Hydrothermal synthesis of Ba2Ti9O20 nano-powder for microwave ceramics

Ba2Ti9O20 nano-powders for microwave ceramics were prepared by a hydrothermal synthesis route. Raw materials of Ba(OH)2·8H2O (AR), TiO2 (CP)and de-ionized water were used, and the mixture was stirred in an auto-clave at 130–200 °C. Resulted powders with particle size of 10–120 nm were washed, dried and pressed into pellets, which were then sintered at 1200–1300 °C. Sintering process was analyzed by TGA and DTA. Microstructures of the powder and sintered ceramics were observed by TEM and SEM. Crystalline phases of the ceramics were identified by X-ray diffraction. Dielectric properties of the samples were also measured, displaying dielectric constant of 25–55 and Qf=1000–15000 GHz at 10 GHz.