Fabrication, microstructure, dielectric, and ferroelectric properties of (Bi0.5Na0.5)0.94Ba0.06TiO3 nanograined ceramics via cold-sintering-assisted sintering

(Bi0.5Na0.5)(0.94)Ba0.06TiO3 nanograined ferroelectric ceramics were successfully fabricated via a simple cold-sintering-assisted sintering method. Here, the cold-sintering-assisted sintering method includes two steps, i.e., cold-sintering and post-annealing. The cold-sintered samples were prepared via moistening (Bi0.5Na0.5)(0.94)-Ba0.06TiO3 powders with de-ionized water followed by compressing under various pressures at 180 degrees C, which exhibit densities as high as 83.7% similar to 93.6% of the theoretical value. Effects of cold-sintering time and pressure on densification and microstructure of the cold-sintered samples were studied. The cold-sintered samples were then annealed at 800 degrees C-900 degrees C, which are far below the temperatures for sintering (Bi0.5Na0.5)(0.94)Ba0.06TiO3 ce-ramics via the conventional solid-state reaction method. After being annealed, the relative densities of the post-annealed ceramics are all higher than 96%. The dielectric and ferroelectric behaviors of the post-annealed ce-ramics were compared with those of the ceramics with the same composition and various mean grain sizes. The cold-sintering-assisted sintering mechanism was discussed based on the transmission electron microscopy measurement. The study provides a simple and efficient cold-sintering-assisted sintering method for obtaining dense (Bi0.5Na0.5)(0.94)Ba0.06TiO3 nanograined ferroelectric ceramics at relatively low temperatures with excellent dielectric and ferroelectric properties.