Sintering of 94Na0.5Bi0.5TiO3-6BaTiO3 with SPS and conventional methods for crystal growth

Abstract

In this study, lead-free 94Na0.5Bi0.5TiO3-6BaTiO3 (94NBT-6BT) piezoelectric ceramics and embedded single crystals in polycrystalline 94NBT-6BT matrix were sintered by conventional (CS) and spark plasma sintering (SPS) techniques. The effects of SPS and CS on the microstructure of the 94NBT-6BT ceramics were discussed and compared. Theoretical density of the CS and SPS treated samples were found to be 94% and almost 99.9%, respectively. High porosity and weak seed-matrix interaction at 1180 ºC for 2 h were obtained from CS sintered ceramics. On the other hand, sintered samples with SPS showed non-porous polycrystalline matrix, and quite strong seed-matrix interface bonding at 950 ºC for 5 min. Also, dielectric properties of sintered ceramics with SPS gave better results than CS. Therefore, SPS assisted 94NBT-6BT samples can be used to grow high quality and high performance single crystals using solid state single crystal growth.