Synthesis of BaTi2O5 Nanopowders by Sol–Gel Method and the Dielectric Properties of the Ceramics

Abstract

A sol–gel process using barium diethoxide and titanium tetraisopropoxide as the sources for Ba and Ti, respectively, was employed to synthesize BaTi2O5 nanopowders and ceramics. BaTi2O5 nanopowders in the range of 20–50 nm in size were obtained by calcination of the gel precursors at 650 °C. By a further firing at 1000 °C, some BaTi2O5 nanopowders were grown to 200 nm in size. Conventional sintering at 1150 °C using these BaTi2O5 nanopowders yields BaTi2O5 ceramics of 80–85% relative density. A dense BaTi2O5 ceramic with a relative density of above 95% was fabricated by spark plasma sintering (SPS) at 1000 °C. Furthermore, by SPS combined with the hot-forging technique, we obtained a certain degree of grain orientation along the b-axis in the dense BaTi2O5 ceramic and observed an increase in the dielectric constant reaching 580.