Preparation and characterization of grain-controlled dense barium titanate ceramics

Barium titanate (BaTiO_3) powder was prepared by high-gravity reactive precipitation (HGRP) process. BaTiO_3 ceramics with average grain size from 0.45μm to 2.2μm were obtained by the conventional ceramic technology and as-prepared powder. The sintering temperature was adjusted in the range of 1200～1300℃. The experimental results showed that as-prepared BaTiO_3 powder had good sintering and electrical properties. Sintered ceramic can reach the relative density of 95% when sintered at 1200℃; The exaggerated grain growth did not appear when increased the sintering temperature, and the grain size and relative density increased and reached 2.2μm and 97.7% at 1300℃, respectively. The grain size effect on the dielectric constant of the sintered ceramics was also studied. The dielectric constant had a maximum (4143) at 1.2μm grain size. Lower dielectric constant of fine-grains ceramic (d=0.45μm) was attributed to the incomplete development of the tetragonal structure from cubic structure.