Densification and texture evolution of Bi4Ti3O12 templated Na0.5Bi0.5TiO3–BaTiO3 ceramics: Effects of excess Bi2O3

Highlights: ► Excess Bi2O3 induces anomalous microstructure in BIT templated NBT-BT ceramics. ► Undoped samples have a high degree grain orientation compared to Bi2O3 doped ones. ► The mechanism of texture development in Bi2O3 liquid phase was put forward. - Abstract: 0.94Na0.5Bi0.5TiO3–0.06BaTiO3 lead-free ceramics were fabricated by templated grain growth method using 5 vol% platelet Bi4Ti3O12 (BIT) templates. The effect of the addition of excess Bi2O3 on the densification and the texture evolution was investigated. A high degree of grain orientation (f ∼ 0.93) and an excellent piezoelectric coefficient d33 of ∼290 pC/N were obtained for undoped samples, however the texture was hardly developed for Bi2O3 doped samples whose densification behavior yet could be significantly improved. It was found that the Bi2O3 liquid phase can promote the particle rearrangement and mass transport, but simultaneously change the surface morphology of BIT templates and matrix grains from an atomically rough to smooth structure. The Ostwald growth was thus induced dominantly in the diametrical direction and little in the thickness direction of plate-like templates. The results provided a good reference for selecting the sintering aid in the fabrication of textured ceramics.