Effect of Cold Pressing on Dielectric Properties of (Sr0.8Pb0.2)TiO3-MgO Composites

(Sr_0.8Pb_0.2)TiO₃-MgO (50:50 by weight) composites are prepared and their dielectric properties are investigated. The dielectric properties of the samples prepared by using the green samples prepared under different cold pressing conditions are compared. The cylindrical samples prepared by using uniaxial pressing (UP) followed by cold isostatic pressing (CIP) show the higher quality of dielectric properties than the plate samples prepared by using only UP. It is found that the forming pressure before CIP also influences the dielectric constant of the sintered products. Furthermore, the dielectric constant of the rectangular composite samples cut out of the disk samples is direction dependent with respect to the UP direction while the tan δ of the composites is almost independent of the measurement directions.