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

Abstract

BaTiO3 (BT) nanopowders were synthesized using the alkoxide-hydroxide route. Formation of BT nanopowders commenced at 60 degrees C and their amount increased with increasing temperature. However, a TiO2 second phase was always developed at temperatures higher than 100 degrees 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 degrees C and subsequently heated to high temperatures (>200 degrees 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 degrees C for 60 h after the formation of the cubic BT nanopowders at 100 degrees C for 20 h.