Effect of Mn<sub>2</sub>O<sub>3</sub> Addition on the Electric and Physical Properties of Lead-Free 0.98(Na<sub>0.5</sub>Bi<sub>0.5</sub>)TiO<sub>3</sub>-0.02 Ba(Sn<sub>0.08</sub>Ti<sub>0.92</sub>)O<sub>3</sub> Piezoelectric Ceramics

Abstract

In this paper, the effect of Mn2O3 additions on the electrical and physical properties of 0.98(Na0.5Bi0.5)TiO3 -0.02Ba(Sn0.08Ti0.92)O3 was investigated. X-ray diffraction analysis revealed that, during sintering, all of the Ba(Sn,Ti)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. The 0.98(Na0.5Bi0.5)TiO3 -0.02Ba(Sn0.08Ti0.92)O3 [0.98NBT-0.02BST] ceramics with the addition of 0~4.0 wt% Mn2O3 have been prepared following the conventional mixed oxide process. For 0.98NBT-0.02BST ceramics by doping 1.0 wt% Mn2O3, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.12 and 0.52, respectively, at the sintering of 1100 oC for 3 h. The 0.98NBT-0.02BST ceramic with 1 wt% Mn2O3 addition exhibit a more homogeneous and grain size of ~3.5 μm. With suitable Mn2O3 doping, a dense microstructure and good piezoelectric properties were obtained.