수열합성법에 의한 미립 BaTiO₃ 분말의 합성

Abstract

BaTiO₃ powders of nanometer-sized were synthesized at the temperature range of 110℃~180℃ in various pH range, and the hydrothermal process, one of the wet-chemical methods, that can make the morphology of powers more homogeneous and finer than solid-state reactions. BaCl₂ and TiCl₄ were used as starting materials, and NH₄OH was a precipitating agent.

The synthesized powders were analysed by the XRD, TG-DTA, SEM, TEM and BET. And then, the dielectric and electronic properties of BaTiO₃ ceramics sintered at the temperature range of 1150~1350℃ were evaluated.

Homogeneous and fine BaTiO₃ powders were obtained at the reaction temperature over 110℃ and the powders synthesized at 130℃ shows that the properties of powders were almost the same regardless of the reaction time.

TEM investigation showed that the size of the BaTiO₃ powder synthesized at 130℃ for 2h was 25~35nm and the result of BET revealed that the surface area of powders was about 77.43㎡/g. The dielectric constant of the ceramic sintered at 1270℃ for 2h was as high as 3000.