Synthesis of highly tetragonal BaTiO₃ nanopowders by a two-step alkoxide-hydroxide route

BaTiO₃ (BT) nanopowders were synthesized using the alkoxide-hydroxide route. Formation of BT nanopowders commenced at 60 °C and their amount increased with increasing temperature. However, a TiO₂ second phase was always developed at temperatures higher than 100 °C due to the insufficient amount of H₂O caused by its evaporation. Therefore, a two-step process is presented herein for the synthesis of homogeneous, highly tetragonal BT nanopowders. The cubic BT nanopowders were synthesized at 100 °C and subsequently heated to high temperatures (>200 °C) to increase their tetragonality. Homogeneous BT nanopowders with an average size of 94.8 nm and a high c/a ratio of 1.0081 were obtained for the specimens synthesized at 260 °C for 60 h after the formation of the cubic BT nanopowders at 100 °C for 20 h.