Effect of Mn2O3 Addition on the Electric and Physical Properties of Lead-Free 0.98(Na0.5Bi0.5)TiO3-0.02 Ba(Sn0.08Ti0.92)O3 Piezoelectric Ceramics

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)O-3 was investigated. X-ray diffraction analysis revealed that, during sintering, all of the Ba(Sn,Ti)O-3 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))O-3 [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 k, reach 0.12 and 0.52, respectively, at the sintering of 1100 degrees C for 3 h. The 0.98NBT-0.02BST ceramic with 1 wt% Mn2O3 addition exhibit a more homogeneous and grain size of 3.5 um. With suitable Mn2O3 doping, a dense microstructure and good piezoelectric properties were obtained.