Preparation And Characterization Of Barium Titanate Powders By Microwave-assisted Sol-hydrothemal Method

Barium titanate as an important electronic ceramic material has been widely used in the preparation of ceramic capacitor, temperature sensor, iron pieces, because of its high dielectric constant, excellent ferroelectric, piezoelectric and insulation performance. Due to the miniaturization of electronic devices, the demand for refined powders becomes ever urgent, resulting in renewed interest in BT nanoparticles. In this paper, we use microwave hydrothermal method for the preparation of barium titanate powders and study their performances.By combining sol-gel method and microwave hydrothermal method, using TiO2 sol as precursor,KOH as the mineralizer, we have discussed the influence of the temperature, alkalinity, and the reaction time on the different reaction conditions. When the alkalinity is 1M, Ba/Ti ratio is 1, the temperature is 180 ℃, and microwave hydrothermal is 20 min, it could be successfully prepared the barium titanate powders of the size of about 50 nm. It’s found that the alkalinity affects not only on the phase structure, but also on the power size, crystallization, and morphology. When the alkalinity equals 1M, the particles show an average size of 50 nm, and when the alkalinity is 5M, the nanoparticles present a ring hollow structure.Prepared by microwave hydrothermal method with TiO2 power as precursor, we studied the influence of different temperature, alkalinity and Ba/Ti ratio on the as-prepared powers. The increase of temperature promotes the reaction of TiO2 and Ba(OH)2 ? 8H2 O, thus increasing the content of barium titanate. The role of the mineralizer KOH is equivalent to the catalyst, and TiO2 and Ba(OH)2?8H2O react in higher alkalinity environment. When the Ba/Ti ratio is 1, the corresponding samples show the strongest diffraction peak intensity.We also studied the performance of the ceramic derived from the above two barium titanate powder, including phase structure, surface morphology, density, dielectric properties and ferroelectric properties. Taking a comparison of the two ceramic powders, it’s found that the barium titanate nanoparticles resulting from the TiO2 sol possess better sintering characters. When the sintering temperature is 1325 ℃, the sintered ceramics are compact and good crystallinity, accompanying with lower dielectric loss and higher dielectric constant. In addition, the ferroelectric properties decrease with the increasing of the sintering temperature.