Preparation of Bi₄Ti₃O₁₂ ceramics via a high-energy ball milling process

Nano-sized bismuth titanate (Bi₄Ti₃O₁₂) powders were prepared by a high-energy ball milling process directly from their oxide mixture of Bi₂O₃ and TiO₂. Bi₄Ti₃O₁₂ phase can be formed from the oxide mixture after milling for 9 h. Almost single phase of Bi₄Ti₃O₁₂ is obtained after milling for 15 h. With increasing milling time, the particle size of the mixture is gradually reduced. Bi₄Ti₃O₁₂ ceramics were obtained by sintering the synthesized powders at temperatures ranging from 750°C to 950°C. The Bi₄Ti₃O₁₂ ceramics sintered at 850°C for 1 h exhibited a density of 7.91 g/cm³, a dielectric of 243 and a dielectric loss of 0.017, and a remnant polarization of 24 μC/cm² and a coercive field of 11 kV/cm, respectively. Piezoelectric parameters of the Bi₄Ti₃O₁₂ ceramics are k₃₃=56%, k₃₁=58%. The Bi₄Ti₃O₁₂ ceramics also possessed good pyroelectric properties. These results indicate that high-energy ball milling process is a promising way to prepare Bi₄Ti₃O₁₂ ceramics.