Enhanced dielectric properties of BaTiO3 based on ultrafine powders by two-step calcination

As high-performance dielectric material, small sizes of barium titanate (BaTiO3) are desirable for the application of multilayer ceramic capacitors. Herein, we synthesized ultrafine BaTiO3 powders with mean particle size of (d(av.)) 156 nm, tetragonality (c/a) of 1.0092 and specific surface area (S-BET) of 6.09 m(2)/g by two-step sintering process. Kinetic analysis of solid-state reaction reveals that the phase-boundary-controlled mechanism dominated the reaction process in two-step sintering process compared with one-step sintering process dominated by the first-order mechanism. It is also shown that enhanced nucleation in two-step calcination is beneficial for improving the tetragonality. In particular, the dielectric constant and dielectric loss of BaTiO3 ceramics at the Curie temperature are found to be about 12800 and 0.003. This work demonstrates a strategy to trigger a method which can effectively improve the dielectric properties of BaTiO3 ceramic.