in the PbZrO3-PbTiO3 (PZT)-based ceramics.The 0.98(Na0.5Bi0.5)TiO3-0.02Ba(Sn0.08Ti0.92)O3 (0.98NBT-0.02BST) ceramics with the addition of 0～2.0 wt.％ Nb2O5 have been prepared following the conventional mixed oxide process.X-ray diffraction analysis revealed that,during sintering,all of the Ba(Sn0.08Ti0.92)O3 diffuse into the lattice of(Na0.5Bi0.5)TiO3 to form a solid solution,in which a hexagonal phase with a perovskite structure was found.For 0.98NBT-0.02BST ceramics with the addition of 0.5 wt.％ Nb2O5,the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.12 and 0.28,respectively,at the sintering of 1100°C for 3 h.The ratio of thickness coupling coefficient to planar coupling coefficient is 2.3.It is obvious that 0.98NBT-0.02BST ceramics by adding low quantities of Nb2O5 are one of the promising lead-free ceramics for high frequency electromechanical transducer applications.