Dielectric Properties of HGRP BaTiO₃ Based X7R Materials

In this work, a sub-micron grained sized (<500nm) ceramic (> 92% of theoretical) has been obtained using nano-sized BaTiO3 powders synthesized through a high-gravity reactive precipitation (HGRP) process. Permittivity of the prepared ceramic is greater than 2500. Also, low change ratio of temperature in the range of −55°C~ 125°C
i.e.< ±15% renders the ceramic to meet the EIA X7R characteristics. In the ceramic compositions, Dy2O3, BaCO3, CaCO3, MnCO3 and MgO were used as dopants. After being mixed and dry-pressed, the above mentioned compositions in reducing atmosphere (N2 and 5% H2) were sintered at 1210°C−1290°C for 2h, respectively. Experimental results show that HGRP BaTiO3 powders have good dielectric properties. The dielectric properties as well as the microstructure of the ceramic are both sensitive to the change of sintering temperature.