Production of Ba0.991Bi0.006TiO3@ZnO-B2O3-SiO2 ceramics with a high dielectric constant, a core-shell structure, and a fine-grained microstructure by means of a sol-precipitation method

摘要

A core shell structure was proved by energy-dispersive spectroscopy (EDS) in both Ba0.991Bi0.006TiO3@ZnO-B2O3-SiO2 (BBT@ZBSO) nanoparticles and ceramics. The effects of ZBSO additive on the phase composition, microstructure, sintering temperature and dielectric properties of the BBT ceramics were studied. An obvious perovskite phase of BBT was detected in all samples, and small amounts of Ba2TiSi2O8 and Ba4ZnTi11O27 were detected in the ceramics with excess ZBSO and the higher sintering temperature. The average grain size of the BBT ceramics was 383 nm at a ZBSO content of 4 wt%, which is close to that of the original BBT nanoparticles (320 nm). The sintering temperature decreased from more than 1300 degrees C to 1140 degrees C. The relative density increased from 70% to 98%, the dielectric constant at the Curie temperature (T-c) reached a maximum of 3600, and the dielectric loss reached a minimum of around 0.005 with a 5 wt% ZBSO coating. The ZBSO coating effectively inhibited grain growth, thereby reducing the sintering temperature and improving the density and dielectric properties of the ceramics. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.