Electrical characterization of BaTiO3 made by hydrothermal methods

The manufacture of multilayer capacitors based on barium titanate requires improved precursor powders. In this paper the dielectric properties of barium titanate ceramics made from hydrothermally preciPitated material are compared with those powders obtained commercially and prepared by calcination. The greater porosity of hydrothermal powders tends to reduce their effective dielectric constant but preheating them to 950 ~ before sintering produced high density ceramic with higher values of ~r. The dielectric losses of these materials are higher than those produced by traditional methods. Their low Curie temperatures (106-8 ~ are related to the high strontium concentration (4.7 mol %) present in the starting materials. The grain sizes of these ceramics are less sensitive to sintering temperature than those made using calcined powders, with no anomalous grain growth.