Microstructure and characteristics of Ba(Ti,Zr)O3 ceramics with addition of glass frit

Microstructure and characteristics of Ba(Ti,Zr)O3 ceramics are significantly influenced by the addition of 4PbO.B2O3. The melting temperature of 4PbO.B2O3 was approximately 500°C, and thus it provides a liquid phase during sintering. At low sintering temperatures, the grain growth of Ba(Ti,Zr)O3 ceramics is enhanced by capillary rearrangement and solution-reprecipitation from the liquid phase. At high sintering temperatures, exaggerated grain growth of Ba(Ti,Zr)O3 ceramics is restrained by the presence of a liquid phase. The spreading liquid can penetrate the solid-solid interfaces. Penetration leads to disintegration of the solid and the subsequent rearrangement of fragments. With increasing amounts of 4PbO.B2O3, the tetragonal c/a ratio and Curie point temperature increase, but the dielectric loss tangent is depressed. With a suitable amount of glass frit and temperature for sintering, the density is enhanced and the values of the planar coupling factor and the poled dielectric constant are improved.