Phase Structure, Microstructure, and Electrical Properties of Bi0.47Na0.47Ba0.06TiO3 Ceramics with (LiNb)4+ Substituted into B-Sites

Due to the substitution of complex ions into B-sites is very interesting in recent, lead-freeBi(0.47)Na(0.47)Ba(0.06)Ti(1- x) (LiNb) x O-3 (BNBT1- x LN x ) ceramics (with x = 0-0.04) were fabricated by the solid-state combustion method. The influence of (LiNb)(4+) (x) on the phase structure, microstructure, and electrical properties was investigated. The X-ray diffraction (XRD) patterns exhibited a pure perovskite structure for all specimens. Coexisting rhombohedral and tetragonal phases were observed in all samples and the tetragonal phase increased with increased x, as analyzed by the Rietveld refinement method. The morphology of the BNBT1- x LNx ceramics, obtained by scanning electron microscopy (SEM), revealed almost-round grain shapes and anisotropic grain growth. The density and average grain sizes decreased from 5.84 to 5.54 g/cm(3) and 1.7 to 0.9 mu m, respectively, when x increased from 0 to 0.04. The grain size distribution decreased with increased (LiNb)(4+) content. A reduction in the dielectric properties was observed, due to the phase ratio changing away from a morphotropic phase boundary (MPB), an inferior microstructure, and low density caused by (LiNb)(4+) substitution. The (LiNb)(4+) substitution induced the transition from non-ergodic relaxor to ergodic relaxor ferroelectric state.

Automated summary

Lead-free BNBT1- x LN x ceramics were fabricated by the solid-state combustion method, and the influence of (LiNb)(4+) substitution on their phase structure, microstructure, and electrical properties was investigated. The results showed that (LiNb)(4+) substitution decreased the density and grain size, and led to a reduction in the dielectric properties of the ceramics.