Abstract
The powder of (Pb, Ba) (Zn, Mg, Nb, Ti)O3 system ceramics developed as the multilayer capacitor material with the optimum firing temperature of 1100°C was mixed with small amount of excess PbO as a sintering aid and ground to submicron by ball-milling using the partially stabilized zirconia balls of 3 mmφ. Microstructures such as density, grain size or liquidus phase of the ceramics fabricated from the powders were examined as a function of excess PbO content by SEM and DTA. Densification was enhanced by addition of excess PbO at the firing temperature lower than 1000°C, and the dense ceramic bodies above 7.7 g/cm3 with small grain were obtained at firing temperature of 750°C. Temperature dependence of dielectric constants were measured by a LF inpedance analyzer at 1 kHz. For the 2 mol%PbO added ceramics sintered at 800°C, relative permittivity at room temperature higher than 10000 was successfully attained without remarkable change of loss factor and insulation resistance from those of the stoichiometric ceramics sintered at 1100°C.
