A novel precipitation-based synthesis for the formation of X8R-type dielectrics composition based on monodispersed submicron Ba0.991Bi0.006TiO3@Nb2O5 particles

To meet the needs of future multilayer ceramic capacitors (MLCCs), thinner dielectric layers are necessary. To achieve this goal, the grain size and uniformity of the MLCC particles must be effectively controlled. In this study, we developed a novel precipitation route to control the dispersion and particle size of Ba0.991Bi0.006TiO3 and Ba0.991Bi0.006TiO3@Nb2O5 particles. We confirmed a core-shell particle structure by means of X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The dielectric properties of the ceramics were measured using an LCR meter. We found monodispersed submicron Ba0.991Bi0.006TiO3 particles (∼233 nm) form a core that was coated with a homogeneous Nb2O5 layer (∼7 nm). Dense, fine-grained Ba0.991Bi0.006TiO3-based ceramics (≤250 nm) were obtained by sintering. The ceramics met the X8R requirements, with a Curie temperature of about 140 °C, a maximum dielectric constant of 2336, and a low dielectric loss at room temperature (<2.0%, with a minimum of 0.5%).