Abstract:

Preparation of ceramics by cold sintering process has attracted great attention, and some progress has been made in the preparation of BaTiO₃ ceramics. In order to improve the performance of cold sintered BaTiO₃ ceramics, BaTiO₃ powder with good dispersion, particle size of 100 nm and tetragonality (crystal parameter c/a of 1.0085) was prepared by hydrothermal method, and then the powder was hydrothermally activated at 100 ℃ for 1 h with 0.1 mol/L acetic acid. Dense BaTiO₃ ceramics were prepared by the Cold Sintering Process at 400 ℃, under a uniaxial pressure of 350 MPa for 1 h using 10% Ba(OH)₂·8H₂O (in mass) as flux. The as-prepared ceramic pellets were further annealed at 600 ℃ for 0.5 h. In the end, BaTiO₃ ceramic sample obtained excellent characteristics with relative density of 96.62%, grain size of 180 nm, dielectric constant (ε_r) of 2836, and dielectric loss (tanδ) of 0.03. An amorphous titanium layer is formed on the surface of the highly active powder after acetic acid treatment, which effectively promotes the densification of ceramics, inhibits the formation of impurity phases and grain growth, improves the dielectric properties, greatly improves the dielectric dispersion phenomenon of cold sintered BaTiO₃ ceramics, and realizes the low temperature cold sintering of BaTiO₃ ceramics.

Key words: nano-BaTiO₃, dielectric ceramics, cold sintering, low temperature preparation, dielectric properties