Investigation of microstructure and properties of BaTi_(0.85)Zr_(0.15)O_3 ceramics prepared by a sol-precipitation route

摘要

The conventional solid state method and the solprecipitation route were used to prepare Ba(Ti_(0.85)Zr_(0.15))O_3 ceramics. The sintering conditions were chosen in order to obtain single phase but finegrained ceramics with potential relaxor behaviour. The sample obtained via sol-precipitation route sintered in the same conditions (1300°C for 4 hours) as the sample obtained via solid state process exhibits a denser, but more heterogeneous microstructure, consisting of regions of small grains (< 1 μm) which alternate with zones of larger grains (～ 6 μm), originating in the nonuniform morphology (isolated particles and aggregates) of the precursor oxide powder. The dielectric investigations indicated that both the relative permittivity and dielectric losses of the BZT ceramics are highly sensitive to the local electrical inhomogeneity, causing complicated dielectric relaxation phenomena.