Untitled

Abstract

Lead-free piezoelectric ceramics have attracted considerable attention as new piezoelectric materials for replacing Pb(Zr,Ti)O 3 (PZT)-based ceramics because of environmental protection reasons. Among lead-free piezoelectric systems, the ternary system of Na 0.5 K 0.5 NbO 3 -LiTaO 3 -LiSbO 3 has proven to be an outstanding lead-free piezoceramic with properties almost comparable to undoped PZT. In this study, addition of LiSbO 3 to the 0.95 Na 0.5 K 0.5 NbO 3 -0.05 LiTaO 3 lead-free piezoceramic composition showed a change from an orthorhombic to a tetragonal crystal system in samples prepared by reaction-sintering. The limit of solid solution along the compositional join, (0.95−x)Na 0.5 K 0.5 NbO 3 -0.05 LiTaO 3 -x LiSbO 3 , occurred at x ∼ 0.06. Differential scanning calorimetry analysis and measurements of dielectric constant as a function of temperature indicated broad Curie peaks from which it was inferred that the samples were not chemically homogeneous. Curie temperatures decreased from ∼425°C for x = 0, to ∼345°C for the limiting x = 0.06 composition. Improvement of dielectric properties was obtained for LiSbO 3 modified samples. Microstructures exhibited secondary recrystallization, with LiSbO 3 addition giving rise to a small reduction in average grain size.