Structural change of hydrothermal BaTiO3 powder

Formation rate of tetragonal BaTiO₃ powder by hydrothermal synthesis and its dielectric property were studied. Submicron tetragonal BaTiO₃ powders were prepared hydrothermally, using Ba(OH)₂ · 8H₂O, TiO₂ (anatase) and KOH as starting chemicals. Characterization via X-ray diffractometry, Field Emission Scanning Electron Microscopy confirmed that increasing calcination temperature (from 1100 to 1300°C) promotes the formation of tetragonal BaTiO₃. Tetragonal BaTiO₃ ceramics obtained from optimum condition (Tetragonal BaTiO₃ powders calcined at 1200°C for 3 h after hydrothermal synthesized at 200°C for 168 h) exhibited submicron size of 0.5–0.7 m, monodispersed type and high relative permittivity.