Preparation of MgO-coated BaTiO3 particles through a surface-induced precipitation method

The effect of particle size of BaTiO 3 on the preparation of magnesia-coated BaTiO 3 particles was studied through a surface-induced precipitation method. MgO-coated BaTiO 3 particles were prepared by a homogeneous precipitation method using MgCl 2 ·6H 2 O and urea. Particle sizes of starting BaTiO 3 powders were ∼30 and ∼400 nm, respectively. Amorphous magnesia precursor with ∼10 nm was heat treated and transformed to crystalline MgO. Crystallization of MgO was observed at the temperature range between 600 and 700 °C. Zeta potentials were all negative such as −2 mV for MgO, −18 mV for 400 nm BaTiO 3 and −22 mV for 30 nm BaTiO 3 at pH 7.0. The MgO-coating layer was observed on BaTiO 3 particles with ∼400 nm, whereas none of the coating layer was observed on BaTiO 3 with ∼30 nm. According to calculation of the total interaction potential energy, the most strong attraction energy was observed between 400 nm BaTiO 3 and MgO particles.