Effect of phase distribution on dielectric properties of ferroelectric-dielectric composite ceramics

Three components of ferroelectric-dielectric composite ceramic 85Vol% Ba 0.5 Sr 0.5 TiO 3 - 15Vol% MgO, 78Vol% Ba 0.45 Sr 0.55 TiO 3 - 22Vol% Mg 2 TiO 4 and 48Vol% Ba 0.4 Sr 0.6 TiO 3 - 52Vol% BaWO 4 were chosen and synthesized by solid-phase reaction. The ferroelectric-dielectric system with different mixing degree was obtained by controlling the milling time. The effects of phase distribution on dielectric properties of composite were reflected. The two-phase distribution of the composite was changed from the layered and columnar dominated structure to the spherical structure, with increasing milling time from 5 min, 30 min, 10 h to 24 h. Permittivity and tunability were increased obviously by the transform of phase distribution patterns. However, the quality factor Q values were strongly deteriorated with extending milling time. Different ball-milling times are used to reflect different phase distribution modes, and the dielectric properties of two-phase composite ceramics in different phase distribution modes are well verified.