Electric field-assisted solid-state reaction of BaCO₃-TiO₂ system

We report phase transition process during the solid-state reaction of BaCO₃-TiO₂ system under the assistance of electric field. Experiments were conducted at a constant heating rate with preset field strength and current limit. Solid-state reaction was completed upon reactive flash sintering taking place at ~1002℃ under 200 V/cm. Hexagonal BaTiO₃ phase, which rarely occurs at such temperatures, was obtained after flash sintering at a current density of 23.5 mA/mm². It is speculated that oxygen deficiency during flash sintering triggered cubic-to-hexagonal transition of BaTiO₃. Furthermore, X-ray diffraction results show that solid-state reaction takes place prior to flash sintering. Electric field could accelerate the reaction but did not alter the sequence of phase evolution.